Three clinically important causes of bleeding in late pregnancy and labor are placenta previa, placenta accreta, and vasa previa. Placenta previa occurs when the placenta implants in the lower uterine segment near or over the internal cervical os, and risks include antepartum bleeding, postpartum hemorrhage, and need for hysterectomy. Transvaginal ultrasound is the preferred method for diagnosing placenta previa. Women with a complete placenta previa should deliver via cesarean section. While in the hospital for bleeding, intravenous access and blood work should be obtained to prepare for potential hemorrhage during delivery.
The document discusses placenta accreta, a condition where the placenta invades and attaches abnormally to the uterine wall. It has increased in incidence 10-fold over the past 50 years due to rising cesarean delivery rates. Risk factors include placenta previa, prior uterine surgery, and increasing maternal age and parity. Ultrasound and MRI can be used to diagnose placenta accreta prenatally based on signs like lack of a hypoechoic zone between the placenta and uterus. Management options for severe postpartum hemorrhage from placenta accreta include uterine packing, arterial ligation, hysterectomy, and the B-Lynch compression suture
Placenta accreta is currently the most common indication for peripartum hysterectomy. It occurs when the placenta invades and attaches abnormally to the myometrium. The risk and incidence of placenta accreta has increased significantly in recent decades due to rising cesarean delivery rates. Prenatal diagnosis using ultrasound and MRI is important to identify high-risk women and allow planning with a multidisciplinary team. Optimal management involves scheduled cesarean hysterectomy between 34-35 weeks gestation. Conservative management can be considered but is associated with higher risks of hemorrhage, infection and need for emergency hysterectomy.
Adherent placenta occurs when there is a defect in the decidua basalis, Resulting in an abnormal invasion of the placenta directly into the substance of the uterus
This document discusses adherent placenta, beginning with an introduction defining it as an abnormal invasion of the placenta directly into the uterus due to a defect in the decidua basalis. It then covers the types of adherent placenta, risk factors, incidence, significance, diagnosis, and methods for diagnosing adherent placenta antenatally through clinical suspicion and ultrasound techniques like color Doppler to improve outcomes. The goal is to emphasize the importance of early antenatal diagnosis to avoid catastrophic emergencies.
Placenta accreta occurs when the placenta abnormally adheres firmly to the uterine wall, due to an absence of the decidua basalis layer. It can lead to significant maternal morbidity and mortality from hemorrhage. The risk factors include placenta previa, previous cesarean deliveries, uterine surgery, and advanced maternal age. Ultrasound and MRI can help predict placenta accreta by identifying placental lacunae, loss of myometrial thickness, and bladder invasion. Management may involve scheduled delivery, a multidisciplinary team, blood salvage, and leaving the placenta in situ with adjunctive procedures to preserve fertility and reduce hysterectomy. The bladder is
This document provides an overview of placenta accreta spectrum (PAS) disorders, including definitions, epidemiology, pathogenesis, clinical presentation, prenatal diagnosis, and management. PAS disorders describe abnormal placentation that can range from superficial to deep invasion of the placenta into the uterine wall. Risk factors include placenta previa, cesarean sections, and uterine surgeries. Prenatal ultrasound and MRI can detect signs such as placental lacunae and vascular abnormalities. Left untreated, PAS disorders can lead to life-threatening hemorrhage.
Conservative management of placenta accreta was described in 3 case studies. Placenta accreta occurs when the placenta abnormally invades the uterine wall. The women were hemodynamically stable and wished to preserve fertility, so expectant management was chosen over hysterectomy. They were monitored closely and expelled placental tissue over time. Two women later had successful pregnancies, while one had two subsequent children. Conservative management can preserve fertility but carries risks of hemorrhage and infection.
ADHERENT PLACENTA DIAGNOSIS & MANAGEMENT BY DR SHASHWAT JANIDR SHASHWAT JANI
1. Adherent placenta occurs when there is a defect in the decidua basalis, resulting in abnormal invasion of the placenta directly into the uterus.
2. Diagnosis is usually made using ultrasound and MRI to detect irregularities in the placenta and loss of tissue planes between the placenta and uterus.
3. Treatment depends on the extent of invasion and patient desires, ranging from conservative surgeries like resection to hysterectomy, with the goal of managing blood loss and preserving the uterus if possible.
The document discusses placenta accreta, a condition where the placenta invades and attaches abnormally to the uterine wall. It has increased in incidence 10-fold over the past 50 years due to rising cesarean delivery rates. Risk factors include placenta previa, prior uterine surgery, and increasing maternal age and parity. Ultrasound and MRI can be used to diagnose placenta accreta prenatally based on signs like lack of a hypoechoic zone between the placenta and uterus. Management options for severe postpartum hemorrhage from placenta accreta include uterine packing, arterial ligation, hysterectomy, and the B-Lynch compression suture
Placenta accreta is currently the most common indication for peripartum hysterectomy. It occurs when the placenta invades and attaches abnormally to the myometrium. The risk and incidence of placenta accreta has increased significantly in recent decades due to rising cesarean delivery rates. Prenatal diagnosis using ultrasound and MRI is important to identify high-risk women and allow planning with a multidisciplinary team. Optimal management involves scheduled cesarean hysterectomy between 34-35 weeks gestation. Conservative management can be considered but is associated with higher risks of hemorrhage, infection and need for emergency hysterectomy.
Adherent placenta occurs when there is a defect in the decidua basalis, Resulting in an abnormal invasion of the placenta directly into the substance of the uterus
This document discusses adherent placenta, beginning with an introduction defining it as an abnormal invasion of the placenta directly into the uterus due to a defect in the decidua basalis. It then covers the types of adherent placenta, risk factors, incidence, significance, diagnosis, and methods for diagnosing adherent placenta antenatally through clinical suspicion and ultrasound techniques like color Doppler to improve outcomes. The goal is to emphasize the importance of early antenatal diagnosis to avoid catastrophic emergencies.
Placenta accreta occurs when the placenta abnormally adheres firmly to the uterine wall, due to an absence of the decidua basalis layer. It can lead to significant maternal morbidity and mortality from hemorrhage. The risk factors include placenta previa, previous cesarean deliveries, uterine surgery, and advanced maternal age. Ultrasound and MRI can help predict placenta accreta by identifying placental lacunae, loss of myometrial thickness, and bladder invasion. Management may involve scheduled delivery, a multidisciplinary team, blood salvage, and leaving the placenta in situ with adjunctive procedures to preserve fertility and reduce hysterectomy. The bladder is
This document provides an overview of placenta accreta spectrum (PAS) disorders, including definitions, epidemiology, pathogenesis, clinical presentation, prenatal diagnosis, and management. PAS disorders describe abnormal placentation that can range from superficial to deep invasion of the placenta into the uterine wall. Risk factors include placenta previa, cesarean sections, and uterine surgeries. Prenatal ultrasound and MRI can detect signs such as placental lacunae and vascular abnormalities. Left untreated, PAS disorders can lead to life-threatening hemorrhage.
Conservative management of placenta accreta was described in 3 case studies. Placenta accreta occurs when the placenta abnormally invades the uterine wall. The women were hemodynamically stable and wished to preserve fertility, so expectant management was chosen over hysterectomy. They were monitored closely and expelled placental tissue over time. Two women later had successful pregnancies, while one had two subsequent children. Conservative management can preserve fertility but carries risks of hemorrhage and infection.
ADHERENT PLACENTA DIAGNOSIS & MANAGEMENT BY DR SHASHWAT JANIDR SHASHWAT JANI
1. Adherent placenta occurs when there is a defect in the decidua basalis, resulting in abnormal invasion of the placenta directly into the uterus.
2. Diagnosis is usually made using ultrasound and MRI to detect irregularities in the placenta and loss of tissue planes between the placenta and uterus.
3. Treatment depends on the extent of invasion and patient desires, ranging from conservative surgeries like resection to hysterectomy, with the goal of managing blood loss and preserving the uterus if possible.
This document discusses placental implantation abnormalities (PIAs) such as placenta previa, placenta accreta, vasa previa, and velamentous cord insertion. It covers the incidence, risk factors, ultrasound findings, diagnosis, complications, and recent advances in managing these conditions. PIAs can cause significant maternal, fetal and neonatal morbidity and mortality. Recent studies have identified additional risk factors such as a history of prelabor cesarean delivery and prior postpartum hemorrhage. Ultrasound is useful for diagnosing PIAs based on criteria like the presence of lacunae, bridging vessels, and thinning of the uterine wall. The Placenta Accreta Index provides a scoring system
The document discusses new trends in the treatment of placenta accreta. It begins by defining placenta accreta and discussing the increasing incidence. Risk is highly associated with the number of prior cesarean deliveries and the presence of placenta previa. Ultrasound is usually sufficient for diagnosis but MRI can provide additional information. Prenatal care involves frequent ultrasound exams and potential adjuvant therapies. Cesarean hysterectomy is the definitive treatment, ideally without attempting placenta removal. A conservative approach may be attempted in select cases for women wishing to preserve fertility, but outcomes are unpredictable and further intervention is often needed. Management of hemorrhage, including techniques such as hemostatic resuscitation,
- Decompression of the abdominal compartment by
opening the abdomen and leaving it open with a
temporary abdominal closure device.
- Aggressive fluid resuscitation should be avoided to prevent dilutional coagulopathy and increased intra-abdominal pressures. Early administration of platelets and fresh frozen plasma in a 1:1:1 ratio with packed red blood cells can help achieve hemostasis earlier.
- Cesarean hysterectomy is usually required for placenta accreta, though in select stable cases a conservative approach retaining the placenta may be attempted with strict follow up given high morbidity.
The document discusses placenta accreta and percreta, which are abnormal placental attachments to the uterine wall that occur more commonly with increasing numbers of cesarean births. It provides background on risk factors, diagnosis using ultrasound and MRI, recommendations for counseling patients and preparing for delivery given risks of hemorrhage. Delivery is recommended before labor to reduce bleeding risks, and a multidisciplinary team approach involving experienced surgeons is advised due to potential need for hysterectomy.
This document discusses morbidly adherent placenta, which occurs when the placenta attaches abnormally deeply into the uterine wall. The incidence has increased from 1 in 2500 deliveries in the 1980s to 1 in 553 deliveries in 2015. Risk factors include prior C-sections, uterine surgery, and multiple pregnancies. Ultrasound is useful for diagnosis but may miss some cases. Management options include C-section hysterectomy, leaving the placenta in situ, myometrial resection, the triple P procedure, compression sutures, and lower segment folding. Conservative options have high risks of infection and bleeding requiring additional surgery.
