Contraceptive use projections: 1990 to 2010.

Factors that will affect both contraceptive use and choice of method during the next 20 years are reviewed. Two factors are predictable: the changing age distribution of women and the revised upper-age limits for oral contraceptive use, with the effect of the latter as yet unknown. Less predictable factors include the number of women in each age group at risk for pregnancy, the effects of delayed childbearing and sterilization, and the impact of new contraceptive methods. Unpredictable factors include adverse publicity about oral contraceptives and breast cancer, concern about sexually transmitted diseases and acquired immunodeficiency syndrome, and changes in the availability of legal abortion. Numbers of women using oral contraception, other reversible methods, sterilization, and no method are projected from 1990 to 2010 under the assumption that use patterns in each age group resemble those observed in 1988. We conclude that discrepancies between projections of contraceptive use and fact are likely to occur because of the unpredictable nature of these few important variables.