A new study by the Women and Infants Research Foundation and the Australian Preterm Birth Prevention Alliance has put the annual cost of premature births at $1.4 billion.

A quarter of the cost identified in the study, published in the Australian and New Zealand Journal of Obstetrics and Gynaecology, comes from the educational assistance needed for children who were born premature.

While many preterm births are unplanned or unavoidable for medical reasons, experts are concerned by a dramatic rise in avoidable "early-term" births.

They say it's translating to more school-aged children having learning problems and behavioural issues.

"A good proportion of them, their origin will be found in the labour wards of your obstetric hospitals eight or 10 years earlier," the Perth-based foundation's chief scientific director John Newnham told AAP.

While extremely preterm babies have the greatest expense, it's the early-term births - those between 37 and 39 weeks - that have increased the most.

Recent federal government data indicates roughly half of all annual elective caesarean sections performed before 39 weeks did not have a stated medical or obstetric indication.

"That is obviously unacceptable," Professor Newnham says.

"It is causing serious alarm at government level and is now being addressed."

Part of the solution lies with correcting what Prof Newnham describes as an entrenched belief - among both doctors and parents - that 37 weeks is the safe threshold.

The fetal brain, he says, puts on half of its weight after 35 weeks, meaning any delivery before 39 weeks risks causing later-life problems.

"For most babies, they will have a normal outcome regardless. We're talking about a percentage only," he says.

"But if you deliver all babies at 37 rather than 39 weeks, eight years later a class of 30 children will have two extra children with behavioural disorders."

Around eight per cent of babies in Australia are born prematurely each year.

Being born too early is a leading cause of disability in Australia and has been linked to cerebral palsy, deafness and blindness.

But it can, in some cases, be prevented.

Premature births reduced by eight per cent in WA within the first year of a prevention program led by the Women and Infants Research Foundation.

The program included targeted education for expecting mothers but also sought to educate medical practitioners on identifying risk factors such as a shortened cervix.

The success of the WA program has since been replicated elsewhere, including in the ACT.

A $13.7 million funding injection in this year's federal budget will help the foundation to roll out the program across the country in coming years.

Prof Newnham, the 2020 Senior Australian of the Year, reckons it's a fantastic opportunity.

"It's a terrific challenge because there are not that many things left in medicine where a public health program based on education and health promotion can have such dramatic improvement in the lives of so many people," he said.

Australian Associated Press