Mothers who have autistic children are less likely to report having taken any form of iron supplements both before and throughout pregnancy, compared to mothers of normally developing children.

A study by researchers with the UC Davis MIND Institute is the first to report links between maternal iron supplementation and having a child with autism.

Rebecca J. Schmidt, assistant professor in the Department of Public Health Sciences, and colleagues analyzed mother-child pairs who were enrolled in the Northern California-based Childhood Autism Risks from Genetics and the Environment (CHARGE) Study from 2002 to 2009. The study’s participants included mothers of autistic children, as well as mothers with children with typical development.

The researchers analyzed iron intake from the mothers during the three months before through to the end of the women’s pregnancies and breastfeeding. The frequency, dosage and brands of iron supplements taken was examined.

It was discovered that low iron intake was linked to a five-fold greater risk of a child having autism if the mother was 35 or older at the time of delivery, or if she suffered from diabetes or obesity hypertension.

“Iron deficiency, and its resultant anemia, is the most common nutrient deficiency, especially during pregnancy, affecting 40 to 50 percent of women and their infants. Iron is crucial to early brain development, contributing to neurotransmitter production, myelination and immune function. All three of these pathways have been associated with autism,” said Schmidt in a statement.

The findings of the study, “Maternal intake of supplemental iron and risk for autism spectrum disorders,” are published online in the American Journal of Epidemiology.