Effects of timing of cord clamping on neonatal hemoglobin and bilirubin levels in preterm and term infants-A prospective observational cohort study.

Background: Delayed cord clamping (DCC) is a proven beneficial intervention, but the suggested timings of DCC vary from 30 to 300 seconds after birth or until cord pulsation stops. This study aimed to find the optimum timing of DCC to maximize the benefits such as an increase in hemoglobin, and hematocrit without increasing the risks of polycythemia and hyperbilirubinemia.

Methods: We conducted a single-center prospective observational cohort study. All singleton neonates with gestational age ≥ 28 weeks born at the center in the 17 months of the study period from November 2020 to March 2022 were enrolled. Participants were divided into four groups based on DCC time: group A: <60 sec, group B: 60-119 sec, group C: 120-180 sec, and group D: >180 sec. The primary outcome was the levels of hemoglobin, hematocrit, and bilirubin at 48 hours of life.

Results: Four hundred and eight neonates were enrolled. They were divided into four groups based on the timing of DCC (group A: n = 52, group B: n = 137, group C: n = 155, group D: n = 64). With an increase in the duration of DCC, there was an increase in the level of hemoglobin and hematocrit without an increase in the risk of polycythemia or neonatal hyperbilirubinemia. The benefits were best in group C (120-180 sec) and group D (>180 sec).

Conclusions: DCC of ≥ 120 seconds appears to be optimal where hemoglobin and hematocrit are highest without an increase in the risk of neonatal hyperbilirubinemia. The risk of adverse effects like polycythemia or neonatal hyperbilirubinemia requiring phototherapy did not increase even after extending the time of cord clamping to >180 seconds.