We often talk about the importance of planning for pregnancy.  In these discussions, we emphasize the importance of supplementation with folic acid as a means of decreasing risk for birth defects and improving neurodevelopmental outcomes in children.  A recent study indicates that adequate levels of iron may also play an important role in fetal brain development and that children born to mothers with anemia during pregnancy may have worse neurodevelopmental outcomes.  

Using data from the Stockholm Youth Cohort, Swedish researchers evaluated 532,232 children born between January 1, 1987 and December 31, 2010, with follow-up of the children in health registers through 2016. They looked at the association between anemia in the mother (recorded at ? 30 weeks or > 30 weeks) and risk for autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD) and intellectual disability (ID) in their children.  

ASD, ADHD, and ID were more commonly reported among children born to mothers with anemia within the first 30 weeks of pregnancy compared with mothers diagnosed with anemia later in pregnancy (4.9% vs. 3.8% for ASD, 9.3% vs. 7.2% for ADHD, 3.1% vs.1.1% for ID).  The results were similar when women with anemia were compared to mothers without anemia (4.9% vs. 3.5% for ASD, 9.3% vs. 7.1% for ADHD, 3.1% vs.1.3% for ID). 

After controlling for potential confounders, researchers observed that anemia diagnosed during the first 30 weeks of pregnancy but not later was associated with increased risk of diagnosis of ASD (odds ratio [OR], 1.44; 95% CI, 1.13-1.84), ADHD (OR, 1.37; 95% CI, 1.14-1.64), and ID (OR, 2.20; 95% CI, 1.61-3.01). While the risk of these disorders is elevated, it is important to note that the absolute increase in risk is relatively small.  

Although maternal anemia may be associated with other factors associated with worse neurodevelopmental outcomes (i.e., malnutrition, inadequate prenatal care, poor adherence to prenatal vitamins), the researchers attempted to control for these factors.  They hypothesize that iron deficiency anemia disrupts fetal brain development, noting that iron is essential for processes including myelination, dendrite arborization, and synthesis of monoamine neurotransmitters.

Given the prevalence of anemia in women of childbearing age, this study underscores the importance of consistent prenatal care and the  usage of prenatal vitamins containing iron. It should be noted that not all prenatal vitamins contain the US recommended daily allowance (RDA) of iron (27 mg/day). Some women, including African-American women, vegetarians, and those with intestinal disorders and other chronic illnesses,  are at higher risk for iron-deficiency anemia and should talk to their physician about iron supplementation during pregnancy,

 

Ruta Nonacs, MD PhD

 

Association of Prenatal Maternal Anemia With Neurodevelopmental Disorders.

Wiegersma AM, Dalman C, Lee BK, Karlsson H, Gardner RM.  JAMA Psychiatry. 2019 Sep 18:1-12.

 

Does maternal anemia affect fetal neurodevelopment? (Contemporary OB/GYN)

 

Anemia in Early Pregnancy Linked to Autism, ADHD, Intellectual Disability in Kids (Medscape – free subscription)

 

Could Mom’s Anemia Hurt Baby’s Brain? (Medpage Today)

 

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