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

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.