You are in labor when the muscles of your uterus contract so that your baby can be born. During labor, the uterine muscles tighten and the opening of the uterus (the cervix) thins and opens. The baby moves down the birth canal to be born. After delivery of the baby, the placenta (afterbirth) also comes out of the uterus. This is the last part of labor.
Every labor is different. How long it lasts and how it moves forward varies from woman to woman and from birth to birth. There are, however, general guidelines for labor that a healthcare provider uses to decide whether it is progressing normally. If it is not progressing normally, you may need medicines to help it along or surgery (a cesarean section, or C-section).
If you have signs of labor before 37 weeks of pregnancy, the labor is considered preterm. You should call your healthcare provider right away if you have any signs or symptoms of labor before 37 weeks.
No one knows exactly what starts labor. We do know that hormones, such as oxytocin and prostaglandin, cause uterine contractions and the thinning (effacement) of the cervix. Perhaps hormones from the baby trigger labor by causing the mother to make more hormones.
Labor starts when uterine contractions are strong and frequent enough to make the cervix open and thin. Signs that your body is getting ready for labor are:
While the 2 signs above are clear warning signs that labor is about to start, the sign that labor has actually begun is regular, strong contractions that:
Sometimes it’s hard to know when labor has started. You may be admitted to the hospital and then sent home if your labor does not progress—that is, if your cervix does not thin or dilate (open).
The 3 stages of labor are:
By the end of the first stage, the cervix has dilated fully to 10 centimeters (cm), or about 4 inches. The cervix needs to open this much for the baby to be able to pass through the birth canal. The first stage of labor is divided into early and active phases. It usually lasts several hours.
The baby is born during the second stage of labor. This is when you push the baby down the birth canal. This stage of labor usually lasts 15 minutes to a little over an hour, but it may last as long as 2 or 3 hours. How long it takes depends on if you have had previous births, the position of the baby's head, the size of the baby, and the size of the birth canal. Sometimes medicine for pain, such as an epidural anesthetic, may slow labor.
During the third stage of labor you deliver the placenta. This usually happens within 30 minutes after the baby is born.
The first few hours after delivery are called postpartum recovery. During this time, you will keep having contractions as the uterus goes back to its normal, smaller size. Pitocin is usually given intravenously (IV) to help keep the uterus contracted and to keep you from bleeding too much. You will have a small amount of bleeding for the next couple of days.
Ensuring that your labor is as normal as possible requires skill, experience, and careful checking by your healthcare provider. Your vital signs, your contractions, and your baby's heart rate must be checked throughout labor. These checks can be done manually or with an electronic monitor. They help your provider find problems and take any necessary actions.
During prenatal visits you and your partner should talk with your healthcare provider about any questions you have about labor. Discuss how you will manage pain. You should also talk about procedures that may become necessary during labor and delivery, such as electronic monitoring, forceps, vacuum extraction, or C-section.
It is very helpful and important for you and your partner to take prenatal classes to learn more about labor, delivery, and postpartum care.