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Labor progresses in three stages. The first stage of labor, dilation, is the longest. It typically lasts 8 to 14 hours for a woman having her first child; for later-born children, the average is 3 to 8 hours. Labor begins when the mother experiences regular uterine contractions spaced at 10- to 15-minute intervals. Initial contractions may feel like a backache or menstrual cramps or may be extremely sharp. The amniotic sac, a membrane containing the fetus surrounded by fluid, may rupture at any time during this stage, often referred to as the “water breaking.” The contractions, which gradually become stronger and closer together, cause the cervix to dilate so that the fetus’s head can pass through, as shown in Figure 3.9.

The second stage of labor, delivery, begins when the cervix is fully dilated to 10 centimeters and the fetus’s head is positioned at the opening of the cervix—known as “crowning.” It ends when the baby emerges completely from the mother’s body. It is during this stage that the mother typically feels an urge to push or bear down with each contraction to assist the birth process. Delivery can take from 30 minutes to an hour and a half.

Description

Figure 3.9 Stages of Labor

Source: Adapted from Tortora and Derrickson (2009).

In the third stage of labor, the placenta separates from the uterine wall and is expelled by uterine contractions. This typically happens about 5 to 15 minutes after the baby has emerged, and the process can take up to a half hour.

The newborn emerges during the second stage of labor.

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