Supplementary Material for: Deferred cord clamping in very preterm triplets and outcomes: A retrospective cohort study

Introduction: There is paucity of data with regards to benefits and harms associated with deferred cord clamping (DCC) in triplets. Objective was to compare outcomes of triplets following exposure of DCC in a national cohort admitted to NICU in Canada with a gestational age of <33 weeks.
Methods: We conducted a retrospective, population-representative, cohort study of triplets born before 33 weeks’ gestation in Canadian NICU. Deferred cord clamping was defined as cord clamping conducted after 30 seconds of birth of neonate. Our primary outcome was survival without neurological injury or late onset sepsis and individual outcomes of neonatal survival, severe neurological injury and late onset sepsis. We utilized target trial emulation technique to analyze data considering discordant exposure, discordant outcomes and correlated nature of outcomes within triplet set.
Results: Of the 226 sets of triplets included in the study, 100 sets had all 3 received DCC, 22 had 2/3 received DCC, 32 had 1/3 received DCC and 72 had none received DCC for a total of 376 neonates who received DCC and 302 did not receive DCC. There was no association of benefit or harm between DCC and any of the outcomes studied in any of the analyses. Univariate comparison of outcomes indicated higher receipt of inotropes and higher length of stay among those who did not receive DCC compared to other groups.
Discussion: In this retrospective cohort study, DCC was not associated with benefit or harm in very preterm triplets.