Alternate delivery systems for contraceptive progestogens.

Research continues toward developing an universally acceptable, safe, and effective contraceptive to inhibit the female reproductive process. Progestational systems, either alone or in combination with small amounts of estrogen, approach such an ideal. The pregnane and 19-nortestosterone progestins were examined in this review with regard to contraceptive mechanisms of action and major side effects, such as menstrual abnormalities, metabolic changes, neoplasia, and teratogenicity. These steroids provide highly effective and long-acting contraception, and bypass the oral route of administration, resulting in fewer gastrointestinal and systemic side effects. Data regarding the lack of a deleterious effect of contraceptive progestogens on fetal malformation or cancer of the breast and genital tract reinforce their safety. Further study and refinement are needed, however, to lower the incidence of menstrual abnormalities, hypertension, and detrimental lipid alterations prior to approval for general use.