6.Normal Labor,Delivery And The Puerperium

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6.Normal Labor,Delivery And The Puerperium

  1. 1. Normal Labor ,Delivery and the Puerperium Department of Obstetrics and Gynecology , The general hospital of Tian Jin medical university Zhang Xuhong
  2. 2. Four major factors determined labor and delivery <ul><li>The power </li></ul><ul><li>The pelvis </li></ul><ul><li>The fetus </li></ul><ul><li>Psychological factors </li></ul>
  3. 3. The power : The characteristics of myometrial muscle are unique which compared with skeletal muscle <ul><li>The degree of shortening of smooth muscle cells with contractions may be greater </li></ul><ul><li>Forces can be exerted in smooth muscles in any direction </li></ul><ul><li>Smooth muscle is organized in different manners </li></ul><ul><li>Multidirectional force generation permits versatility in expulsive force directionality </li></ul>
  4. 4. An important ancillary force in expulsion of the fetus is that produced by increased maternal intra-abdominal pressure.
  5. 5. Pelvic Planes <ul><li>The pelvis is divided into 3 planes: </li></ul><ul><li>The plane of the pelvic inlet: The fetal head enters the pelvis through this plane in the transverse position. </li></ul><ul><li>The midplane: is the most important. Because most instances of arrest of descent occur at this level. </li></ul><ul><li>The plane of the pelvic outlet: is formed by two triangular planes with a commom base at the level of the ischial tuberosities.This plane is the site of a low pelvic arrest. </li></ul>
  6. 6. Main pelvic diameters <ul><li>Pelvic inlet : anteroposterior; transvers;left and right oblique </li></ul><ul><li>Midplane : bispinous diameter </li></ul><ul><li>Pelvic outlet : bituberous diameter; posterior sagittle diameter; subpubic angle </li></ul>
  7. 7. Cervical Effacement <ul><li>Prior to the onset of parturition </li></ul><ul><li>Become soft and thin frequently </li></ul><ul><li>Take up into the lower uterine segment </li></ul><ul><li>Mucous plug released </li></ul><ul><li>Bloody show </li></ul>
  8. 11. Psychological factors :recent research has shown that it act an important role in labor.because of fearing labor pain,a considerable number of women suffered dystocia.
  9. 12. Labor <ul><li>Is a physiologic process that permits a series of extensive physiologic changes in the mother. </li></ul><ul><li>Allow for the delivery of the fetus through the birth canal. </li></ul><ul><li>It is defined as progressive cervical effacement and dilatation, resulting from the regular uterine contractions. </li></ul>
  10. 13. What is the regular contraction ? <ul><li>The regular contraction : Occurs at least every 5 minutes and last 30 to 60 seconds,with greater intensity . </li></ul><ul><li>The contractions appear to arise in the upper coronal regions of the uterus, </li></ul><ul><li>then near the fundus,spread to the lower pole progressively. </li></ul>
  11. 14. Preparation for labor <ul><li>Lightening : two or more weeks before labor,fetal head in most primigravid women settles into the brim of the pelvis. </li></ul><ul><li>False labor : during last 4~8 weeks of pregnancy,the uterus undergoes irregular contractions. </li></ul><ul><li>Cervical effacement . </li></ul><ul><li>These are not associated with progressive cervical dilatation. </li></ul>
  12. 15. Engagement <ul><li>Engagement occurs when the widest diameter of the fetal presenting part has passed through the pelvic inlet. (in cephalic presentations, the widest diameter is occipitofrontal diameter ) </li></ul><ul><li>When the fetal head has engaged, that means the bony presenting part is at the level of the ischial spine. </li></ul>
  13. 16. <ul><li>The station of the presenting part in the pelvic canal is defined as its level above or below the plane of the ischial spine. </li></ul><ul><li>The level of the ischial spines assigned as “zero”(S -0 ), each centimeter above or below this level is given a minus or plus designation(S -1 ; S +2… … ). </li></ul>
  14. 18. <ul><li>When the presenting is out of the pelvis, it is freely movable, it is considered to be floating . </li></ul><ul><li>When it has passed through the plane of the inlet ,but is not yet engaged, it is considered to be dipping . </li></ul>
  15. 19. Labor is divided into three stages <ul><li>First stage : From the onset of regular contraction of uterine to complete dilation of the cervix.(10cm) </li></ul><ul><li>It consists of two phases: The latent phase : onset of true labor to cervical effacement and early dilation.(3cm); The active phase : the cervical dilation is more rapid occurs.(4cm~10cm). </li></ul><ul><li>Second stage : From complete dilation of the cervix to the birth of the baby. </li></ul>
  16. 20. Third stage : is from the birth of the baby to the delivery of placenta and membrances .
