[Roundtable: advances in hormonal contraception]

In this work seven areas in which significant contraceptive research is underway are identified and four themes are explored in greater detail. Cyclofem a monthly injectable combining 25 mg of medroxyprogesterone acetate with 5 mg of estradiol cypionate is under study in 11 family planning centers in Chile. Its Pearl index is 0.12 and its rate of discontinuation at 12 months is 24.1% with 8.2% discontinuing for menstrual alterations and 2.1% for medical reasons. Reversibility is considered rapid and complete. Cyclofem has the same contraindications as any combined oral contraceptive. It may be used by nulliparas and offers better cycle control than other injectables. The Norplant subdermal implant system consists of six flexible capsules containing 36 mg of levonorgestrel which is released in a continuous small dose that provides effective contraception for at least five years. The Pearl index is 0.2 for the first two years. Continuation rates are high. Menstrual alterations constitute the most common reason for discontinuation. Advances in subdermal contraception are being sought through a reduction in the number of capsules or the total steroid dose and through use of new progestins with fewer side effects. Several different types of silastic vaginal rings have been tested. Rings containing 5 mg of levonorgestrel released at the rate of 20 mcg daily are designed for continuous use for 90 days. A vaginal ring containing progesterone for use by lactating mothers is currently in multicenter trials in several countries. A ring containing ethinyl estradiol and norethindrone or desogestrel is also in development. It offers the advantage of better cycle control. Antiprogestins are in the initial stages of use in contraception. Use as an emergency postcoital contraceptive appears thus far to be the most promising. RU-486 is the only antiprogestin that has been studied at different phases of the menstrual cycle. More study of efficacy and adverse effects of prolonged use will be required before a method based on RU-486 can be marketed.