Parturition involves many physiological and hormonal changes in which prostaglandin plays a critical role. The release of cortisol initiates parturition process by down-regulating progesterone, which ends the uterine quiescence. Cortisol enhances estrogen receptors’ expression, which makes uterine more sensitive to other uterotonic agents. Estrogen causes myometrial contractions, which will trigger the hypothalamus to release oxytocin hormone. Oxytocin will also cause uterine contractions and enhances prostaglandin synthesis. When prostaglandin is released, it induces even more myometrial contractions and dilation of the cervix. Additionally, prostaglandin has a stronger effect as it is regulated by a positive feedback to generate strong coordinated
