Delayed cord clamping is associated with improved dynamic cerebral autoregulation and decreased incidence of intraventricular hemorrhage in preterm infants

Delayed cord clamping (DCC) improves neurologic outcomes in preterm infants through a reduction in intraventricular hemorrhage (IVH) incidence. The mechanism behind this neuroprotective effect is not known. Infants born 28 wk gestation were recruited for longitudinal monitoring. All infants underwent 72 h of synchronized near-infrared spectroscopy (NIRS) and mean arterial blood pressure (MABP) recording within 24 h of birth. Infants with DCC were compared with control infants with immediate cord clamping (ICC), controlling for severity of illness [clinical risk index for babies (CRIB-II) score], chorioamnionitis, antenatal steroids, sedation, inotropes, and delivery mode. Autoregu-latory dampening was calculated as the transfer function gain coefficient between the MABP and NIRS signals. Forty-five infants were included (DCC; n 15, paired 2:1 with ICC controls n 30). ICC and DCC groups were similar including gestational age (25.5 vs. 25.2 wk, P 0.48), birth weight (852.3 vs. 816.6 g, P 0.73), percent female (40 vs. 40%, P 0.75), and dopamine usage (27 vs. 23%, P 1.00). There was a significant difference in IVH incidence between the DCC and ICC groups (20 vs. 50%, P 0.04). Mean MABP was not different (35.9 vs. 35.1 mmHg, P 0.44). Compared with the DCC group, the ICC group had diminished autoregulatory dampening capacity (12.96 vs. 15.06 dB, P 0.01), which remained significant when controlling for confounders. Dampening capacity was, in turn, strongly associated with decreased risk of IVH (odds ratio 0.14, P 0.01). The results of this pilot study demonstrate that DCC is associated with improved dynamic cerebral autoregulatory function and may be the mechanism behind the decreased incidence of IVH.