Association of Deferred vs Immediate Cord Clamping With Severe Neurological Injury and Survival in Extremely Low-Gestational-Age Neonates

IMPORTANCE Deferred cord clamping (DCC) is recommended for term and preterm neonates to reduce neonatal complications. Information on the association of DCC with outcomes for extremely low-gestational-age neonates is limited. OBJECTIVE To compare neonatal outcomes after DCC and immediate cord clamping (ICC) in extremely low-gestational-age neonates. DESIGN, SETTING, AND PARTICIPANTS In this retrospective cohort study, eligible neonates born between January 1, 2011, and December 31, 2015, were divided into 2 groups: DCC and ICC. Neonates were recruited from tertiary neonatal intensive care units participating in the Canadian Neonatal Network, and analysis began in January 2018. Neonates were eligible if they were born at 22 to 28 weeks' gestational age and admitted to a participating Canadian Neonatal Network neonatal intensive care unit during the study period. Neonates who were born outside a tertiary-level neonatal intensive care unit, were moribund at birth, needed palliative care before delivery, had major congenital anomalies, or lacked cord clamping information were excluded. MAIN OUTCOMES AND MEASURES Composite of severe neurological injury (intraventricular hemorrhage grade >= 3 with or without persistent periventricular echogenicity) or mortality before discharge. RESULTS Of 8221 admitted neonates, 4680 were included in the study, of whom 1852 (39.6%) received DCC and 2828 (60.4%) received ICC. There were 974 (52.7%) male neonates in the DCC group and 1540 (54.5%) male neonates in the ICC group. Median (interquartile range) gestational age was 27 (25-28) weeks for the DCC group and 26 (25-27) weeks for the ICC group. Median (interquartile range) birth weight was 930 (760-1120) g and 870 (700-1060) g for DCC and ICC groups, respectively. Neonates who received DCC had significantly reduced odds of the composite outcome of severe neurological injury or mortality (adjusted odds ratio [AOR], 0.80; 95% CI, 0.67-0.96), mortality (AOR, 0.74; 95% CI, 0.59-0.93), and severe neurological injury (AOR, 0.80; 95% CI, 0.64-0.99). The odds of bronchopulmonary dysplasia (AOR, 1.00; 95% CI, 0.84-1.19), retinopathy of prematurity stage 3 or higher (AOR, 0.94; 95% CI, 0.71-1.25), necrotizing enterocolitis stage 2 or higher (AOR, 0.86; 95% CI, 0.66-1.12), late-onset sepsis (AOR, 1.02; 95% CI, 0.85-1.22), and receipt of 2 or more blood transfusions (AOR, 0.93; 95% CI, 0.79-1.10) did not differ between the groups. Propensity score-matched analyses revealed lower odds of mortality (AOR, 0.79; 95% CI, 0.65-0.95), late-onset sepsis (AOR, 0.81; 95% CI, 0.69-0.95), and treatment for hypotension (AOR, 0.75; 95% CI, 0.60-0.95) in the DCC group. CONCLUSIONS AND RELEVANCE In this study of extremely low-gestational-age neonates who received DCC or ICC, DCC was associated with reduced risk for the composite outcome of severe neurological injury or mortality.