Question

Menstrual flow occurs due to lack of

• A. FSH
• B. Oxytocin
• C. Vasopressin
• D. Progesterone

Answer 1

The correct option is D Progesterone

In human females, the menstrual cycle starts with the menstrual phase, when menstrual flow occurs and it lasts for 3 - 5 days. The menstrual flow results due to the breakdown of the endometrial lining of the uterus and its blood vessels, which is discharged out through the vagina. Menstruation only occurs if the released ovum is not fertilised. The ovulation (ovulatory phase) is followed by the luteal phase during which the remaining parts of the Graafian follicle, after ovulation on the 14th day, transform as the corpus luteum. The corpus luteum secretes large amounts of progesterone which is essential for maintenance of the endometrium. Such an endometrium is necessary for implantation of the fertilized ovum and other events of pregnancy. During pregnancy, all events of the menstrual cycle stop and there is no menstruation. In the absence of pregnancy, corpus luteum is not formed and progesterone levels rapidly decline leading to menstrual flow.

So, the correct answer is 'Progesterone'