Objective To evaluate the cross-sectional relationship between migraine and pre-gravid obesity; and to assess the risk of adult weight gain among women with history of a pediatric diagnosis of migraine. Background Obesity, comorbid with pain disorders including migraine, shares common pathophysiological characteristics including systemic inflammation, and derangements in adipose-tissue derived cytokines. Despite biochemical and epidemiological commonalities, obesity-migraine associations have been inconsistently observed. Methods A cohort of 3,733 women was interviewed during early pregnancy. We ascertained participants’ self-reported history of physician-diagnosed migraine and collected self-reported information about pre-gravid weight, adult height and net weight change from age 18 to the 3-monthsperiodpriorto pregnancy. Using pre-gravid body mass index, we categorized participants as follows: lean (<18.5 kg/m2); normal (18.5–24.9 kg/m2); overweight (25–29.9 kg/m2), obese (30–34.9 kg/m2), severely obese (35–39.9 kg/m2), and morbidly obese (≥ 40 kg/m2). Logistic regression procedures were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results After adjusting for confounders, relative to normal weight women, obese women had a 1.48-fold increased odds of migraine(OR=1.48; 95%CI 1.12–1.96). Severely obese (OR=2.07; 95%CI 1.27–3.39) and morbidly obese (OR=2.75; 95%CI 1.60–4.70) had the highest odds of migraines. Women with a history of diagnosed pediatric migraine had a 1.67-fold higher odds of gaining ≥10.0 kg above their weight at age 18, as compared with non-migraineurs (OR=1.67; 95%CI 1.13–2.47). Conclusion These data support earlier observations of migraine-obesity association among women, and extend the literature to include evidence of adult weight gain among women with a history of pediatric migraine.