Neurodevelopmental effects of maternal folic acid supplementation: a systematic review and meta-analysis

Folic acid, a water-soluble vitamin B nutrient, plays an important role not only in maintaining a healthy pregnancy but also in offspring brain development and function, however, it remains unclear whether maternal folic acid (FA) supplementation associated with the risk of different postnatal neurodevelopmental outcomes. Here, we performed a systematic review and meta-analysis on the impact of maternal FA supplementation on a wide range of postnatal neurodevelopmental outcomes which include intellectual development, risk of autistic traits, ADHD, behavior, language, and psychomotor problems, using studies extracted from the following databases, including MEDLINE, Web of Science, Cochrane Library, Scopus, EMBASE, and PsychInfo. Thirty-two cohort studies and seven case-control studies were included in this meta-analysis. In the present study, we found that prenatal FA supplementation had a positive impact on offspring's neurodevelopmental outcomes, including improved intellectual development and reduced risk of autism traits, ADHD, behavioral, and language problems. We also found that FA over-supplementation was not associated with an improvement in offspring's brain development, and may have a negative impact on offspring's neurodevelopmental outcomes. This study proved the first panoramic review on the relationship of FA supplementation with offspring's neurodevelopment. Further studies focusing on different dosages and periods of FA supplementation are needed. Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2021.1993781 .

Automated summary

In this study, a systematic review and meta-analysis were conducted to investigate the impact of maternal folic acid supplementation on postnatal neurodevelopmental outcomes. The findings suggest that prenatal folic acid supplementation has positive effects on offspring's neurodevelopment, including improved intellectual development and reduced risk of autism traits, ADHD, behavioral, and language problems. However, excessive folic acid supplementation may not improve offspring's brain development and may even have negative impacts on neurodevelopmental outcomes.