Labor, Delivery & Changes after Birth

1. Labor, Delivery & Changes after Birth Module B – Part II

2. Objectives • Differentiate between the stages of labor and delivery and list the significant complications that can occur during each. • List and differentiate between the abnormal situations that can occur during the gestational period and state how they may impact delivery and post-uterine life. • Identify and describe the factors that cause changes in cardiopulmonary anatomy and physiology during the first minutes of post-uterine life.

4. Maternal History • Gravida – Total number of pregnancies (including therapeutic and spontaneous abortions). • Primigravida (first pregnancy) • Multigravida (more than one pregnancy) • Parity (Para) – Total number of live born (delivered past 20 weeks). • The condition of having carried a pregnancy to a point of viability regardless of outcome.

5. Maternal History • Spontaneous Abortion (SAb) • Therapeutic Abortion (TAb) • Examples: • Gravida 1, Para 0 • Gravida 1, Para 1 • Gravida 1, Para 2 • Gravida 1, Para 3 • Gravida 5, Para 4, SAb 1

6. Parturition • Parturition: The process of giving birth. • 5 events to the birthing process • Rupture of membranes. • Dilation of Cervix. • Contraction of the uterus. • Separation of the placenta. • Shrinking of the uterus.

7. Labor • Stage I: Onset of regular contractions to full dilation and effacement of the cervix. • Three phases: Early, Active, Transition. • Stage II: Delivery of the fetus. • Stage III: Delivery of placenta. • Recovery Stage: Shrinkage of uterus and return to normal homeostasis.

8. False Labor • False labor • Contractions are called Braxton-Hicks. • Rhythmic and fairly mild compared to true contractions.

9. Stage I of Labor • Effacement & dilation begins at the first contraction. • Cervix stretches and thins (effacement). • Widening of the cervix (dilation). • Effacement is measured as a %. • 100% effacement means the cervix is imperceptible against the uterine wall. • Dilation is measured in centimeters. • Full Dilation is 10 cm.

10. Stage II of Labor • Delivery of the fetus • Uterus differentiates into a thick muscular upper portion and a thin lower section. • The descent of the fetus is aided by contraction of the abdominal muscles and diaphragm. • 95% of deliveries occur in the head – down or vertex position. • Head turns to a face-down position. • Umbilical Cord is clamped.

11. Vertex Position

12. Stage III of Labor • Expulsion of the placenta. • 5 - 45 minutes • After delivery of the fetus, the uterus continues to contract, tearing the placenta from its walls. • May be facilitated with breast feeding and the secretion of oxytocin. • Increase uterine contractions.

13. Premature Labor • Incidence of premature labor. • 40% in high risk patients. • Incidence of premature delivery. • 20% in high risk patients. • Tocolysis • Process of stopping labor. • Beta sympathomimetic (adrenergic) drugs • Relax smooth muscle in uterine wall • Terbutaline & Ritodrine • Magnesium Sulfate

14. Tocolysis • Indications for Tocolysis • Baby must be between 20 – 36 weeks gestation OR Placenta Previa is present. • True Labor (3 contractions in 20 minutes). • Cervix cannot be dilated more than 4 cm & effaced more than 50%. • Intact amniotic membranes. • No fetal distress. • Informed consent by the mother.

15. Dystocia • Difficult Labor. • Stage I & II exceed 20 hours. • Stage II exceeds 2 hours in primigravidas and 1 hour in multigravidas. • As length of labor increases , morbidity and mortality increase for three main reasons: • Abruptio placenta (premature separation of placenta from uterine wall). • Compression of the umbilical cord. • Risk of infection increases after membrane rupture.

16. Causes of Dystocia • Uterine dysfunction. • Abnormal fetal presentation. • Excessive fetal size. • Hydrocephalus. • Abnormality in size or shape of the birth canal.

17. Fetal Presentations • Any position other than vertex. • Complete Breech • Feet, legs and buttocks all present together • Incomplete Breech • Footling • Frank Breech • Buttocks is the presenting part • Transverse lie • Other presentations • Brow, face, shoulder

18. Types of Breech Deliveries COMPLETE FOOTLING FRANK

19. Other Delivery Presentations FACE BROW

20. Transverse Lie • Usually requires C-Section

21. Fetal Skull • The fetal skull is not a solid structure as in an adult. • Several bony plates separated by sutures. • During delivery, the plates overlap, decreasing the size of the fetal skull. • In face/brow presentations the plates cannot overlap & the head must pass through at full size – severe facial edema occurs.

