MONDAY, Oct. 18, 2004 (HealthDayNews) -- For nine months, the umbilical cord is a lifeline between mother and baby, sending oxygenated blood to the growing fetus. Once the baby is born, however, that connection is often quickly severed.
But, in the case of premature infants, a new review of past studies suggests that waiting as little as 30 seconds to cut that cord can make a dramatic difference in the health of a newborn.
The review, which appears in the October issue of the Cochrane Collaboration, also found that delaying the clamping of the umbilical cord for up to 120 seconds in premature infants can lead to an increased number of red blood cells, the need for fewer transfusions due to anemia or low blood pressure, and a decreased risk of bleeding in the brain.
"A slight delay in cord clamping for preterm infants is beneficial with regard to better blood pressure after birth, less need of blood transfusion in the first weeks of life and less incidence of severe intra-ventricular hemorrhage," said the review's author, Dr. Heike Rabe, a consultant neonatologist at Brighton & Sussex University Hospitals in Great Britain.
An infant is considered preterm or premature if born before 37 weeks' gestation. About one in 10 babies in the United States is born prematurely, according to the National Institutes of Health. Some of the biggest problems premature infants face are respiratory distress, bleeding in the brain and feeding problems.
The reason that waiting to clamp the umbilical cord can make a difference in a baby's health is because the delay allows blood to return from the umbilical cord back to the baby, which can help keep blood pressure normal and keep the red blood cell count up, the research found.
On the other hand, waiting too long to clamp the umbilical cord can cause the red blood cell count to rise too high, which thickens the blood. And, since respiratory problems are common in premature infants, delaying clamping the cord may cause a delay in treating respiratory distress.
The current review included seven studies with a total of 297 infants born prematurely.
Clamping times varied in the studies between 30 and 120 seconds, according to Rabe. While it's not clear what the optimum time for cord clamping is based on current studies, 120 seconds is the maximum time before clamping a preterm infant, said Rabe.
Rabe and the other reviewers concluded that waiting 30 to 120 seconds before clamping the umbilical cord in preterm infants is associated with less bleeding in the brain and a reduced need for transfusions.
"This study seems to make good sense. We know that the amount of blood has a direct influence on blood pressure and that blood pressure has an influence on bleeding on the brain," said Dr. James Pelegano. He is director of neonatology at Maimonides Medical Center and Lutheran Medical Center in New York City.
Pelegano said it's often standard practice to clamp off the cord immediately so that breathing and other problems can be dealt with immediately. He said there's no way to make a blanket statement that all babies should have a delay before the umbilical cord is clamped.
"It has to be done on a case-by-case basis," said Pelegano. "It's better if you don't have to clamp quickly, but you don't always have that option."
But, he added, "In a situation where the baby is not at risk from respiratory problems, delaying cord clamping up to 30 seconds can have a benefit."
Another study in the October issue of the Cochrane Collaboration looked at another important issue in newborn care -- pain relief during circumcision. A review of nearly 2,000 babies from 35 different studies found that topical or injected pain medications appeared to help reduce the pain of circumcision significantly. Oral pain relievers, sugar water and playing comforting music had little effect on the babies' response to circumcision pain.
Unfortunately, the researchers concluded that no method was able to completely eliminate the infants' responses to pain.
To learn more about premature infants, visit the National Library of Medicine.