## **Core Concept**
Ulipristal acetate is a selective progesterone receptor modulator used for emergency contraception. It works by delaying or inhibiting ovulation. The efficacy of ulipristal acetate for emergency contraception is well established, and it is considered an effective option when used within a specific timeframe after unprotected sex.

## **Why the Correct Answer is Right**
The correct dose of ulipristal acetate for emergency contraception is **30 mg**. This dose has been shown to be effective in preventing pregnancy when taken within 120 hours (5 days) after unprotected sex. Ulipristal acetate exerts its effect by modulating the progesterone receptor, which plays a crucial role in ovulation and implantation of the embryo. The 30 mg dose is specifically approved for this indication and has been demonstrated to have a favorable efficacy and safety profile.

## **Why Each Wrong Option is Incorrect**
- **Option A:** 10 mg - This dose is lower than the approved dose for emergency contraception. While ulipristal acetate at 5 mg/day is used for the treatment of moderate to severe symptoms of uterine fibroids, 10 mg is not the correct dose for emergency contraception.
- **Option B:** 20 mg - Although closer, this is still not the approved dose for emergency contraception.
- **Option D:** 60 mg - This dose is higher than the recommended dose for emergency contraception and is not approved for this indication.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that ulipristal acetate is effective for emergency contraception when taken up to 120 hours (5 days) after unprotected sex, making it a valuable option for women seeking post-coital contraception. Additionally, it's worth noting that ulipristal acetate may have interactions with certain medications, and its use should be discussed with a healthcare provider.

## **Correct Answer:** . 30 mg