Maternal obesity and depression reported at the first antenatal visit

Background: Maternal obesity and depression are common and both have been associated with adverse pregnancy outcomes. Aims: The aim of this observational study was to examine the relationship between maternal body mass index (BMI) category and self-reported depression at the first antenatal visit. Methods: Women who delivered a baby weighing ≥ 500 g over nine years 2009–2017 were included. Self-reported sociodemographic and clinical details were computerised at the first antenatal visit by a trained midwife, and maternal BMI was calculated after standardised measurement of weight and height. Results: Of 73,266 women, 12,304 (16.7%) had obesity, 1.6% (n = 1126) reported current depression and 7.5% (n = 3277) multiparas reported a history of postnatal depression. The prevalence of self-reported maternal depression was higher in women who had obesity, > 35 years old, were socially disadvantaged, smokers, had an unplanned pregnancy and used illicit drugs. After adjustment for confounding variables, obesity was associated with an increased odds ratio (aOR) for current depression in both nulliparas (aOR 1.7, 95% CI 1.3–2.3, p < 0.001) and multiparas (aOR 1.8, 95% CI 1.5–2.1, p < 0.001) and postnatal depression in multiparas (aOR 1.4, 95% CI 1.3–1.5, p < 0.001). The prevalence of current depression was higher in women with moderate/severe obesity than in women with mild obesity (both p < 0.001). Conclusions: We found that self-reported maternal depression in early pregnancy was independently associated with obesity. The prevalence of depression increased with the severity of obesity. Our findings highlight the need for implementation of strategies and provision of services for the prevention and treatment of both obesity and depression.