Effect and safety of timing of cord clamping on neonatal hematocrit values and clinical outcomes in term infants: A randomized controlled trial

Objective To evaluate the effect and safety of different umbilical cord clamping (UCC) timing. Study design This was a randomized trial of 720 term mothers/infants from the Tianjin Central Hospital of Obstetrics and Gynecology delivered from December 2014 to May 2015 and randomized to immediate cord clamping (ICC) within 15 s, delayed cord clamping (DCC) by 30, 60, 90, 120, 150, or 180 s, or when the umbilical cord pulsation ceased. Results 24 h after delivery, the mean infant hematocrit levels were 56.5, 57.3, 58.8, 59.7, 59.5, 59.7, 60.3, and 61.0% in the ICC, 30, 60, 90, 120, 150, and 180-second DCC, and no pulsation groups, respectively (P - 0.021, 0.001, 0.003, 0.001, <0.001, and <0.001, respectively; standard deviations ranging 5.4-8.7%). There was no significant difference between the 30-second DCC and ICC groups. No significant differences were found in other neonatal and maternal outcomes among these groups. Conclusion For term infants, DCC increases the hematocrit values, without apparent harmful effects on the infants and their mothers.