During childbirth, a baby normally moves through the birth canal head first, states the Office on Women’s Health. This process, which is aided by the mother pushing during contractions, typically takes between 20 minutes and two hours.
During birth, the cervix dilates up to 10 centimeters to allow a baby to be pushed through. With the help of muscle contractions, the baby is pushed out of the uterus and out through the cervix and vaginal canal, as shown on Womenshealth.gov.
A newborn baby's skull is divided into several plates separated by soft areas. These soft areas lend the skull enough flexibility to fit through the cervix and birth canal without incurring damage, notes Parents. In many cases, a baby turns her body during the birthing process in order to find the easiest way out. Once the baby's head has cleared the birth canal, the rest of the body usually follows more quickly and easily.
In some cases, a doctor makes a small cut, called an episiotomy, to expand the vaginal opening and allow the baby to fit through more easily. This incision is repaired immediately after the birth, notes the Office on Women’s Health. Sometimes a baby is positioned to be born legs first, a condition called breech. Because breech births put the baby at a higher risk for complications or death, a doctor may either attempt to turn the baby by manually manipulating the abdomen prior to delivery or recommend a cesarean section.