Emergency contraception prevents pregnancy by all of the following mechanisms, except :
**Core Concept**
Emergency contraception works through several mechanisms to prevent pregnancy, including inhibiting or delaying ovulation, interfering with fertilization, and altering the endometrium to prevent implantation. The **hormonal** and **copper intrauterine device (IUD)** methods are commonly used for emergency contraception.
**Why the Correct Answer is Right**
The correct answer choice is not provided, however, emergency contraception typically does not work by **accelerating** ovulation, as most methods aim to either prevent or delay it. The **progestin-only** pills and the **copper IUD** can prevent fertilization or implantation, while also affecting ovulation.
**Why Each Wrong Option is Incorrect**
**Option A:** This choice is not provided, but typically, emergency contraception can prevent ovulation or make the environment less favorable for fertilization.
**Option B:** Similarly, this choice is missing, but altering the **endometrium** to prevent implantation is a known mechanism.
**Option C:** Again, this option is not given, but interfering with **sperm function** or **egg transport** could be considered.
**Option D:** This choice is also not provided, however, emergency contraception often involves **delaying** ovulation.
**Clinical Pearl / High-Yield Fact**
It's crucial to remember that emergency contraception is most effective when used promptly after unprotected sex, and the **copper IUD** can be used up to 5 days after.
**Correct Answer:** Not provided, as the options and correct answer text are missing.