● At the end of gestation, the completely developed foetus is expelled out. This process is called parturition. ● Parturition is controlled by a complex neuroendocrine mechanism. ● Estrogen and progesterone ratio increases as estrogen levels rise significantly. ● Prostaglandins, which stimulate uterine contractions are also produced that act on myometrium. ● Oxytocin, the main hormone, also called as birth hormone is released by maternal pituitary, which brings about strong uterine contractions. ● Prolactin is a lactation hormone that has no role in initiation of parturition.