Contraceptive Failure in the United States: Estimates from the 2006-2010 National Survey of Family Growth.

CONTEXT

Contraceptive failure rates measure a woman's probability of becoming pregnant while using a contraceptive. Information about these rates enables couples to make informed contraceptive choices. Failure rates were last estimated for 2002, and social and economic changes that have occurred since then necessitate a reestimation.

METHODS

To estimate failure rates for the most commonly used reversible methods in the United States, data from the 2006-2010 National Survey of Family Growth were used; some 15,728 contraceptive use intervals, contributed by 6,683 women, were analyzed. Data from the Guttmacher Institute's 2008 Abortion Patient Survey were used to adjust for abortion underreporting. Kaplan-Meier methods were used to estimate the associated single-decrement probability of failure by duration of use. Failure rates were compared with those from 1995 and 2002.

RESULTS

Long-acting reversible contraceptives (the IUD and the implant) had the lowest failure rates of all methods (1%), while condoms and withdrawal carried the highest probabilities of failure (13% and 20%, respectively). However, the failure rate for the condom had declined significantly since 1995 (from 18%), as had the failure rate for all hormonal methods combined (from 8% to 6%). The failure rate for all reversible methods combined declined from 12% in 2002 to 10% in 2006-2010.

CONCLUSIONS

These broad-based declines in failure rates reverse a long-term pattern of minimal change. Future research should explore what lies behind these trends, as well as possibilities for further improvements.