In amenorrhea due to HPA axis impairment, withdrawal of progesterone therapy would most likely result in which of the following?

• A. No menses after withdrawal
• B. Menses after withdrawal
• C. Immediate ovulation
• D. Heavy menses after withdrawal

Answer: (B)

Progesterone withdrawal bleed concept. If the endometrium has been primed by estrogen, giving progesterone prepares the endometrium for a luteal phase-like state. When the progesterone is stopped, the endometrium sheds, producing a menstrual-like bleed. In amenorrhea due to impaired HPO axis, estrogen production and endometrial response can still be adequate even if ovulation is absent. Thus stopping exogenous progesterone reveals menses because the endometrium is ready to shed. If there were no menses after withdrawal, that would suggest inadequate estrogen priming or an atrophic endometrium. Immediate ovulation isn’t the expected result of stopping progesterone, and heavy menses isn’t the typical outcome in this scenario.