This means that doctors could make earlier diagnosis and monitor 'at risk' women throughout their pregnancies.

They could also be given vitamin supplements to help reduce or eliminate the condition.

Pre-eclampsia affects about 4% of all pregnancies and is the major cause of maternal and foetal morbidity and death.

Tommy's believe that the research we fund into pre-eclampsia, and other problems in pregnancy, is the only way to find the answers to why these conditions happen

A spokesperson for Tommy's

It causes a pregnant woman's blood pressure to rise to very high levels.

This causes complications such as fluid retention and can lead to the condition eclampsia, which is associated with dangerous convulsions.

The cause of the condition is unknown, but it is closely related to problems with the placenta restricting blood supply to the developing foetus.

Tommy's, the baby charity, studied women who were at high risk of developing pre-eclampsia.

High risk

These were women who had either suffered from the condition before and needed to be delivered before 37 weeks, or those whose blood flow to their womb was found to be abnormal.

Throughout the pregnancies they did several tests looking at oxygen flow to the womb; placental problems and fats in the blood.

They found that evidence of problems in these areas could mean that the women were more likely to suffer from pre-eclampsia.

Vitamins can reduce the chances of pre-eclampsia

Professor Lucilla Poston, one of the authors of the study, published in the American Journal of Obstetrics and Gynaecology, said it was vital to identify the high risk women as early as possible.

"We have shown that if you give women anti-oxidants early enough in pregnancy you can reduce the incidence.

"It does prevent people getting pre-eclampsia, not 100%, but by about 75%."

Major study

Professor Poston, of King's College, London, a Professor of Maternal and Foetal health at Tommy's, said there had already been a huge interest shown in the test, which they hope to have on the market within three years.

She said the next stage would be a massive international study, which could be starting in January.

A spokesperson for Tommy's welcomed the findings.

"Tommy's believe that the research we fund into pre-eclampsia, and other problems in pregnancy, is the only way to find the answers to why these conditions happen.

"We now have a much greater understanding of pre-eclampsia, but there is still some way to go before a preventative treatment is common place in pregnant women."

Mike Rich, chief executive of Action on Pre-eclampsia, said that finding markers indicating the condition was not new.

But he welcomed the fact that there could soon be a test.

"It is exciting. If this does come to pass it will enable health professionals to take the risk into account and to manage it much more carefully.

"It will let doctors to take special care of these women."