File photo: Pre-eclampsia occurs when there is a problem with the placenta which links the baby’s blood supply to the mother’s.

Pregnant women with pre-eclampsia could be spared from needlessly having their baby delivered prematurely, thanks to a test developed by UK doctors.

Pre-eclampsia occurs when there is a problem with the placenta which links the baby’s blood supply to the mother’s.

In the most severe cases the only solution is to deliver the baby immediately, to save the mother. But this poses a huge risk, with 1 000 infants dying every year as a result in the UK.

Now doctors in London have developed a test which can tell with 84 percent accuracy whether a mother is at immediate risk. It relies on 12 pieces of information, including blood pressure, liver function and the level of toxins in the blood and urine. Combined, this information gives doctors a clear view of whether pre-eclampsia will cause a severe health problem in the next 48 hours.

Professor Hywel Williams, of the NHS National Institute for Health Research which funded the study, said: "This should make a difference to the health of mothers and babies in the NHS."