Birth is the process through which a new individual emerges from the body of a parent, typically following a period of gestation. In humans, this process usually occurs after about nine months of pregnancy, during which the fetus develops inside the uterus. Birth can happen through vaginal delivery or cesarean section, depending on various factors related to the health of the parent and the baby. During birth, the body undergoes a series of changes to facilitate the delivery. Contractions of the uterine muscles help push the baby through the birth canal. Once the baby is born, it begins to breathe independently, and the umbilical cord, which provided nourishment during pregnancy, is cut. This marks the beginning of the baby's life outside the womb.