Mortality and Major Neonatal Morbidity in Preterm Infants with Serious Congenital Heart Disease.

Objectives To investigate the trend of 1-year mortality and neonatal morbidities in preterm infants with serious congenital heart disease (CHD). Study design Cohort study using a population based administrative dataset of all liveborn infants 26-36 weeks gestational age (GA) with serious CHD born in California from 2011 to 2017. We assessed 1-year mortality and major neonatal morbidity (retinopathy of prematurity, bronchopulmonary dysplasia, necrotizing enterocolitis, intraventricular hemorrhage > grade II, periventricular leukomalacia) across the study period and compared these outcomes to infants without CHD. Results We identified 1921 preterm infants with serious CHD. The relative risk (RR) of death decreased by 10.6% for each year (RR 0.89, 95% CI 0.84-0.95) of the study period. The RR of major neonatal morbidity increased by 8.3% for each year (RR 1.08, 95% CI 1.02-1.15). When compared with preterm neonates without any CHD (n=234,522), the adjusted risk difference (ARD) for mortality was highest at 32 weeks of GA (9.7%, 95% CI 8.3-11.2), for major neonatal morbidity it was highest at 28 weeks (21.9%, 95% CI 17.0-26.9) and for the combined outcome it was highest at 30 weeks (ARD 26.7, 95% CI 23.3-30.1). Conclusions Mortality in preterm neonates with serious CHD decreased over the last decade, and major neonatal morbidity increased. Preterm infants with a GA of 28-32 weeks have the highest mortality or morbidity when compared with their peers without CHD. These results support the need for specialized and focused medical neonatal care in preterm neonates with serious CHD.