How to reduce maternal morbidity and mortality in women with morbidly adheren...Zakaria Sanad
This power point presentation displays definition, types, risk factors and diagnosis of morbidly adherent placenta.In addition, this presentation discusses maternal morbidity and mortality associated with MAP and practical steps to reduce these morbidity and mortality.
Placenta praevia, placenta praevia accreta and vasa praeviaAboubakr Elnashar
This document provides guidelines for screening, diagnosis, management and delivery planning for three conditions: placenta praevia, placenta accreta, and vasa praevia. For placenta praevia and suspected accreta, routine ultrasound screening at 20 weeks is recommended, with follow up imaging based on findings. Management involves preventing anemia, planning for possible preterm labor and hemorrhage. Delivery planning includes consent discussions, availability of blood products, and ensuring appropriate staff and facilities are available. For placenta accreta, conservative management of the placenta is preferable to disruption if possible. Vasa praevia screening is not routinely recommended, but diagnosis is by ultrasound and management involves
Radiological evaluation of the PlacentaLenon D'Souza
The document discusses the evaluation of the placenta through ultrasound imaging. It describes normal placental development and appearance at various gestational ages. Common abnormalities that can be assessed include placental location, size, texture, and lesions. Placental positioning such as placenta previa is discussed. Rare conditions like placenta accreta that require MRI are also covered. The roles of ultrasound and MRI in evaluating high-risk placentas are summarized.
Morbidly Adherent Placenta and Peripartum HysterectomyAnkur Shah
This document describes a case of a 25-year-old woman who was 38 weeks pregnant with her second child. She had a previous cesarean delivery and was diagnosed with placenta praevia and placenta increta for her current pregnancy. She underwent a planned cesarean section and peripartum hysterectomy due to life-threatening bleeding from the morbidly adherent placenta that could not be removed manually. The surgery was successful and she recovered well after receiving multiple blood transfusions.
Cervical incompetence, or premature cervical dilation, can complicate 0.1-2% of pregnancies and cause 15% of preterm births between 16-28 weeks. While the exact cause is often unknown, it may result from congenital cervical weakness, trauma, or DES exposure. Diagnosis is based on recurrent second trimester miscarriage without other identifiable causes. Treatment options include bed rest or a cervical cerclage procedure to stitch the cervix closed and prolong the pregnancy. Cerclage placement can be elective, urgent based on cervical shortening, or emergency if dilation has already begun. The McDonald and Shirodkar techniques are most common, with choice depending on cervical anatomy and prior trauma. Cer
This case report describes a caesarean scar ectopic pregnancy in a 28-year old woman with two previous caesarean deliveries. Ultrasound found the gestational sac located in the lower uterine segment within the region of the previous caesarean scar. 3D imaging confirmed these findings. The differential diagnosis considered cervical ectopic pregnancy and missed abortion but color Doppler showed peripheral flow around the sac, confirming a caesarean scar ectopic pregnancy. Early detection of caesarean scar ectopic pregnancies by ultrasound is important to reduce risks of complications like hemorrhage which can require emergency hysterectomy.
This document discusses lessons learned from three cases of placenta accreta and provides information about risk factors, diagnosis, and management of placenta accreta. It notes that the incidence of placenta accreta is increasing due to rising Caesarean section rates. Prenatal diagnosis using ultrasound and MRI is important but can miss some cases. Management may involve elective delivery with a multidisciplinary team prepared for potential hysterectomy or attempts at uterus preservation such as balloon catheterization and selective arterial embolization. Close monitoring is required if attempting expectant or medical management.
1. Cervical insufficiency can be treated with a cerclage suture around the cervix to prevent recurrent second-trimester loss and preterm delivery. A transabdominal cerclage places the suture at a higher level through the abdomen for more severe cases.
2. Evidence supports laparoscopic transabdominal cerclage as a safe and effective procedure that results in improved obstetric outcomes for women with refractory cervical insufficiency or a prior failed vaginal cerclage. It is associated with higher rates of delivery beyond 34 weeks of gestation.
3. Studies have shown laparoscopic transabdominal cerclage has similar or better neonatal survival
The document discusses several assisted reproductive techniques for treating male severe oligospermia or azoospermia including artificial insemination using processed semen, micro-assisted fertilization techniques like ICSI, and epididymal sperm aspiration. It also covers techniques like IVF where eggs are retrieved, fertilized in vitro, and embryos are transferred, with the first "test-tube baby" born in 1978.
This document discusses placenta accreta syndrome, including risk factors, diagnostic methods, and management strategies. It begins with an overview of placenta accreta classifications. Ultrasound and MRI are important diagnostic tools, with ultrasound being the primary method. Risk factors include prior c-sections, placenta previa, and uterine surgeries. Early diagnosis allows for elective c-section and interventions like arterial embolization to reduce bleeding. Hysterectomy is often needed to control hemorrhage but conservative approaches aim to preserve the uterus. Proper multidisciplinary care and prevention of delays in management can improve outcomes for this serious condition.
An ectopic pregnancy occurs when a fertilized egg implants outside of the uterus, usually in the fallopian tubes. Symptoms include vaginal bleeding, abdominal pain, and amenorrhea. Diagnosis is confirmed through beta-hCG blood tests and ultrasound imaging showing no intrauterine pregnancy. Treatment depends on factors like rupture and includes emergency surgery, medical management with methotrexate, or expectant management for very low beta-hCG levels.
Ultrasonographic screening of the cervix can help predict preterm birth risk but has limitations. A cervical length below 25mm has low predictive value in low-risk women but higher value in high-risk groups. Screening is best done between 16-22 weeks as most cervical changes occur then. Therapeutic cerclage for progressive cervical shortening or funneling may help prevent preterm delivery but randomized trials have had mixed results. Transabdominal cerclage is an alternative for women with prior failed vaginal cerclages or cervical abnormalities.
Este documento describe los diferentes tipos de distocias o partos difíciles, incluyendo distocias dinámicas, mecánicas, del canal blando y de partes blandas. Explica las causas, factores de riesgo, diagnóstico y manejo de cada tipo de distocia con el objetivo de que los médicos puedan detectar y tratar adecuadamente cualquier complicación que surja durante el parto.
La placenta es un órgano temporal que se forma durante el embarazo para conectar a la madre y al feto. Proporciona nutrientes y oxígeno al feto y elimina desechos. Existen complicaciones como la placenta previa, cuando la placenta cubre parcial o totalmente el cuello uterino, y la placenta accreta, cuando se adhiere fuertemente a la pared uterina. Estos trastornos pueden causar sangrado abundante y requieren cesárea.
This document discusses placental implantation abnormalities (PIAs) such as placenta previa, placenta accreta, vasa previa, and velamentous cord insertion. It covers the incidence, risk factors, ultrasound findings, diagnosis, complications, and recent advances in managing these conditions. PIAs can cause significant maternal, fetal and neonatal morbidity and mortality. Recent studies have identified additional risk factors such as a history of prelabor cesarean delivery and prior postpartum hemorrhage. Ultrasound is useful for diagnosing PIAs based on criteria like the presence of lacunae, bridging vessels, and thinning of the uterine wall. The Placenta Accreta Index provides a scoring system
The document discusses new trends in the treatment of placenta accreta. It begins by defining placenta accreta and discussing the increasing incidence. Risk is highly associated with the number of prior cesarean deliveries and the presence of placenta previa. Ultrasound is usually sufficient for diagnosis but MRI can provide additional information. Prenatal care involves frequent ultrasound exams and potential adjuvant therapies. Cesarean hysterectomy is the definitive treatment, ideally without attempting placenta removal. A conservative approach may be attempted in select cases for women wishing to preserve fertility, but outcomes are unpredictable and further intervention is often needed. Management of hemorrhage, including techniques such as hemostatic resuscitation,
- Decompression of the abdominal compartment by
opening the abdomen and leaving it open with a
temporary abdominal closure device.
- Aggressive fluid resuscitation should be avoided to prevent dilutional coagulopathy and increased intra-abdominal pressures. Early administration of platelets and fresh frozen plasma in a 1:1:1 ratio with packed red blood cells can help achieve hemostasis earlier.
- Cesarean hysterectomy is usually required for placenta accreta, though in select stable cases a conservative approach retaining the placenta may be attempted with strict follow up given high morbidity.
The document discusses placenta accreta and percreta, which are abnormal placental attachments to the uterine wall that occur more commonly with increasing numbers of cesarean births. It provides background on risk factors, diagnosis using ultrasound and MRI, recommendations for counseling patients and preparing for delivery given risks of hemorrhage. Delivery is recommended before labor to reduce bleeding risks, and a multidisciplinary team approach involving experienced surgeons is advised due to potential need for hysterectomy.
This document discusses morbidly adherent placenta, which occurs when the placenta attaches abnormally deeply into the uterine wall. The incidence has increased from 1 in 2500 deliveries in the 1980s to 1 in 553 deliveries in 2015. Risk factors include prior C-sections, uterine surgery, and multiple pregnancies. Ultrasound is useful for diagnosis but may miss some cases. Management options include C-section hysterectomy, leaving the placenta in situ, myometrial resection, the triple P procedure, compression sutures, and lower segment folding. Conservative options have high risks of infection and bleeding requiring additional surgery.
How to reduce maternal morbidity and mortality in women with morbidly adheren...Zakaria Sanad
This power point presentation displays definition, types, risk factors and diagnosis of morbidly adherent placenta.In addition, this presentation discusses maternal morbidity and mortality associated with MAP and practical steps to reduce these morbidity and mortality.
Placenta praevia, placenta praevia accreta and vasa praeviaAboubakr Elnashar
This document provides guidelines for screening, diagnosis, management and delivery planning for three conditions: placenta praevia, placenta accreta, and vasa praevia. For placenta praevia and suspected accreta, routine ultrasound screening at 20 weeks is recommended, with follow up imaging based on findings. Management involves preventing anemia, planning for possible preterm labor and hemorrhage. Delivery planning includes consent discussions, availability of blood products, and ensuring appropriate staff and facilities are available. For placenta accreta, conservative management of the placenta is preferable to disruption if possible. Vasa praevia screening is not routinely recommended, but diagnosis is by ultrasound and management involves
Radiological evaluation of the PlacentaLenon D'Souza
The document discusses the evaluation of the placenta through ultrasound imaging. It describes normal placental development and appearance at various gestational ages. Common abnormalities that can be assessed include placental location, size, texture, and lesions. Placental positioning such as placenta previa is discussed. Rare conditions like placenta accreta that require MRI are also covered. The roles of ultrasound and MRI in evaluating high-risk placentas are summarized.
