When you are ready to have your baby, you'll go through labor. Labor is the process of giving birth. Signs that you might be going into labor include
Call your health care provider if you have any of these signs, even if it is before your due date. Preterm labor can start before 37 completed weeks of pregnancy.
Labor happens in three stages. The first stage begins with contractions. It continues until your cervix has become thinner and dilated (stretched) to about 4 inches wide. The second stage is the active stage, in which you begin to push downward. Crowning is when your baby's scalp comes into view. Shortly afterward, your baby is born. In the third stage, you deliver the placenta. The placenta is the organ that supplied food and oxygen to your baby during pregnancy.
Mothers and babies are monitored closely during labor. Most women are able to have a baby through normal vaginal delivery. If there are complications, the baby may need to be delivered surgically by a Cesarean section.
NIH: National Institute of Child Health and Human Development