The risk of death and disability in the first two years of childhood for very premature babies is reduced by almost one-fifth if they are waiting 60 seconds to be born.
The study looked at health outcomes of more than 1,500 premature babies two years after they entered the world. Newborns who had their cords cut one minute later had better survival rates at two years of age.
"This is so significant as it is such a simple technique, suitable for almost all preterm babies that helps saves lives," Jonathan Morris from the University of Sydney said in 2017, before the researchers began their latest study, tracking infant health for another two years."
The extra red blood cells, immune cells, and stem cells are thought to help newborns achieve healthy oxygen levels and control. This could be important for the 1 million babies born at 30 weeks' gestation each year.
Babies with delayed cord clamping have a better chance of survival in the first days of life, according to previous research. The latest analysis shows infant health outcomes at two years of age for over 1,600 very premature babies, born 10 weeks early.
It's the largest-ever clinical trial comparing delayed and immediate cord clamping for premature babies. Within 10 seconds of birth, maternity staff held off on the clamping of the baby's cords.
When the researchers combined their data on 1,531 babies with the results from one other trial, they found that waiting more than 30 seconds reduced the risk of death and disability by 20%.
The results show that the odds of survival for newborns were better if cord clamping was delayed, as there was no difference in major disability such as cerebral palsy, vision loss, deafness, or speech problems.
For full-term babies, delayed cord clamping is a standard practice. The cords of premature babies were cut immediately after birth so they could receive medical care.
A study in Australia found that if cord clamping was delayed, fewer infants needed blood transfusions.
"Delaying cord clamping ensures that the changes happening at the time of birth can happen and there are clearly very good outcomes, especially for premature babies," says a midwifery expert who was not involved in the study.
Delayed cord clamping is recommended for newborns who don't need immediate breathing support, but it is not always used.
Anna Lene Seidler, a health researcher and biostatistician, told The Sydney Morning Herald that it can be scary for clinicians to wait before they intervene.
A quarter of the babies in the delayed clamping group of the Australian trial had their cords cut before 60 seconds.
"These babies are so tiny and sick, so for clinicians not to do something straight away requires quite a rethink," said Seidler, who led another recent analysis of 42 clinical trials involving more than 5,770 babies.
Delayed cord clamping was found to be safe and slightly improved survival, though more evidence was needed to assess alternative strategies.
Researchers hope that reversing the decades-old practice of cutting the cords of premature babies immediately after birth could improve health outcomes for thousands of kids.
An extra 50,000 babies could survive without major disability in the next decade if the method was applied consistently worldwide, according to a University of Sydney biostatistician.
For every 20 very preterm babies who get delayed, one more will survive without major disability.
More data on the timing of cord clamping from a variety of settings would help to solidify the findings, give clinicians more confidence, rule out potential harms, and track health outcomes further into childhood.
The evidence suggests that intensive staff training in the new protocols will be vital as it can be daunting to delay treatment in very early and sick babies, but this results in the best outcomes for these children.
The research was published in a journal.
