Objective: To investigate the effects of interventions promoting placental transfusion at delivery (delayed cord clamping or umbilical cord milking) compared with early cord clamping on outcomes among premature neonates of less than 32 weeks of gestation.
Data sources: A systematic search was conducted of PubMed, Embase, and ClinicalTrials.gov databases (January 1965 to December 2013) for articles relating to placental transfusion strategies in very preterm neonates.
Methods of study selection: Literature searches returned 369 articles with 82 considered in full. We only included data from studies with an average gestational age of less than 32 weeks of gestation enrolled in randomized trials of enhanced placental-fetal transfusion interventions (delayed cord clamping or umbilical cord milking) compared with early cord clamping.
Tabulation, integration, and results: We identified 12 eligible studies describing a total of 531 neonates with an average gestation of 28 weeks. Benefits of greater placental transfusion were decreased mortality (eight studies, risk ratio 0.42, 95% confidence interval [CI] 0.19-0.95, 3.4% compared with 9.3%, P=.04), lower incidence of blood transfusions (six studies, risk ratio 0.75, 95% CI 0.63-0.92, 49.3% compared with 66%, P<.01), and lower incidence of intraventricular hemorrhage (nine studies, risk ratio 0.62, 95% CI 0.43-0.91, 16.7% compared with 27.3%, P=.01). There was a weighted mean difference of -1.14 blood transfusions (six studies, 95% CI -2.01-0.27, P<.01) and a 3.24-mmHg increase in blood pressure at 4 hours of life (four studies, 95% CI 1.76-4.72, P<.01). No differences were observed between the groups across all available safety measures (5-minute Apgar scores, admission temperature, incidence of delivery room intubation, peak serum bilirubin levels).
Conclusions: Results of this meta-analysis suggest that enhanced placental transfusion (delayed umbilical cord clamping or umbilical cord milking) at birth provides better neonatal outcomes than does early cord clamping, most notably reductions in overall mortality, lower risk of intraventricular hemorrhage, and decreased blood transfusion incidence. The optimal umbilical cord clamping practice among neonates requiring immediate resuscitation remains uncertain.