Effects of maternal pre-pregnancy body mass index and gestational weight gain on antenatal mental disorders in China: a prospective study

BACKGROUND: Maternal obesity is the most common medical condition among women of reproductive age worldwide. The pre-pregnancy body mass index and gestational weight gain have been suggested to be associated with maternal mental disorders. This study aimed to investigate the effects of the pre-pregnancy body mass index and gestational weight gain on antenatal depression, stress, and anxiety. METHODS: In total, 4,890 pregnant women were enrolled in the present study, which is based on an ongoing prospective cohort study. We used self-reported pre-pregnancy weights and the last weights measured prior to delivery (using professional instruments) to calculate the pre-pregnancy body mass index and gestational weight gain. The questionnaires used included the Center for Epidemiologic Studies Depression Scale (CES-D), Self-Rating Anxiety Scale (SAS), and 10-item version of the Perceived Stress Scale (PSS-10). We used Pearson product-moment correlation and multivariable logistic regression models to examine the impact of the pre-pregnancy body mass index and gestational weight gain on different maternal mental disorders. RESULTS: After adjusting for conception, annual household income, occupation, education, smoking status, and drinking status, excessive gestational weight gain during pregnancy was associated with a greater chance of anxiety symptoms in the entire sample (adjusted model: odds ratio = 1.479, 95% confidence interval = 1.128, 1.938) and especially in women with a normal body mass index (adjusted model: odds ratio = 1.668, 95% confidence interval = 1.209, 2.302). However, the relationship between the maternal pre-pregnancy body mass index and mental health was not significant. CONCLUSION: Pregnant women with a normal pre-pregnancy body mass index had a greater chance of experiencing anxiety symptoms before delivery if gestational weight gain was excessive; however, its effects on depression or stress symptoms were not observed. The maternal pre-pregnancy body mass index may not be independently associated with maternal mental disorders.