When a baby is born prematurely, doctors often snip the umbilical cord and whisk the infant away for immediate medical intervention. But a new meta-analysis suggests they should not be so quick to sever the cord, which delivers oxygen and antibody-rich blood to the newborn.
To compare umbilical cord practices for preterm births, researchers collected raw data from dozens of randomized controlled trials involving nearly 10,000 premature babies from several countries. Their results, published in the Lancet, indicate that when doctors wait to clamp and cut the cord they reduce the risk of death for preemies, nearly one million of whom die annually worldwide.
In a companion study, the researchers found survival rates were best when doctors waited at least two minutes to clamp the cord—longer than most public health organizations currently recommend. “These are strong findings … that longer is better,” says Jessica Illuzzi, an expert on obstetric intervention at the Yale School of Medicine. “If you cut the cord too quickly, their heart is trying to pump, and there's just not enough blood.”
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Immediate cord clamping became commonplace only in the 20th century as childbirth practices moved from the home to the hospital. Over the past dozen years, however, research has increasingly shown that delayed cord clamping can boost a newborn's overall blood volume, red blood cell count and iron stores, as well as ease the transition to breathing. Many doctors now delay cord clamping.
Yet obstetricians often still balk at delayed clamping with premature babies, who are frequently born with visible health issues, says Anna Lene Seidler, a biostatistician at the University of Sydney and lead author on both studies. “They're sometimes not moving [or] breathing properly.”
Some circumstances probably still warrant rapid clamping, such as when the mother is hemorrhaging or the infant needs immediate resuscitation. Yet as Seidler points out, much medical care, such as warming and stimulating babies, can be given with the cord intact. “We've come full circle,” she says, adding that although modern medicine has vastly improved life for preemies, in this one respect the old ways were best all along.