Obesity and contraceptive use among women 20-44years of age in the United States: results from the 2011-15 National Survey of Family Growth (NSFG).

OBJECTIVE: Obesity has increased dramatically in the United States in recent decades. Our objective was to explore associations of contraceptive choices of US women, aged 20-44years, with body mass index (BMI) and relevant covariates.

STUDY DESIGN: Data are based on interviews with a national sample of 11,300 women in the 2011-2015 National Survey of Family Growth. We analyzed women ages 20-44 at risk of unintended pregnancy. The primary dependent variable was BMI category. Covariates analyzed included age, parity, race/ethnicity, marital status, self-reported health and education. Data were analyzed via cross-tabulation and logistic regression. We determined unadjusted and adjusted odds ratios for three categories of contraceptive method: female sterilization, intrauterine device (IUD) and hormonal contraception.

RESULTS: Obese women have higher odds of female sterilization (BMI 30.0-34.9 kg/m2 : adjusted odds ratio (aOR)=1.96, 95% confidence interval (CI) 1.45-2.66; BMI 35.0 kg/m2 and higher: aOR=1.56, 95% CI 1.13-2.14) compared to women with normal BMI. Odds of IUD use are significantly higher among women with BMI >35 kg/m2 (aOR=1.64, 95% CI 1.20-2.25). Odds of hormonal contraceptive use are correspondingly reduced (aOR=0.78, 95% CI 0.62-0.98) for women in the highest BMI category.

CONCLUSIONS: Contraceptive use varies by BMI category even after adjusting for usual correlates of use. Differences in contraceptive use by BMI category have implications for contraceptive counseling and provision.

IMPLICATIONS: Findings that obese women are more likely to rely on female sterilization raise questions about how weight concerns and obesity affect contraceptive decision making. Future research could explore associations between obesity and contraceptive use in adolescent women.