## **Core Concept**
Mifepristone and misoprostol are medications used for medical termination of pregnancy (MTP). Mifepristone is a **progesterone receptor antagonist** that blocks the action of progesterone, which is essential for maintaining pregnancy. Misoprostol is a **prostaglandin E1 analog** that induces uterine contractions.

## **Why the Correct Answer is Right**
The combination of mifepristone and misoprostol is effective for terminating pregnancies up to a certain gestational age. Mifepristone works by blocking progesterone receptors, leading to pregnancy termination, while misoprostol induces uterine contractions to expel the pregnancy. This regimen is approved and widely used for **early pregnancy termination**, specifically up to **10 weeks (70 days) of gestation**. The efficacy and safety of this combination have been established within this timeframe.

## **Why Each Wrong Option is Incorrect**
- **Option A:** 7 weeks - While the regimen can be used within this timeframe, it is not the upper limit.
- **Option B:** 12 weeks - This exceeds the typical recommended gestational age for the use of mifepristone and misoprostol for MTP.
- **Option D:** 20 weeks - This is far beyond the recommended gestational age for medical termination of pregnancy using mifepristone and misoprostol.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the use of mifepristone and misoprostol for medical termination of pregnancy is most effective and approved up to **10 weeks (70 days) of gestation**. Beyond this period, other methods or a combination of methods might be considered, but their efficacy and safety profiles may differ.

## **Correct Answer:** C. 10 weeks.