Effect of timing of umbilical cord clamping on cerebral regional tissue oxygenation: A secondary analysis of the COSGOD III trial

Aim: To determine how different cord clamping strategies affect cerebral oxygenation in the first 15 min after birth in preterm infants. Methods: A post-hoc secondary outcome analysis of a multicentre prospective randomised clinical trial (COSGOD III) conducted between October 2017 and October 2021 in 11 tertiary neonatal intensive care units in six countries in Europe and in Canada. In the present ancillary study, all included premature neonates (<32 weeks gestation) were retrospectively assigned to three groups according to the timing of cord clamping (G1<30 s, G2 30-60 s, G3>30 s). The aim of this study was to evaluate differences in cerebral regional oxygen saturation (crSO₂) and cerebral fractional tissue oxygen extraction (cFTOE) within the first 15 min after birth in preterm neonates based on the timing of cord clamping. Results: 572 infants (n=339 (G1), n=164 (G2) and n=69 (G3)) were included in the final ancillary analysis. There were no statistically significant differences in crSO₂ and cFTOE between the three groups. There were no statistically significant differences between the three groups in neonatal morbidities, particularly importantly in the degree of cerebral injury, as measured by any degree of intraventricular haemorrhage or cystic periventricular leukomalacia. Conclusions: No significant differences in crSO₂ and cFTOE during the first 15 min after birth were observed; however, some effect may have been modified by protocol-guided titration of supplemental oxygen in the intervention arm. Thus, in our study, we did not find a correlation between deferred cord clamping and improved cerebral oxygenation immediately after birth. Trial registration number: NCT03166722.