Emergency contraceptive of choice is :
**Emergency Contraception**
**Core Concept**
Emergency contraception refers to the use of medications or devices to prevent pregnancy after unprotected sex or contraceptive failure. It is most effective when used within 72 hours of the incident.
**Why the Correct Answer is Right**
The emergency contraceptive of choice is levonorgestrel, a progestin-only medication that works by inhibiting ovulation or fertilization. It is available over-the-counter in many countries and is most effective when taken within 72 hours of unprotected sex. Levonorgestrel works by:
* Inhibiting ovulation by suppressing the release of gonadotropin-releasing hormone (GnRH)
* Thickening cervical mucus to prevent sperm penetration
* Altering the uterine environment to prevent implantation
**Why Each Wrong Option is Incorrect**
**Option A:** Copper IUDs are effective for emergency contraception when inserted within 5 days of unprotected sex, but they are not the first-line emergency contraceptive.
**Option B:** Ulipristal acetate is another emergency contraceptive option, but it is not the first-line choice due to its higher cost and potential side effects.
**Option C:** Ethinyl estradiol and levonorgestrel combined oral contraceptives are not typically used for emergency contraception due to their higher estrogen content and potential side effects.
**Clinical Pearl / High-Yield Fact**
When prescribing emergency contraception, it's essential to consider the patient's age, weight, and potential side effects, as well as the timing of the incident and the patient's menstrual cycle.
**Correct Answer:** C. Levonorgestrel.