Morbidly Adherent Placenta and Peripartum HysterectomyAnkur Shah
This document describes a case of a 25-year-old woman who was 38 weeks pregnant with her second child. She had a previous cesarean delivery and was diagnosed with placenta praevia and placenta increta for her current pregnancy. She underwent a planned cesarean section and peripartum hysterectomy due to life-threatening bleeding from the morbidly adherent placenta that could not be removed manually. The surgery was successful and she recovered well after receiving multiple blood transfusions.
Cervical incompetence, or premature cervical dilation, can complicate 0.1-2% of pregnancies and cause 15% of preterm births between 16-28 weeks. While the exact cause is often unknown, it may result from congenital cervical weakness, trauma, or DES exposure. Diagnosis is based on recurrent second trimester miscarriage without other identifiable causes. Treatment options include bed rest or a cervical cerclage procedure to stitch the cervix closed and prolong the pregnancy. Cerclage placement can be elective, urgent based on cervical shortening, or emergency if dilation has already begun. The McDonald and Shirodkar techniques are most common, with choice depending on cervical anatomy and prior trauma. Cer
This case report describes a caesarean scar ectopic pregnancy in a 28-year old woman with two previous caesarean deliveries. Ultrasound found the gestational sac located in the lower uterine segment within the region of the previous caesarean scar. 3D imaging confirmed these findings. The differential diagnosis considered cervical ectopic pregnancy and missed abortion but color Doppler showed peripheral flow around the sac, confirming a caesarean scar ectopic pregnancy. Early detection of caesarean scar ectopic pregnancies by ultrasound is important to reduce risks of complications like hemorrhage which can require emergency hysterectomy.
This document discusses lessons learned from three cases of placenta accreta and provides information about risk factors, diagnosis, and management of placenta accreta. It notes that the incidence of placenta accreta is increasing due to rising Caesarean section rates. Prenatal diagnosis using ultrasound and MRI is important but can miss some cases. Management may involve elective delivery with a multidisciplinary team prepared for potential hysterectomy or attempts at uterus preservation such as balloon catheterization and selective arterial embolization. Close monitoring is required if attempting expectant or medical management.
1. Cervical insufficiency can be treated with a cerclage suture around the cervix to prevent recurrent second-trimester loss and preterm delivery. A transabdominal cerclage places the suture at a higher level through the abdomen for more severe cases.
2. Evidence supports laparoscopic transabdominal cerclage as a safe and effective procedure that results in improved obstetric outcomes for women with refractory cervical insufficiency or a prior failed vaginal cerclage. It is associated with higher rates of delivery beyond 34 weeks of gestation.
3. Studies have shown laparoscopic transabdominal cerclage has similar or better neonatal survival
The document discusses several assisted reproductive techniques for treating male severe oligospermia or azoospermia including artificial insemination using processed semen, micro-assisted fertilization techniques like ICSI, and epididymal sperm aspiration. It also covers techniques like IVF where eggs are retrieved, fertilized in vitro, and embryos are transferred, with the first "test-tube baby" born in 1978.
This document discusses placenta accreta syndrome, including risk factors, diagnostic methods, and management strategies. It begins with an overview of placenta accreta classifications. Ultrasound and MRI are important diagnostic tools, with ultrasound being the primary method. Risk factors include prior c-sections, placenta previa, and uterine surgeries. Early diagnosis allows for elective c-section and interventions like arterial embolization to reduce bleeding. Hysterectomy is often needed to control hemorrhage but conservative approaches aim to preserve the uterus. Proper multidisciplinary care and prevention of delays in management can improve outcomes for this serious condition.
An ectopic pregnancy occurs when a fertilized egg implants outside of the uterus, usually in the fallopian tubes. Symptoms include vaginal bleeding, abdominal pain, and amenorrhea. Diagnosis is confirmed through beta-hCG blood tests and ultrasound imaging showing no intrauterine pregnancy. Treatment depends on factors like rupture and includes emergency surgery, medical management with methotrexate, or expectant management for very low beta-hCG levels.
Ultrasonographic screening of the cervix can help predict preterm birth risk but has limitations. A cervical length below 25mm has low predictive value in low-risk women but higher value in high-risk groups. Screening is best done between 16-22 weeks as most cervical changes occur then. Therapeutic cerclage for progressive cervical shortening or funneling may help prevent preterm delivery but randomized trials have had mixed results. Transabdominal cerclage is an alternative for women with prior failed vaginal cerclages or cervical abnormalities.
Este documento describe los diferentes tipos de distocias o partos difíciles, incluyendo distocias dinámicas, mecánicas, del canal blando y de partes blandas. Explica las causas, factores de riesgo, diagnóstico y manejo de cada tipo de distocia con el objetivo de que los médicos puedan detectar y tratar adecuadamente cualquier complicación que surja durante el parto.
La placenta es un órgano temporal que se forma durante el embarazo para conectar a la madre y al feto. Proporciona nutrientes y oxígeno al feto y elimina desechos. Existen complicaciones como la placenta previa, cuando la placenta cubre parcial o totalmente el cuello uterino, y la placenta accreta, cuando se adhiere fuertemente a la pared uterina. Estos trastornos pueden causar sangrado abundante y requieren cesárea.
Triage is the process of sorting patients based on the urgency of their condition to provide the right care to the right patient at the right time. It involves initially assessing patients at arrival to identify those needing immediate care, determine the appropriate treatment area, and avoid congestion. The goals are to treat the most severely injured first while maximizing survival in a mass casualty event. Triage categories range from resuscitation to non-urgent to ensure critical patients receive rapid medical attention. Reassessment is important as a patient's condition may deteriorate while waiting.
Este documento describe las distintas formas de distocia o dificultad en el parto, incluyendo distocias dinámicas relacionadas con las contracciones uterinas, distocias mecánicas debidas a problemas en el canal de parto o el feto, y cómo detectar y tratar cada tipo de distocia. Como matronas, es fundamental saber monitorear las contracciones y conocer los procedimientos adecuados para cada situación de dificultad, especialmente en casos como la distocia de hombros donde tenemos un papel clave.
Este documento describe los diferentes tipos de partos distócicos o complicados. Explica que un parto distócico ocurre cuando hay problemas con el feto, como presentaciones anormales, o problemas con la madre, como una pelvis pequeña. Luego detalla los diferentes tipos de distocias causadas por problemas con el feto, la placenta, el cordón umbilical, el líquido amniótico y las membranas. También cubre las distocias causadas por problemas con las contracciones uterinas, el canal de parto, el cuello uterino, la vagina y
Este documento describe varias anomalías de la placenta y el cordón umbilical, incluyendo placentas múltiples, placentas grandes, placenta previa, placenta acreta e increta, pólipos placentarios, y anomalías en la longitud y circulación del cordón umbilical. Las anomalías de la placenta pueden causar hemorragias, dificultad en la extracción después del parto, y restricción del crecimiento fetal. Las anomalías del cordón umbilical también pueden traer consecuencias como coloración meconial, parto pre
El documento describe diferentes tipos de parto. Explica que hay partos eutócicos (normales) y distócicos (con complicaciones) y describe brevemente cada uno. También describe diferentes técnicas para aliviar el dolor durante el parto, incluyendo opciones farmacológicas como la epidural y no farmacológicas como clases de preparación y apoyo de una persona. Además, resume diferentes enfoques al parto como el natural, humanizado y sin violencia.
El documento describe la placenta, incluyendo su morfología, partes fetal y materna, circulación fetal, funciones, fisiología del transporte, endocrinología, variaciones de forma y anormalidades. La placenta es un órgano temporal que permite el intercambio de nutrientes y gases entre la madre y el feto durante el embarazo.
Emergency is the gateway to the hospital, patients with pain and agony, relative emotionally charged enter the emergency department at any hour of the day or night, expecting immediate treatment and solace.
This document discusses placenta previa, a condition where the placenta covers part or all of the cervical opening. It can cause bleeding in late pregnancy. The document defines placenta previa and notes its increasing rates. Risk factors include prior c-sections, advanced maternal age, smoking, and multiple pregnancies. Diagnosis is via ultrasound. Precise diagnosis is important to determine management and optimize outcomes for mother and baby.
This document discusses placenta accreta spectrum (PAS), a group of disorders involving abnormal placental invasion into the uterine wall. PAS is a major cause of severe maternal morbidity and its incidence has increased significantly with rising cesarean delivery rates. The document summarizes the risk factors, grading system, diagnosis, and management of PAS. Ultrasound is usually used to diagnose PAS, and findings include loss of the clear zone and abnormal vasculature. Standard management is a scheduled cesarean hysterectomy between 34-36 weeks to minimize risks.
Mercer Clin Perinatol 2004, Rpm Diagnosis And ManagementEliana Cordero
1) Preterm premature rupture of the membranes (PROM) complicates approximately 8% of pregnancies and is responsible for about one third of preterm births.
2) The diagnosis of PROM is usually made clinically based on history, physical exam, and adjunctive tests showing fluid leakage. Management depends on gestational age and factors necessitating delivery.
3) For previable PROM (before 23 weeks), expeditious delivery is usually recommended given the high risks of maternal complications and fetal/neonatal death. Conservative management may be considered with strict monitoring and bed rest.
This document provides information on ectopic pregnancy, including:
1. Ectopic pregnancy occurs when a fertilized egg implants outside the uterus, most commonly in the fallopian tubes.
2. Risk factors include previous ectopic pregnancy, pelvic inflammatory disease, IUD use, infertility treatments, and smoking.
3. Symptoms can include abdominal pain, vaginal bleeding, and shoulder tip pain. Diagnosis is usually made through ultrasound and beta-hCG levels.
4. Treatment options include expectant management, surgery (laparoscopy or laparotomy), and methotrexate injections. The approach depends on factors like embryo viability, size, and symptoms.
