Spontaneous expulsion or extraction of the fetus and its connected matter from the maternal organism. Delivery is a complex event in which a mobile body, the fetus, passes through a canal, the pelvic canal or birth canal, under the impulse of a force provided by uterine contractions. The progress of delivery therefore depends on the anatomical characteristics of the birth canal, on the manner in which the fetus presents itself at the entrance of the birth canal, the dimensions of the fetus itself, and the efficiency of contractions. The stages of delivery are known as: preparatory stage, dilation stage, expulsion stage, and placental stage.

Surgical extraction of the fetus from the uterus through an incision in the abdomen. Cesarean section is indicated when vaginal delivery is impossible or risky. This situation arises in the following cases: placenta previa, detached placenta, breech presentation, fetus head too large for maternal pelvis, and, in general, when labor is painful. Before the advent of anesthesia (1850-1860), Cesarean sections were rarely performed on live mothers; when they were, they caused extremely high mortality, mainly due to secondary hemorrhaging from the uterine wound and septic peritonitis. In 1876, Edoardo Porro (1842-1902) introduced the technique known as Cesarean hysterectomy, which consisted in amputating the cervix after the extraction. This significantly reduced mortality. Today, the uterus is preserved and antibiotic therapy has cut mortality to 0.1%, making Cesarean section preferable to any instrumental procedure.