Pregnancies occurred after tubal sterilisation in 3 to 5% of patients.

Contraceptive effectiveness is a key factor influencing contraceptive choice for patients. Tubal sterilisation has been reported as more than 99% effective in preventing pregnancy (Obstet Gynecol 2019; 133: e194-e207), but much of the data are from the 1980s. Using nationally representative data from four waves of a US survey conducted between 2002 and 2015, researchers estimated pregnancy rates after tubal sterilisation among premenopausal adults (age range, 15 to 44 years). Pregnancies from assisted reproductive technologies were excluded.

Key results include the following:

• overall, 4184 participants self-reported 167 first pregnancies after tubal sterilisation
• rates of pregnancy after tubal sterilisation varied across the study’s four waves. The lowest rate was 2.9% (2006 to 2010), and the highest was 5.2% (2013 to 2015)
• about 21% of pregnancies were ectopic
• age at time of tubal sterilisation was a powerful predictor of contraceptive efficacy. Across the study’s four waves, the 10-year predicated probability of pregnancy was 0% in participants who were aged 35 years or older, 2 to 8% among those who were aged 25 to 34 years, and 4 to 13% among those who were younger than 25 years
• no data were available on the type of tubal sterilisation procedure provided.

Comment: The tubal sterilisation failure rates observed in this study need validation, but the about 5% rate remains lower than those of common contraceptive choices, such as the contraceptive pill and patch (about 9%), and might be acceptable to some patients. Patients seeking to minimise risk for pregnancy might prefer long-acting reversible contraceptive options (implant and intrauterine devices), as these have failure rates lower than 1%.

Marie Claire O’Dwyer, MB BCh BAO, MPH, Clinical Assistant Professor in Family Medicine, University of Michigan Medical School, Ann Arbor, USA.

Schwarz EB, et al. Pregnancy after tubal sterilization in the United States, 2002 to 2015. NEJM Evid 2024; 3: a2400023.