Question

Which of the following is not a mechanism of action of hormonal contraceptives?

• A. Inhibiting the release of gonadotropins
• B. Making the uterus unsuitable for implantation
• C. Modifying the estrogen receptors in the uterus
• D. Secretion of thick mucus which blocks the entry of sperms

Answer 1

The correct option is C Modifying the estrogen receptors in the uterus

The chemical contraceptives could be of steroidal nature or non steroidal in nature. Steroidal hormones are also known as hormonal contraceptives. The hormonal contraceptives use preparations that contain small amounts of progesterone only, or a combination of progesterone-estrogen. Progesterone however is not used in its natural form, rather a synthetic equivalent called progestogen is used.
Progestogen acts on the hypothalamus and inhibits the release of GnRH. As a result, the anterior pituitary is not stimulated to release the gonadotropins LH and FSH.
In the absence of LH and FSH, the ovarian follicles don’t develop inside the ovaries. Therefore, no estrogen is released. The estrogen component of the contraceptives helps maintain the normal thickening of the uterine wall. However, there is no proliferation of uterine cells, hence the endometrium is unsuitable for implantation.
The use of hormonal contraceptives causes the secretion of thick mucus which blocks the cervix and acts as a plug, blocking the entry of the sperm.
Hormonal contraceptives don’t modify the estrogen receptors in the uterus. This is done by the non hormonal preparations.