The document provides an overview of emergency contraception (EC), including its history, methods, efficacy, side effects, and guidelines for use. It discusses the Yuzpe method (combined pill), Plan B (progestin-only pill), high-dose estrogen, and copper IUD. Key points are that EC prevents pregnancy by delaying or inhibiting ovulation and works best the sooner it is taken after unprotected sex. Advance provision of EC has been shown to reduce unintended pregnancies.