The most common and important undesirable effect of injectable contraceptive depot medroxyprogesterone acetate is:

Correct Answer: B

Rationale: The correct answer is B: Disruption of cyclic menstrual bleeding. Injectable contraceptive depot medroxyprogesterone acetate can cause irregular menstrual bleeding patterns, such as prolonged spotting or amenorrhea. This occurs due to the suppression of ovulation and the thinning of the endometrial lining. Nausea and vomiting (choice A) are less common side effects and usually subside after the initial injections. Venous thrombosis (choice C) and hypertension (choice D) are more associated with combined hormonal contraceptives containing estrogen.

Correct Answer: A

Rationale: Step 1: Mifepristone is a progesterone receptor antagonist. Step 2: In the late luteal phase, progesterone levels drop, leading to menstruation. Step 3: By inhibiting progesterone action, mifepristone induces menstruation. Step 4: Therefore, the correct answer is A - induces menstruation. Summary: B is incorrect as mifepristone does not postpone menstruation. C is incorrect as it does not prevent luteolysis but rather triggers it. D is incorrect as mifepristone does not cause decidualization of endometrium.

Correct Answer: D

Rationale: The correct answer is D, "All of the above." Norethindrone, Nafarelin, and Danazol are all beneficial in managing endometriosis. Norethindrone is a progestin that helps regulate menstrual cycles and reduce pain. Nafarelin is a gonadotropin-releasing hormone agonist that suppresses ovarian function, reducing estrogen levels. Danazol is a synthetic androgen that suppresses estrogen production and inhibits the growth of endometrial tissue. Therefore, all three medications address different aspects of endometriosis, making them effective treatment options.

Correct Answer: A

Rationale: Progesterone administration suppresses menstruation by maintaining the endometrial lining. It inhibits the shedding of the endometrium, postponing the onset of menstruation. Choice B and D are incorrect as progesterone thickens cervical mucus and promotes glandular activity, not watery secretions. Progesterone does not sensitize the uterus to oxytocin (Choice C).

Correct Answer: D

Rationale: The correct answer is D because clomiphene citrate is a medication commonly used to treat both female infertility due to anovular cycles and male infertility due to oligozoospermia. For females, clomiphene citrate helps stimulate ovulation, increasing the chances of conception. In males with oligozoospermia, clomiphene citrate can improve sperm count and motility. Option A is correct as mentioned, and option B is also correct as clomiphene citrate can be used in male infertility cases. Option C, endometriosis, is incorrect as clomiphene citrate is not indicated for this condition.