Foetal ejection reflex → oxytocin release → uterine contraction → birth The process of parturition begins with signals from the fully developed foetus and placenta, which initiate mild uterine contractions - this is known as the foetal ejection reflex. This reflex triggers the maternal pituitary to release oxytocin, which then acts on the uterine muscles to strengthen contractions. These stronger contractions enhance oxytocin release, continuing the positive feedback loop, and ultimately lead to the birth of the baby.