Labor is described in three stages, and together these stages complete the delivery and the passage of the placenta.
The first stage is the process of reaching full cervical dilatation . This begins with the onset of uterine labor contractions, and it is the longest phase of labor. The first stage is divided into three phases: latent, active, and deceleration.
- In the latent phase , the contractions become more frequent, stronger, and gain regularity, and most of the change of the cervix involves thinning, or effacement. The latent phase is the most variable from woman to woman, and from labor to labor. It may take a few days, or be as short as a few hours. We typically expect the latent phase to be 10 to 12 hours for a woman who has had children. For first pregnancies, it may last closer to 20 hours. For many women, the latent phase of labor can be confused with Braxton Hicks contractions. Membranes may spontaneously rupture in the early- to mid-portion of the first stage of labor. If they rupture, the labor process usually speeds up.
- The next portion of the first stage of labor is the active phase , which is the phase of the most rapid cervical dilatation. For most women this is from 3 to 4 centimeters of dilatation until 8 to 9 centimeters of dilatation. The active phase is the most predictable, lasting an average of five hours in first-time mothers and two hours in mothers who have birthed before.
- Finally, there is the deceleration phase , during which the cervical dilation continues, but at a slower pace, until full dilation. In some women the deceleration phase is not really noticeable, blending into the active phase. This is also a phase of more rapid descent, when the baby is passing lower into the pelvis and deeper into the birth canal. The deceleration phase is also called transition, and, in mothers with no anesthesia, it’s often punctuated by vomiting and uncontrollable shaking. These symptoms can be frightening to watch, but they’re a part of normal birth, and they signal that the first state is almost completed.
The second stage is the delivery of the infant . During the second stage, mom actively pushes out the baby. For first time mothers, this can take two to three hours, so it’s important to save your energy and pace yourself. For second babies and beyond, the second stage often lasts less than an hour – and sometimes, only a few minutes.
The third stage of labor is the passage of the placenta , which can be immediate, or take up to thirty minutes. The process may be sped up naturally by breastfeeding (which releases oxytocin), or medically by administering a drug called pitocin.
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