Vitamin D deficiency during pregnancy increases the risk of autism in children.

Is it true that vitamin D deficiency during pregnancy increases the risk of autism in children?

Partly. Observational work, including a systematic review and one cohort, reports an association between low maternal vitamin D and higher autism risk, but the review rates the evidence strength as very low. A randomized trial found high-dose vitamin D3 supplementation in pregnancy had no effect on autism risk, so the causal claim is only partially and conflictingly supported.

Verdict: CONTESTED PARTIAL · 2 sources for, 1 against · Last checked 3 Oct 2026

The private library was unavailable for some searches in this check. Missing library results are not evidence against the claim.

Uçar, N., Grant, W., Peraita-Costa, I., & Suárez-Varela, M. M. M. (2020). How 25(OH)D Levels during Pregnancy Affect Prevalence of Autism in Children: Systematic Review. doi.org. https://doi.org/10.3390/nu12082311

Aagaard, K., Jepsen, J. R. M., Sevelsted, A., Horner, D., Vinding, R., Rosenberg, J. B., Brustad, N., Eliasen, A., Mohammadzadeh, P., Følsgaard, N., Hernández-Lorca, M., Fagerlund, B., Glenthøj, B. Y., Rasmussen, M. A., Bilenberg, N., Stokholm, J., Bønnelykke, K., Ebdrup, B. H., & Chawes, B. (2024). High-dose vitamin D3 supplementation in pregnancy and risk of neurodevelopmental disorders in the children at age 10: A randomized clinical trial.. doi.org. https://doi.org/10.1016/j.ajcnut.2023.12.002

Maternal Vitamin D Levels During Pregnancy and Offspring Autism Spectrum Disorder - PMC Lock. (n.d.). pmc.ncbi.nlm.nih.gov. https://doi.org/10.1016/j.biopsych.2021.07.012