Umbilical Cord Management at Term and Late Preterm Birth: A Meta-analysis

Context: The International Liaison Committee on Resuscitation prioritized scientific review of umbilical cord management at term and late preterm birth.

Objective: To assess effects of umbilical cord management strategies (clamping timing and cord milking) in infants ≥34 weeks' gestational age.

Data sources: Cochrane Central Register of Controlled Trials, Medline, PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature, and trial registries searched July 2019.

Study selection: Two authors independently assessed eligibility of randomized controlled trials.

Data extraction: Two authors independently extracted data and assessed evidence certainty (Grading of Recommendations Assessment, Development and Evaluations).

Results: We identified 46 studies (9159 women and their infants) investigating 7 comparisons. Compared with early cord clamping (ECC) <30 seconds, delayed cord clamping (DCC) ≥30 seconds (33 studies), intact-cord milking (1 study), and cut-cord milking (2 studies) probably improve hematologic measures but may not affect survival without neurodisability, anemia in early infancy, or maternal postpartum hemorrhage. No differences in major neonatal morbidities are seen in studies comparing methods of optimizing placental transfusion (DCC versus cut-cord milking [3 studies], longer delays in clamping [7 studies], or physiologic parameters [3 studies]). Strategies that promote increased placental transfusion may be associated with greater phototherapy use. Evidence for all outcomes was low or very low certainty.

Limitations: Incompleteness and low certainty of findings limit applicability.

Conclusions: Compared with ECC, DCC or cord milking increases hemoglobin and hematocrit immediately after birth in infants ≥34 weeks' gestational age. The uncertain effects of DCC and cord milking compared with ECC on major morbidities limit usefulness of available evidence for policy and practice.