The role of epidemiology in the regulation of oral contraceptives.

The U.S. Food and Drug Administration (FDA) has relied to a great degree on epidemiologic studies in the regulation of oral contraceptives (OC). These epidemiologic studies range from individual case reports of adverse reactions to case-control studies and cohort studies. Important findings about adverse reactions to OCs have been communicated through "labeling," which includes information leaflets provided as package inserts for physicians and patients. Also, the FDA communicates its position through publications in medical journals, the FDA Drug Bulletin, public advisory committee meetings, workshops, and symposia. The agency responds to new epidemiologic information; labeling guidelines are under continuing review and revision. Patterns of oral contraceptive use have been affected by the dissemination of this information. There has been a decline in the use of OCs, a shift to formulations with lesser steroidal content, and a greater emphasis on OC use in optimal groups, such as young, nonsmoking women. Considered for future epidemiologic studies that may have an impact on regulatory action are a clarification of the role of various progestins in regard to blood lipid alteration and atherogenesis, a delineation of the possible persistence of cardiovascular risk after termination of OC use, and further clarification in regard to neoplasia, particularly breast and cervical carcinoma.