Lecture Notes: Labor and Delivery Process

Introduction

• Parturition: The process of delivering a baby, starting with uterine contractions and ending with the delivery of the placenta.
• Full Term: Labor typically occurs between 37 and 42 weeks of gestation.

Pre-Labor Signs

• Bloody Show: Release of mucus and blood from the cervix.
• Water Breaking: Rupture of the amniotic sac.
• True vs. False Labor: True labor contractions must be distinguished from Braxton Hicks contractions (practice contractions).

Labor Duration

• Generally lasts 12-18 hours for first-time pregnancies.
• Shorter duration for subsequent pregnancies.

Stages of Labor

First Stage: Dilation of the Cervix

Early Phase (Latent Phase)

• Duration: Up to 20 hours.
• Cervical Dilation: From 0 to 6 cm.
• Initial contractions every 5-30 minutes, lasting 30 seconds.
• Regular contractions every 3-5 minutes, lasting over a minute.

Active Phase

• Cervical Dilation: From 6 to 10 cm.
• Intense contractions lasting 60-90 seconds with 30 seconds to 2 minutes of rest.
• Amniotic sac typically ruptures if it hasn't already.

Second Stage: Pushing Stage

• Power: Uterine contractions.
• Passenger: The baby.
• Passage: The birth canal including the pelvis.
• Critical for the baby (especially the head) to navigate through the maternal pelvis.
• Fetal Size: Head size is critical.
• Fetal Attitude: Should be fully flexed.
• Fetal Lie: Ideal position is longitudinal.
• Fetal Presentation: Cephalic (head-first) is most common; vertex presentation is ideal.
• Cardinal Movements: Descent, flexion, internal rotation, extension, restitution, and expulsion.

Third Stage: Delivery of the Placenta

• Uterus contracts to separate placenta from uterine wall.
• Essential to ensure no placental remnants remain.

Fourth Stage (Postpartum)

• Occurs several hours after delivery.
• Major physiological changes: adaptation to blood loss and uterine involution.

Recap

• First Stage: From true labor contractions to full dilation and effacement of the cervix.
• Second Stage: Pushing stage ending with the baby’s birth.
• Third Stage: Ends with placental delivery.