  17. 21. Length of stages 5~15min 5~15min Duration of third stage 5~30min 1~2hours Duration of second stage 1.5cm/hour 1.2cm/hour Rate of cervical dilatation during active phase 6~8 hours 11~12 hours Duration of the first stage multipara primipara
  18. 22. Management of first stage <ul><li>Drawing picture of stages of labor(partogram). </li></ul><ul><li>Record maternal pulse rate,BP,respiratory rate,temperature ,urine output every 1~2 hours; descent of the fetal head. </li></ul><ul><li>Auscultate the fetal heart rate(FHR) every 30 minutes </li></ul><ul><li>Monitor the uterine contraction every 30 minutes for frequency,duration,intensity </li></ul><ul><li>Do vaginal examination every 2 hours to determine the progress of labor. </li></ul><ul><li>Amniotomy: amniotic fluid; meconium? </li></ul><ul><li>augment uterine contractility </li></ul>
  19. 23. Second stage of labor----Descent of the fetal head T he mechanism of the labor : six-movements of the baby enable it to adapt to the maternal pelvis. They are: <ul><li>Descent </li></ul><ul><li>Flexion </li></ul><ul><li>Internal rotation </li></ul><ul><li>Extension </li></ul><ul><li>External rotation </li></ul><ul><li>Expulsion </li></ul>
  20. 24. Descent <ul><li>: Is brought by </li></ul><ul><li>※ The force of the uterine contractions </li></ul><ul><li>※ Maternal bearing down(Valsalva) efforts </li></ul><ul><li>※ Gravity if the patient is upright </li></ul>
  21. 25. Flexion <ul><li>Partial flexion exists before labor. </li></ul><ul><li>Further flexion is caused by: </li></ul><ul><li>(1)resistance from the cervix </li></ul><ul><li>(2)walls of the pelvis </li></ul><ul><li>(3)pelvic floor </li></ul><ul><li>It can change the presenting diameter from the occipitofrontal to the smaller suboccipitobregmatic. </li></ul>
  22. 26. Internal Rotation <ul><li>Transverse or oblique diameter rotates so that the occiput turns anteriorly toward the symphysis pubis. </li></ul><ul><li>It occurs as the fetal head meets the muscular sling of the pelvic floor. </li></ul><ul><li>The presenting part reach the lever of the ischial spines. </li></ul>
  23. 27. Extension <ul><li>The vaginal outlet is directed upward and forward </li></ul><ul><li>Bulge of the perinium </li></ul><ul><li>Crowning: the largest diameter of the fetal head is encircled by the vulvar ring. </li></ul><ul><li>Episiotomy: mediolateral and midline episiotomy. To reduce perineal resistance and avoid tearing and stretching of perineal tissues. </li></ul>
  24. 28. External Rotation <ul><li>The delivered head returns to its origional position at the time of engagement(restitution) </li></ul><ul><li>Shoulders undergo an internal rotation to anteroposterior position within the pelvis </li></ul>
  25. 29. Expulsion <ul><li>Anterior shoulder delivers, followed by the posterior shoulder and body of the child </li></ul>
  26. 31. Clinical management of second stage <ul><li>To encourage the patient to hold her breath and to bearing –down with each contractions. </li></ul><ul><li>Monitor the fetal heart rate every 5 minutes. </li></ul><ul><li>Vaginal examination every 30 minutes. </li></ul><ul><li>After delivery, the cord is clamped and cut within 15~20 seconds. Delayed cord clamping can result in hyperbilirubinemia as additional blood is transferred to the newborn infant. </li></ul>
