Over 13 million infants are born prematurely worldwide each year, posing significant risks to their survival and long-term health. One area of major interest in neonatal care is the timing of umbilical cord clamping. While delayed clamping (waiting at least 60 seconds after birth) is beneficial for term infants, its effects on preterm infants, particularly those born extremely preterm, are more uncertain. Various strategies like early clamping, delayed clamping, and cord milking have been proposed, but their relative effectiveness is less clear.
To address this uncertainty, a comprehensive systematic review and individual participant data meta-analysis was conducted. This approach, considered the gold standard for combining trial data, involved pooling de-identified participant-level data from 48 randomised trials and more than 6,000 babies. The researchers wanted to evaluate the effects of deferred cord clamping, cord milking, and immediate clamping on mortality and morbidity in preterm infants. The methods included thorough searches of medical databases and trial registries and data quality checks.
The meta-analysis found with high certainty that deferred cord clamping, compared to immediate clamping, significantly reduces the risk of death before discharge in preterm infants. This beneficial effect of deferred clamping was consistent across various subgroups of preterm infants. In contrast, the evidence for cord milking was less clear, with no significant difference in mortality compared to immediate clamping. However, they did find that cord milking might increase the risk of severe intraventricular hemorrhage, particularly in infants born before 28 weeks of gestation. Both deferred clamping and cord milking were associated with reduced need for blood transfusion.
This meta-analysis provides robust evidence that deferred cord clamping is beneficial for preterm infants, potentially guiding changes in clinical practice and international guidelines. The findings highlight the need for careful consideration of cord clamping strategies in preterm births, particularly for the most vulnerable infants. While the benefits of deferred clamping are clear, the authors say the potential risks associated with cord milking need to be investigated further.
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