Timing of cord clamping and placental exchange capacity in two-step delivery

BACKGROUND: The aim is to investigate the effect of early (ECC) and delayed cord clamping (DCC) on placental transfusion and exchange capacity in term infants delivered by ‘two-step’ approach.METHODS: Ninety infants were included to ECC (at 1 minute) or DCC (at 3 minutes) before two-step delivery wherein 83 (39 with ECC and 44 with DCC) received the allocated intervention. The primary outcome was the placental transfusion defined by ∆ hematocrit (Hct) from cord blood at birth and capillary heel blood at 48 h of age, accounting for body weight decrease, with the power estimate based on Hct levels, in the ECC and DCC neonate groups. The secondary outcomes were the contemporary readings of arterial cord blood gas analysis components.RESULTS: It was found that ECC or DCC did not affect cord blood Hct levels. Conversely, Hct levels were significantly increased at 48 hours of age in the DCC group (50.778±1.102 vs. 55.051±0.979, P=0.0051), supporting a significantly higher ∆ Hct (1.278±5.29 vs. 6.287±0.998, P=0.011) despite a comparable body weight decrease, In addition, the analysis of cord blood gas components revealed a trend towards significantly higher PaO2 (29.505 [26.881-32.129] 25.134 [22.237-28.031] mmHg; P=0.029) and lower PaCO2 (39.682 [36.286-43.078] s 44.03 [40.854-48.352] mmHg; P=0.057), all pointing to a higher placental-fetal exchange in the DCC group.CONCLUSIONS: Comparing ECC with DCC in infants born by ‘two-step’ delivery, DCC results in a higher placental transfusion and exchange capacity, without potentially detrimental neonatal outcomes.