Cord stripping in preterm neonates

Krueger and colleagues conducted an RCT to determine whether cord stripping in addition to delayed cord clamping resulted in improved outcomes compared with delayed cord clamping alone (1). They describe both the control and intervention manoeuver sufficiently for each to be replicated by other clinicians. However, there are a number of limitations. The method of treatment allocation is somewhat unusual. Rather than using a computer to randomly generate treatment allocations which are then placed in sequentially numbered, sealed opaque envelopes, this study had equal numbers of envelopes which were scrambled by a third-party registered nurse. In theory, this is a form of random allocation, but it lacks the robustness of more conventional methods. It is unclear whether the neonatal team was present during the allocated treatment or whether they were able to see which intervention was applied. The authors acknowledge that recruitment to this trial was challenging, with only 32% of eligible infants enrolled. This highlights the important issue of reliance on an antenatal consent process, particularly the limited generalizability inherent in delivery room studies which rely solely on antenatal consent. The choice of primary outcome (haematocrit) is conventional in this field but unlikely, by itself, to convince clinicians to change their practice. It does, however, allow the researchers to answer a question in a single centre and can be viewed as a hypothesis-generating study. Having found no difference in their primary outcome, the authors present a subanalysis of their primary outcome by gestational age. This was apparently decided upon post hoc, and the infants were not stratified for this baseline variable at randomization. It is unclear why the cut point of 28 weeks was chosen. The interesting observation that cord stripping reduced haematocrit in infants equal to or above 28 weeks, but increased it in those less than 28 weeks is perhaps most likely due to chance. The authors findings contrast with those of a recent meta-analysis of cord stripping which found that cord stripping increased haematocrit as well as reducing bronchopulmonary dysplasia and intraventricular haemorrhage (2). Two of the studies in that systematic review compared cord stripping with delayed cord clamping. The authors claim that they were evaluating the additional benefits of cord stripping on delayed cord clamping is worth closer examination. The control group had their cords cut at 30 seconds, shorter than the conventional definition of at least one minute used in most randomised trials (3). The procedure in the intervention group occurred during the first 30 seconds, but the four stripping events and four to five seconds between each event would have taken most of that time. There are now at least eight RCTs including more than 500 infants investigating the safety and efficacy of umbilical cord stripping. The ground work has been performed, and agencies need to be encouraged to fund a large-scale multicenter RCT of this therapy, powered to detect a difference in important outcomes including mortality and neurodevelopment in infancy. Such a trial is required before this promising technique becomes standard practice.