Influence of corticosteroids on the fetal heart

Steroids given to mother at risk of premature birth reduce risk of lung problems in their babies, but may affect how a baby’s heart develops.
  • Authors list

    Lenka Hrabalkova, Sarah Stock, Karen Chapman, Matt Kemp, John Newnham, Alan Jobe

Start: April 2018

End: April 2019

This project took place at our Edinburgh centre which operated between 2008 and 2021. 

Why do we need this research?

Drugs called corticosteroids are sometimes given to pregnant women who are at risk of premature birth. These drugs can help prevent lung disease in babies who are born too early.

However, there is increasing evidence that corticosteroids might have unintended effects on other organs. Researchers think that they might affect how the heart develops, which could contribute towards the increased risk of heart disease faced by people who were born prematurely.

We need to better understand how and why corticosteroids affect the development of the heart, so that we can prevent health problems in later life for premature babies.

What happened in this project?

Researchers funded by Tommy’s looked at the hearts of lambs who had been had been born prematurely. Sheep were involved in these experiments because they have a relatively long gestation of around five months, and their heart is similar enough to a human’s. This means that findings from this research can be more easily applied to premature birth in humans.

Some of the ewes had been given doses of a corticosteroid called betamethasone (also known as Celestone), and some had not. The results suggest that betamethasone may slow the growth of heart muscle cells and reduce the density of heart cells in the fetus. These changes occurred in the right ventricle, the part of the heart which is responsible for pumping blood to the lungs to get oxygen. 

Interestingly, our scientists found that a modified version of this drug, called betamethasone acetate, appeared to not affect the heart as much. The team are now continuing to study how steroid drugs affect the development of the heart, and how to minimise the risk of complications.

What difference will this project make?

This project has revealed the impact that commonly used drugs can have on the fetal heart. Understanding how things that happen before a baby is born can affect how the heart grows will help us give premature babies the best chance at a healthy life.

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