Parturition is induced from the fully developed foetus and the placenta. Parturition involves foetal ejection reflex which are mild contractions of the placenta. This reflex triggers release of oxytocin from the maternal pituitary which acts on the uterine muscles and causes stronger uterine contractions and that further stimulates secretion of oxytocin. This stimulatory reflex between uterine muscle contraction and oxytocin secretion continues resulting in stronger contractions and eventually leading into expulsion of the baby out of the uterus.