UCSF

Background

Tubal sterilization is the most commonly used method of contraception in the United States. Because contraceptive effectiveness influences contraceptive selection, we examined typical use failure rates after tubal sterilization in the United States.

Methods

We estimated rates of pregnancy after tubal sterilization using data from four waves of the National Survey of Family Growth (NSFG), representative samples of U.S. women aged 15 to 44 years, collected in 2002, 2006 to 2010, 2011 to 2013, and 2013 to 2015. Survey weighting was used in survival analysis to examine time to first pregnancy after tubal sterilization. Data from these participants were censored after a tubal reversal procedure, infertility treatment, hysterectomy, or bilateral oophorectomy. Reported pregnancy rates after tubal sterilization procedures were examined by using Kaplan-Meier curves and then multivariable Cox proportional-hazards models to examine the effects of age at tubal sterilization, race/ethnicity, education, Medicaid funding, and postpartum versus interval procedures.

Results

Pregnancy after tubal sterilization was reported by 2.9 to 5.2% of participants across NSFG waves. In the most recent survey wave (2013 to 2015), the estimated percentage of participants with pregnancies within the first 12 months after a tubal sterilization procedure was 2.9%; at 120 months after tubal sterilization, the estimated percentage with a pregnancy was 8.4%. At all the time points examined, pregnancy after tubal sterilization was less common after postpartum procedures than after interval procedures; however, this difference was not evident in multivariable models. In multivariable models, chance of pregnancy decreased with age at time of tubal sterilization. Race/ethnicity, education, and Medicaid funding were not consistently associated with pregnancy after tubal sterilization.

Conclusions

These data suggest that there may be nontrivial rates of pregnancy after tubal sterilization.