Delayed cord clamping in small for gestational age preterm infants

Abstract

Background: Infants with restricted growth for age are frequently exposed to insufficient placental circulation and are more likely to develop postnatal complications. Delayed cord clamping at birth for these infants requires further exploration.

Objective: This study aimed to compare the short-term neonatal outcomes of delayed cord clamping with that of early cord clamping in small for gestational age preterm infants and to explore whether the effects of delayed cord clamping in small for gestational age preterm infants are different from that in non-small for gestational age preterm infants.

Study design: We conducted a national retrospective cohort study, including infants born at <33 weeks' gestation and admitted to the Canadian Neonatal Network units between January 2015 and December 2017. Small for gestational age infants (birthweight of <10th percentile for gestational age and sex) who received delayed cord clamping ≥30 seconds were compared with those who received early cord clamping. In addition, non-small for gestational age infants who received delayed cord clamping were compared with those who received early cord clamping. The main study outcomes included composite outcome of mortality or major morbidity, neonatal morbidity rate, mortality rate, peak serum bilirubin, and number of blood transfusions. Multivariable logistic and linear regression models with a generalized estimation equation approach were used to account for the clustering of infants within centers.

Results: Overall, 9722 infants met the inclusion criteria. Of those infants, 1027 (10.6%) were small for gestational age. The median (interquartile range) gestational age was 31 weeks (range, 28-32 weeks). After adjusting for potential confounders, delayed cord clamping in small for gestational age infants was associated with a reduction in the composite outcome of mortality or major morbidity (adjusted odds ratio, 0.60; 95% confidence interval, 0.42-0.86) compared with early cord clamping. There was no difference between the 2 groups in peak serum bilirubin. Many associated benefits of delayed cord clamping in small for gestational age infants were similar to those in non-small for gestational age infants.

Conclusion: Delayed cord clamping in small for gestational age preterm infants was associated with decreased odds of mortality or major morbidity. Many of the benefits of delayed cord clamping in the small for gestational age preterm infants were similar to those identified in the non-small for gestational age preterm infants.

Keywords: blood transfusion; early cord clamping; hyperbilirubinemia; infant; intrauterine growth restriction; morbidity; mortality; peak serum bilirubin; placental transfusion; temperature.