Frequency of C-Section vs SVD, Necessity or Malpractice Hussain Karimi
Previous vaginal delivery gives the family and the doctors a false sense of security that overshadows the need for vigilant antenatal and intrapartum care. The method of previous deliveries shouldn’t be the primary criteria upon which the current delivery is decided. Rather, every pregnancy should be treated with as much concern and care as the first. (the physicians should display obligation In such circumstances and assess the pregnancy thoroughly before heading towards a massive scheme. Rather than promoting the doctors’ own interests and convenience, Mothers’ health and wellbeing should be considered the first priority and every possible measures should be taken to ensure that. The antenatal care should be the utmost preference and necessary investigations should be practiced. WHO recommends a minimum of four antenatal visits, comprising interventions such as tetanus toxoid vaccination, screening and treatment for infections, and identification of warning signs during pregnancy. With all the adequate steps taken, the rate and reasons of cesarean sections could be monitored and restricted hence progressing to initiate a huge stride for maternal and fetal health.
Ultrasound is essential for evaluating pelvic pain and vaginal bleeding in women of childbearing age. It can identify many potential causes of these presentations including pregnancy location, ectopic pregnancies, retained products of conception, and complications of pregnancy. Transvaginal ultrasound in particular provides high resolution imaging of the pelvis and adnexal structures to accurately diagnose conditions. Doppler ultrasound further aids evaluation by identifying blood flow patterns.
Safe Prevention of the Primary Cesarean Delivery.pdfpriyashukla80
This document discusses safe reduction of primary cesarean delivery rates in the United States. The rate of cesarean births increased rapidly from 1996 to 2011 without clear evidence of improved outcomes. Variation in cesarean rates between hospitals and regions suggests clinical practice patterns affect cesarean use. The most common reasons for primary cesareans are labor dystocia, abnormal fetal heart rate, breech presentation, twins, and suspected large baby. Efforts to safely lower the rate include redefining labor progression, standardizing fetal monitoring, increasing support for women in labor, and attempting vaginal breech and twin deliveries when possible.
Placenta previa occurs when the placenta implants in the lower uterine segment, over or near the internal cervical os. It occurs in about 0.5% of pregnancies and has a 4-8% recurrence rate. While the exact cause is unknown, it is associated with uterine scarring from surgeries or infections. Management involves bed rest, monitoring for bleeding, and delivery via cesarean section if bleeding occurs late in pregnancy or labor begins. Complications include blood loss for the mother and restricted growth/prematurity for the baby.
This document provides information on ectopic pregnancy, including:
1. Ectopic pregnancy occurs when a fertilized egg implants outside the uterus, most commonly in the fallopian tubes.
2. Risk factors include STIs, IUD use, infertility history, smoking, and assisted reproduction.
3. Symptoms can include abdominal/pelvic pain, vaginal bleeding, and in severe cases, hypovolemic shock from rupture. Diagnosis involves ultrasound and beta-hCG levels.
4. Treatment options are expectant management, surgery (laparoscopy or laparotomy), or medical management with methotrexate depending on factors like size and symptoms. The goal is to preserve
An ectopic pregnancy occurs when a fertilized egg implants outside of the uterus, most commonly in the fallopian tubes. Risk factors include a history of pelvic inflammatory disease, prior tubal surgery or ectopic pregnancy. Clinical presentation may include vaginal bleeding, abdominal or pelvic pain. Diagnosis involves serum hCG and progesterone levels, transvaginal ultrasound and laparoscopy. Treatment options are medical, using methotrexate, or surgical. The goal is to terminate the pregnancy safely while preserving fertility.
Placenta previa is a condition where the placenta covers part or all of the cervical os. It can cause significant bleeding during the third trimester. Treatment depends on gestational age and severity of bleeding, and may involve expectant management, cesarean delivery, or in rare cases vaginal delivery. Complications include maternal hemorrhage and fetal issues like prematurity. Proper diagnosis and management are needed to prevent adverse outcomes.
Placenta previa is a condition where the placenta partially or fully covers the internal cervical os. It increases the risks of postpartum hemorrhage and morbidity for both the mother and neonate. The incidence is 0.3-2% of pregnancies in the third trimester and is increasing due to rising cesarean section rates. Risk factors include advanced maternal age, multiparity, smoking, prior uterine procedures, assisted reproduction, and history of cesarean sections or placenta previa. Diagnosis is made using ultrasound and MRI imaging. Complete placenta previa requires delivery by cesarean section while incomplete or marginal types may allow for vaginal delivery if bleeding does not occur. Treatment
Cervical incompetence is premature dilation of the cervix during pregnancy before labor begins. It affects 0.1-2% of pregnancies and causes around 15% of preterm births between 16-28 weeks. While the cause is often unknown, it can be due to congenital weaknesses, prior trauma, or connective tissue disorders. Diagnosis relies on history of preterm births and physical findings like dilation of the cervix when not pregnant. Cervical cerclage placement is the standard treatment and involves surgically stitching the cervix closed to prevent premature dilation. The document discusses various cerclage techniques and their appropriate uses.
APH affects 3-5% of pregnancies and is a leading cause of preterm birth. Clinical assessment of APH involves history, examination, and ultrasound to determine the cause and severity of bleeding and risk to the mother and fetus. Management priorities are resuscitation of the mother, monitoring the fetus, restricting activity and delivery depending on gestational age and severity of the condition.
This document discusses placental implantation abnormalities (PIAs) such as placenta previa, placenta accreta, vasa previa, and velamentous cord insertion. It covers the incidence, risk factors, ultrasound findings, diagnosis, and complications of these conditions. Key points include:
- PIAs account for 5.6-8.7% of preterm births and are the second leading cause of preterm delivery.
- Risk factors for placenta accreta include previous cesarean sections, placenta previa, and number of prior cesareans.
- Ultrasound criteria can diagnose placenta accreta with 81.1% sensitivity and 98
ECTOPIC PREGNANCY. An ectopic pregnancy occurs when a fertilized egg implants outside the uterus, usually in the fallopian tubes. Risk factors include previous pelvic inflammatory disease or use of an intrauterine device. Clinical presentation includes amenorrhea, abdominal pain, and vaginal bleeding. Diagnosis is made through pregnancy tests, ultrasound, and clinical examination. Treatment options include surgery such as salpingectomy or salpingotomy. Conservative treatment with methotrexate may also be used. Complications can include hemorrhage and shock.
2. and III. In cases where the literature does not provide
convincing evidence for management of these condi-tions,
we have described our experience and techniques.
PLACENTA PREVIA
Definition
The term placenta previa refers to a placenta that
overlies or is proximate to the internal os of the
cervix. The placenta normally implants in the upper
uterine segment. In placenta previa, the placenta
either totally or partially lies within the lower uterine
segment. Traditionally, placenta previa has been cat-egorized
into 4 types (Fig. 1):
1. Complete placenta previa, where the placenta
completely covers the internal os.
2. Partial placenta previa, where the placenta
partially covers the internal os. Thus, this scenario
occurs only when the internal os is dilated to some
degree.
3. Marginal placenta previa, which just reaches the
internal os, but does not cover it.
4. Low-lying placenta, which extends into the lower
uterine segment but does not reach the internal os.
Clinical Importance
Morbidities associated with placenta previa include
antepartum bleeding (relative risk [RR] 9.81, 95%
confidence interval [CI] 8.92–10.79), need for hyster-ectomy
(RR 33.26, 95% CI 18.19–60.89), morbid
adherence of the placenta, intrapartum hemorrhage
(RR 2.48, 95% CI 1.55–3.98), postpartum hemor-rhage
(RR 1.86, 95% CI 1.46 –2.36), blood transfusion
(RR 10.05, 95% CI 7.45–13.55), septicemia (RR 5.5,
95% CI 1.31–23.54), and thrombophlebitis (RR 4.85,
95% CI 1.50 –15.69).1 In the United States, maternal
mortality occurs in 0.03% of cases of placenta previa.2
Women with placenta previa may suffer considerable
emotional distress because of recurrent bleeding
along with hospitalizations that frequently occur in
the second half of pregnancy. Placenta previa is also
associated with an increase in preterm birth and
perinatal mortality and morbidity.3 Finally, there is a
higher rate of congenital malformations among
women with placenta previa, although the precise
mechanisms for these are unclear.3
Incidence and Risk Factors
Placenta previa complicates approximately 0.3–0.5%
of pregnancies.2 A United States population-based
study for the years 1979–1987 found the overall
annual incidence of placenta previa to be 4.8 per
1,000 deliveries (0.48%).2 Several studies have found
that risk factors for placenta previa include a history
of prior cesarean delivery,4 termination of pregnancy
or uterine surgery,4,5 smoking,6 increasing age,7 mul-tiparity,
7 cocaine,8 and multiple pregnancy.9 The like-lihood
of placenta previa increases in a dose-response
fashion with a greater number of prior cesarean
deliveries and with greater parity, with relative risks of
previa rising from 4.5 (95% CI 3.6 –5.5) in women
with one prior cesarean delivery to 44.9 (95% CI
13.5–149.5) in women with 4 prior cesarean deliver-ies,
respectively.7
Pathophysiology
It is unclear why some placentas implant in the lower
uterine segment rather than in the fundus.10 It does
appear that uterine scarring may predispose to pla-cental
implantation in the lower segment. With the
progression of pregnancy, more than 90% of these
low-lying placentas identified early in pregnancy will
appear to move away from the cervix and out of the
lower uterine segment. Although the term “placental
migration” has been used, most authorities do not
believe the placenta moves.10 Rather, it is felt that the
placenta grows preferentially toward a better vascu-larized
fundus (trophotropism), whereas the placenta
overlying the less well vascularized cervix may un-dergo
atrophy.10 In some cases, this atrophy leaves
vessels running through the membranes, unsupported
by placental tissue or cord (vasa previa).10 In cases
where the atrophy is incomplete, a succenturiate lobe
may develop. The apparent movement of the pla-centa
may also be due to the development of the
lower uterine segment. Contractions and cervical
effacement and dilation that occur in the third trimes-ter
cause separation of the placenta, which leads to
small amounts of bleeding. This bleeding may stimu-late
further uterine contractions, which, in turn, stim-ulates
further placental separation and bleeding.
Rarely are these initial bleeds a major problem,
although they may be a reason for hospitalization. In
labor, as the cervix dilates and effaces, there is usually
placental separation and unavoidable bleeding.
Diagnostic Approach
The classic clinical presentation of placenta previa is
painless bleeding in the late second trimester or early
third trimester. However, some patients with placenta
previa will experience painful bleeding, possibly the
consequence of uterine contractions or placental sep-aration,
whereas others will experience no bleeding at
all before labor. Placenta previa may also lead to an
unstable lie or malpresentation in late pregnancy.
