Question

Which of the following hormones, if present in higher concentration at the end of gestation, will likely delay the process of parturition in the human female?

• A. Prostaglandin
  
• B. Oxytocin
  
• C. Estrogen
  
• D. Progesterone

Answer 1

The correct option is D Progesterone

Parturition is induced by a complex neuroendocrine mechanism. There are different hormones that play a crucial role in the process of parturition such as estrogen, oxytocin, relaxin, prostaglandins etc.

Oxytocin: It helps in uterine contraction during parturition, which makes the foetus push towards the birth canal. It helps in milk secretion as well during breastfeeding of the newborn.

Estrogen: This is a very important hormone for the process of parturition. It induces the expression of oxytocin receptors on the uterine wall due to which there is more secretion of oxytocin and hence more contraction. It also antagonises the pregnancy hormone i.e. progesterone.

Progesterone maintains pregnancy by relaxing the muscles of the wall of the uterus until the stage of puberty. At the time of parturition, estrogen antagonises the impact of progesterone and makes the wall contract to push out the foetus from the womb.

If the level of progesterone remains the same then the contraction will take a longer time.

Prostaglandins: Synthesized within the amnion and chorion layer; help in myometrium contraction and also facilitate cervix ripening (softening of the cervix onset of labour contraction).