Major use of mifepristone in obstetrics and gynaecology is for management of:
**Core Concept**
Mifepristone is a synthetic steroid with potent antiglucocorticoid and antiprogestin activities. It acts as a competitive antagonist at the progesterone receptor, thereby disrupting the normal progesterone-mediated effects on the endometrium and embryo.
**Why the Correct Answer is Right**
Mifepristone is primarily used in obstetrics and gynaecology for medical abortion. It is administered orally in combination with a prostaglandin analogue (misoprostol) to induce uterine contractions and expel the embryo. The antiprogestin activity of mifepristone leads to decidual cast shedding, followed by cervical dilation and uterine contractions, ultimately resulting in abortion. The mechanism of action involves the blockade of progesterone receptors, preventing the maintenance of the early pregnancy.
**Why Each Wrong Option is Incorrect**
**Option A:** Mifepristone is not primarily used for treating endometriosis. Although it has been investigated for its potential to reduce endometriosis symptoms, this is not its major use in obstetrics and gynaecology.
**Option B:** Mifepristone is not used for managing ectopic pregnancy. In cases of ectopic pregnancy, methotrexate is the preferred treatment.
**Option C:** Mifepristone is not typically used for managing postmenopausal bleeding. While it may have some application in this area, its primary use is for medical abortion.
**Clinical Pearl / High-Yield Fact**
Mifepristone's effectiveness as an abortifacient is largely due to its ability to disrupt the normal progesterone-mediated effects on the endometrium, leading to decidual cast shedding and uterine contractions.
**Correct Answer:** C. Medical abortion.