Examining the relationship between autism spectrum disorder and neural tube defects

Folate and vitamin B₁₂ deficiencies have been strongly associated with neural tube defects, preliminary research suggests folate and B₁₂ deficiency may also be associated with autism spectrum disorder (ASD). We examined the association between neural tube defects and ASD as a further avenue to examine the hypothesis that ASD is related to maternal folate and B₁₂ deficiency during pregnancy. A retrospective case–control study was performed using the Military Health System Data Repository. Cases and matched controls were followed from birth until at least 6 months after their first autism diagnosis. International Classification of Diseases, 9th Revision, codes were used to identify neural tube defects in the health records. A total of 8760 cases between the ages of 2 and 18 years were identified. The prevalence of any neural tube defect was 0.11% in children without ASD and 0.64% in children with ASD. Children with autism were over 6 times as likely to have a neural tube defect. The increased odds of neural tube defect in children diagnosed with ASD, found through our methodology, supports prior studies. Although additional studies are needed to elucidate the relationship between ASD and maternal folate and vitamin B₁₂ deficiency during pregnancy this study supports their use during pregnancy.