  27. 32. Clinical management of third stage <ul><li>After the baby’s delivery,to inspect the cervix and vagina for laceration and surginal repair performed if necessary. </li></ul><ul><li>To add 20 units of oxytocin to the intravenous infusion to enforce the contractions to reduce uterine bleeding. </li></ul><ul><li>Separation of the placenta occurs within 2~10minutes </li></ul>
  28. 33. Signs of placental separation <ul><li>A fresh show of blood from the vagina. </li></ul><ul><li>The umbilical cord lengthens outside the vagina natually. </li></ul><ul><li>The fundus of the uterus rises up. </li></ul><ul><li>The uterus becomes firm and globular. </li></ul>
  29. 34. Perineal laceration classified as: <ul><li>First degree : a laceration involving the vaginal epithelium or perineal-skin. </li></ul><ul><li>Second degree : a laceration extending into the subepithelial tissues of the vagina or perineum with or without involvement of the muscles of the perineal. </li></ul><ul><li>Third degree : a laceration involving the anal sphincter. </li></ul><ul><li>Fourth degree : a laceration involving the rectal mucosa. </li></ul>
  30. 36. Puerperium <ul><li>The puerperium : after delivery of the baby and placenta to approximately 6 weeks postpartum.During the puerperium ,the reproductive organs and maternal physiology return to the prepregnancy state. </li></ul><ul><li>In women who do not nurse, menstrual flow will return by 6~8 weeks. Ovulation may not occur for several months. </li></ul>
  31. 37. lochia <ul><li>First few days after delivery, the uterine discharge is red.---- lochia rubra </li></ul><ul><li>After 3~4 days, the lochia becomes paler.--- lochia serosa </li></ul><ul><li>By tenth day, it becomes a white or yellow-white color.---- lochia alba . </li></ul><ul><li>Complete involution of the uterus(about 42 days). </li></ul>
  32. 38. Lactation <ul><li>Two events are instrumental in initiating lactation: (1) the drop in placental hormones (particularly estrogen)allows lactation to occur, (2)Sucking stimulate the release of prolactin and oxytocin. Sucking is thought important for milk production and the ejection. </li></ul><ul><li>The second day after delivery, colostrum is secreted. </li></ul><ul><li>After about 3~6 days, the colostrum is replaced by mature milk. </li></ul>
  33. 39. Induction and Augmentation of labor <ul><li>The indications and contraindications for induction and augmentation of labor . (text book P162). </li></ul><ul><li>Bishop Score (cervix position, consistency, effacement, dilatation,fetal head station) to assess likelihood of successful induction of labor . If the score >6,the induction may be successful. </li></ul>
  34. 40. Several principles about oxytocin used should be note: <ul><li>Oxytocin must be given intravenously. </li></ul><ul><li>A dilute infusion must be used. 5%Glucose 500ml + oxytocin 2.5U iv. </li></ul><ul><li>The drug is best infused with calibrated infusion pump. </li></ul><ul><li>The induction of labor should not exceed 72 hours. </li></ul><ul><li>If adequented labor is estabilished, the infusion rate and the concentration may be reduced. </li></ul>
  35. 41. Complications of induction <ul><li>Hyperstimulation: case fetal distress from ischemia </li></ul><ul><li>Rupture of the uterus. </li></ul><ul><li>Antidiuretic effect: coma. </li></ul><ul><li>Uterine muscle fatigue,postdelivery uterine atony : to increase the risk of postpartum hemorrhage. </li></ul>
  36. 42. thanks! thank!

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