Umbilical cord milking versus delayed cord clamping in term and late-preterm infants: a systematic review and meta-analysis

Objective To conduct a systematic review and meta-analysis to compare the efficacy and safety of umbilical cord milking (UCM) versus delayed cord clamping (DCC) in term and late-preterm infants. Methods MEDLINE, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials, Clinical trial registries, and Gray literature were searched for randomized controlled trials (RCTs) comparing UCM with DCC in term and late-preterm infants for both short-term and long-term outcomes. Intact and cut UCM were compared separately with DCC using subgroup analysis. We used fixed effect model to pool the data. Random effects model was used when there was significant heterogeneity. Results Nine studies (1632 infants) were included in the systematic review. Milking was performed on intact cord (i-UCM) in five studies (n = 829) and on cut cord (c-UCM) in four studies (n = 803). Cord milking significantly improved hemoglobin level at 48-72 h of life when compared to DCC (six studies, n = 924, mean difference 0.36 g/dL; 95% CI: 0.19-0.53). In addition, hemoglobin level at six to eight weeks of age was also significantly higher in the studies comparing i-UCM with DCC (two studies, n = 550: mean difference 0.16 g/dL; 95% CI: 0.06-0.27). There was no difference between the UCM group and DCC group for any other outcome. Only one study provided information on growth and hematological parameters at one year of age. Neurodevelopmental outcomes were not reported. None of the studies included non-vigorous infants. The grade of evidence was low to very low for all the outcomes studied. Conclusion UCM is comparable to DCC in improving short-term hematological outcomes in term and late-preterm vigorous infants. Trials assessing the effect of UCM on important clinical and long-term outcomes among non-vigorous mature preterm infants are urgently required.