Placental transfusions have become standard procedure in neonatal care. This transfer of residual blood to the newborn is usually accomplished by waiting about 60 seconds after birth to clamp and cut the umbilical cord (called delayed cord clamping). However, some preterm infants require immediate treatment such as resuscitation, precluding delayed cord clamping. In these infants, an alternative placental transfusion method, umbilical cord milking-squeezing blood gently into the newborn before clamping the cord-can be completed without delaying resuscitation.
A pilot trial involving preterm infants found that umbilical cord milking improved neonatal blood flow, and cognitive and language scores at two years of age, compared with delayed cord clamping. To better assess whether umbilical cord milking and delayed cord clamping provide preterm infants similar benefits, researchers conducted a randomized clinical trial of babies born at less than 32 weeks' gestation. Pregnant women were recruited from nine university and private medical centers in four countries between June 2017 and September 2018. Only 474 infants of a planned 1,500 had participated when the trial was stopped early because of evidence of harm.
The study was terminated after researchers discovered a significantly higher rate of severe intraventricular brain hemorrhage in the umbilical cord milking group-8% versus 3% in the delayed cord clamping group. Among infants born between 23 and 27 weeks' gestation, 22% who received umbilical cord milking suffered severe brain bleeding compared with 6% who received delayed cord clamping, a significant difference. The rate of brain bleeding was not significantly different, however, among infants born at 28 to 32 weeks' gestation. The authors suggest increased blood flow from umbilical cord milking may cause extremely preterm infants' fragile cerebral blood vessels to rupture. They also found no statistically significant difference in death rates between the umbilical cord milking and delayed cord clamping groups and noted no harm from umbilical cord milking in previous trials.
The study's findings are inconclusive because of the early termination, which lead to a diminished sample size and need for post-hoc analysis. Since the higher rate of severe brain bleeding associated with umbilical cord milking was observed in newborns of 23 to 27 weeks' gestation, a new trial will compare cognitive status at two years of age among preterm infants born at 30 to 32 weeks' gestation who received umbilical cord milking or delayed cord clamping. Infants from this current study will be included.-Lucy Wang Halpern