Women are being warned about a link between pregnancy disorder pre-eclampsia and heart disease, as new evidence emerged connecting the two.

Two studies were published in the British Medical Journal, with one suggesting they share a common origin.

The other by a London team found women who have pre-eclampsia were twice as likely to develop heart disease.

Women who have pre-eclampsia should take precautions to protect themselves from heart disease, experts said.

Pre-eclampsia is a serious condition where abnormally high blood pressure and other disturbances develop in the second half of pregnancy.

It affects about 5% of all first-time pregnancies and is dangerous for both mother and child.

"A history of pre-eclampsia should be considered in the evaluation of women's risk of cardiovascular disease" said researcher David Williams.

His team from the London's Institute for Women's Health analysed 25 studies involving over three million women.

They found women with a history of pre-eclampsia were four times more likely to suffer from high blood pressure and twice as likely to develop heart disease, stroke, and blood clots in later life.

And they found no increase in risk of any cancer, suggesting the increase in heart disease was more likely to be due to pre-eclampsia.

The report said the reasons for this remain unclear, but added that it could lead to women being introduced to preventative treatments at an earlier age.

The second study, carried out by the Norwegian University of Science and Technology found high blood pressure and cholesterol, led to a seven times increase in the risk of pregnancy complications.