Does Anemia During Pregnancy Raise the Risk of Heart Defects in Newborns?

Recent research suggests that iron deficiency anemia (IDA) during early pregnancy may significantly increase the risk of congenital heart defects (CHDs) in newborns. With CHDs being one of the most common birth anomalies, this finding has important public health implications—especially in regions where maternal anemia is widespread.

A 2021 study by researchers at the University of Oxford, published in Nature Communications, used mouse models to explore how maternal iron deficiency affects fetal heart development. They discovered that severe IDA in the first trimester disrupts normal cardiac formation, leading to structural heart defects. The risk was especially pronounced in embryos with genetic predispositions, such as Down syndrome, highlighting the compounded effect of nutritional and genetic risk factors.

Timing emerged as a critical factor. The fetal heart begins forming around the third week of gestation—often before pregnancy is even confirmed. The researchers found that iron supplementation given after this window failed to reverse the cardiac abnormalities, underscoring the need for preconception care and early intervention.

This is particularly concerning given that iron deficiency is the most common nutritional disorder worldwide. The World Health Organization estimates that up to 40% of pregnant women are anemic, with iron deficiency being the leading cause. In low- and middle-income countries, the lack of routine screening and late prenatal visits can delay diagnosis and treatment.

What Can Be Done?

• Preconception Screening: Women planning pregnancy should have their iron levels checked and corrected before conception if needed .

• Early Iron Supplementation: Starting iron supplements early—ideally before or shortly after conception—may reduce the risk of CHDs.

• Dietary Support: A diet rich in iron (e.g., red meat, legumes, leafy greens) and vitamin C can help maintain healthy iron stores.

Takeaway

While more human studies are needed to confirm these findings, the existing evidence points to maternal iron status as a potentially modifiable risk factor for congenital heart disease. Ensuring adequate iron intake before and during early pregnancy may offer a simple yet powerful way to protect fetal heart development.

References:

1. Nair, M., et al. (2025) Maternal Anaemia and Congenital Heart Disease in Offspring: A Case–Control Study Using Linked Electronic Health Records in the United Kingdom. BJOG An International Journal of Obstetrics & Gynaecology. doi.org/10.1111/1471-0528.18150.

2. Sparrow DB et al., Nature Communications, 2021

2. World Health Organization, 2021

3. University of Oxford News Release, 2021

(Input from various sources)

(Rehash/Dr. Shreya Vohra/MSM)

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