Atrial septal defect is commonly considered a minor CHD, but morbidity and mortality are higher compared to the background population. Maternal pre-eclampsia is associated with CHD in the offspring in large registry-based studies. However, the association between pre-eclampsia and atrial septal defects might be subject to detection bias, as many atrial septal defects are asymptomatic or might remain undiagnosed until late in life.

We investigated the association between maternal pre-eclampsia and the risk of atrial septal defects in a population-based cohort of neonates examined with echocardiography.

Neonates included in the Copenhagen Baby Heart Study, who were examined using transthoracic echocardiography within 30 days of birth, were systematically assessed for atrial septal defects and patent foramen ovale using a standardised algorithm. Using log-linear binomial regression and polytomous logistic regression, we compared the risk of atrial septal defects in neonates exposed to maternal pre-eclampsia with the risk in neonates not exposed to pre-eclampsia.

Our study cohort included 12,354 neonates (mean age, 11 days), including 462 exposed to maternal pre-eclampsia. Atrial septal defect was found in 5.9% (n = 732) of the study cohort and compared with unexposed neonates, neonates exposed to maternal pre-eclampsia had a modestly increased risk of atrial septal defects (adjusted risk ratio 1.19, 95% confidence interval 0.83, 1.64). Estimates were robust to various exclusions in sensitivity analyses.

There appears to be an association between maternal pre-eclampsia and atrial septal defect in the neonate in a population-based cohort of neonates.

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.

An interatrial communication is present in most neonates. The majority are considered the “normal” patency of the oval foramen, while a minority are abnormal atrial septal defects. Differentiation between the two with transthoracic echocardiography may be challenging, and no generally accepted method of classification is presently available. We aimed to develop and determine the reliability of a new classification of interatrial communications in newborns.

An algorithm was developed based on echocardiographic criteria from 495 newborns (median age 11[8;13] days, 51.5% females). The algorithm defines three main categories: patency of the oval foramen, atrial septal defect, and no interatrial communication as well as several subtypes. We found an interatrial communication in 414 (83.6%) newborns. Of these, 386 (93.2%) were categorised as patency of the oval foramen and 28 (6.8%) as atrial septal defects.

Echocardiograms from another 50 newborns (median age 11[8;13] days, 36.0% female), reviewed by eight experts in paediatric echocardiography, were used to assess the inter- and intraobserver variation of classification of interatrial communications into patency of the oval foramen and atrial septal defect, with and without the use of the algorithm. Review with the algorithm gave a substantial interobserver agreement (kappa = 0.66), and an almost perfect intraobserver agreement (kappa = 0.82). Without the use of the algorithm, the interobserver agreement between experienced paediatric cardiologists was low (kappa = 0.20).

A new algorithm for echocardiographic classification of interatrial communications in newborns produced almost perfect intraobserver and substantial interobserver agreement. The algorithm may prove useful in both research and clinical practice.