The majority of cases of placenta previa are
928 Oyelese and Smulian Placenta Previa, Accreta, and Vasa Previa OBSTETRICS & GYNECOLOGY
3. diagnosed during routine sonography in asymptom-atic
women, usually during the second trimester.
Although transabdominal sonography is frequently
used for placental location, this technique lacks some
precision in diagnosing placenta previa.11,12 Numer-ous
studies have demonstrated the accuracy of trans-vaginal
sonography for the diagnosis of placenta
previa, uniformly finding that transvaginal sonogra-phy
is superior to transabdominal sonography for this
indication (Fig. 2).11,12 False-positive and -negative
rates for the diagnosis of placenta previa using trans-abdominal
sonography range from 2% to 25%.11 A
study by Smith and colleagues11 of 131 women be-lieved
to have a placenta previa by transabdominal
sonography found that anatomic landmarks crucial
for accurate diagnosis were poorly recognized in 50%
of cases. In 26% of the cases of suspected placenta
previa, the initial diagnosis was changed after trans-vaginal
sonography because it was incorrect.
The superiority of transvaginal sonography over
transabdominal sonography can be attributed to sev-eral
factors:
1. The transabdominal approach requires bladder
filling, which results in approximation of the anterior
and posterior walls of the lower uterine segment, with
the result that a normally situated placenta may
falsely appear to be a previa.
2. Vaginal probes are closer to the region of
interest, and typically of higher frequency, and there-fore
obtain higher resolution images than transab-dominal
probes.
3. The internal cervical os and the lower placental
edge frequently cannot be imaged adequately by the
transabdominal approach. The position of the inter-nal
os is assumed rather than actually seen.
4. The fetal head may obscure views of the lower
placental edge when using the transabdominal ap-proach,
and a posterior placenta previa may not be
adequately imaged.
The improved accuracy of transvaginal sonogra-phy
over transabdominal sonography means that
fewer false-positive diagnoses are made; thus, the rate
of placenta previa is significantly lower when using
transvaginal sonography than when using transab-dominal
sonography.11,13 Lauria and colleagues,13 per-forming
routine transvaginal sonography, found an
incidence of placenta previa of only 1.1% at 15–20
weeks, considerably lower than the second trimester
placenta previa incidence of 15–20% reported by
previous investigators using transabdominal sonogra-phy.
14 Numerous studies have demonstrated the
safety of transvaginal sonography for the diagnosis of
placenta previa.12,15 Importantly, this imaging tech-nique
does not lead to an increase in bleeding.15 This
is for 2 main reasons: 1) the vaginal probe is intro-duced
at an angle that places it against the anterior
fornix and anterior lip of the cervix, unlike a digital
examination, where articulation of the hand allows
introduction of the examining finger through the
cervix (Fig. 3);15 2) the optimal distance for visualiza-tion
of the cervix is 2–3 cm away from the cervix, so
the probe is generally not advanced sufficiently to
make contact with the placenta.15 Nonetheless, the
examination should be performed by personnel ex-perienced
in transvaginal sonography, and the trans-vaginal
probe should always be inserted carefully,
with the examiner looking at the monitor to avoid
putting the probe in the cervix.
Translabial sonography has been suggested as an
alternative to transvaginal sonography and has been
shown to be superior to transabdominal sonography
for placental location.16 However, because transvagi-nal
sonography is accurate, safe, and well tolerated, it
should be the imaging modality of choice.
Several studies have demonstrated that the ma-jority
of placentas that are in the lower uterine
segment in the second trimester will no longer be in
the region of the cervix by the time of delivery (Table
1).13,17–21 Persistence to term can be predicted based
on whether or not the placenta overlaps the internal
os in the second trimester, and to what extent.13,17–21
The later in pregnancy that placenta previa is diag-nosed,
the higher the likelihood of persistence to
delivery.22 Women who at 20 weeks have a low-lying
placenta that does not overlie the internal os will not
have a placenta previa at term and need no further
sonographic examinations for placental location.
However, the presence of a low-lying placenta in the
second trimester is a risk factor for developing a vasa
previa, and therefore, in these cases, a sonogram
should be performed later in pregnancy to exclude
that condition.
Management
In the past, suspected placenta previa was managed
by vaginal examination and immediate cesarean de-livery
if placenta previa was confirmed. It was be-lieved
that the first bleed (usually occurring in the
early third trimester) would lead to maternal death.
However, MacAfee23 showed that, in the absence of
interference, this almost never happened, and that the
high perinatal mortality from placenta previa was
primarily due to prematurity, which could be reduced
considerably by conservative expectant management
and delivery as close to term as possible.
VOL. 107, NO. 4, APRIL 2006 Oyelese and Smulian Placenta Previa, Accreta, and Vasa Previa 929
4. Women who present with bleeding in the second
half of pregnancy should have a sonographic exami-nation
(preferably by the transvaginal approach) for
placental location prior to any attempt to perform a
digital examination. Digital vaginal examination with
a placenta previa may provoke catastrophic hemor-rhage
and should not be performed.
It is reasonable to hospitalize women with pla-centa
previa while they are having an acute bleeding
episode or uterine contractions. One to two wide-bore
intravenous cannulas should be inserted and blood
taken for a full blood count and type and screen. In
the absence of massive bleeding or other complica-tions,
coagulation studies are not helpful. The blood
bank must be capable of making available at least 4
Fig. 1. Types of placenta previa.
Illustration: John Yanson.
Oyelese. Placenta Previa, Accreta,
and Vasa Previa. Obstet Gynecol
2006.
units of compatible packed red blood cells and coag-ulation
factors at short notice. Rh immune globulin
should be administered to Rh-negative women. A
Kleihauer-Bettke test for quantification of fetal-mater-nal
transfusion should also be performed in Rh-negative
women because the mother may require
increased doses of Rh immune globulin.
Small studies have suggested a benefit of tocolytic
therapy for women with placenta previa who are
having contractions.24,25 Contractions may lead to
Fig. 2. Transvaginal sonogram of a complete placenta
previa (PP). Note that both the placenta and the internal
cervical os (arrow) are clearly depicted. A, anterior lip of
cervix; P, posterior lip of cervix. The placenta just overlaps
the internal os. One can see how this could become a
partial placenta previa covering just the anterior lip of the
cervix if cervical dilation were to occur.
Oyelese. Placenta Previa, Accreta, and Vasa Previa. Obstet
Gynecol 2006.
Fig. 3. Diagram demonstrating the technique for transvag-inal
sonography of placenta previa. T, transvaginal trans-ducer;
A, anterior lip of cervix; P, posterior lip of cervix.
Complete placenta previa is shown completely covering
the internal os (arrow). The transvaginal transducer lies
within the vagina, about 2 cm from the anterior lip of the
cervix. The angle between the transducer and the cervical
canal is 35 degrees, demonstrating why the probe does not
enter the cervix. Illustration: John Yanson.
Oyelese. Placenta Previa, Accreta, and Vasa Previa. Obstet
Gynecol 2006.
930 Oyelese and Smulian Placenta Previa, Accreta, and Vasa Previa OBSTETRICS & GYNECOLOGY
5. Table 1. Studies of Second Trimester Transvaginal Sonography in the Prediction of Placenta Previa at
cervical effacement and changes in the lower uterine
segment, provoking bleeding which, in turn, stimu-lates
contractions, creating a vicious cycle. Sharma
and colleagues24 carried out a small randomized study
using the -adrenergic ritodrine and found a signifi-cant
prolongation in pregnancy and higher birth
weights in women treated with ritodrine when com-pared
with women treated with placebo. Similarly,
Besinger and colleagues,25 in a retrospective study,
found that use of intravenous magnesium sulfate
and/or oral or subcutaneous terbutaline in women
with symptomatic placenta previa was associated with
greater prolongation of pregnancy and higher birth
weight than in women who were not treated with
tocolytics. Thus, cautious use of tocolytics in women
with placenta previa who are having contractions,
when both mother and fetus are stable, appears
reasonable.
Steroids should be administered in women be-tween
24 and 34 weeks of gestation, generally at the
time of admission for bleeding, to promote fetal lung
maturation. The patient and her family should have a
neonatology consultation so that the management of
the infant after birth may be discussed. In women
who have a history of cesarean delivery or uterine
surgery, detailed sonography should be performed to
exclude placenta accreta. Because prematurity is the
main cause of perinatal mortality associated with
placenta previa, it is desirable to prolong gestation as
long as safely possible. Therefore, before 32 weeks of
gestation, moderate-to-severe bleeding when there is
no maternal or fetal compromise may be managed
aggressively with blood transfusions, rather than re-sorting
to delivery.26 When the patient has had no
further bleeding for 48 hours, she may be considered
for discharge as long as there are appropriate home
conditions to allow outpatient management. Specifi-cally,
the patient should have access to a telephone,
have a responsible adult and transportation available
at all times, and must live within reasonable distance
of a hospital. She should return to the hospital imme-diately
if she experiences bleeding or contractions.
Although there are no data to support the efficacy of
avoidance of intercourse and excessive activity, com-mon
sense suggests that these should be avoided. Simi-larly,
bedrest is often advised, but there is no evidence
that demonstrates that this practice is beneficial.
Outpatient Versus Inpatient Management
Whether women with placenta previa should be
managed as inpatients or outpatients has been a
matter of controversy. A few retrospective studies
have addressed this issue and have found no differ-ence
in outcomes, whether patients were managed in
hospital or at home, and found that outpatient man-agement
may be associated with lower costs.27,28
These studies concluded that outpatient management
of selected women with placenta previa was safe.
However, in another retrospective study, D’Angelo
and Irwin29 found an increase in perinatal mortality,
lower gestational age at delivery, increased neonatal
hospitalization duration, and neonatal morbidity
among women who were managed as outpatients
when compared with those managed expectantly as
inpatients. In one of the few prospective randomized
studies dealing with placenta previa, Wing et al30
randomized 53 women with placenta previa at gesta-tional
ages between 24 and 36 weeks, who had been
initially stabilized in hospital, to inpatient or outpa-tient
management and found no significant difference
in outcomes. Thus, women who are stable and asymp-tomatic,
and who are reliable and have quick access to
hospital, may be considered for outpatient management.
Cerclage
Arias31 randomized 25 women who were admitted to
hospital with symptomatic placenta previa at 24–30
weeks gestation to cerclage or no cerclage and found
a higher mean birth weight and gestational age at
delivery and fewer neonatal complications in the
cerclage group. Women with cerclage had lower
hospitalization costs and fewer bleeding episodes.
