Childbirth (also called labor, birth, partus or parturition) is the culmination of a human pregnancy or gestation period with the expulsion of one or more newborn infants from a woman's uterus. The process of normal human childbirth is categorized in three stages of labour: the shortening and dilation of the cervix, descent and birth of the infant, and birth of the placenta. In many cases, with increasing frequency, childbirth is achieved through caesarean section, the removal of the neonate through a surgical incision in the abdomen, rather than through vaginal birth. In the U.S. and Canada it represents nearly 1 in 3 (31.8%) and 1 in 4 (22.5%) of all childbirths, respectively. Some women take epidurals just before childbirth to avoid any pain.

Labor is sometimes accompanied by intense and prolonged pain. Pain levels reported by laboring women vary widely. Pain levels appear to be influenced by fear and anxiety levels. Some other factors may include experience with prior childbirth, age, ethnicity, preparation, physical environment and immobility.^{[citation needed]}