Delayed cord clamping in preterm twin infants: a systematic review and meta-analysis

Objective: To compare the effects of delayed cord clamping (DCC) versus early cord clamping (EDD) on all-cause in-hospital mortality and selected morbidities among preterm twin neonates.

Data sources: A search of PubMed, Ovid Medline, Embase, Cochrane database, Web of Science and CINAHL was conducted in December 2023 for studies comparing DCC to ICC in preterm twin neonates.

Study eligibility criteria: Studies were deemed eligible if they included preterm twin neonates (< 37 weeks of gestation), compared delayed (≥ 30 seconds) vs early (<30 seconds) umbilical cord clamping at delivery and described at least one outcome of interest. Outcomes of interest were mortality, maternal hemorrhage, transfusion, severe interventricular hemorrhage (grade III or IV), bronchopulmonary dysplasia, necrotizing enterocolitis, retinopathy of prematurity (stage IV or receiving treatment) and length of hospital stay.

Study appraisal and synthesis methods: Two reviewers independently selected the studies, assessed bias and extracted data. Risk ratio and mean difference with 95% confidence intervals were determined by fixed effects models, heterogeneity by I² statistics.

Results: Five studies compared DCC vs ECC in 2075 infants. Meta-analysis showed a significant reduction in mortality [(RR) 0.70 (95% CI 0.53-0.93)], a significant decrease in the risk of red blood cell transfusion [(RR) 0.42 (95% CI 0.28 - 0.64)] as well as a lower risk of retinopathy of prematurity [(RR) 0.50 (95% CI 0.26-0.96)] with DCC in twin population. DCC had no impact on the incidence of intraventricular hemorrhage [(RR) 1.01 (95% CI 0.79, 1.28)], of bronchopulmonary dysplasia [(RR) 0.67 (95% CI 0.36, 1.24)], of necrotizing enterocolitis [(RR) 1.02 (95% CI 0.60, 1.73)]. There was no significant effect on length of hospital stay [-0.10 (-0.20, -0.00)]. None reported maternal hemorrhage.

Conclusion: DCC may decrease mortality risk in preterm twin infants without affecting major neonatal morbidities. Further evidence is needed to support its safety in preterm twins.