Umbilical cord management in extremely preterm infants born by cesarean delivery

Deferred cord clamping reduces mortality in preterm infants. However, there is a controversy about whether deferred cord clamping is as effective in cesarean delivery as in vaginal delivery.

This study aimed to compare the mortality and short-term outcomes of extremely preterm singleton infants who received deferred cord clamping after cesarean delivery with those who received deferred cord clamping after vaginal delivery and those who received early cord clamping after cesarean delivery.

A national retrospective review of maternal, perinatal, and neonatal data of preterm infants born at <29 weeks of gestation who were admitted to units participating in the Canadian Neonatal Network between January 2015 and December 2022 was conducted. The rates and trends of deferred cord clamping (≥ 30 seconds) were evaluated, and the outcomes of infants who received deferred cord clamping after cesarean delivery were compared with (a) those who received deferred cord clamping after vaginal delivery and (b) those who received early cord clamping (<30 seconds) after caesarean delivery. The primary outcome was hospital mortality/severe brain injury (defined as grade 3/4 intraventricular hemorrhage and/or periventricular leukomalacia). Multivariate regression models with generalized estimating equations were used to account for clustering of infants within each site after adjusting for potential confounders.

Of 6137 infants included in the study, 1952 (31.8%) received deferred cord clamping after cesarean delivery, 1804 (29.4%) received deferred cord clamping after vaginal delivery, and 2381 (38.8%) received early cord clamping after cesarean delivery at a median gestational age of 27 (interquartile range, 25-28), 26 (interquartile range, 25-28) and 26 (interquartile range, 25-28) weeks, respectively. There was a slow increase in the practice of deferred cord clamping in cesarean delivery from 32% in 2015 to approximately 50% in 2021-2022. After adjustment for potential confounders, infants who received deferred cord clamping after cesarean delivery had lower odds of a composite of mortality/severe brain injury (281/1952 [14%]) than those who received deferred cord clamping after vaginal delivery (347/1804 [19%]; adjusted odds ratio, 0.69 [95% confidence interval, 0.54-0.87]) and those who received early cord clamping after cesarean delivery (543/2381 [23%]; adjusted odds ratio, 0.69 [95% confidence interval, 0.57-0.83]). Deferred cord clamping after cesarean delivery was not associated with changes in other adverse short-term outcomes.

Deferred cord clamping was associated with a reduction in a composite of mortality/severe brain injury in singleton preterm infants born at <29 weeks of gestation via cesarean delivery.