The relationship between body mass index and unintended pregnancy: results from the 2002 National Survey of Family Growth

Contraception. 2008 Apr;77(4):234-8. doi: 10.1016/j.contraception.2007.10.012. Epub 2008 Mar 4.


Background: The study was conducted to characterize the relationship between body mass index (BMI) and unintended pregnancy, contraceptive use patterns, and perceived fertility.

Methods: This study employed a cross-sectional, nationally representative database (2002 National Survey of Family Growth). Unintended pregnancy was compared among BMI groups [normal (<25 m/kg(2)), overweight (25-30 m/kg(2)) and obese (>30 m/kg(2))]. Analyses also evaluated the association between demographic, socioeconomic, behavioral and health-related variables and BMI. Multiple logistic regression with adjustment for sampling design was used to measure associations of interest.

Results: BMI data were available from 6690 nonpregnant women. Of these, 3600 (53.6%) were normal weight, 1643 (25%) were overweight and 1447 (21.4%) were obese. Compared to women with normal BMIs, the risk of unintended pregnancy in the last 5 years did not differ among overweight [adjusted OR 0.95 (95% CI 0.77-1.17)] or obese [adjusted OR 0.87 (95% CI 0.70-1.09)] women. There were no differences in contraceptive use patterns or perceived fertility among BMI groups.

Conclusion: Data from the 2002 NSFG do not support an association between obesity and unintended pregnancy.

MeSH terms

  • Body Mass Index*
  • Cross-Sectional Studies
  • Female
  • Health Surveys
  • Humans
  • Obesity / complications*
  • Odds Ratio
  • Overweight / complications
  • Pregnancy
  • Pregnancy, Unplanned*
  • United States