• Posted November 15, 2023

Waiting to Clamp Umbilical Cord May Save Preemies' Lives

The timing of a simple, standard part of childbirth could mean the difference between life and death for premature babies, a pair of new evidence reviews have concluded.

Preemies whose umbilical cords are clamped 30 seconds to two minutes after birth are less likely to die before leaving the hospital, compared to those whose cords are immediately clamped, researchers report in the Nov. 14 issue of The Lancet.

“Our new findings are the best evidence to date that waiting to clamp the umbilical cord can save the lives of some premature babies,” said lead researcher Dr. Anna Lene Seidler. from the University of Sydney in Australia.

Almost 13 million babies are born prematurely each year worldwide, and close to 1 million die shortly after birth, Seidler said.

Holding off clamping the umbilical cord allows blood to flow from the placenta to the baby while the baby's lungs fill with air, potentially easing the transition into breathing, researchers said.

The extended blood flow also could reduce the risk of iron deficiency in the infant.

“Until recently, it was standard practice to clamp the umbilical cord immediately after birth for premature babies so they could be dried, wrapped, and if necessary, resuscitated with ease,” lead study statistician Dr. Sol Libesman, a research fellow at the University of Sydney, said in a journal news release.

The first analysis of 21 studies including nearly 3,300 infants found that preemies whose cord is clamped 30 seconds or more after birth have a lower risk of dying in the hospital than those whose cord is clamped right away.

Delayed clamping in these studies ranged from 30 seconds to more than three minutes, while immediate clamping occurred within 10 seconds.

Overall, 6% of preemies who received delayed clamping died in the hospital, compared with more than 8% of those whose cords were cut immediately -- equating to a 32% reduced risk of death.

The second analysis indicated that even longer is even better.

Evidence from 47 trials including nearly 6,100 babies suggests that waiting two minutes before clamping the cord could reduce a preemie's risk of death, compared with clamping earlier.

For this analysis, clamping was divided into four groups: immediate clamping, short deferral (15 to 45 seconds), medium deferral (45 seconds to two minutes) and long deferral (two minutes or more).

Waiting at least two minutes to clamp the cord reduced the risk of death by two-thirds (69%), compared to immediate clamping, researchers found.

“Our study shows that there is no longer a case for immediate clamping and, instead, presently available evidence suggests that deferring cord clamping for at least two minutes is likely the best cord management strategy to reduce the risk of premature babies dying shortly after birth,” Libesman said.

It's currently recommended that babies born at full term have their cords clamped after waiting a minute or two, researchers noted.

But previous research has been unclear whether waiting as long would be beneficial for preemies, leading to conflicting recommendations in national and international guidelines, the researchers noted.

The two new studies provide the most comprehensive analysis yet of all the available medical evidence, researchers said.

“We are already working with international guideline developers to make sure these results are reflected in updated guidelines and clinical practice in the near future,” Seidler added.

However, the researchers warned that their findings shouldn't be applied when a preemie requires immediate resuscitation, unless the hospital can provide breathing support while the cord remains intact.

“We need further research into how to best provide immediate care to the sickest premature babies while the cord is intact,” Seidler said. “Even for healthier premature babies, it may seem counterintuitive to some doctors to defer cord clamping when the baby requires care, but with appropriate training and equipment, along with a full team approach involving midwives, doctors and parents, it is possible to successfully defer cord clamping whilst ensuring the baby is warm, breathing and cared for.”

More information

The Cleveland Clinic has more about premature birth.

SOURCE: The Lancet, news release, Nov. 14, 2023