Babies of anaemic mothers have smaller brains, study finds

The study, conducted by King's College London and the University of Cape Town, followed more than 300 mothers and their babies in Cape Town, scanning the infants' brains several times between three months and two years of age. On average, the total brain volume of infants born to anaemic mothers was 4% lower than that of infants born to non-anaemic mothers, even though all the anaemic mothers had only been diagnosed with a mild form of the condition. The differences were observed in three specific regions: the putamen, caudate nucleus and corpus callosum.

“All three of these brain regions are implicated in key neuropsychological functions,” said Jessica Ringshaw, first author and researcher at King's Institute of Psychiatry, Psychology & Neuroscience and the University of Cape Town, citing processing speed, emotion regulation and executive function as examples.

The gap between the two groups widened during the first two years of life. For instance, the corpus callosum was about 4% smaller at 12 months in babies whose mothers had been anaemic, and 6% smaller by 24 months. Earlier research in South Africa on toddlers and school-age children found comparable differences in brain volume. “These aren't children who are catching up,” Ringshaw said. “They are still there when the children are six years old and going to school, and when these things might then start translating into more noticeable cognitive difficulties.”

The findings may explain why children born to anaemic mothers scored lower on developmental tests in previous studies. Ringshaw noted that the anaemic and non-anaemic mothers in the study were otherwise very similar in factors such as household income and food security, giving her confidence that maternal anaemia caused the observed brain differences.

Ringshaw stressed the importance of tackling anaemia in women of reproductive age. “We should be screening for anaemia and iron deficiency, particularly during pregnancy,” she said, recommending oral or intravenous iron supplementation where appropriate. She noted that anaemia has complex causes, including infectious diseases, and that the study found higher rates of anaemia in women living with HIV, so appropriate infection management was also important.

More than a third of pregnant women worldwide have anaemia, a condition typically caused by iron deficiency in which the number of red blood cells is lower than normal. Symptoms include fatigue, shortness of breath and dizziness, and rates are highest in sub-Saharan Africa and South Asia. While the World Health Organization lists reducing anaemia as a priority, progress has stagnated over the past two decades. “Now more than ever, anaemia needs to be placed at the forefront of public health efforts if we are to ensure that children are not only surviving but thriving,” said Ringshaw.

The research, published in the journal Brain Communications, used new MRI scanners that are cheaper and more portable than conventional hospital machines. It compared images taken with traditional high-field MRI machines with those from portable low-field options and found the latter sensitive enough to detect the same differences in the brains of babies born to anaemic mothers. Steve Williams, professor of neuroimaging at King's, said: “This study has proved that our novel technology can measure the impact of malnutrition on the developing brain, at scale, in some of the most challenging environments. This will provide an early, sensitive assessment of planned interventions.”