Necrotising enterocolitis and mortality in very preterm babies with severe congenital heart disease

Abstract Background Prematurity and congenital heart disease (CHD) are risk factors for neonatal morbidity, including necrotising enterocolitis (NEC), and mortality. We describe the rates of NEC and survival in very preterm babies with severe CHD (sCHD), requiring cardiac intervention before discharge. Methods Retrospective cohort study utilizing the National Neonatal Research Database that included babies born <32weeks’ gestation admitted to neonatal units in England and Wales, 2012–2020. Exposure: Babies born <32weeks’ gestation with sCHD, that require intervention before discharge (excluding patent arterial ducts). Outcomes: rates of sCHD, severe NEC (requiring surgery or death) and mortality (death before 37 weeks’ CGA or neonatal discharge, whichever occurred first). Results 438/68,423 babies had a sCHD diagnosis (6.4 per 1000 admissions <32weeks). Compared to non-CHD infants, sCHD infants had a higher rate of severe NEC (7.1% (95% CI 5.0–9.9%) vs.3.7% (95% CI 3.6–3.8%), ( p < 0.001)) and higher mortality before 37weeks’ corrected gestational age (CGA) (31%, (95% CI 26.8–35.4%) vs. 10% (95% CI, 9.7, 10.2%) ( p < 0.001)). Adjusted models showed that very preterm sCHD babies were two times more likely to develop NEC and six times more likely to die before 37weeks’ CGA. Conclusion Very preterm babies with sCHD have higher rates of NEC and mortality before cardiac intervention. Impact Prematurity and severe congenital heart disease increase the risk of necrotising enterocolitis (NEC) and death. We found that in very preterm babies with severe CHD the odds of developing severe NEC were twice as high, and the odds of death were six times greater, compared to very preterm babies without sCHD. Careful planning and counselling are needed in preterm deliveries of babies with severe CHD to reduce the odds of NEC and mortality.