The effect of delayed cord clamping on early cardiac and cerebral hemodynamics, mortality, and severe intraventricular hemorrhage in preterm infants < 32 weeks: a systematic review and meta-analysis of clinical trials.

UNLABELLED: The purpose of this study is to evaluate the impact of DCC (> 30 s) compared to immediate cord clamping (ICC) or umbilical cord milking (UCM) on early cardiac and cerebral hemodynamics, mortality, and severe intraventricular hemorrhage (IVH) in very preterm infants. We searched Ovid Medline, EMBASE, and Cochrane CENTRAL from inception to September 28, 2023, and included randomized controlled trials (RCTs) comparing preterm infants < 32 weeks who received DCC to ICC or UCM. The results were obtained using the Mantel-Haenszel and pooled with a random-effects model. Fifteen articles (2967 patients) were selected, comparing DCC to ICC (10), DCC to UCM (4), and one three-arm study. DCC resulted in a slight increase in superior vena cava (SVC) flow compared to ICC (MD 16.09 ml/kg/min, 95% CI = 4.03 to 28.15, I2 = 20%; low-certainty evidence). There was little to no difference in right ventricular output (RVO) after DCC compared to ICC (MD - 2.09 ml/kg/min, 95% CI = - 26.20 to 22.02, I2 = 17%; low-certainty evidence). DCC resulted in a large reduction in mortality compared to ICC (RR 0.64, 95% CI = 0.47 to 0.88) but was very uncertain compared to UCM. DCC may reduce severe IVH compared to UCM (RR 0.54, 95% CI = 0.28 to 1.06).

CONCLUSION: DCC improves outcomes in preterm infants < 32 weeks when compared with ICC, as indicated by an increase in SVC flow and regional cerebral oxygenation (rSO2) (moderate- and low-certainty evidence) and reduced mortality. There is low- and very-low-certainty evidence to suggest little to no difference in mortality and cardiac and cerebral hemodynamics after DCC compared to UCM.

WHAT IS KNOWN: • DCC or UCM assists the physiological transition from intrauterine to extra-uterine life by increasing the amount of circulating blood at birth in preterm neonates. • In comparison to ICC, DCC or UCM were shown to reduce mortality, NEC, and infection in preterm infants < 32 weeks; however, a higher incidence of severe IVH was a concern in the UCM group.

WHAT IS NEW: • Although DCC has been associated with a large reduction in mortality for preterm infants < 32 weeks compared to ICC, the current evidence is of moderate certainty. However, there appears to be little or no difference in early cardiac hemodynamic parameters and cerebral near-infrared spectroscopy parameters (low or very-low certainty evidence). • Current evidence, which is of low and very low certainty, suggests that there is little or no difference in cardiac and cerebral hemodynamics, mortality, and severe IVH with DCC compared to UCM.