Association between body mass index, sexually transmitted infections, and contraceptive compliance

Recent studies have examined the relationship between body mass index (BMI) and sexual behaviors, but little information exists on this relationship among racially diverse, low-income women using objectively measured clinical data. The purpose of this study was to examine the association between BMI and sexual behaviors, rates of sexually transmitted infections (STIs) and unintended pregnancy, and contraceptive adherence among adolescent and young adult women.

As part of a larger study, 1,015 Hispanic (54.2%), Black (18.6%) and White (24.8%) women aged 16 to 24 years seeking family planning services at publicly funded reproductive health clinics provided data on their baseline sexual behaviors, and contraceptive use and pregnancy history over 12 months. Objective clinical data were available from medical records at baseline (i.e., height, weight, and Papanicolaou [Pap] smear results), and over a 12-month period (i.e., STI results). Multivariable analyses were used to compare sexual behaviors, STI rates, contraceptive compliance, and unintended pregnancy rates between obese, overweight, and normal weight participants after adjusting for age, race/ethnicity, and other confounders.

Overall, 423 (36.6%), 304 (26.3%), and 288 (24.9%) participants were classified as normal weight, overweight, and obese, respectively. No statistically significant association was observed between BMI and sexual behaviors, STI rates (overweight odds ratio [OR] 0.67; 95% confidence interval [95% CI] [0.4, 1.08]; obese OR 0.68; 95% CI [0.42, 1.10]); contraceptive compliance (overweight OR 0.89; 95% CI [0.69, 1.16]; obese OR 0.89; 95% CI 0.68, 1.16]), or unintended pregnancy (overweight OR 1.08 95% CI [0.73, 1.60]; obese OR 1.09; 95% CI [0.72, 1.63]).

STI history and contraceptive compliance did not vary by BMI. Therefore, all women should receive equal contraceptive counseling (including condoms) to reduce the risk of unplanned pregnancy and STIs.