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BookmarkScienceDaily (Apr. 19, 2008) — Waiting just a few minutes to clamp the umbilical cord after a baby is born could boost iron stores in the newborn's blood, but delayed cord clamping comes with an increased risk of jaundice, according to a new review of studies.
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Clamping the cord within 30 to 60 seconds after birth is one of three steps in an "active management" approach to the third stage of labor, a time when a new mother is vulnerable to excessive blood loss. Studies show that active management reduces the risk for hemorrhage, but now lead review author Susan McDonald and other investigators are refining that research.
"We've started to ask 'Is it necessary that we do all three" Which part of this is most important" Did timing of clamping the cord make a difference"'" said McDonald, a professor of midwifery at La Trobe University and the Mercy Hospital for Women in Melbourne, Australia.
McDonald said of the studies included in the review: "We found in terms of the amount of bleeding, delayed clamping did not increase the mother's risk of bleeding."
The review appears in a recent issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
The review of 11 studies evaluates the maternal and infant benefits of delaying cord clamping until after the cord stops pulsing, a sign that blood is no longer flowing between the mother's placenta and the baby.
McDonald said in most cases the time difference between early and late cord clamping is just one or two minutes, but the delay allows for an additional infusion of blood from mother to child.
McDonald's analysis found that newborns in the delayed-clamping group had larger stores of iron in their blood. The amount of iron in the blood at birth can influence health, particularly an infant's risk for anemia in the first months of life.
However, the study also found that infants in the delayed-clamping group were more vulnerable to jaundice. Many babies get a mild form of jaundice at birth because the liver is immature and cannot process bilirubin, a yellow byproduct of the breakdown of old red blood cells.
"When the liver can't process all the bilirubin it tends to get pushed out to the tissue and the baby looks a little bit yellow," McDonald said.
Most newborn jaundice subsides without treatment or is treated with simple exposure to sunlight. The review found that infants in the delayed-clamping group had a higher risk for jaundice that needed extra treatment with phototherapy.
"In most places in Western countries where there is a higher income, people have access to hospitals where babies can get that therapy," McDonald said.
"But if you are working in an area where you don't have easy access to treat a child with more severe jaundice, then as a clinician you would need to weigh up the benefits and risks. Allowing the baby to get the extra blood and maybe become jaundiced is a particular problem if you don't have the facilities. In that case, perhaps, you would err on the side of clamping the cord a little earlier," she said.
"There's a happy medium you try to strike," said Joyce Roberts, a certified nurse midwife, professor and coordinator of the Nurse-Midwifery Track at the University of Michigan School of Nursing.
Roberts said many midwives put the baby on the mother's abdomen, above the level of the placenta, so blood continues to flow, but not to excess.
Reference :McDonald SJ, Middleton P. "Effect of timing of umbilical cord clamping of term infants on maternal and neonatal outcomes (Review)." Cochrane Database of Systematic Reviews 2008, Issue 2.
