Prepregnancy body mass index, gestational weight gain, and the likelihood of major depressive disorder during pregnancy

Objective: We assessed the relation between prepregnancy body mass index (BMI) and the likelihood of major depressive disorder (MDD) during pregnancy and tested whether this association was modified by gestational weight gain. Method: Women (N = 242) were enrolled at <20 weeks gestation into a prospective cohort study. Diagnosis of MDD was made with the Structured Clinical Interview for DSM-IV at 20, 30, and 36 weeks gestation. Gestational weight gain was compared with the 1990 Institute of Medicine weight gain recommendations. To assess the independent association between prepregnancy BMI and the odds of MDD, MDD at each time point was used as the dependent measure in a multivariable longitudinal logistic regression model employing generalized estimating equations. The data were collected from 2003-2007. Results: There was a strong, positive dose- response association between prepregnancy BMI and the likelihood of MDD (P = .002). Compared with a BMI of 18, the adjusted odds ratios (95% confidence interval) for BMIs of 23, 28, and 33 were 1.4 (1.1 to 1.7), 1.9 (1.3 to 2.9), and 2.6 (1.4 to 4.3), respectively. Gestational weight gain significantly modified this effect. Among women with weight gains within and above the 1990 Institute of Medicine recommendations, pregravid overweight was associated with a greater likelihood of MDD. In contrast, all women with weight gains below recommended levels had an elevated odds of depression regardless of their pregravid BMI (P < .05). Conclusions: Because pregravid overweight, poor gestational weight gain, and MDD all pose substantial risks for fetal development and birth outcomes, health care providers should monitor depression levels in these women to facilitate appropriate depression intervention.