Associations of mood symptoms with ante- and postnatal weight change in obese pregnancy are not mediated by cortisol

Background. Both maternal obesity and disordered mood have adverse effects on pregnancy outcome. We hypothesized that maternal very severe obesity (SO) is associated with increased anxiety and depression (A&D) symptoms during pregnancy, with adverse effects on gestational weight gain (GWG), postpartum mood and postpartum weight retention (PPWR) and explored any mediation by circulating glucocorticoids. Method. We measured A&D symptoms with validated questionnaires at weeks 17 and 28 of pregnancy and 3 months postpartum in 135 lean [body mass index (BMI) <= 25 kg/m(2)] and 222 SO (BMI >= 40 kg/m(2)) pregnant women. Fasting serum cortisol was measured by radioimmunoassay; GWG and PPWR were recorded. Results. A&D symptoms were higher in the SO group during pregnancy and postpartum despite adjusting for multiple confounders including previous mental health diagnosis (p < 0.05), and were non-linearly correlated with total GWG (anxiety R-2 = 0.06, p = 0.037; depression R-2 = 0.09, p = 0.001). In the SO group only, increased maternal anxiety (beta = 0.33, p = 0.03) and depression (beta = 0.19, p = 0.04) symptoms at week 17 of pregnancy were associated with increased PPWR, independent of total GWG and breastfeeding. Anxiety symptoms at week 28 of pregnancy, but not depression, were non-linearly correlated with serum cortisol level at week 36 of pregnancy (R-2 = 0.06, p = 0.02). Cortisol did not mediate the link between A&D symptoms and GWG. Conclusions. Maternal SO was associated with increased A&D symptoms, and with adverse effects on GWG and PPWR independent of circulating glucocorticoids. Strategies to optimize GWG and postpartum weight management in SO women should include assessment and management of maternal mood in early pregnancy.