Although the current practice with a very-low-birth-weight infant is to clamp the umbilical cord immediately after delivery, this action prevents additional transfer of blood from the placenta into the infant's circulation. Research has shown that delaying clamping can increase blood volume and perhaps result in a better hemodynamic state in the infant.

Mercer and colleagues compared immediate and delayed cord clamping among 72 infants born before 32 weeks' gestation to see whether either had any effect on the development of two primary outcomes: bronchopulmonary dysplasia and necrotizing enterocolitis. The average time from birth to cord clamping was seven seconds in the group randomized to undergo immediate cord clamping, and 32 seconds in the group in which clamping was delayed and the infant held in a sterile towel or blanket below the level of the placenta. There were no differences noted between the groups in terms of either of the primary outcomes, initial blood pressure or temperature, long-term oxygen or ventilator use, long-term lung damage, number of transfusions required, retinopathy, or survival rates.

But infants in the delayed-clamping group had a lower rate of late-onset sepsis than did the infants in the immediate-clamping group (zero of 23 boys and six of 19 boys, respectively) and a lower rate of intraventricular hemorrhage (two of 23 boys versus eight of 19 boys, respectively). These findings indicate that delayed cord clamping at delivery of infants born at less than 32 weeks' gestation may offer protective benefits (especially to boys) from both late-onset sepsis and intraventricular hemorrhage, common complications of premature birth.

Mercer JS, et al. Pediatrics 2006;117:1235-1242.