About one third of all babies are breech at 24 weeks, but by the 32nd week most babies are in the head-down position. When there are twins, often one of them is in the breech position. If your baby is in the breech position, your health care provider may try to turn the baby to the head-down position after 36 weeks. He or she may use a procedure called external cephalic version to do this. If it is not successful, your provider will leave your baby in the breech position until you deliver.
Most babies change position by the time labor begins.
Because your breech baby's head will be the last part to come through the birth canal, special problems might occur that could make vaginal delivery unsafe. If the baby's head is not delivered quickly after the rest of the body, there is a risk of brain damage, suffocation, and death. The head is the largest part of the baby that must fit through the birth canal. During a normal head-first delivery, there is time during labor for your baby's head to slowly mold itself so that the diameter of the head is smaller. The head can then pass through the birth canal more easily.