According to a British research, women who take large quantities of vitamin supplements during pregnancy are at the high risk of developing pre-eclampsia.
Vitamins C and E were thought to cut the risk, but a Lancet study by the charity Tommy's found women at high-risk should not take large doses of any kind of vitamins.
Up to 25,000 British women are affected annually by pre-eclampsia, which causes blood pressure to rise to levels, which threatens mother and child, the BBC said.
The ailment has been linked to the production of highly charged, toxic molecules.
Some 2,400 expectant mothers with high blood pressure, kidney problems, clotting disorders or diabetes were given either extra vitamin supplements or a placebo. Researchers found pre-eclampsia appeared about a week earlier among those who received the vitamins.
"Careful management has long been seen as the best way to deal with pre-eclampsia -- that remains the same," the report said.