Parturition and Oxytocin Role — NEET Biology
✅ Asked in NEET 2021The average duration of human pregnancy is about 9 months which is called the gestation period. Vigorous contraction of the uterus at the end of pregnancy causes expulsion/delivery of the foetus. This process of delivery of the foetus (childbirth) is called parturition. Parturition is induced by a complex neuroendocrine mechanism. The signals for parturition originate from the fully developed foetus and the placenta which induce mild uterine contractions called foetal ejection reflex. This triggers release of oxytocin from the maternal pituitary. Oxytocin acts on the uterine muscle and causes stronger uterine contractions, which in turn stimulates further secretion of oxytocin. The stimulatory reflex between the uterine contraction and oxytocin secretion continues resulting in stronger and stronger contractions. This leads to expulsion of the baby out of the uterus through the birth canal – parturition. Soon after the infant is delivered, the placenta is also expelled out of the uterus. What do you think the doctors inject to induce delivery?
NTA tests whether students understand that parturition (childbirth) is induced by oxytocin, a hormone released from the maternal pituitary in response to fetal signals. The neuroendocrine mechanism involves a positive feedback loop: uterine contractions → oxytocin release → stronger contractions → more oxytocin, continuing until delivery. Students often confuse oxytocin with prolactin (which stimulates milk production after delivery) or forget the positive feedback mechanism. To answer correctly: remember that oxytocin alone triggers parturition, doctors inject oxytocin (Pitocin) to induce labor, and the cycle is self-amplifying. This concept is crucial for understanding hormonal control of reproduction and could appear in questions about labor induction or endocrine mechanisms.
Which of these is not an important component of initiation of parturition in humans?
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