Placental Abnormalities 1. Placenta - Physiology and function A. Fetus entirely dependent on placenta until birth. B. Maternal and fetal blood kept separate by placental barrier. C. Protects the infant from infection and harmful substances. D. Acts as endocrine organ - makes hormones to maintain pregnancy. E. Made of 12-20 cotyledons. F. Fetal blood transported to placenta via two umbilical arteries.
Placental Abnormalities (con’t) G. Umbilical arteries get smaller and become arterioles then villi. H. Villi suspended in pools of maternal blood in the lacunae. I. Fetal blood returns to fetus via umbilical vein.
Abruptio Placenta 1.Definition - Separation of the normally situated placenta from its uterine site of implantation after 20 weeks gestation, but before delivery of the placenta.
Abruptio Placenta (con’t) 2. Placental Grades : A. Grade 0 - Patient asymptomatic.Small retroperitoneal clot seen after delivery. B. Grade 1 - Vaginal bleeding, may have abdominal tenderness or slight uterine tetany,mom and baby not in distress. C. Grade 2 - Uterine tenderness, tetany with or without evidence of bleeding, baby shows signs of distress. D. Grade 3 - Uterine tetany,severe bleed- ing may not be visible. Baby is dead. Mom often has coagulopathy.
Abruptio Placenta 3. Incidence - Varies from 1-55 to 1-250 cases. Incidence greater with increasing parity or history of abruption.
Abruptio Placenta (con’t) 4. Etiology - Unknown. Possibly begins with degenerative changes in the small arterioles that supply the intervillous spaces, resulting in thrombosis, degeneration of the decidua, and finally rupture of the vessel. Then tearing and bleeding in the inner layer of the endometrium and decidua basalis. Hematoma forms along with retroperitoneal clot, compresses adjacent placenta, causing local destruction. Further bleeding causes increased pressure behind the placenta which causes further separation.
Abruptio Placenta (con’t) 5. Conditions associated with abruption: A. Hypertension - 5x higher B. Trauma C. Short umbilical cord D. Polyhydramnios E. IV cocaine use F. Uterine anomalies
Abruptio Placenta (con’t) 5. Conditions associated with abruption (con’t) : G. OB history 1. History of spontaneous abortions 2. Premature labor 3. Antepartum hemorrhage 4. Stillbirth or neonatal death 5. 6x greater with parity > 7 6. 30x greater with hx. of abruption 7. Cigarette smoking - decidual necrosis.
Abruptio Placenta (con’t) 6. S/S - Depends on type of abruption A. Mild c/o labor pains, may only have slight uterine irritability. May have no or only small amount of bleeding. B. Severe knife-like pain with board-like abdomen. May/may not see bleeding. C. Uterus could be tender at point of separation or may be generalized over entire abdomen. D. Increased uterine distention - elevated fundal height
Abruptio Placenta (con’t) 6. S/S - (con’t) - E. Bleeding may be minimal or diffuse. Can be port-wine, dark, or bright red. F. Symptoms are determined by amount of blood lost. G. Shock is severe. H. Fetal distress or death.
Abruptio placenta (con’t) 7. Diagnosis - A. Based on hx.,physical exam,lab values B. No analgesia/anesthesia until diagnosis confirmed C.Vaginal bleeding with/without pain D. Increased uterine tone, tenderness E. Shock F. Fetal distress G. U/S for placental localization,position H. Palpation of abdomen, measure fundal height I. Confirm after delivery-inspect placenta.
Abruptio Placenta (con’t) 8. Maternal/ fetal outcome - mortality rate <1%, if undetected until fetal death, mortality rate is 10% A. DIC - 30% B. Renal failure from hypovolemia C. Amniotic fluid embolus D. Uterine rupture E. Postpartum endometritis F. Postpartum hemorrhage
Abruptio Placenta (con’t) 9. Medical management- A. US to R/O placenta previa B. Bedrest (lateral position) C. IV with large bore catheter D. Type and crossmatch, CBC, platelet count, fibrinogen, bleeding time E. Frequent vital signs F. Assess for signs of shock - cold, clammy skin, pale, anxious, thirsty G. Assess FHR and uterine activity H. Mark top of fundus (check to see if rising
Abruptio Placenta (con’t) 9. Medical Management - (con’t) I. Observe for signs of vaginal bleeding J.C/S for fetal distress, maternal blood loss or compromise, coagulopathy, poor labor progress K. Strict I & O L. Amniotomy to assess blood in fluid M. Oxygen per mask N. Avoid episiotomy O. Be aware of postpartum hemorrhage
Placenta Previa 1. Definition - Abnormally implanted placenta placed totally or partially in the lower segment of the uterus, rather than in the fundus. When the cervix begins to dilate and efface the placenta separates, allowing bleeding form the open vessels.
Placenta Previa (con’t) 2. Classifications - A. Complete - Internal os is completely covered by the placenta. B. Partial - a portion of the cervical os is covered by the placenta. C. Marginal - The edge of the placenta extends to the edge of the cervical os.