Delivery
Author
Gestational Age at
Sonogram (wk)
Number of
Women
Incidence of Placenta Previa
at First- or Second-Trimester
Sonography [n (%)]
Incidence at
Delivery [n (%)]
Becker17 20–23 8,650 99 (1.1) 28 (0.32)
Taipale21 18–23 3,969 57 (1.5) 5 (0.14)
Hill19 9–13 1,252 77 (6.2) 4 (0.31)
Mustafa20 20–24 203 8 (3.9) 4 (1.9)
Lauria13 15–20 2,910 36 (1.2) 5 (0.17)
Rosati18 10–16 2,158 105 (4.9) 8 (0.37)
VOL. 107, NO. 4, APRIL 2006 Oyelese and Smulian Placenta Previa, Accreta, and Vasa Previa 931
6. However, in a later study, Cobo and colleagues32
randomized 39 women with placenta previa at 24–30
weeks to cerclage or no cerclage and found no
statistically significant differences in gestational age at
delivery, prolongation of pregnancy, or in amount of
blood lost between the 2 groups. In view of the lack of
convincing data to support cerclage in these women,
cerclage should not be performed for treatment of
placenta previa.
Mode of Delivery
There is consensus that a placenta previa that totally
or partially overlies the internal cervical os requires
delivery by cesarean. However, the mode of delivery
when the placenta lies in proximity to the internal os
is more controversial. Three small retrospective stud-ies
using transvaginal or translabial sonography have
evaluated the role of ultrasonography in determining
the optimal mode of delivery for women whose
placentas were in proximity to the internal cervical
os.33–35 All 3 studies found that women in whom the
distance between the lower placental edge and the
internal cervical os was greater than 2 cm could safely
have a vaginal delivery. Conversely, among women
with a placenta-internal os distance less than 2 cm, the
overwhelming majority required cesarean delivery,
usually for bleeding. However, in none of these
studies were the clinicians blinded to the results of the
scan, and this may have influenced obstetric manage-ment.
Furthermore, these studies had relatively small
numbers. Nonetheless, the studies suggest that
women with placenta previa should have a transvag-inal
sonogram in the late third trimester, and that
those with a placental edge to internal os distance of
less than 2 cm should be delivered by cesarean. It has
been our experience that women with a placenta-internal
os distance of less than 2 cm who undergo a
trial of labor almost invariably experience significant
bleeding during labor, necessitating cesarean deliv-ery.
Consequently, it is now our practice to deliver
these women by elective cesarean. Women whose
placentas are 2 cm or more from the os undergo a
normal labor. It is important though to realize that, in
women with a placenta that extends into the noncon-tractile
lower uterine segment who have a vaginal
delivery, there is potential for postpartum hemorrhage.
When there is an anterior placenta previa, there is
a considerable likelihood of incising through the
placenta during delivery. This could lead to signifi-cant
maternal and fetal blood loss and also to diffi-culty
with delivery, but this rarely constitutes a signif-icant
problem. Alternative strategies have been
proposed and used to avoid incision into the placenta.
These include use of a fundal vertical uterine incision,
especially in women who have no desire for further
childbearing.36 This may especially be useful when
there is a complete placenta previa with a fetal
transverse lie with the fetal back down. Sonography
before surgery for placental location enables the
surgeon to plan the most appropriate incision.36 Gen-erally,
we perform a lower segment transverse uterine
incision, incising the placenta when it is unavoidable.
The infant is delivered as rapidly as possible, and the
cord is clamped immediately to avoid hemorrhage
from fetal vessels.
Timing of Delivery
As gestational age advances, there is an increased risk
of significant bleeding, necessitating delivery. It is
preferable to perform a cesarean delivery for placenta
previa under controlled scheduled conditions rather
than as an emergency. Therefore, in a stable patient,
it is reasonable to perform a cesarean delivery at
36–37 weeks of gestation, after documentation of fetal
lung maturity by amniocentesis. If the amniocentesis
does not demonstrate lung maturity, we deliver the
women by elective cesarean at 38 weeks, without
repeating the amniocentesis, if they remain stable, or
earlier if bleeding occurs or the patient goes into
labor.
Anesthesia for Delivery
In the past, it was generally recommended that cesar-ean
deliveries for placenta previa be performed under
general anesthetic.37 It was believed that this allowed
more controlled surgery. At least 2 studies, including
a prospective randomized trial, have found that cesar-ean
deliveries for placenta previa performed under
general anesthetic were associated with significantly
greater estimated blood loss and greater requirements
for blood transfusion than those performed under
regional anesthesia,38,39 possibly due to increased uter-ine
relaxation associated with general anesthetic. Oth-erwise,
there was no difference in the incidence of
intraoperative or anesthesia complications between
regional and general anesthesia. A survey of anesthe-siologists
in the United Kingdom found a wide variety
of opinions regarding whether general or regional
anesthesia should be used for cesarean for placenta
previa. However, anesthesiologists who did more
obstetric anesthesia were more likely to employ re-gional
anesthesia.40 Another U.K. survey found that,
60% of the time, anesthesiologists used regional anes-thesia
for cesarean for placenta previa.37 At our
institution, we generally perform cesarean deliveries
for placenta previa under regional anesthesia.
932 Oyelese and Smulian Placenta Previa, Accreta, and Vasa Previa OBSTETRICS GYNECOLOGY
7. PLACENTA ACCRETA
Definition
Placenta accreta refers to a placenta that is abnor-mally
adherent to the uterus (Fig. 4). When the
placenta invades the myometrium, the term placenta
increta is used, whereas placenta percreta refers to a
placenta that has invaded through the myometrium
and serosa, sometimes into adjacent organs, such as
the bladder. The term placenta accreta is often used
interchangeably as a general term to describe all of
these conditions.
Clinical Significance
Placenta accreta may lead to massive obstetric hem-orrhage,
resulting in such complications as dissemi-nated
intravascular coagulopathy, need for hysterec-tomy,
surgical injury to the ureters, bladder, and other
viscera, adult respiratory distress syndrome, renal
failure, and even death.41,42 The average blood loss at
delivery in women with placenta accreta is 3,000–
5,000 mL.41 Indeed, in several centers, placenta ac-creta
has become the leading reason for cesarean
hysterectomy.43 Rarely, placenta accreta may lead to
spontaneous uterine rupture in the second or third
trimester, resulting in intraperitoneal hemorrhage, a
life-threatening emergency.44 Minor degrees of pla-centa
accreta may occur, which may lead to slightly
heavier postpartum bleeding, but may not require the
aggressive management that is often employed with
more extensive placenta accreta.
Incidence and Risk Factors
Miller and colleagues,45 reviewing 155,670 deliveries
at their hospital between 1985 and 1994, found that
62 (one in 2,510) were complicated by placenta
accreta. The incidence of placenta accreta is increas-ing,
primarily as a consequence of rising cesarean
delivery rates. A recent study by Wu and colleagues46
looking at placenta accreta over a 20-year period
(1982–2002) found an incidence of 1 in 533 pregnan-cies
at their institution. Placenta accreta occurs most
frequently in women with one or more prior cesarean
deliveries who have a placenta previa in the current
pregnancy. Clarke and colleagues47 found that, in the
presence of a placenta previa, the risk of having
placenta accreta increased from 24% in women with
one prior cesarean delivery to 67% in women with 3
or more prior cesareans.
It has been proposed that the abnormality of the
placental-uterine interface in women with placenta
accreta will lead to leakage of fetal alpha-fetoprotein
into the maternal circulation, resulting in elevated
levels of maternal serum alpha-fetoprotein
(MSAFP).48 Kupferminc and colleagues,49 reviewing
44 cases of women who had cesarean hysterectomies,
found that 9 of the 20 (45%) with placenta accreta had
elevated MSAFP levels (between 2.7 and 40.3 multi-ples
of the median [MoMs]), whereas the controls all
had MSAFP levels within normal limits ( 2.0
MoMs). Similarly, Zelop and colleagues48 found ele-vated
second-trimester MSAFP levels (between 2.3
and 5.5 MoMs) in 45% of 11 women with placenta
accreta, whereas none of the controls who had pla-centa
previa without accreta had MSAFP elevations.
Although these studies are small, they suggest that
women with elevated MSAFP levels with no other
obvious cause should be considered at increased risk
of placenta accreta.
Pathophysiology
Placenta accreta is thought to be due to an absence or
deficiency of Nitabuch’s layer or the spongiosus layer
of the decidua.10 Benirschke and Kaufmann10 suggest
that this is the consequence of failure of reconstitution
of the endometrium/decidua basalis after repair of a
cesarean incision. Histology usually shows that the
trophoblast has invaded the myometrium without
intervening decidua.10 This becomes a problem at
delivery when the placenta does not separate and
massive bleeding ensues (Fig. 5).
Fig. 4. Hysterectomy specimen demonstrating placenta
accreta. This placenta accreta was diagnosed prenatally.
The placenta (p) has invaded the myometrium (arrow) and
after hysterectomy could not be separated from the uterus.
There were no planes of demarcation between placenta
and myometrium. cx, cervix; f, uterine fundus; c, umbilical
cord.
Oyelese. Placenta Previa, Accreta, and Vasa Previa. Obstet
Gynecol 2006.
VOL. 107, NO. 4, APRIL 2006 Oyelese and Smulian Placenta Previa, Accreta, and Vasa Previa 933
8. Diagnostic Approach
It is important to make the diagnosis of placenta
accreta prenatally because this allows effective man-agement
planning to minimize morbidity. This diag-nosis
is usually made by ultrasonography or magnetic
resonance imaging (MRI). Placenta accreta should be
suspected in women who have both a placenta previa
and a history of cesarean delivery or other uterine
surgery.41,50 Vigilance is particularly indicated when
the placenta is anterior and overlies the cesarean scar.
