Syn: parturition. Delivery of an infant capable of independent existence, an event that occurs naturally when the cervix is fully dilated, at which stage the uterine, abdominal, and pelvic muscles expel the fetus from the uterus. Independent existence of an infant is possible after it has reached 28 weeks' gestation and is considered viable (although it is now common for infants of lower gestational age treated in neonatal intensive care to survive). See also childbirth.
Subjects: Regional and National History.