The aim of this study was to investigate obstetric variables potentially associated with obesity among 486 Brazilian childbearing-age women aged 15-59 residing in the municipality of Belo Horizonte, Minas Gerais State. Body fat (BF) was measured through impedance analysis, and obesity was defined as BF > 30%. The association between obstetrics factors and obesity was evaluated through multivariate logistic regression. The following variables remained in the logistic regression after adjustments for total income, smoking, alcohol consumption, and physical activity: age at menarche < 12 years (OR = 3.02; 95% CI: 1.62-5.61), age > 30 and < 39 (OR = 1.72; 95% CI: 1.01-2.92), age > 40 years (OR = 3.32; 95% CI: 1.76-6.27), age at first childbirth (OR = 1.99; 95% CI: 1.07-3.68), and the following interaction: age group > 30 and < 39 and age at menarche (OR = 0.27; 95% CI: 0.09-0.83). It appears that obstetric factors affect obesity through a complex network of interrelations that involve the covariates studied above. It is important to support efficient programs to prevent obesity, as well as family planning programs emphasizing a reduction in the prevalence of teenage pregnancies.