Michael P Meyer, Elizabeth Nevill, Maisie M Wong

Placental transfusion (by means of delayed cord clamping (DCC), cord milking, or cord stripping) confers benefits for preterm infants. It is not known if providing respiratory support to preterm infants before cord clamping improves outcomes. To assess the efficacy and safety of respiratory support provided during DCC compared with no respiratory support during placental transfusion (in the form of DCC, milking, or stripping) in preterm infants immediately after delivery. We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL, 2017, Issue 5), MEDLINE via PubMed (1966 to 19 June 2017), Embase (1980 to 19 June 2017), and CINAHL (1982 to 19 June 2017). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomized controlled trials and quasi-randomized trials. Randomized, cluster randomized, or quasi-randomized controlled trials enrolling preterm infants undergoing DCC, where one of the groups received respiratory support before cord clamping and the control group received no respiratory support before cord clamping. All review authors assisted with data collection, assessment, and extraction. Two review authors assessed the quality of evidence using the GRADE approach. We contacted study authors to request missing information. One study fulfilled the review criteria. In this study, 150 preterm infants of less than 32 weeks' gestation undergoing 60 second DCC were randomized to a group who received respiratory support in the form of continuous positive airway pressure (CPAP) or positive pressure ventilation during DCC and a group that did not receive respiratory support during the procedure. Mortality during hospital admission was not significantly different between groups with wide confidence intervals (CI) for magnitude of effect (risk ratio (RR) 1.67, 95% CI 0.41 to 6.73). The study did not report neurodevelopmental disability and death or disability at two to three years of age. There were no significant differences between groups in condition at birth (Apgar scores or intubation in the delivery room), use of inotropic agents (RR 1.25, CI 0.63 to 2.49), and receipt of blood transfusion (RR 1.03, 95% CI 0.70 to 1.54). In addition, there were no significant differences in the incidences of any intraventricular haemorrhage (RR 1.50, 95% CI 0.65 to 3.46) and severe intraventricular haemorrhage (RR 1.33, 95% CI 0.31 to 5.75). Several continuous variables were reported in subgroups depending on method of delivery. Unpublished data for each group as a whole was made available and showed peak haematocrit in the first 24 hours and duration of phototherapy did not differ significantly. Overall, the quality of evidence for several key neonatal outcomes (e.g. mortality and intraventricular haemorrhage) was low because of lack of precision with wide CIs. The results from one study with wide CIs for magnitude of effect do not provide evidence either for or against the use of respiratory support before clamping the umbilical cord. A greater body of evidence is required as many of the outcomes of interest to the review occurred infrequently. Similarly, the one included study cannot answer the question of whether the intervention is or is not harmful.