Congenital Heart Defects and Measures of Prenatal Brain Growth: A Systematic Review.

BACKGROUND: We summarize the evidence for an association between congenital heart defects and prenatal brain growth through a systematic literature review. Congenital heart defects are among the most common malformations, affecting approximately six per 1000 live births. The association between congenital heart defects and long-term neurodevelopmental disorders is well established. Increasing evidence suggests an association between impaired prenatal brain growth and neurodevelopmental disorders in children with congenital heart defects.

METHODS: Systematic literature searches were performed in PubMed and EMBASE. We included original studies comparing fetuses or newborns with congenital heart defects to reference fetuses or newborns with respect to brain biometrics, including biparietal diameter, brain volume, and head circumference at birth. The study characteristics and the results were extracted and presented in tables. No meta-analysis was undertaken.

RESULTS: Twenty-eight studies were included. All except two studies found an association between congenital heart defects and measures of reduced prenatal brain growth. The strongest evidence concerned hypoplastic left heart syndrome, tetralogy of Fallot, and transposition of the great arteries.

CONCLUSIONS: The literature suggests an association between congenital heart defects and measures of impaired prenatal brain growth. However, most studies were small and failed to include important potential confounding factors and to address other sources of potential bias as well. Future large-scale studies that address potential confounders are warranted.