Improving early detection of critical congenital heart disease in a high-performing prenatal screening system: the OXYNAT interventional cohort study

Background Early detection of critical congenital heart disease (CHD) is essential to prevent cardiovascular collapse and improve neonatal outcomes. While prenatal screening has advanced significantly in high-income countries, postnatal detection remains a safety net, particularly for left-sided lesions. Although pulse oximetry (PO) screening has been evaluated in several settings with high prenatal detection rates, the added value of combining it with systematic paediatric examination, and its impact on care pathways remains incompletely characterised in such contexts. Objective To evaluate the diagnostic performance and care pathway impact of PO screening—alone and combined with routine paediatric examination—for detecting critical CHD in a high-performing regional prenatal screening system. Methods The OXYNAT study was a prospective, population-based interventional cohort in 28 maternity hospitals in Nouvelle-Aquitaine, France. 19 639 newborns were enrolled. PO was performed between 6 and 24 hours of life, followed by routine paediatric examination. Critical cases with CHD were identified through active multisource surveillance and followed for 1 year (supplemental file 1, visual abstra). Results Among the 14 infants diagnosed postnatally with a critical CHD, one death occurred in relation to delayed diagnosis of truncus arteriosus. PO alone yielded a sensitivity of 53.8% and specificity of 99.2% for detecting critical CHD. The combined strategy with paediatric examination improved sensitivity to 92.9% while maintaining high specificity (97.7%). However, only 4 of 14 infants postnatally followed an optimal care trajectory. Delays were mainly due to misinterpretation of early signs, incomplete echocardiographic assessment and coordination gaps. Conclusions In a healthcare setting with high antenatal CHD detection, PO alone is insufficient. Integrating systematic paediatric examination significantly improves diagnostic performance. Trial registration number NCT03078218 .