All of the following agents are used for emergency contraception, EXCEPT
**Core Concept**
Emergency contraception refers to the use of medications or devices to prevent pregnancy after unprotected sex or contraceptive failure. It is essential to identify the correct agents used for emergency contraception to prevent unintended pregnancies.
**Why the Correct Answer is Right**
The primary mechanism of emergency contraception is to inhibit or delay ovulation, prevent fertilization, or interfere with implantation of the fertilized egg. Effective agents include hormonal contraceptives, such as levonorgestrel (Plan B) and ulipristal acetate (Ella), which work by inhibiting or delaying ovulation. Copper intrauterine devices (IUDs) are also effective as emergency contraception by inducing a local inflammatory response that prevents fertilization.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it is not a recognized agent for emergency contraception.
**Option B:** Incorrect because it is not a primary agent for emergency contraception, although it may have some efficacy in preventing implantation.
**Option C:** Incorrect because it is a recognized agent for emergency contraception, which works by inhibiting or delaying ovulation.
**Clinical Pearl / High-Yield Fact**
It is essential to note that emergency contraception is most effective when used within 72 hours after unprotected sex. The choice of agent depends on the timing of the event and the individual's medical history and preferences.
**Correct Answer: A.**