Low Supplemental Iron Intake During Pregnancy Tied to Increased Risk of Autism in Children

A new study ties mother's low intake of iron supplements before and during pregnancy to a five-fold increased risk of autism in their offspring.

In a latest finding, researchers at the UC Davis MIND Institute found that mothers of children with autism, a developmental disability, were more likely to have had poor intake of iron supplements before and during their pregnancies as compared to mothers of normal children.

The risk of having children with autism was high if the mother was aged 35 years or older at the time of childbirth or if she had certain metabolic conditions including obesity, diabetes and hypertension. This is the first study that evaluated the link between maternal iron intake and risk of giving birth to child with autism spectrum disorder (ASD). In 2011, researchers of the current study for the first time highlighted the link between supplemental folic acid and lower risk of ASD.

"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 at the Department of Public Health Sciences and a researcher affiliated with the MIND Institute. "Further, the risk associated with low maternal iron intake was much greater when the mother was also older and had metabolic conditions during her pregnancy."

The current study was conducted on mother-child pairs who were a part of the Northern California-based Childhood Autism Risks from Genetics and the Environment study (CHARGE) between 2002 and 2009. The study participants included mothers of children diagnosed with autism and 346 mothers of children with typical development.

The maternal iron intake was measured among the participants, including vitamins and other nutritional supplements, breakfast cereals during the three months prior to through the end of women's pregnancies as well as breastfeeding. The daily iron intake was examined while considering the frequency, dosage and the brands of supplements they consumed.

"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."

One of the most common health issues is the deficiency of iron. The study, however, suggests that women should continue taking vitamins throughout the pregnancy and take the recommended daily dosage. 

The finding was documented in the American Journal of Epidemiology.