Contraceptive failure in the first two years of use: Differences across socioeconomic subgroups

Context: While differences in levels of contraceptive use across socioecono mic subgroups of women have narrowed greatly over time, large disparities r emain in rates of unintended pregnancy. One reason is variations in the eff ectiveness with which women and their partners use contraceptive methods. Methods: Data on contraceptive use and accidental pregnancy from the 1988 a nd 1995 National Surveys of Family Growth were corrected for abortion under reporting and pooled for analysis. Use-failure rates were estimated for rev ersible methods during the first year, second year and first two years of u se, for subgroups of women of various characteristics. Results: The average failure rate for all reversible methods, adjusted for abortion under reporting, declines from 13% to 8% from the first year of me thod use to the second year. First-year failure rates are highest among wom en using spermicides, withdrawal and periodic abstinence ton average, 23-28 % in the first year), and lowest for women relying on long-acting methods a nd oral contraceptives (4-8%). On average, they exceed 10% for all users ex cept women aged 30-44, married women and women in the highest poverty-statu s category The chance of accidental pregnancy does not differ significantly between method users younger than 18 and those aged 18-19. Conclusion: Both user and method characteristics determine whether contrace ptive users will be able to avoid unintended pregnancy. Family planning pro viders should help clients to identify methods that they are most likely to use successfully and counsel them on how to be consistent users and to avo id behaviors that contribute to method failure.