Delayed Versus Immediate Cord Clamping in Preterm Infants EDITORIAL COMMENT

Systemic reviews have shown that delaying the time of umbilical cord clamping can improve outcomes of preterm newborns. One such study found enhanced placental transfusion through delayed cord clamping, cord-palpation, or a combination of the 2 practices caused a lower infection and mortality rate when compared with immediate clamping. Despite this recent body of evidence, concerns exist about harm from delayed resuscitation and hyperbilirubinemia causing current professional guidelines to vary significantly.

This unblinded, randomized controlled trial compared the rates of a composite outcome of death and major morbidity between delayed and immediate cord clamping in infants born before 30 weeks of gestation. This study took place in 25 participating centers across 25 countries between 2010 and 2017. Eligible participants were randomly assigned to receive either immediate cord clamping defined as clamping within 10 seconds after delivery or delayed clamping defined as clamping at 60 or more seconds without cord palpation. The primary study outcomes were death, severe brain injury, severe retinopathy of prematurity, necrotizing enterocolitis, and late-onset sepsis, each diagnosed by 36 weeks of postmenstrual age. Tests for interaction were used to detect heterogeneity in the data between the primary outcomes across 3 subgroups: gestational age (= 27 week), sex, and method of delivery.

A total of 1566 infants were deemed eligible for the study with 782 assigned to immediate cord clamping and 784 assigned to delayed cord clamping. The average times of clamping for the delayed and immediate cohorts were 60 seconds and 5 seconds, respectively. Adherence to the randomized protocol varied between the groups (94.9% for the immediate cohort, 73.2% in the delayed cohort) with the primary reason for nonadherence in the delayed cohort being clinical concern about infant well-being. No significant difference was found in the primary outcome at 36 weeks between immediate clamping (37.2%) and delayed clamping (37.0%) (relative risk [RR], 1.00; 95% confidence interval [CI], 0.88-1.13; P = 0.96). Death by 36 weeks postmenstrual age occurred in 9.0% of those in the immediate cohort and 6.4% in the delayed clamping group (RR, 0.69; 95% CI, 0.49-0.97; P = 0.03 unadjusted and 0.39 after post hoc adjustment for multiple secondary comparisons). More infants in the immediate clamping cohort received red blood cell tranfusions (60.5% vs 52.1% in the delayed clamping cohort). There were no significant differences in Apgar score, peak bilirubin level, or other major morbidities.

The results of this study show that there is no significant difference on the rates of mortality or major morbidity at 36 weeks of gestation among preterm infants receiving immediate umbilical cord clamping versus delayed clamping.