The impact of early versus delayed cord clamping on hematological and cardiovascular changes in preterm newborns between 24 and 34 weeks' gestation: a randomized clinical trial

Arch Gynecol Obstet. 2023 Jul 12. doi: 10.1007/s00404-023-07119-0. Online ahead of print.


Purpose: This study aimed to investigate hematological and cardiac changes after early (ECC) versus delayed cord clamping (DCC) in preterm infants at 24-34 weeks of gestation.

Methods: Ninety-six healthy pregnant women were assigned randomly to the ECC (< 10 s postpartum, n = 49) or DCC (45-60 s postpartum, n = 47). Primary endpoint was evaluation of neonatal hemoglobin, hematocrit and bilirrubin levels within the first 7 days after birth. A postpartum blood test was performed in the mother and a neonatal echocardiography in the first week of life.

Results: We found differences in hematological parameters during the first week of life. On admission, the DCC group had higher hemoglobin levels than the ECC group (18.7 ± 3.0 vs. 16.8 ± 2.4, p < 0.0014) and higher hematocrit values (53.9 ± 8.0 vs. 48.8 ± 6.4, p < 0.0011). Around day 7 of life, hemoglobin levels were also higher in the DCC group compared with the ECC group (16.4 ± 3.8 vs 13.9 ± 2.5, p < 0.005), as was the hematocrit (49.3 ± 12.7 vs 41.2 ± 8.4, p < 0.0087). The need of transfusion was lower in the DCC compared to the ECC (8.5% vs 24.5%; OR: 0.29, 95% CI: 0.09-0.97, p < 0.036). The need for phototherapy was also higher in the DCC (80.9% vs 63.3%; OR: 0.23, 95% CI: 0.06-0.84, p < 0.026). No differences in cardiac parameters or maternal blood tests.

Conclusion: DCC improved neonatal hematological parameters. No changes in cardiac function were found and maternal blood loss did not increase to require transfusion.

Keywords: Delayed cord clamping; Early cord clamping; Neonatal; Neonatal outcome; Preterm; Surfactant; Ventilation.