Which of the following is not involved in the initiation of parturition in humans?

Parturition is the process of giving birth to a child. One of the main roles of oxytocin is to prepare a pregnant woman for childbirth. When the fetus is ready to be born, it releases cortisol, which starts a process that causes the mother's pituitary gland to release oxytocin. Once the hormone is released, it causes the uterus to contract, which in turn helps push the baby out. This hormone also plays a role in milk expression. An increase in the estrogen to progesterone ratio indicates that the amount of estrogen is more as compared to progesterone. This is known as estrogen dominance and has many adverse effects on the female body such as tenderness of breast, accelerated aging, and cancer. Prolactin promotes milk production (lactation) in mammals after childbirth under the control of dopamine released by the hypothalamus. Prostaglandins are hormones synthesized from essential fatty acids by almost all nucleated cells. They act as autocrine and paracrine lipid mediators that act upon platelets, endothelium, uterine, and mast cells. Thus, the correct answer is option B. The release of prolactin is primarily involved in lactation (milk production) after childbirth, not the initiation of parturition itself.