Mothers who have anaemia in the first 100 days of pregnancy have a higher chance of having a child with congenital heart disease
New research by the British Heart Foundation has shown the impact of anaemia during pregnancy on congenital heart disease risk, highlighting the potential of iron supplements before and during pregnancy to help prevent some heart defects at birth.
For the first time in the UK population, researchers have identified a link between the heart defect and maternal anaemia in early pregnancy. The researchers estimate that maternal anaemia could account for one in 20 congenital heart disease cases in the UK.
The study used data from 16,500 mothers in the UK
The study analysed data from 16,500 mothers and found that anaemia within the first 100 days of pregnancy was associated with a 47% higher risk of the child developing the heart defect compared to the baseline risk of about one in 100. This association remained even after accounting for other risk factors, such as maternal age.
Previous research has focused on the effects of severe anaemia in the later stages of pregnancy, and there has been little research into the impact during early pregnancy when the foetal heart is developing.
In low- and middle-income countries, where anaemia during pregnancy is much more common, the researchers estimate that it may account for even more cases of congenital heart disease than in the UK.
Associate Professor Duncan Sparrow, British Heart Foundation Senior Research Fellow at the University of Oxford, who led the research, said: “We already know that a variety of factors can raise the risk of congenital heart disease, but these results develop our understanding of anaemia specifically and take it from lab studies to the clinic. Knowing that early maternal anaemia is so damaging could be a game-changer 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.”
Congenital heart disease is the most common kind of birth defect
Congenital heart disease is diagnosed on average in 13 babies every day in the UK and is a significant cause of death in infants.
The researchers initially found the link between anaemia and heart disease in mice and progressed to investigating this link in humans. Over 2,700 mothers who had a child with congenital heart disease were identified. The researchers then found nearly 14,000 mothers at the same GP practices whose children did not have the disease, but whose pregnancies started at similar times.
Blood test results from the first 100 days of each pregnancy were used to determine if the mothers had anaemia at this time. In the group of mothers who had a child with congenital heart disease, 4.4% had anaemia. This was compared to 2.8% of the mothers who did not have a child with the disease.
Iron tablets could offer new hope to anaemic mothers
The researchers hope to confirm whether anaemia, specifically caused by iron deficiency, is linked to the heart condition. If this is the case, the researchers could trial iron supplements to reduce cases of congenital heart disease.
Dr Sonya Babu-Narayan, our Clinical Director, 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.
“Whilst observational studies like this can show us links, they cannot tell us about cause. 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 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.”
