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

To compare the effects of delayed cord clamping vs early cord clamping on all-cause in-hospital mortality and selected morbidities among preterm twin neonates.

A search of PubMed, Ovid Medline, Embase, Cochrane database, Web of Science, and CINAHL was conducted in December 2023 for studies comparing delayed cord clamping to immediate cord clamping in preterm twin neonates.

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.

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.

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

Delayed cord clamping may decrease mortality risk in preterm twin infants without affecting major neonatal morbidities. Further evidence is needed to support its safety in preterm twins.