Contraceptive failures in overweight and obese combined hormonal contraceptive users

Obstet Gynecol. 2013 Mar;121(3):585-592. doi: 10.1097/AOG.0b013e31828317cc.

Abstract

Objective: To estimate weather contraceptive failure rates among combined oral contraceptive pill (OCP), patch, and vaginal ring users was associated with increasing body mass index (BMI).

Methods: Females enrolled in a large contraceptive study offering the reversible method of their choice at no cost were followed-up for 2-3 years. We compared the failure rates (pregnancy) among users of the OCP, transdermal patch, and contraceptive vaginal ring stratified by BMI.

Results: Among the 7,486 participants available for this analysis, 1,523 chose OCPs, patch, or ring at enrollment. Of the 334 unintended pregnancies, 128 were found to be a result of OCP, patch, or ring failure. Three-year failure rates were not different across BMI categories (BMI less than 25 8.44%, 95% confidence interval [CI] 6.1-11.5; BMI 25-30 11.03%, 95% CI 7.5-16.0; BMI more than 30 8.92%, 95% confidence interval 7.6-11.5). Increasing parity (hazard ratio [HR] 3.06, CI 1.31-7.18) and history of a previous unintended pregnancy (HR 2.82, CI 1.63-4.87), but not BMI, were significant risk factors for unintended pregnancy.

Conclusion: Overweight and obese females do not appear to be at increased risk for contraceptive failure when using the OCP, patch, or vaginal ring.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Cutaneous
  • Adolescent
  • Adult
  • Body Mass Index*
  • Contraceptive Devices, Female*
  • Contraceptives, Oral, Combined*
  • Female
  • Humans
  • Obesity*
  • Overweight*
  • Pregnancy
  • Pregnancy, Unplanned*
  • Young Adult

Substances

  • Contraceptives, Oral, Combined