Hormonal emergency contraception: a clinical primer.

Unintended and teenage pregnancies are major public health concerns in the United States. Emergency contraception is used to prevent pregnancy after failure of a contraceptive method or after unprotected intercourse. Expanded use of emergency contraception has the potential to reduce unintended pregnancy and induced abortions, while reducing state and federal healthcare expenditures. The recent approval of Plan B as an over-the-counter medication for individuals over 18 years of age should improve access to this medication. However, there are still widespread misconceptions about the mechanisms and implications of emergency contraception. Expanded access to emergency contraception is associated with increased use, but not associated with decreased efficacy, increased sexual risk-taking behavior, or less consistent use of traditional birth control methods. This review is designed to provide clinicians with information regarding the use of emergency contraception for reproductive age patients. It includes a brief description of methods of use, mechanisms of action, and side effect profiles of the most commonly used methods of emergency contraception, levonorgestrel and the Yuzpe method.