Placenta Previa (con’t) 3. Incidence - Depends on which trimester pregnancy is in. A. 2nd trimester - 45% in lower uterine segment B. 3rd trimester - 0.5 to 1% in lower uterine segment C. Occurs more often in multips - 80% D. History of previa - 12x more likely E. More common with history of abortions C/S, molar pregnancies, fibroids, uterine surgery.
Placenta Previa (con’t) 4. Etiology - unknown cause A. It is thought that when the embryo is ready to implant and the decidua in the fundus is deficient, it will choose another spot lower in the uterine segment. B. Placentas are larger on the maternal side, cord often has marginal or vellamen- tous insertion. Suggests that the placenta was growing toward more favorable decidua.
Placenta Previa (con’t) 4. Etiology - (con’t) - C. Endometriosis after previous pregnancy. D. Uterine scars - abortions, C/S, molar pregnancy E. Tumors altering contour of uterus. F. Close pregnancy spacing G. Multiparity H. Large placenta- in multiple gestations or erythroblastosis fetalis I. High altitudes J. Male fetus
Placenta Previa (con’t) 1. Painless bright red vaginal bleeding - usually 1st bleeding episode not before 30 wks. 2. Sometimes suspected with oblique or transverse lie. 3. Diagnosed by U/S 4. 80-90% - bleeding occurs without warning 5. Uterus non-tender - no rise in fundal height. 6. Often occurs when sleeping 7. 1 st episode usually scant, each episode more 8. Shock 9. May deliver by C/S if placenta covers cervix
Placenta Previa (con’t) 1. Maternal and fetal outcome- A. Mortality less than 1%, morbidity 20% B. Most will have at least one significant hemorrhage , 25% will go into shock C. Vaginal and cervical lacerations occur more often with vaginal delivery. D. Poor endometrium may contribute to placenta accreta. E. Fetal mortality 20% - prematurity, hypoxia, developmental disorders.
Placenta Previa (con’t) 1. Medical Management - Depends on gestational age and severity of bleed. A. Strict bedrest B. IV - large bore catheter (16 gauge) C. CBC, type & screen, platelet count, fibrinogen, bleeding time D. If HCT less than 30% transfuse E. No pelvic exams F. Adequate hydration, accurate I & O
Placenta Previa (con’t) 1. Medical Management - (con’t) G. Tocolysis for contractions H. No douching or intercourse I. Oxygen per mask J. Serial U/S to check for placental placement, fluid level, fetal growth. K. C/S for large blood loss
Vasa Previa Rare circumstance that may occur with velamentous insertion of the cord where umbilical vessels cross the internal os presenting ahead of the fetus. Requires a C/S.
Velamentous Insertion of the Cord 1% singleton term births. Vessels of cord separate a distance away the margin of the placenta surrounded only by a fold of amnion. If bleeding is seen it should be tested for fetal Hgb - Kleihauer -Betke - fetus may become hypovolemic.
Definition - a rare condition
all or part of placenta adherent
to the myometrium.
The normal spongy layer of decidua
is absent or defective, therefore placntal
villi grows down through the endometrium
into the myometrium
2. Types -
A. Accreta - Villi extends too far into
B. Increta - Villi invade into myometrium
C. Percreta - Villi invade through
myometrium to the serosa layer.
Placenta Accreta (con’t) 3. Incidence - 1-7000 4. Predisposing factors - A. Implantation over a previous C/S scar or other surgical scar in the uterine cavity. B. Previous curretagge C. Prior hx. Of endometritis or other endometrial trauma D. High parity E. Placenta previa sometimes precludes accreta
Placenta Accreta (con’t) 5. S/S - None until delivery A. Depends on depth, site of penetration, number of cotyledons involved. B. If accreta is partial some cotyledons may separate from the uterine wall leaving open, bleeding vessels. The uterus is unable to contract because of the adherent placenta still within the uterine cavity. Profuse hemorrhage. C.If total accreta, tearing occurs when doctor tries to deliver placenta. Uterine inversion may occur.
Placenta Accreta - (con’t) 6. Diagnosis - Attempts to remove placenta reveals placental adherence. 7. Outcome - A. hemorrhage B. Shock C. Hysterectomy D. Uterine inversion
Placenta Accreta (con’t) 8. Treatment - A. Large bore IV catheter B. IV fluids, blood C. Ultrasound D. Type and Screen, CBC, platelet count, fibrinogen, bleeding time E. Accurate I & O F. Assess vital signs G. D & C / hysterectomy
Battledore Placenta Cord inserted at or near the placental margin, rather than in the center. Circumvellate Placenta The fetal surface of the placenta is exposed thorough a ring of chorion and amnion opening around the umbilical cord.
Succenturiate Placenta One or more accessory lobes of the villi have developed. Vessels from the major to the minor lobes are only supported by membrane. This increases the likelihood that the minor lobe(s) are may be retained during the third stage of labor.
Couvelaire Uterus Occurs in severe abruptio placenta when blood collects in the uterine musculature beneath the uterine serosa, into connective tissue of the broad ligaments and even into the peritoneal cavity. Suturing followed by administration of IV oxytocin postpartally usually controls postpartum hemorrhage.