Impact of Deferred Cord Clamping on Mortality and Severe Neurologic Injury in Twins Born at <30 Weeks of Gestation

OBJECTIVE: To determine whether deferred cord clamping (DCC) compared with early cord clamping (ECC) was associated with reduction in death and/or severe neurologic injury among twins born at <30 weeks of gestation. STUDY DESIGN: We performed a retrospective cohort study including all liveborn twins of <30 weeks admitted to a tertiary-level neonatal intensive care unit (NICU) in Canada between 2015 and 2018 using the Canadian Neonatal/Preterm Birth Network database. We compared DCC ≥30 seconds vs ECC <30 seconds. Our primary outcome was a composite of death and/or severe neurologic injury (severe intraventricular hemorrhage grade III/IV and/or periventricular leukomalacia). Secondary outcomes included neonatal morbidity and health care utilization outcomes. We calculated aORs and β coefficients for categorical and continuous variables, along with 95% CI. Models were fitted with generalized estimated equations accounting for twin correlation. RESULTS: We included 1597 twins (DCC, 624 [39.1%]; ECC, 973 [60.9%]). Death/severe neurologic injury occurred in 17.8% (n = 111) of twins who received DCC and in 21.7% (n = 211) of those who received ECC. The rate of death/severe neurologic injury did not differ significantly between the DCC and ECC groups (aOR 1.07; 95% CI, 0.78-1.47). DCC was associated with reduced blood transfusions (adjusted β coefficient, -0.49; 95% CI, -0.86 to -0.12) and NICU length of stay (adjusted β coefficient, -4.17; 95% CI, -8.15 to -0.19). CONCLUSIONS: The primary composite outcome of death and/or severe neurologic injury did not differ between twins born at <30 weeks of gestation who received DCC and those who received ECC, but DCC was associated with some benefits.