23. Problems with the Umbilical Cord • Prolapsed Cord • Umbilical cord passes through the cervix into the birth canal ahead of the presenting part • Common in breech presentations & multiple births • Occult Prolapse • Compression of the cord in the uterus where the cord is not visible. • Both type can lead to asphyxia

24. Placental Abnormalities • The embryoblast normally attaches itself near the upper portion of the uterine cavity. • If implantation occurs in the lower portion of the uterus, it is called placenta previa. • Low implantation – does not cover cervical opening. • Partial placenta previa. • Total placenta previa.

25. Types of Placenta Previa Partial

26. Abruptio Placentae • Abruptio Placentae – is premature separation of a normally placed placenta from the uterine wall. • Usually causes labor to begin. • Maternal mortality is 2-10%. • Fetal mortality approaches 50%. • Mortality rates are attributed to blood loss. • Most common cause is maternal hypertension (preeclampsia).

27. Abruptio Placentae • Placental separation can be partial or complete • If no bleeding is seen • Concealed hemorrhage • Bleeding from the vagina • Apparent hemorrhage • Maternal hypovolemic shock

28. Cesarean Delivery

29. Cesarean Delivery • aka C-section • Indications: • Prior C-section • Breech presentation • Fetal Distress • Complications: • Cutting of placenta, cord or fetus. • TTN often occurs (failure to adequately clear lung fluid.

30. Multiple Gestations • Twins: 1 in 99 births • Other multiples more rare: • In 2000, 6,742 triplets, 506 quadruplets, 77 quintuplets or more. • Van Houten sextuplets • Born on 3 different days (1/7, 1/16, & 1/17/2004) • All doing well in Grand Rapids • Higher risk to mother. • Higher incidence of premature labor. • 2nd twin more compromised. • Boys worse than girls.

31. Adaptation to Extrauterine Life • Fetal breathing movements actually occur in utero. • As early as week 18; usually within last 10 weeks. • Multiple “reasons” for initiation of the first breath: • Asphyxia: Increased PaCO2, decreased PaO2, and decreased pH all lead to stimulation of chemoreceptors and a gasp. • Recoil of thorax. • Environmental changes: • Initiation of the cry reflex caused by entering a cold, loud and bright environment. • Tactile stimulation.

32. The First Breath • Initial pressure necessary to overcome ST can be as high as –100 cm H20. • Pressure decreases with each succeeding breath as FRC is established. • As the alveoli deflate, surfactant prevents the alveoli from collapsing. • Each breath requires less energy and becomes less difficult.

33. First Breaths Egan Fig. 7-6 p. 145

34. Changes in Circulation • Umbilical Cord is clamped. • Blood flow to placenta is stopped and blood perfuses the lower extremities. • High vascular resistance develops and the high pressure increases back to the left side of the heart. • This helps to close the foramen ovale.

35. Pulmonary and Systemic Vascular Resistance • The first breaths decrease pulmonary vascular resistance (PVR) due to the rise in PaO2. • This decreases the pressure in the pulmonary artery, right heart & pulmonary capillaries. • Complete reversal of heart pressures & vascular resistance has occurred. • PVR is low, SVR is high. • Left Atrial Pressure > Right Atrial Pressure

36. Ductus Arteriosus • During the last few weeks of gestation, smooth muscle develops surrounding the ductus arteriosus. • The ductus has stayed open due to the presence of prostaglandins. • Prostaglandins are inhibited by high PaO2. • With first breath and increasing PaO2 closure of the ductus arteriosus occurs. • If PaO2 should fall, the ductus arteriosus may reopen. This is called a Patent Ductus Arteriosus (PDA).

37. Ductus Venous & Umbilical Vein • With the umbilical cord clamped, blood no longer flows through the umbilical vein, arteries and ductus venosus. • These vessels constrict and become ligaments.