Iron Deficiency in Mothers With Crohn’s Disease Could Lead to ADHD in Offspring

Mother’s with inflammatory bowel disease (IBD) and iron deficiency anemia (IDA) could increase the risk of offspring attention deficit/hyperactivity disorder (ADHD), according to new research.

A team, led by Nora Shero, Medical University of the Americas, identified the relationship between maternal Crohn’s disease with iron deficiency anemia and ADHD in children.

Pregnant women with IBD often also have iron deficiency anemia. However, while studies have shown certain maternal autoimmune diseases are linked to ADHD in children, there has been no research showing a relationship specifically between IDA in pregnant women with IBD and ADHD in their children.

“Although studies have shown an association between certain maternal autoimmune diseases and ADHD in offspring, not much is known about how maternal inflammatory bowel diseases, such as Crohn's disease, affect neurodevelopment in progeny,” the authors wrote. “Studies have suggested that inflammation from autoimmune disorders is the main trigger of the fetal neurodevelopment that leads to ADHD.”

Examining the Data

In the study, the investigators reviewed various studies on pregnant women with Crohn’s disease and IDA and children with ADHD, including nested case-control studies, cohort studies, cross-sectional studies, case-control studies, and literature reviews published between 2012-2021.

Overall, there were 876 articles found, with 11 studies included in the final analysis. Animal studies were also eliminated from the analysis.

The investigators found that ADHD in progeny could contribute to maternal Crohn’s disease. However, there were no studies found that show iron deficiency anemia in mothers with Crohn’s disease is related to ADHD in the offspring.

The Relationship Between IDA and ADHD

On the other hand, there were several studies showing a positive correlation between maternal IDA and ADHD in offspring. There were also some studies suggesting inflammation in IBD during pregnancy leading to inflammation of the central nervous system and ultimately leading to ADHD in the offspring.

Overall, the summarized results of the 11 studies selected support the hypothesis that IDA in mothers with Crohn’s disease is a risk factor for ADHD in offspring and that iron is a contributory function in the pathophysiology of ADHD.

“IDA is a prevalent complication in [Crohn’s disease], and inadequate iron levels are associated with neurodevelopmental problems, such as ADHD,” the authors wrote. “Iron therapy for pregnant mothers diagnosed with [Crohn’s disease] is suggested to prevent ADHD in offspring.”

Theories on Why?

One reason for this is brain development could become impaired due to iron deficiencies, which can increase the risk of ADHD in children.

And patients with Crohn’s disease are more likely to develop anemia due to malabsorption or bleeding caused by the disease. Other autoimmune diseases also contribute to ADHD among children, including asthma and psoriasis.

The results also support previous findings indicating children diagnosed with ADHD have lower serum ferritin compared to children without ADHD.

There are several reasons why patients with IBD often have iron deficiencies, including increased iron loss from mucosal bleeding caused by gastrointestinal inflammation, a decrease in iron absorption in short bowel syndrome, decreased appetite during IBD outbreaks, and inflammation-driven blockage of intestinal iron acquisition and macrophage iron reutilization.

Inflammatory cytokines can also directly inhibit iron absorption and stimulate the uptake and retention of iron in macrophages.

The study, “Impact of Crohn's disease during pregnancy on children with attention deficit hyperactivity disorder: A review,” was published online in the Annals of Medicine and Surgery.