Objective: To describe the association between reported prepregnancy body mass index (BMI) and screening positive for depression.
Design: Cohort study.
Setting: Four urban hospitals in Utah, USA.
Population: Women delivering a term, singleton, live-born infant at one of four urban hospitals in Utah in the period 2005-2007.
Methods: Women were enrolled immediately postpartum. Demographic, anthropometric, stressors, psychiatric, and medical/obstetric and family-history data were obtained. Prepregnancy height, weight, and pregnancy weight gain were self-reported. The primary exposure variable, prepregnancy BMI, was calculated. Women were stratified into the six World Health Organization BMI categories (underweight, normal weight, pre-obese, or obese class 1-3).
Main outcome measure: At 6-8 weeks postpartum, women were screened for depression using the Edinburgh Postnatal Depression Scale (EPDS). The primary outcome measure was a prespecified EPDS score of > or =12.
Results: Among the 1053 women studied, 14.4% of normal weight women screened positive for postpartum depression. This proportion was greater in women classed as underweight (18.0%, n = 11), pre-obese (18.5%, n = 38), obese class 1 (18.8%, n = 16), obese class 2 (32.4%, n = 11), and obese class 3 (40.0%, n = 8) (P < 0.01). Controlling for demographic, psychological, and medical/obstetric factors, prepregnancy class-2 (aOR 2.87, 95% CI 1.21-6.81) and class-3 (aOR 3.94, 95% CI 1.38-11.23) obesity remained strongly associated with screening positive for postpartum depression, compared with women of normal weight.
Conclusions: Self-reported prepregnancy obesity may be associated with screening positive for depression when measured postpartum.