London: A simple ten-minute test in the UK can predict whether a woman is going to give birth prematurely, doctors claim.
The early-warning system measures a pregnancy protein, using a cervical swab in women who start contractions weeks before they are due.
High readings mean a woman`s chances of having a premature baby in the next fortnight are doubled.
But women with low readings can be safely sent home as having had a false alarm, the Daily Mail reported.
The new test is expected to replace a less accurate test used in National Health Service (NHS) hospitals and could stop thousands of women from having unnecessary treatment.
The test was developed by researchers at Guy`s and St Thomas` Hospital, London, funded by the baby charity Tommy`s.
The swab measures the level of a protein known as fetal fibronectin (fFN), which should appear at 22 weeks and again at the end of pregnancy.
If it appears between these dates, coupled with early contractions, it suggests an early labour is imminent.
A test to measure fibronectin levels is already used in the NHS, but the updated test is much more accurate, said Professor Andrew Shennan of Guy`s, who led the research.
He said the wide range of predicted risk shown by the current test meant more than 90 per cent of women were being wrongly diagnosed as high-risk.
"The updated fetal fibronectin test reduces the need for low-risk women to stay in for observation or get treatment when they don`t have to," Shennan added.
"This updated test is more precise. Trials show a high reading doubles the risk of a woman giving birth in the following two weeks," Shennan said.
In the trials, 75 per cent of women with high readings gave birth before 34 weeks of pregnancy ? at least six weeks early.
Women at high risk may be prescribed bed rest and given drugs to improve the baby`s health after premature delivery, including steroids to help mature the baby`s lungs.
They may also have treatment to try to prolong the pregnancy, such as medication or a stitch in the neck of the womb. The new test measures protein levels in just ten minutes ? the current test takes 23 minutes.
Guy`s is the first hospital to use the test but the updated equipment has been installed in 133 other NHS hospitals.