Babies born to anaemic mothers have smaller brains, study finds

A study looking at anaemia in pregnancy and the brain development of babies. Photograph: The Institute of Psychiatry, Psychology & Neuroscience, King’s College LondonView image in fullscreenA study looking at anaemia in pregnancy and the brain development of babies.

About this contentKat Lay, Global health correspondentWed 9 Sep 2026 00. 00 EDTSharePrefer the Guardian on GoogleBabies born to mothers with anaemia have smaller brains, particularly in key regions linked to movement, learning and the regulation of emotion, according to a study.

Researchers said the differences, first detected at the age of one, could lead to cognitive problems when children started school.

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 in the body is lower than normal.

Symptoms include fatigue, shortness of breath and dizziness. Rates are highest in sub-Saharan Africa and south Asia.

Researchers from King’s College London in the UK, and the University of Cape Town in South Africa, followed more than 300 mothers and their babies in Cape Town, scanning the brains of the infants several times between the ages of three months and two years.

On average, the total brain volume of babies born to anaemic mothers was 4% lower than that of babies born to non-anaemic mothers – despite all the anaemic mothers being diagnosed only with a mild version of the condition.

Differences were recorded in three specific regions of the brain: the putamen, caudate nucleus and corpus callosum.

The gap between the groups of babies widened over the first two years of life – the corpus callosum, for instance, was about 4% smaller at 12 months in the group whose mothers had been anaemic but 6% by 24 months.

Earlier research in South Africa looking at toddlers and school-age children found comparable differences in brain volume.

Os resultados oferecem uma explicação potencial para estudos anteriores que mostraram que crianças nascidas de mães com anemia tiveram pontuações menores em testes de desenvolvimento, ela acrescentou.

The mothers with and without anaemia were otherwise very similar in terms of factors such as household income and food security, Ringshaw said, making her confident that maternal anaemia caused the differences the team observed.

The results reinforced the importance of tackling anaemia in women of reproductive age, Ringshaw said. “We should be screening for anaemia and iron deficiency, particularly during pregnancy,” she said, recommending the use of oral or even intravenous iron supplementation where appropriate.

The causes of anaemia were complex and could include infectious diseases, she said, with the study finding higher rates of anaemia in women living with HIV, “so having our iron interventions, but also appropriate infection management in conjunction with that [is important]”.

While the World Health Organization lists reducing rates of anaemia as a priority, progress has stagnated over the past two decades.

The research, published in the journal Brain Communications, used special new MRI scanners that are cheaper and more portable than the conventional machines used in hospitals.

It compared images taken using the traditional “high-field” MRI machines with those taken by the portable “low-field” options, and found the latter were 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.”.