Mother's low iron level dampens newborn's brain development

Researchers have shown in a first-of-its-kind study that a mother’s iron intake during pregnancy results in subtle effects on the infant’s brain development. Higher maternal prenatal iron intake enhances the complexity and maturity of neurons in gray matter, while lower intake diminishes it, according to results of a study published online November 24, 2015 in Pediatric Research.

The research indicates that even modest changes in maternal dietary health have the potential to affect the newborn. “Women who have low iron intake that does not attract medical attention still may be influencing their infant's brain development,” said co-principal investigator Catherine Monk, PhD, Associate Professor of Clinical Psychology and Co-Director of the Sackler Parent Infant Project at Columbia University Medical Center in New York, NY.

In this study, researchers recruited 40 pregnant, generally healthy adolescents (ages 14-19) to assess their dietary iron intake. Because of the demands of maternal and fetal growth, adolescent mothers are at high risk for iron deficiency. Even though most of the subjects received prenatal care and endorsed taking prenatal vitamins, 58% had blood hemoglobin levels below normal, 20% were getting less than the U.S. Recommended Daily Allowance of iron for pregnant women, and 14% met the criterion for mild anemia.

At an average of 20 days after birth, the researchers studied the newborns using diffusion tensor imaging (DTI), which evaluates the organization and integrity of brain tissue. This type of imaging allowed researchers to associate maternal iron intake during pregnancy to differences in cortical gray matter and, to a lesser extent, in major axonal pathways within the underlying white matter of the brain. 

The scientists found that maternal iron intake correlated inversely with tissue organization throughout the gray matter of the brain. This suggested that higher dietary iron intake was associated with greater complexity and therefore greater maturity of cortical gray matter shortly after birth. It also suggested the converse—that lower dietary iron was associated with lesser complexity and more immaturity of the developing gray matter.

“These findings are consistent with our expectations,” said co-principal investigator Bradley S. Peterson, MD, Director of the Institute for the Developing Mind at Children’s Hospital Los Angeles, in Los Angeles, CA. “Neurons become increasingly more complex in their extensions and connections as the brain matures, and the maturational delays reported previously in animal models and human behavioral studies of iron deficiency would predict that lower iron intake would produce neurons in cortical gray matter that are structurally less complex and more immature. That is what our DTI findings suggest is the case.”

Because the highly technical nature of brain assessment limited the number of adolescent women and their infants who could be studied, the findings bear further investigation.

Nevertheless, “Our imaging findings add brain-based assessments to the growing evidence that common inadequacies in maternal nutrition influence a child’s development, even before birth,” the researchers concluded.