Advances in research on relationship between folic acid supplementation period, dosage and offspring autism during perinatal period

Recent studies have found that folic acid nutrition during perinatal and early pregnancy has an important impact on the occurrence of autism. Insufficient folate intake during pregnancy can increase the risk of autism in offspring. Folic acid supplementation during pregnancy with low folate metabolism can reduce the risk of children with reproductive autism. This paper reviews the literatures on maternal supplementation of folic acid and childhood autism spectrum disorders (ASD) from 2013 to 2018. Based on epidemiological studies, the effects of folic acid supplementation time, dosage and interaction with environmental pollutants such as air pollutants, pesticides, diseases and smoking on children’s ASD were discussed, the advantages and limitations of these studies were summarized, and then future research priorities were inspired. Regarding the multi-level exposure of environmental chemical factors, genetic aggregation and ASD subtype heterogeneity, the optimal intake of folic acid based on the Chinese diet is yet to be explored. Key words: Autism spectrum disorders; Folic acid; Vitamin B9; Perinatal period; Child