Changes in Cord Arterial Blood Gas Parameters by the Onset of Spontaneous Respiration during Delayed Cord Clamping

Abstract

Background: The initiation of crying is an easy way to evaluate neonatal condition. Doubt arises about a neonate’s condition if the initiation of crying occurs late during delayed cord clamping (DCC). This study aimed to detect any difference in cord arterial blood gas (cABG) parameters depending on when spontaneous respiration (SR) started during DCC in a cesarean section. Methods: This retrospective study analyzed cABG results in relation to SR start time during DCC. The study included full-term (n = 41) and preterm (n = 17) neonates who were born by cesarean section with DCC. If the neonate cried within 60 s of DCC, the crying start time was considered as the time of the first SR. The cABG results of the preterm and full-term neonates were then examined. Each group was further divided into groups of 5, 10, and 30 s according to time-to-SR onset (time-to-SR). Subsequently, the cABG results were analyzed between these time-to-SR subgroups. The Mann–Whitney test was used for the comparisons, and p < 0.05 was considered statistically significant. Results: The time-to-SR was not significantly different in the preterm and full-term neonates. In preterm neonates, no significant difference was observed in any cABG parameter. In full-term neonates, the partial pressure of carbon dioxide (PaCO2) was significantly higher in the time-to-SR (T) ≥5 s (T ≥5 s) subgroup than in the T <5 s subgroup (p < 0.05), and bicarbonate and PaCO2 were both significantly higher in the T ≥10 s subgroup than in the T <10 s subgroup (p < 0.05). Conclusions: All neonates had normal cABG results regardless of the SR start time. However, given the small number of cases and limitations of this study, we cautiously suggest that maintaining DCC in cesarean deliveries may be considered, even when the start of crying is delayed. Especially, in preterm neonates with immature gas exchange mechanisms, the decision to maintain DCC must be carefully considered.