New research suggests mothers of children with autism are significantly less likely to report taking iron supplements both before and during their pregnancies.

Low maternal iron intake was found to lead to as much as a five times higher risk of autism in children if the mother was 35 and older or suffered from metabolic conditions, the University of California - Davis Health System reported. The study is the first to look at how maternal iron intake influences the chances of having a child with autism spectrum disorder. In 2011 the research team was also the first to report a link between folic acid and reduced instances of autism spectrum disorder.

"The association between lower maternal iron intake and increased ASD risk was strongest during breastfeeding, after adjustment for folic acid intake," said Rebecca J. Schmidt, assistant professor in the Department of Public Health Sciences and a researcher affiliated with the MIND Institute.

To make these findings the researchers looked at mother-child pairs enrolled in the Northern California-based Childhood Autism Risks from Genetics and the Environment (CHARGE) Study. The mothers' iron intake was looked at from three months before pregnancy though breastfeeding from a number of sources including supplements and breakfast cereals.

"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," Schmidt said. "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."

Iron deficiencies are a common occurrence in women, especially those with metabolic conditions; despite this link the researchers warned the study's results will not be confirmed until it is properly duplicated.

"In the meantime the takeaway message for women is do what your doctor recommends. Take vitamins throughout pregnancy, and take the recommended daily dosage. If there are side effects, talk to your doctor about how to address them," Schmidt concluded. 

The findings were published Sept. 22 in the American Journal of Epidemiology.