Vitamins could prevent women developing a dangerous pregnancy complication which can prove fatal for mother and child, researchers suggest.
The study will look at women who are at high-risk of pre-eclampsia
A new study will give women at high-risk of pre-eclampsia vitamin supplements in an attempt to stop them developing the condition.
Pre-eclampsia causes a pregnant woman's blood pressure to rise to dangerously high levels.
The condition affects up to 25,000 women in the UK each year.
In 2001, pre-eclampsia killed 50 babies in England and Wales, and another 119 were stillborn.
Delivering the baby early is the only way of protecting the mother and baby.
But many babies suffer from respiratory problems, blindness or deafness due to their premature births.
The symptoms of pre-eclampsia have been linked to the production of toxic molecules called free radicals by the placenta.
Antioxidants, such as vitamins C and E can "mop up" these free radicals, preventing their damaging effects.
In the study, carried out by researchers from Tommy's, women will be given extra reserves of the vitamin supplements to see if additional antioxidants can prevent women developing pre-eclampsia.
Researchers will study 2,400 expectant mothers, all of whom are known to have high blood pressure, kidney problems, clotting disorders or diabetes.
The £1.3m two-year study, funded by the Wellcome Trust, will also make sure giving mothers-to-be the extra vitamins does not harm the babies.
An initial study indicated that taking the vitamins early in pregnancy halved rates of pre-eclampsia in high-risk women.
Professor Lucilla Poston, one of the researchers who will carry out the study, said: "This is a devastating disease which kills thousands of pregnant women around the world and is the cause of many premature births.
"Until now we have been unable to treat this condition effectively but this study gives us the opportunity to make a huge difference.
"Finding a way of preventing pre-eclampsia could save many lives, both of babies and mothers, as well as dramatically reducing health costs."
Mike Rich, chief executive of the charity Action on Pre-eclampsia, told BBC News Online if the results of the trial were positive, it would be "exceptionally significant" for women at risk of the condition.
"For women at risk of pre-eclampsia, it could have massive consequences.
"It should mean that fewer women are giving birth early, and a reduction in the number of babies stillborn every year.
"It would give women the chance to have the pregnancies they started out looking forward to."