Update on oral contraceptive pills.

Oral contraceptive pills are widely used and are generally safe and effective for many women. The World Health Organization has developed a risk classification system to help physicians advise patients about the safety of oral contraceptive pills. The choice of pill formulation is influenced by clinical considerations. By choosing appropriately from the available pill formulations, family physicians can minimize negative side effects and maximize noncontraceptive benefits for their patients. Additional monitoring and follow-up are necessary in special populations, such as women over 35 years of age, smokers, perimenopausal women and adolescents. Third-generation progestins are additional options for achieving noncontraceptive benefits, but their use has raised new questions about thrombogenesis. The U.S. Food and Drug Administration has labeled emergency postcoital contraception for use following unprotected coitus. Oral contraceptive pills are associated with few clinically significant drug interactions, although consideration of interactions remains important.