Neurodevelopmental disorders occur in up to 50% of children with CHD. Small head circumference at birth has been associated with impaired neurodevelopment in patients with complex CHD. It is unknown if patients with simple CHD such as septal defects have smaller head circumferences. The objective of this study was to investigate the head circumference at birth in neonates with either an atrial or a ventricular septal defect.

This study is part of the Copenhagen Baby Heart Study; a prospective, population-based cohort study of more than 25,000 neonates. The neonates were examined with a comprehensive transthoracic echocardiography within the first 30 days of birth including assessment for atrial or ventricular septal defects. The head circumference at birth in term neonates with septal defects was compared to the head circumference in matched controls, term neonates without septal defects from the same birth cohort.

Neonates with septal defects (n = 1,030; 45.2% male; mean birthweight 3,534g ± 483g) had a mean head circumference of 34.8 cm (95% confidence interval 34.7–34.9 cm), compared to neonates without septal defects (n = 5,150; 45.6% male; mean birthweight 3,546g ± 476g) of 34.7 cm (95% confidence interval 34.7–34.8 cm); p-value 0.07. Mean calculated z-score of head circumferences was 0.05 for neonates with septal defects and –0.01 for neonates without septal defects, p = 0.07. Dividing cases into neonates with atrial septal defects, ventricular septal defects, and those without septal defects did not show differences between groups, p = 0.14.

The head circumference in term neonates with septal defects did not differ from matched controls without septal defects.