Stillbirth risk increased by CHD in pregnancy –

A recent study reveals an association between a diagnosis of congenital heart disease during pregnancy and a substantially increased risk of stillbirth

An estimated 16,000 babies are stillborn in the UK each year.

A new study published in BMJ Open today suggests a key factor related to this is congenital heart disease (CHD) in pregnancy. The research is conducted by Southend University Hospital’s obstetric team and is based on data from the Amniotic Band Study.

The Amniotic Band Study is the largest collaboration of its kind in the world and aims to understand why stillbirth rates are higher in parts of the UK with a high incidence of CHD.

Stéphane Muthaveeu-Desjardins, research co-ordinator for the study said:

“We now know that mothers who have a CHD diagnosis during pregnancy are 50% more likely to have a stillbirth and that women of childbearing age with an absolute risk of pregnancy loss [over 0.5%] face an estimated 23% increased risk of stillbirth. Maternal health researchers around the world will now be examining the findings and looking at ways of preventing stillbirths.”

This is the second large-scale study of stillbirths in recent months to focus on a major cause of pregnancy loss. The National Viable Birth Data Project, which is led by Imperial College London, identified an association between overweight mothers and stillbirth but no association between low birth weight and stillbirth.

The researchers involved in this research put forward some possible explanations for the increased risk of stillbirth seen in women with a diagnosed CHD. They suggest:

that women with chldiscular heart disease may be more than five times more likely to miscarry than women with no history of heart disease

that women with past histories of heart disease are more likely to miscarry, but may have different risks for CHD that a new pregnancy would introduce

that women with recent chldiscular heart disease may be at a higher risk of stillbirth. However, the extra risks are relatively small and there are many other factors that increase stillbirth risk such as maternal health and the number of prior pregnancies a woman has had

Dr Sabrina Winger, obstetric research fellow at the university, said:

“Our results support the importance of appropriately monitoring women who have a history of CHD in pregnancy. Our research looks at only the short term, and over time our results are likely to be confirmed by other studies but our study does provide important information.”

Dr Olivier van der Shouw, consultant obstetrician at Southend University Hospital added:

“This study does show that, although it is not uncommon for women to miscarry with a newly-diagnosed heart condition, it is important to note that a risk of stillbirth should not deter a woman from considering having a second pregnancy.”

The Amniotic Band Study is supported by the Society for Maternal Medicine and the National Institutes of Health.

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