VMBO Year 3 · Reproduction and sexuality · Section 2.5

Birth

How does birth take place?

During a vaginal birth, the baby passes from the uterus through the cervix and vagina. Several stages can be distinguished. Engagement occurs when the baby's presenting part, usually the head, moves down into the pelvis. This may happen weeks before labour or during labour itself.

From contractions to full dilation

Labour involves contractions of the muscular wall of the uterus. These help the cervix become thinner and open wider, a process called dilation. During labour, the foetal membranes may rupture, allowing amniotic fluid to leave through the vagina. This is often called the waters breaking, although it can happen before contractions begin.

Delivery of the baby

Once the cervix is fully dilated, strong contractions and pushing by the abdominal muscles help move the baby through the birth canal. This stage is called delivery or expulsion. The head usually appears first. After birth the baby begins breathing; the umbilical cord is clamped and cut. Feeding then starts separately from the placenta's nutrient supply.

The afterbirth

Further uterine contractions separate and deliver the placenta, the remaining cord and the foetal membranes. Together these are called the afterbirth. This completes the third stage of labour.