The supplement that could prevent a birth defect affecting 13 UK babies every day

Low iron levels during early pregnancy significantly increase the risk of babies being born with congenital heart disease (CHD), according to groundbreaking new research.

The discovery marks a major advancement in understanding and potentially preventing this common birth defect, which affects an estimated 13 babies daily in the UK.

Congenital heart disease arises when the heart develops abnormally in the womb and is a leading cause of infant mortality.

The research reveals a crucial link between anaemia in expectant mothers and CHD, suggesting that low iron levels could be responsible for around 5 per cent of CHD cases in the UK.

The prevalence of anaemia among pregnant women is substantial, affecting nearly a quarter of expectant mothers in the UK and over a third globally.

As part of the new work, published in BJOG: An International Journal of Obstetrics and Gynaecology, experts will now investigate whether taking iron supplements before and during pregnancy could help prevent heart defects.

The study looked at data from 16,500 mothers and found that, if the mother was anaemic in the first 100 days of pregnancy (around the first three months), the likelihood of having a child with congenital heart disease was much higher than usual.

The study said: “After adjusting for potential confounders, the odds of giving birth to a congenital heart disease-diagnosed child were 47 per cent higher among anaemic mothers.”

It is is already known that severe anaemia in the later stages of pregnancy causes problems such as low birth weight and premature delivery, but this is the first time anaemia in the early stages has been identified as an issue.

Associate professor Duncan Sparrow, from the University of Oxford, who led the study funded by the British Heart Foundation, said: “Knowing that early maternal anaemia is so damaging could be a gamechanger worldwide.

“Because iron deficiency is the root cause of many cases of anaemia, widespread iron supplementation for women – both when trying for a baby and when pregnant – could help prevent congenital heart disease in many newborns before it has developed.”

The researchers previously found a link between anaemia during pregnancy and congenital heart disease in mice.

To investigate this link, they used anonymised data from GP records to see what was happening in mothers and babies.

More than 2,700 mothers who had a child with congenital heart disease were identified and matched with women whose children did not have the condition.

Blood test results from the first 100 days of each pregnancy were then used to determine whether the mothers had anaemia at that point.

In the group of mothers who had a child with congenital heart disease, 4.4 per cent had anaemia.

This was compared to 2.8 per cent of mothers having anaemia whose children did not develop congenital heart disease.

Dr Sonya Babu-Narayan, clinical director at the British Heart Foundation and consultant cardiologist, said: “If low iron turns out to be one of the culprits, then replenishing iron levels during early pregnancy when the baby’s heart is forming could have significant benefit for a baby’s lifelong heart health.

“Larger studies are needed to confirm the finding and determine which type of congenital heart disease may be linked to low iron.

“It is also important to note that the usual risk of having a child with a congenital heart disease is around 1%, so even with the increase that this study suggests, the individual risk for people with no family history of congenital heart disease is still relatively small.”