Silverman ME, et al. - Researchers conducted the largest study to date on the association between body mass index (BMI) and postpartum depression (PPD) using clinically ascertained BMI and diagnosis of depression. A prospective cohort of all women with live singleton births in Sweden 1997-2008, was included in this study. Findings revealed PPD risk to be associated with first trimester of pregnancy BMI. Depression history was identified further modifying this risk. While all women with low BMI were at risk for PPD, being overweight increases risk of PPD only in women without a history of depression.