“If you clamp the cord after the infant has started breathing, the outcomes for babies are significantly better,” said Monash University physiologist Professor Stuart Hooper of the study.
When Norwegian researchers analysed 15,000 births in Tanzania, they found that if clamping occurred after a baby was breathing, the likelihood of the baby dying or being admitted to intensive care was significantly reduced.
Professor Hooper, who is the head of the Ritchie Centre at MIMR-PHI Institute Medical Research (a merger of the Monash Institute of Medical Research and Prince Henry’s Institute) and Monash University, has recently published research demonstrating the physiology on which the Tanzanian study was based.
He said the delay helps because a continuity of blood flow is maintained while the baby experiences the shift in heart and lung function that occurs in the transition from fetus to newborn.
The knowledge is particularly significant for low-resource countries because it is such a simple intervention.
“There is no expense and no equipment needed. All the attendant has to do is pause, let the baby breathe and then clamp the cord,” he said.
In a fetus, much of the blood pumped by the heart comes from the placenta, via a shunt bypassing the lungs, which are filled with liquid.
At birth, the shunt closes and the baby’s physiology changes as blood begins passing through the lungs, which become the primary source of blood for the heart to pump.
But blood can only be passed efficiently through the lungs once they are functioning. And at the same time, when the umbilical cord is cut, blood supply from the placenta ceases.
“The heart can only pump the blood it receives, so delaying cord clamping until a baby is breathing is simply a matter of sustaining the input to the pump,” Professor Hooper said.
“It allows the input to immediately switch from the placenta to the lung when the cord is cut because the lungs are already aerated.”
Read more about Professor Stuart Hooper’s research in Science gives babies time to breathe in the October issue of Monash magazine.