Emerging evidence suggests that an impaired foetal environment—defined as maternal factors such as hypertensive disorders and diabetes—might contribute to outcomes in neonates with CHD. With this multicentre study, we prospectively collected data regarding impaired foetal environment to assess the impact on mortality in two ventricle and single ventricle neonates with CHD.

A module of prospectively collected maternal-foetal environment data was linked to established Pediatric Cardiac Critical Care Consortium data from June 2019 to July 2020. All neonates undergoing cardiothoracic surgery were included in this study. The outcome was in-hospital mortality. The primary predictor was the degree of impaired foetal environment defined as none, mild, or significant based on the presence of maternal hypertensive and glucose homeostasis disorders.

There were a total of 1913 neonates included in this study from 26 different centres. 218 patients had at least 1 missing impaired foetal environment data field (11.8%). Impaired foetal environment was not associated with increased mortality; however, there was a strong trend in the preterm single ventricular population.

While the overall cohort did not demonstrate a statistically significant relationship between impaired foetal environment and mortality, a notable trend emerged among preterm infants with single-ventricle physiology, suggesting increased mortality associated with more severe impaired foetal environment. The absence of statistical significance in this subgroup is likely attributable to the limited sample size and the substantial proportion of missing data highlighting the challenges of the mother-baby dyad in data collections.