Study shows how congenital heart disease affects blood supply before birth

CHD is a common birth defect that affects the development of the heart and brain

Researchers from the School of Biomedical Engineering and Imaging Sciences and clinicians at Evelina London Children’s Hospital, as part of Guy’s and St Thomas’s NHS Foundation Trust, have shown how congenital heart disease (CHD) can affect early brain development in children.

The study found that how CHD affects the blood supply to the brain prior to birth could be key to understanding early brain development.

CHD is the most common birth defect and comprises a group of conditions in which the heart does not develop normally in the womb.

Children affected by CHD have also been shown to have abnormal brain development and difficulties learning. However, the reasoning for this has been unclear.

After splitting up different types of CHD into groups according to cerebral substrate delivery – how CHD could affect oxygen delivery and nutrients, including glucose, to the brain – researchers used advanced foetal magnetic resonance imaging (MRI) on over 500 women to identify brain growth.

Professor Serena Counsell, head of advanced neuroimaging at the Centre for Developing Brain at the School of Biomedical Engineering and Imaging Sciences, explained that “foetal neuroimaging enables alterations in brain development to be identified in utero”.

Compared to a group of unaffected pregnancies, the groups of CHD with lower cerebral substrate delivery had smaller brains in comparison to CHD groups with normal cerebral substrate delivery, which showed no differences in brain growth.

“Understanding the biological mechanisms behind the impairments in brain development that we see in some cases of CHD is important for trying to decode how and why they occur and what we might be able to do to prevent their occurrence in the first place,” said Daniel Cromb, a clinical research fellow at the School of Biomedical Engineering and Imaging Sciences.

He added: “Information about the different types of CHD and their association with foetal brain growth helps clinicians when having discussions with women and families who are pregnant with a foetus with CHD.”