Measuring Contraceptive Failure

One of the most vexing problems for practitioners and policymakers concerned with family planning, not to mention for women and men trying to make the best choices for their reproductive lives, is contraceptive failure—the occurrence of pregnancy among couples who are trying not to conceive. Decades of research, employing increasingly sophisticated statistical techniques, have documented the incidence of contraceptive failure, with the aim of learning how to bring down levels of unintended pregnancy. Back in 1973, an analysis of data from the 1970 National Fertility Study was one of the first efforts to examine failure and how it differed by contraceptive method and among subgroups of ever-married women. In 1982, the National Survey of Family Growth (NSFG) had become the go-to data source, and researchers applied new multivariate techniques to more fully understand disparities, but only among married women. Fast-forward to 2017: The NSFG is still the go-to source, data are adjusted for abortion underreporting, women are included regardless of their marital status, and failure is measured not only by method, but also by duration of use.

The good news in the most recent report, reflecting the experiences of 2006–2010 survey respondents, is that failure rates associated with most reversible methods have been declining; some are at all-time lows for the U.S. Not only that, but the overall failure rate for reversible methods is approaching the goal set in the federal government’s Healthy People initiative. Still, differences by method and among demographic subgroups suggest the continuing importance of efforts to ensure that U.S. women and men have access to a full range of contraceptives and receive the information they need to use them effectively.

Cover illustrations of Margaret Sanger © Matthew and Eve Levine