‘Milking’ umbilical cord before clamping benefits newborns who are not breathing well: study
Babies who are not breathing well at birth benefit from a procedure known as “milking” of the umbilical cord before it is clamped, according to a new study from an international team of neonatal researchers.
The guidelines for healthy babies are to wait between 30 seconds and a minute after birth for blood to be drawn through the cord as the child begins to breathe. But that doesn’t work in about 10 per cent of babies, who are deemed non-vigorous at birth because they aren’t breathing, are limp or are breathing poorly. This may happen because the cord is wrapped around the baby’s neck during labour or the baby has an infection, or because the baby’s heart rate may drop during contractions.
Until now, the standard medical practice has been to clamp the cord immediately and begin resuscitation of non-vigorous infants, who are at risk for low oxygen levels in the brain, cerebral palsy and stroke.
“An alternative could be this milking, where you squeeze the cord and allow it to refill four times before clamping, so you can get more blood into the baby,” explains co-principal investigator Georg Schmölzer, professor in the University of Alberta’s Faculty of Medicine & Dentistry and director of The Centre for the Studies of Asphyxia and Resuscitation, the largest such research centre in North America.
Schmölzer notes the milking procedure takes only 15 to 30 seconds to perform. He is hopeful the findings will lead to a change in the international guidelines for resuscitating newborns by the International Liaison Committee on Resuscitation.
Helping future generations
The study was carried out by a group of researchers from the United States, Poland and Canada who have a long-standing collaboration on neonatal research. The new research involved more than 16,000 infants born at between 35 and 42 weeks of gestation at 10 hospitals between January 2019 and May 2021. Of those, 1,730 infants were deemed non-vigorous and were randomly assigned to receive either umbilical cord milking or immediate cord clamping.
They found that babies in the milking group had higher average hemoglobin, which carries oxygen and carbon dioxide through the blood. Sixty-one per cent of the milking group required heart and respiratory support, compared with 71 per cent for the clamping group. The milking group also had fewer incidences of moderate to severe hypoxic ischemic encephalopathy, a brain injury caused by low oxygen in the brain at birth that can lead to cerebral palsy and other neurodevelopmental issues. This occurred in 1.5 per cent of the babies in the milking group compared with three per cent in the clamping group.
The final difference the researchers found was that 23 per cent of the babies who received umbilical cord milking were admitted to neonatal intensive care, versus 28 per cent of those who got early cord clamping.
“While the difference in NICU admissions was not statistically significant, it was definitely important for the parents, who want their babies to stay with the family,” says Schmölzer, who is also a neonatologist at Edmonton’s Royal Alexandra Hospital.
Schmölzer notes that an earlier study of preterm babies born at 23 to 27 weeks of gestation showed they did not benefit from umbilical cord milking, because it caused an increase in blood pressure that could lead to brain bleeds. The team is now analyzing results for preterm babies born at 28 to 32 weeks of gestation and plans to publish those results soon.
The study was funded by the U.S. National Institutes of Health, and Schmölzer is a member of the Women and Children’s Health Research Institute. Schmölzer gives particular credit to the parents who consent to participate in studies, even though their own child may not benefit from the findings.
“Birth is the most dangerous day in life, because the baby has been growing in the womb and then suddenly circulation and breathing must adapt to the world outside,” he says.
“We can’t use studies from any other time of life to extrapolate, so we are very grateful to parents who are happy to participate in research to get the evidence that will help future generations.”