Associations of Prepregnancy Body Mass Index and Gestational Weight Gain with Intelligence in Offspring: A Systematic Review and Meta-analysis

Background: As a growing health problem, maternal obesity may have an adverse effect on offspring neurodevelopment. The effects of maternal overweight and obesity and excessive gestational weight gain on offspring intelligence remains unclear. This meta-analysis aimed to assess the influence of prepregnancy body mass index (BMI) and gestational weight gain on children’s intelligence.Methods: We systematically searched PubMed, Embase, Cochrane Library and Ovid Medline from their inception through July 2020. Studies assessing the association between prepregnancy BMI or gestational weight gain and children’s intelligence (from 3 years to 10 years) were screened manually before final inclusion. We included prospective and retrospective cohorts that analysed the association between prepregnancy BMI or gestational weight gain and intelligence of offspring. We used the Mantel-Haenszel fixed-effects method to compute the weight mean difference (WMD) and 95% confidence interval (CI) of each study.Results: Twelve articles were included in the systematic review, and six of them were included in the meta-analysis. There was a significant full-scale IQ reduction in children of overweight and obese women, with WMDs of -3.25 (95% CI: -3.05, -2.42) and -4.85 (95% CI: -5.93, -3.76), respectively. Compared with that in the control group, the WMDs for performance IQ were -2.40 (95% CI: -3.45, -1.34) and -5.28 (95% CI: -7.22, -3.34) in the overweight and obesity groups, respectively, and the WMDs for verbal IQ were -3.47 (95% CI: -4.38, -2.56) and -5.71 (95% CI: -7.13, -4.29), respectively. However, there was no significant reduction in children’s full-scale intelligence scores due to excessive weight gain; the WMD was -0.14 (95% CI: -0.92, 0.65).Conclusions: Prepregnancy overweight and obesity might have disadvantageous consequences on children’s intelligence; however, we observed no significant difference between excessive and normal gestational weight gain. Therefore, weight control before pregnancy is more important than that during pregnancy in terms of children’s intelligence.Trial registration: This systematic review and meta-analysis have been registered in PROSPERO (Number: CRD42020199215).