Pregnancy week by week: Labor and Birth

Summary

Key Points

• In the weeks before birth, the body alters hormone production, increasing prostaglandins to soften the cervix and oxytocin to trigger contractions. 0:33
• True labor contractions are rhythmic, painful, and consistently strengthen, causing the uterus to tighten and pull the cervix open. 0:40
• The mucus plug, which sealed the cervix during pregnancy, may be expelled before or during labor. 0:55
• When the amniotic sac ruptures, it is commonly referred to as the water breaking, and can manifest as a trickle or a gush. 1:05
• The cervix begins to open and thin, a process called dilation and effacement. 1:16
• Active labor starts around four centimeters dilation, with contractions becoming stronger and closer together. 1:24
• Transition, typically around eight centimeters dilation, is often considered the most painful phase of labor. 1:28
• At ten centimeters dilation, the cervix is fully open, and the urge to push signals the beginning of the second stage of labor. 1:34
• During the second stage, the baby moves down the birth canal, with the bones in their head temporarily overlapping to facilitate passage. 1:48
• Crowning occurs when the widest part of the baby's head becomes visible, followed by the emergence of the baby's face, shoulders, and body. 1:54
• The third stage of labor involves the detachment and expulsion of the placenta after the baby is born. 1:57