An anti-cancer drug may help to stop babies being born too soon.
Prematurity can lead to serious health problems
A team from the University of Newcastle upon Tyne found the drug Trichostatin A (TSA) has the potential to control early labour contractions.
It is hoped the work, which is still at an early stage, will eventually help to reduce the 70,000 premature births in the UK each year.
Many premature babies require special care and can face a lifetime of health problems.
Lead researcher Dr Nick Europe-Finner said: "Premature birth is a huge problem, not just in the UK but across the globe, and currently there is no effective treatment.
"Babies born too early can go on to suffer problems throughout their lives, and prematurity costs the NHS millions of pounds each year."
Dr Europe-Finner said drugs currently used to stop premature labour can have severe side effects for both mother and baby, including long-term heart problems.
"We have shown that we can regulate the receptors that send messages to the muscles to make them relax during pregnancy.
"If we can keep those muscles relaxed, then we can prevent early labour."
A hormone called hCG is released by the placenta during pregnancy.
It triggers muscle cells in the uterus to produce a natural relaxant.
But in some women the number of receptors on the surface of the muscle cells drops, reducing their ability to produce the relaxant.
This can lead to the uterine contractions and early labour.
More work needed
In laboratory tests, the Newcastle team has shown that TSA can keep the number of cell receptors high.
The charity Action Medical Research is funding further work, which it is hoped will lead to clinical trials.
TSA is currently used to treat breast, bowel and lung cancer.
Mr Liu, a consultant obstetrician and gynaecologist at City Hospital, Nottingham, urged caution.
He told the BBC News website the relationship between hCG and production of the muscle relaxant was still not completely clear, and the causes of prematurity were complex.
He also stressed that much more work would be needed before an anti-cancer drug could be used to treat pregnant women.
"At this stage I would be circumspect about its utility, even if there is a proven physiological or pharmacological effect," he said.
Professor David James, an expert in fetomaternal medicine at Queen's Medical Centre, Nottingham, said the drug seemed to have potential.
But he added: "A number of drugs and preparations have been put forward as the solution to preterm labour over the years but have failed to deliver.
"We should reserve judgement on this latest candidate."