Ultrasonography
Several studies have documented the efficacy of
sonography in the diagnosis of placenta accreta.50–52
Comstock,50 in a recent review, described the sono-graphic
features suggestive of placenta accreta. These
include irregularly shaped placental lacunae (vascular
spaces) within the placenta, thinning of the myome-trium
overlying the placenta, loss of the retroplacental
“clear space,” protrusion of the placenta into the
bladder, increased vascularity of the uterine serosa-bladder
interface, and, on Doppler ultrasonography,
turbulent blood flow through the lacunae (Figs. 5, 6).51
In a previous study, Comstock and colleagues51 had
found, at 15–20 weeks of gestation, that the presence
of lacunae in the placenta was the most predictive
sonographic sign of placenta accreta, with a sensitivity
of 79% and a positive predictive value of 92%. These
lacunae may give the placenta a “moth-eaten” or
“Swiss cheese” appearance (Fig. 5). The risk of pla-centa
accreta increases with an increased number of
lacunae.52 Obliteration of the retroplacental “clear
space,” which is the finding most commonly thought
to be associated with placenta accreta, had only a 57%
sensitivity and a false-positive rate of 48.4%.51 After 20
weeks of gestation, the sensitivity of these findings
increased, with values of 93% and 80% for lacunae
and obliteration of the retroplacental clear space,
respectively.51 The investigators found that a sono-graphic
appearance of apparent bulging into the
bladder may occur in cases of placenta accreta with-out
increta or percreta.50 Thus, this finding may not
reliably differentiate between cases in which the
placenta has invaded the bladder and cases in which
it has not.50
Power and color Doppler are often used for the
diagnosis of placenta accreta, demonstrating turbulent
flow through placental lacunae (Fig. 6).53 However, in
the majority of cases, this imaging modality does not
significantly improve the diagnosis over that achieved
by grayscale sonography alone. Thus, in the majority
of clinical situations, Doppler should not be the
primary technique used to diagnose placenta accreta.
A retrospective review of images of first-trimester
sonograms of cases of placenta accreta found that, in
all the cases, the gestational sac was in the lower
uterine segment and that the gestational sac was
abnormally close to the uterine scar, suggesting at-tachment
to the scar.54 This finding in the first trimes-ter,
therefore, in women with a prior cesarean deliv-ery,
should lead to a suspicion of placenta accreta.
Magnetic Resonance Imaging
Several articles have described the use of MRI in the
diagnosis of placenta accreta.55–57 Most were retro-spective,
limited to a few cases, and lacked pathologic
correlation.56 Although most studies have suggested
reasonable diagnostic accuracy of MRI for placenta
accreta, it appears that MRI is no more sensitive than
ultrasonography for diagnosing placenta accreta.50,57
Ultrasonography is readily available in most centers,
whereas MRI is costly and relatively inaccessible.
Therefore, at the present time, sonography is the
primary imaging modality for diagnosing accreta.
However, when there is a posterior placenta accreta,
ultrasonography may be less than adequate, and MRI
Fig. 5. Grayscale sonogram of placenta percreta. Note the
prominent placental lacunae (arrows) giving the lower
uterine segment a “moth-eaten” appearance. The diagnosis
was confirmed at delivery. p, placenta; h, fetal head; b,
bladder.
Oyelese. Placenta Previa, Accreta, and Vasa Previa. Obstet
Gynecol 2006.
934 Oyelese and Smulian Placenta Previa, Accreta, and Vasa Previa OBSTETRICS GYNECOLOGY
9. may be superior to ultrasonography for this specific
indication.50,57
Therapeutic Approach
It is generally accepted that placenta accreta is ideally
treated by total abdominal hysterectomy. In addition,
there is almost universal consensus that the placenta
should be left in place; attempts to detach the placenta
frequently result in massive hemorrhage. However,
the physician should be aware that focal placenta
accreta may exist that may not require such aggres-sive
therapy. It is better to perform surgery for
placenta accreta under elective, controlled conditions
rather than as an emergency without adequate prep-aration.
Therefore, scheduled delivery at 36–37
weeks of gestation, after documentation of fetal lung
maturity by amniocentesis, seems reasonable. If am-niocentesis
fails to document fetal lung maturity, the
patient, if stable, should be delivered by cesarean by
38 weeks, or earlier, if she bleeds or goes into labor. A
study comparing emergency with elective peripartum
hysterectomy found that women in the emergency
hysterectomy group had greater intraoperative blood
loss, were more likely to have intraoperative hypoten-sion,
and were more likely to receive blood transfu-sions
than women who had elective obstetric hyster-ectomies.
58
Prevention of complications ideally requires a
multidisciplinary team approach. The patient
should be counseled preoperatively about the need
for hysterectomy and the likely requirement for
transfusion of blood and blood products.59 Al-though
scheduled delivery should be the goal,
contingency plans should be made for possible
emergent delivery if necessary. It is important that
delivery be performed by an experienced obstetric
surgeon, with other surgical specialties such as
urology and gynecological oncology readily avail-able
if required. It is not unusual for the lower
uterine segment to be markedly enlarged and vas-cular,
with distortion of normal anatomy and tissue
planes. Preoperative cystoscopy with placement of
ureteric stents may help prevent urinary tract in-jury.
At our center, we usually insert a 3-way Foley
catheter in the bladder via the urethra, allowing
simultaneous irrigation and drainage of the bladder
during the surgery. In instances where tissue plane
identification is difficult because of adhesions or the
invasive placenta, we have the option of distending
the bladder to aid in its identification and then
emptying it to avoid injury while we proceed with
surgery. Use of a vertical skin incision facilitates
adequate exposure. Generally, a vertical incision in
the uterus allows delivery of the infant while avoid-ing
the placenta. There should be no attempt to
detach the placenta from the uterine wall. The
edges of the uterine incision should be oversewn for
hemostasis, after which a total abdominal hysterec-tomy
should be performed. Although some have
advocated supracervical hysterectomy, in the ma-jority
of cases the lower uterine segment is involved
in the morbid adhesion and therefore needs to be
removed.
It is important to minimize blood loss and ensure
that the blood lost is replaced promptly and adequate-ly.
59 Because of the large volumes of blood that are
typically lost, as well as the replacement with packed
red blood cells, these patients are at risk of dissemi-nated
intravascular coagulopathy. Thus, coagulation
factors should be replaced liberally, adequately, and
quickly. Donor-directed blood transfusions and use of
a blood cell saver may reduce the need for transfusion
with blood from another donor.59 Some centers use
acute normovolemic hemodilution to reduce the need
for blood.41 The role of experienced anesthesiology
personnel who are skilled in obstetric anesthesia
cannot be overemphasized, and they should be in-volved
in preoperative assessment of the patient.59
Regional anesthesia has been shown to be safe in the
management of placenta accreta.
Balloon Catheter Occlusion and Embolization
Balloon catheter occlusion or embolization of the
pelvic vessels decreases blood flow to the uterus and
potentially leads to reduced blood loss and makes it
possible to perform surgery under easier, more con-trolled
circumstances, with less profuse hemor-rhage.
60–62 Two different approaches have been de-scribed.
In one approach, several investigators
preoperatively place occlusive balloon catheters in
the internal iliac arteries. These catheters are inflated
after delivery of the fetus, allowing surgery under
controlled circumstances, and are deflated after the
surgery. In the other major approach, catheters with
or without balloons are placed preoperatively in the
internal iliac arteries, and embolization of the vessels
is performed after delivery of the fetus and before
hysterectomy. These studies are for the most part
retrospective and limited by small numbers. Levine
and colleagues62 did not find that pelvic vessel embo-lization
improved surgical outcomes when compared
with women who did not have embolization. Kidney
et al61 reported 5 cases of placenta accreta where
prophylactic hypogastric artery balloon catheter em-bolization
was performed after the cesarean delivery
and before hysterectomy. These authors suggested
VOL. 107, NO. 4, APRIL 2006 Oyelese and Smulian Placenta Previa, Accreta, and Vasa Previa 935
10. that embolization was both effective and safe, but
there was no comparison group. A study by Alvarez
and colleagues60 found that elective embolization
resulted in improved outcomes when compared with
embolizations done emergently. At our center, the pa-tient
has occlusive balloon catheters placed in the ante-rior
branch of the internal iliac arteries before surgery.
After delivery of the infant, the balloons are inflated and
embolization is performed before hysterectomy.
Management Without Hysterectomy
Hysterectomy removes any prospect of future fer-tility
and is associated with considerable morbidity
and potential mortality, including that of surgical
injury, given the distorted tissue planes and the
need to operate in what is sometimes a blood-filled
field. To minimize these complications and pre-serve
fertility, recently there has been some interest
in attempting to conserve the uterus and avoid
hysterectomy.63– 66 Generally, in these cases, the
placenta is left in situ, with no attempt at removal.
Adjunctive procedures include embolization of the
internal iliac vessels, treatment with methotrexate,
resection of the affected segment of the uterus, use
of uterine compression sutures, and oversewing of
the placental bed.63– 66 A problem with several of
these reports is that varying criteria are used for the
diagnosis of placenta accreta, and in most cases,
there was no pathologic confirmation of the diag-nosis.
56,65 Thus, it is possible that some cases did not
have a placenta accreta. A further problem is that,
in several cases, the patients developed severe
hemorrhage necessitating either emergency surgi-cal
intervention or embolization.64,67 It is preferable
to deal with massive hemorrhage in a controlled
setting with all resources available, rather than to
have to deal with it as an emergency at an unpre-dictable
time. Conservative management also car-ries
the risk of intrauterine infection, which could
potentially be life threatening.
Nevertheless, conservative management may
have a limited role in carefully selected patients who
desire future fertility. It has been suggested that
delayed surgery leads to a less vascular surgical field
and may have potential benefits when there is bladder
involvement.42 Women offered conservative manage-ment
should be counseled extensively that the out-comes
are unpredictable and that there is a significant
risk of serious complications including death. It is
possible that, in the future, conservative management
will assume a more important role in the management
of placenta accreta. However, at the present time, this
option cannot be recommended as a mainstay of
therapy. Further studies are required to identify
women who may be ideal candidates for conservative
management and to define the risks associated with
this approach.
Methotrexate Therapy
Methotrexate, a folate antagonist, has been proposed
as a conservative treatment for placenta accreta.63
Methotrexate acts primarily against rapidly dividing
cells and therefore is effective against proliferating
trophoblast. However, more recently, others have
argued that, after delivery of the fetus, the placenta is
no longer dividing and therefore methotrexate is of
no value. Mussalli and colleagues68 reported 3 cases of
suspected placenta accreta managed conservatively
with methotrexate therapy. In 2 of the 3 cases, uterine
conservation was possible. However, the use of meth-otrexate
did not prevent delayed hemorrhage. At
least 2 reports have documented failed conservative
treatment of placenta accreta with methotrexate.64,67
No large studies have compared methotrexate with
no methotrexate in the treatment of placenta accreta.
