There are three stages of labor: dilation of the cervix, passage of the baby through the birth canal, and delivery of the placenta. Pain during labor is caused by cervical dilation and uterine contractions that affect blood vessels and accumulate metabolites. Pain management options include natural breathing techniques, pain killing drugs like epidurals, and in some cases a cesarean section may be necessary for medical reasons. It is important for expectant mothers to understand the labor process and know when to seek medical care.