Umbilical Cord Management for Newborns <34 Weeks' Gestation: A Meta-analysis

The International Liaison Committee on Resuscitation prioritized scientific review of umbilical cord management strategies at preterm birth.

To determine the effects of umbilical cord management strategies (including timing of cord clamping and cord milking) in preterm infants <34 weeks' gestation.

Cochrane Central Register of Controlled Trials, Medline, PubMed, Embase, CINAHL, and trial registries were searched through July 2019 for randomized controlled trials assessing timing of cord clamping and/or cord milking.

Two authors independently assessed trial eligibility, extracted data, appraised risk of bias, and assessed evidence certainty (GRADE).

We identified 42 randomized controlled trials (including 5772 infants) investigating 4 different comparisons of cord management interventions.

Compared to early cord clamping, delayed cord clamping (DCC) and intact-cord milking (ICM) may slightly improve survival; however, both are compatible with no effect (DCC: risk ratio: 1.02, 95% confidence interval: 1.00 to 1.04, n = 2988 infants, moderate certainty evidence; ICM: risk ratio: 1.02, 95% confidence interval: 0.98 to 1.06, n = 945 infants, moderate certainty evidence). DCC and ICM both probably improve hematologic measures but may not affect major neonatal morbidities.

For many of the included comparisons and outcomes, certainty of evidence was low. Our subgroup analyses were limited by few researchers reporting subgroup data.

DCC appears to be associated with some benefit for infants born <34 weeks. Cord milking needs further evidence to determine potential benefits or harms. The ideal cord management strategy for preterm infants is still unknown, but early clamping may be harmful.