High doses of estrogens, with or without a progestin, have been used for many years to prevent pregnancy after unprotected coitus (Medical Letter, 31:93, 1989). Now the FDA has approved marketing of the Preven Emergency Contraceptive Kit (Gynetics, Inc.) for this indication. The kit, which will require a prescription, includes four tablets, each containing 50 g of ethinyl estradiol and 0.25 mg of levonorgestrel, and a pregnancy test to rule out a pre-existing pregnancy, which would be a contraindication to taking the hormones.

Two types of oral contraceptives are available in the USA: combination oral contraceptives that contain both an estrogen and a progestin, and progestin-only contraceptives, or "mini-pills."Used as directed, all oral contraceptives marketed in the USA are similarly effective in preventing pregnancy.

An oral contraceptive (Yasmin - Berlex) containing 3 mg of drospirenone and 30 mcg of ethinyl estradiol is being promoted as having a low incidence of adverse effects.

Intrauterine devices (IUDs) and the etonogestrel implant are the most effective reversible contraceptive methods available. Hormonal oral contraceptives, patches, rings, and injectables are also effective in preventing pregnancy. When used alone, barrier and behavioral methods generally have higher failure rates than other methods (see Table 1). Selection of a contraceptive method is usually based on patient-specific factors and personal preference