Taken together, we hypothesize that: 1) maternal obesity, estimated as women weighing ≥ 85 to < 186 kg (with obesity group) versus those without (> 38 to < 65.6 kg; lean group), is associated with an increased rate of postpartum psychological distress; and 2) insulin treatment given during the gestational period will result in a reduced rate of postpartum psychological distress (abbreviated here as PPD) in women with obesity. This evidence concerns the gene INS and obesity disorder.