Prenatal Prediction of Delayed Abdominal Closure in Isolated Congenital Diaphragmatic Hernia Using Observed-to-Expected Lung-to-Head Ratio.

Objective: O/E LHR is a well-established prenatal severity marker in congenital diaphragmatic hernia (CDH), but its capacity to predict the postnatal need for delayed abdominal wall closure (DAC) remains undefined. We aimed to determine its predictive capacity. Method: Retrospective analysis of neonates with isolated left-sided CDH (2015-2026), comparing primary closure with DAC. Discriminative capacity was assessed by ROC analysis and the optimal cut-off was determined by bootstrap-aggregated approach. Logistic regression estimated univariate and liver herniation adjusted multivariate odds ratios (OR). Result: 45 neonates were included, 28 underwent primary closure and 17 required DAC. DAC was associated with lower gestational age, higher rates of liver herniation, greater ECMO requirement, and higher mortality than primary closure (all p < 0.01). O/E LHR showed excellent discriminative ability for DAC (AUC 0.939), with an optimal cut-off of 34.1% (sensitivity 82.35%, specificity 82.14%, positive predictive value 73.68%, negative predictive value 88.46%). O/E LHR was independently associated with DAC after multivariate analysis (OR 0.821, 95% CI 0.668-0.939, p = 0.002). Conclusions: O/E LHR was independently associated with DAC risk beyond liver herniation. These preliminary findings suggest a potential role for O/E LHR in prenatal risk stratification for DAC, pending external validation.