Initiation of Parturition in Humans

Initiation of parturition, also known as labor, is a complex process that involves multiple biological mechanisms. The following are the important components of initiation of parturition in humans:

Increase in Estrogen and Progesterone Ratio

During pregnancy, the placenta produces high levels of estrogen and progesterone that maintain the pregnancy and prevent premature labor. However, as the fetus nears maturity, the ratio of estrogen to progesterone increases, which triggers a cascade of events that lead to labor.

Synthesis of Prostaglandins

Prostaglandins are hormone-like substances that are produced in various tissues, including the uterus, during pregnancy. In the late stages of pregnancy, the concentration of prostaglandins in the uterus increases, which causes the smooth muscle of the uterus to contract and prepares the cervix for delivery.

Release of Oxytocin

Oxytocin is a hormone that is produced by the pituitary gland and plays a crucial role in labor. It stimulates the smooth muscle of the uterus to contract and promotes the release of prostaglandins, which further enhance uterine contractions. Oxytocin also stimulates the release of milk during breastfeeding.

Release of Prolactin

Prolactin is a hormone that is primarily involved in the production of milk during lactation. Although it is not a direct component of initiation of parturition, it can indirectly influence the onset of labor by promoting breast development and milk production.

Conclusion

Therefore, the correct answer is option 'A', as the release of prolactin is not an important component of initiation of parturition in humans. While prolactin can indirectly influence the onset of labor, it is not a direct mediator of the labor process.

Prostaglandin help in contraction of smooth muscle at the time of parturition