Deferred cord clamping in very and extremely preterm monochorionic twins: A retrospective cohort study.

OBJECTIVE: To assess whether deferred cord clamping (DCC) is associated with reduced death and/or severe brain injury compared to early cord clamping (ECC) in very and extremely preterm monochorionic-diamniotic (MCDA) twins. STUDY DESIGN: This multicenter retrospective cohort study included liveborn MCDA twins born under 32 weeks of gestation and admitted to any tertiary-level neonatal intensive care unit (NICU) participating in the Canadian Neonatal Network (CNN) in Canada between 2018 and 2023. We compared DCC ≥30s to ECC<30s. The primary composite outcome was death before discharge and/or severe brain injury (intraventricular hemorrhage ≥ grade III and/or cystic periventricular leukomalacia). Secondary outcomes included neonatal morbidities and interventions. Adjusted odds ratios (aORs) for categorical variables and ratio of means for continuous variables were estimated with 95% confidence intervals (CIs). Generalized estimating equation (GEE) models accounted for the correlation between twins. RESULTS: Approximately 42% of first-born and 54% of second-born MCDA twins received DCC. The primary composite outcome of death and/or severe brain injury occurred in 10% (48/488) of twins who received DCC and 16% (82/529) of those who received ECC (aOR 0.93; 95% CI 0.60-1.45). Among secondary outcomes, there were no significant differences in neonatal morbidities or interventions, except for a significant reduction in red blood cell transfusions, with 24% (115/488) of twins in the DCC group receiving at least one transfusion versus 43% (229/529) in the ECC group (aOR 0.46; 95% CI 0.33-0.66). CONCLUSIONS: Among MCDA twins born at < 32 gestational weeks, DCC did not impact the risk of death and/or severe brain injury compared to ECC but it was associated with decreased need for transfusions.