Identify the incorrect statement regarding the action of RU- 486

Options

A. Blocks the action of progesterone essential for implantation of embryo
B. It is antagonistic to estrogen
C. Leads to death of embryo followed by spontaneous abortion
D. Inhibit the release of hCG from placenta

Answer

To identify the incorrect statement regarding the action of RU-486 (mifepristone), let's analyze each option step by step.

### Step 1: Understand RU-486 (Mifepristone)
RU-486, also known as mifepristone, is a medication primarily used for medical abortion. It works by blocking the action of progesterone, a hormone essential for maintaining pregnancy.

### Step 2: Analyze Each Statement
**Option A:** "It blocks the action of progesterone essential for the implantation of the embryo."
- This statement is **correct**. RU-486 blocks progesterone, which is necessary for the implantation of the embryo in the uterus.

**Option B:** "It is antagonistic to estrogen."
- This statement is **incorrect**. Mifepristone does not act as an antagonist to estrogen; instead, it can increase the levels of estrogen in the body.

**Option C:** "It leads to the death of the embryo followed by spontaneous abortion."
- This statement is **correct**. By blocking progesterone, RU-486 causes the embryo to die and leads to a spontaneous abortion.

**Option D:** "It inhibits the release of hCG from the placenta."
- This statement is **correct**. RU-486 inhibits the release of human chorionic gonadotropin (hCG), which is necessary for maintaining the pregnancy.

### Conclusion
The incorrect statement regarding the action of RU-486 is **Option B**, which claims that it is antagonistic to estrogen.