Therefore, at the present time, there are no convinc-ing
data for or against the use of methotrexate for
accreta.
Bladder Involvement
The bladder is the most frequently involved extra-uterine
organ when there is a placenta percreta.
Bladder involvement is associated with significant
morbidity.69–72 Washecka and Behling73 carried out a
meta-analysis of 54 reported cases of placenta per-creta
with bladder involvement. They found that
predelivery hematuria was only present in 17 cases
(31%). Although cystoscopy was performed in 12 of
these patients, in no case did it help in making the
diagnosis. In 33% of the cases, the diagnosis was made
prenatally by ultrasonography or MRI. The maternal
morbidity was high, with 39 urologic complications.
These included laceration of the bladder (26%), uri-nary
fistula (13%), gross hematuria (9%), ureteral
transaction (6%), and small capacity bladder (4%).
Partial cystectomy was necessary in 24 cases (44%).
There were 3 maternal deaths (5.6%) and 14 fetal
deaths (25.9%).
Management of the patient with bladder involve-ment
requires careful perioperative planning and should
involve a urogynecologist, a urologist, and/or a gyneco-logical
oncologist. Preoperative cystoscopy and place-ment
of ureteric stents may aid in identification of the
ureters, leading to a reduced risk of damage or injury to
these structures. Involvement of the bladder may re-quire
resection of the bladder and, occasionally, of the
936 Oyelese and Smulian Placenta Previa, Accreta, and Vasa Previa OBSTETRICS GYNECOLOGY
11. ureters. Intentional cystotomy may be helpful in identi-fying
the extent of involvement and location of the
ureters (Bakri YN, Sundin T. Cystotomy for placenta
previa percreta with bladder invasion [letter]. Urology
1992;40:580).
VASA PREVIA
Definition
Vasa previa refers to fetal vessels running through the
membranes over the cervix and under the fetal pre-senting
part, unprotected by placenta or umbilical
cord.74 The condition usually results either from a
velamentous insertion of the cord into the membranes
rather than the placenta (Fig. 7) or from vessels
running between lobes of a placenta with one or more
accessory lobes.74,75
Clinical Importance
Vasa previa is a condition which, undiagnosed, is
associated with a perinatal mortality of approximately
60%.76 The condition is important because, when the
membranes rupture, spontaneously or artificially, the
fetal vessels running through the membranes have a
high risk of concomitant rupture, frequently resulting
in fetal exsanguination and death.74,77 Because the
fetal blood volume is only about 80–100 mL/kg, loss
of even small amounts of blood could prove disas-trous
to the fetus. Pressure on the unprotected vessels
by the presenting part could lead to fetal asphyxia and
death.
Fig. 6. Color Doppler of placenta percreta (same patient as
in Fig. 5). Note the vascularity of the bladder wall (b). At
surgery, the bladder wall was involved. p, placenta; f, fetus.
Oyelese. Placenta Previa, Accreta, and Vasa Previa. Obstet
Gynecol 2006.
Fig. 7. Placenta after delivery showing vasa previa. Vessels
are seen running unprotected through the membranes. p,
placenta
Oyelese. Placenta Previa, Accreta, and Vasa Previa. Obstet
Gynecol 2006.
Fig. 8. Vasa previa. Transvaginal ultrasonography with
color Doppler showing the fetal vessels running over
internal os of the cervix (arrow). h, fetal head.
Oyelese. Placenta Previa, Accreta, and Vasa Previa. Obstet
Gynecol 2006.
VOL. 107, NO. 4, APRIL 2006 Oyelese and Smulian Placenta Previa, Accreta, and Vasa Previa 937
12. Incidence and Risk Factors
The estimated incidence of vasa previa is approxi-mately
1 in 2,500 deliveries.74 Risk factors for the
condition include a second-trimester low-lying pla-centa
(even if the “low-lying” placenta or placenta
previa resolves in the third trimester),78 pregnancies in
which the placenta has accessory lobes, multiple
pregnancies, and pregnancies resulting from in vitro
fertilization.79
Pathophysiology
The pathophysiology of vasa previa was discussed
earlier under the pathophysiology of placenta previa.
Diagnostic Approach
Vasa previa is most commonly diagnosed when rup-ture
of the membranes is accompanied by vaginal
bleeding and fetal distress or death. The diagnosis is
often confirmed only when the placenta is inspected
after delivery. Consequently, until recently, most ob-stetricians
have been resigned to the belief that the
death of a fetus from a ruptured vasa previa is
unavoidable. Very rarely (and fortuitously), vasa pre-via
may be diagnosed during a digital cervical exam-ination
when the examiner’s fingers palpate fetal
vessels running through the membranes. Use of an
amnioscope in this situation may allow direct visual-ization
of the vessels. When bleeding occurs in preg-nancy
or during labor, a test to determine the pres-ence
of fetal blood cells in the vaginal blood, such as
the Apt test or Kleihauer-Bettke test, may aid in the
diagnosis of vasa previa.74 However, when acute
bleeding occurs from a ruptured vasa previa, emer-gent
delivery is frequently indicated, and there may
be no time to test for fetal blood cells. Whenever
bleeding accompanies rupture of the membranes in
labor, especially if there are associated fetal heart rate
decelerations, fetal bradycardia, or a sinusoidal fetal
heart rate pattern, the obstetrician should have a high
index of suspicion for a ruptured vasa previa.80,81 In
these situations, most frequently, immediate delivery
by cesarean is indicated. Even when the neonate has
lost considerable blood, immediate transfusion may
be lifesaving.82
Numerous reports and studies have demonstrated
that vasa previa can be diagnosed prenatally with
ultrasonography.75,83 The grayscale sonographic ap-pearance
of vasa previa is of linear echolucent struc-tures
overlying the cervix.83 When color or power
Doppler is used, flow can be demonstrated through
these vessels, and pulsed Doppler will demonstrate a
fetal umbilical arterial or venous waveform (Fig. 8). It
is important to differentiate a vasa previa from a funic
presentation. In the latter, the vessels will move when
the patient changes position, especially when the
patient is placed in the Trendelenburg position. Con-versely,
the vessels do not move when there is a vasa
previa. The majority of prenatally diagnosed cases of
vasa previa are detected incidentally in women who
have transvaginal sonography for evaluation of low-lying
placentas. However, studies have demonstrated
that the majority of cases of vasa previa in asymptom-atic
women can be diagnosed prenatally through a
policy of routinely evaluating the placental cord in-sertion
when an ultrasound examination is performed
and considering vaginal sonography with color Dopp-ler
if the placental cord insertion cannot be identified
or if there is a low-lying placenta or a suspected
succenturiate placental lobe.75,83,84
At least 4 studies have prospectively evaluated
the use of ultrasonography in routine screening for
vasa previa in large populations.75,83–85 These studies
found that sonographic identification of placental
cord insertion was accurate and sensitive and added
little or no extra time to the duration of the obstetric
sonographic examination. In all the prenatally diag-nosed
cases, the neonatal survival of infants without
congenital malformations was 100%.
Therapeutic Approach
Good outcomes with vasa previa depend on prenatal
diagnosis and delivery by cesarean before rupture of
the membranes. We previously carried out a multi-center
retrospective study of 155 cases of vasa previa,
evaluating the impact of prenatal diagnosis on out-comes
of pregnancies complicated by vasa previa.76
In 61 of these cases, the diagnosis was made prena-tally.
We determined that, in the absence of prenatal
diagnosis, the perinatal mortality was 56%, whereas
97% of fetuses survived when the diagnosis was made
prenatally.76 Among survivors, when the diagnosis
was not made prenatally, the median 1- and 5-minute
Apgar scores were only 1 and 4, respectively, com-pared
with 8 and 9, respectively, when the condition
was diagnosed prenatally.76 Two thirds of women had
a low-lying placenta in the second trimester, whereas,
by the time of delivery, only one third of these (20%)
had a low-lying placenta. In one third of cases, the
placenta was bi-lobed. The main predictors of sur-vival
were prenatal diagnosis and gestational age at
delivery.
Consideration should be given to hospitalization
at about 30–32 weeks and administration of cortico-steroids
to promote fetal lung maturation. Hospital-ization
allows proximity to the operating room for
938 Oyelese and Smulian Placenta Previa, Accreta, and Vasa Previa OBSTETRICS GYNECOLOGY
13. emergent cesarean delivery if the membranes rup-ture.
Approximately 10% of women will rupture their
membranes before the onset of labor, so this risk is
significant. However, in selected asymptomatic pa-tients,
there may be a role for outpatient manage-ment,
especially if the patient has no signs of labor or
uterine activity and has a long-closed cervix on
transvaginal sonography. Delivery should occur at an
institution where there are adequate facilities for
neonatal resuscitation that might include emergent
blood transfusions. It is preferable that, before sur-gery,
the surgeon is aware of the position of the fetal
vessels and plans the incision to avoid lacerating these
vessels. We have previously described the use of
3-dimensional ultrasonography with power Doppler
angiography to map out the fetal vessels and thereby
make the optimal uterine incision.86,87 It is desirable to
deliver the fetus en caul, with intact membranes,
avoiding incising the membranes.
A gestational age of between 35 and 36 weeks is
the optimal age for cesarean delivery in women with
vasa previa, with a reasonable tradeoff between pre-maturity
with the risk of respiratory distress syndrome
and that of rupture of the membranes with the risk of
fetal exsanguination and death.76 Although amniocen-tesis
is generally recommended before elective cesar-ean
delivery before 39 weeks in most conditions, in
vasa previa, if the membranes rupture, the risks of
fetal death or adverse outcome are so severe that we
feel it is justifiable to deliver these women by 36
weeks without amniocentesis documentation of lung
maturity
We can think of no other condition in which
prenatal diagnosis and appropriate perinatal manage-ment
makes such a dramatic impact on the difference
between survival and death for an otherwise healthy
infant. Thus, especially because it adds little in terms
of time to the routine obstetric sonogram, it is our
opinion that screening for vasa previa should be
routine.
CONCLUSION
Achieving optimal outcomes with placenta previa,
placenta accreta, and vasa previa depends on prenatal
diagnosis and appropriate management at the time of
delivery. Advances in ultrasonography have made it
possible to diagnose all 3 conditions with reasonable
accuracy, which allows appropriate management
planning. Women with these conditions should be
considered at high risk and should be delivered at
institutions with skilled personnel, adequate blood
transfusion facilities, and good neonatal resources.
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