Do elevated symptoms of depression predict adherence and outcomes in the UPBEAT randomised controlled trial of a lifestyle intervention for obese pregnant women?

Background: Lifestyle interventions for obese pregnant women have been widely researched but little is known about predictors of low adherence or poor outcomes. This study evaluated the prospective associations between elevated symptoms of antenatal depression and gestational diabetes, adherence and gestational weight gain in a large RCT of a behavioural intervention for obese pregnant women. The effect of the intervention on symptoms of depression at follow-up was also examined. Methods: The UPBEAT RCT randomised 1555 obese pregnant women to receive a dietary and physical activity lifestyle intervention or standard care. Symptoms of antenatal depression were assessed with the Edinburgh Postnatal Depression Scale at baseline (15(+0)-18(+6) weeks' gestation) and follow-up (27(+0)-28(+6) weeks' gestation). Gestational diabetes was assessed with an oral glucose tolerance test at 27(+0)-28(+6) weeks' gestation. Adherence was pre-defined as receiving at least 5 of 8 intervention sessions. Gestational weight gain was calculated as the difference between pre-pregnancy weight (estimated as measured baseline weight minus 1.25 kg) and last measured weight at 34(+0)-36(+0) weeks' gestation. Due to substantial missing data in certain variables, multiple imputation was used to impute missing data. Women who were no longer pregnant at 27(+0)-28(+6) weeks' gestation were excluded from the sample for these analyses. Results: One thousand five-hundered twenty-six women were included in these analyses following multiple imputation; 797 (52.2%) had complete data. 13.4% had elevated symptoms of antenatal depression at baseline. There was no evidence for associations between antenatal depression status and gestational diabetes (adjusted OR 0.80, 95% CI 0.52 to 1.22, p = 0.30), adherence (adjusted OR 1.16, 95% CI 0.63 to 2.15, p = 0.63) or gestational weight gain (adjusted regression coefficient 0.52, 95% CI -0.26 to 1.29, p = 0.19). The intervention was not associated with change in depressive symptoms at follow-up (regression coefficient 0.003, 95% CI -0.49 to 0.49, p = 0.99). Similar results were obtained in complete case analyses. Conclusions: Elevated symptoms of antenatal depression did not predict gestational diabetes, adherence or gestational weight gain in this large RCT of a lifestyle intervention for obese pregnant women. The intervention also did not influence symptoms of depression at follow-up. Obese pregnant women with elevated symptoms of depression should not be excluded from lifestyle interventions.