Importance  Neurodevelopmental impairments are common in children with congenital heart disease.

Objectives  To compare neurodevelopmental outcomes by cardiac diagnosis and identify associations between medical and social factors and early neurodevelopmental outcomes among children with congenital heart disease.

Design, Setting, and Participants  This cross-sectional analysis used neurodevelopmental follow-up data obtained between May 1, 2019, and June 30, 2022, and entered into the Cardiac Neurodevelopmental Outcome Collaborative (CNOC) registry, with linkage to the Pediatric Cardiac Critical Care Consortium registry. Children younger than 30 months from 25 CNOC sites were studied. Data analysis was performed between January 2023 and December 2024.

Exposures  Patients undergoing cardiac surgical repair or palliation requiring cardiopulmonary bypass at younger than 12 months who completed a neurodevelopmental assessment before 30 months of age.

Main Outcomes and Measures  Outcomes are the cognitive, language, and motor indexes on the Bayley Scales of Infant and Toddler Development-III/4. Factors analyzed by multivariable regression modeling include cardiac diagnosis and other previously identified medical risk factors and social drivers of adverse neurodevelopmental outcomes in patients with congenital heart disease.

Results  The study included 942 assessments from 868 children (median [IQR] age at index operation, 20 [6-127] days; 481 [56.1%] male, 102 [11.8%] with a genetic diagnosis). Across cardiac diagnostic groups, those with genetic diagnoses (n = 116 assessments) scored more than 1 SD lower on all Bayley indexes than those without (cognitive: 18.8; 95% CI, 15.3-22.4; language: 16.1; 95% CI, 12.2-20.0; motor: 20.9; 95% CI, 18.3-23.5; P < .001 for each). After adjustment for other characteristics, cardiac diagnosis was significantly associated with the cognitive and motor indexes, with patients with dextro-transposition of the great arteries (reference group) exhibiting the highest scores, whereas the mean scores for all other diagnoses were within the normal range (β coefficients [95% CIs] of –4.5 [–7.8 to –1.2] for coarctation, –3.8 [–10.8 to 3.1] for ventricular septal defect, –2.4 [–6.7 to 1.8] for tetralogy of Fallot, –4.0 [–6.4 to –1.7] for single-ventricle physiology, –2.4 [–9.7 to 5.0] for atrioventricular septal defect, and –3.4 [–6.1 to–0.6] for other cardiac diagnoses). Lower birth weight, male sex, older age at initial surgery, longer hospital length of stay, more cardiac catheterizations, and lower primary caregiver educational level were independently associated with worse performance on all indexes.

Conclusions and Relevance  In this cross-sectional study of early neurodevelopmental outcomes in children with congenital heart disease, there was significant variation in neurodevelopmental outcomes according to cardiac diagnosis; regardless of cardiac diagnosis, the presence of a genetic diagnosis was associated with lower neurodevelopmental scores. The heterogeneous outcomes found in this study reinforce the importance of surveillance for all infants undergoing heart surgery in the first year of life.