Maternal body mass index and risk of neonatal adverse outcomes in China: a systematic review and meta-analysis

BACKGROUND: Maternal body mass index is linked to short- and long-term unfavorable health outcomes both for child and mother. We conducted a systematic review and meta-analysis of population-based cohort studies to evaluate maternal BMI and the risk of harmful neonatal outcomes in China. METHODS: Six databases identified 2454 articles; 46 met the inclusion criteria for this study. The dichotomous data on maternal BMI and harmful neonatal outcomes were extracted. Pooled statistics (odds ratios, ORs) were derived from Stata/SE, ver. 12.0. Sensitivity analyses assessed the robustness of the results. Meta-regression and subgroup meta-analyses explored heterogeneity. RESULTS: The meta-analysis revealed that compared with normal BMI, high maternal BMI is associated with fetal overgrowth, defined as macrosomia ≥4000 g (OR 1.91, 95% CI 1.75–2.09); birth weight ≥ 90% for gestational age (OR 1.88, 95% CI 1.64–2.15); and increased risk of premature birth (OR 1.38, 95% CI 1.25–2.52) and neonatal asphyxia (OR 1.74, 95% CI 1.39–2.17). Maternal underweight increased the risk of low birth weight (OR 1.61, 95% CI 1.33–1.93) and small for gestational age (OR 1.75, 95% CI 1.51–2.02). CONCLUSIONS: Raised as well as low pre-pregnancy BMI is associated with adverse neonatal outcomes. Management of weight during pregnancy might help reduce their adverse neonatal outcomes in future intervention studies or programmes. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12884-019-2249-z) contains supplementary material, which is available to authorized users.