An estimated 50,000 women per year worldwide die from preeclampsia. Preeclampsia is more likely to develop in women whose mothers had preeclampsia than in women whose mothers did not.

According to data on approximately 1.7 million births in Norway, a woman who becomes pregnant by a man who has already had a child with a different woman who had preeclampsia during that pregnancy has a risk of preeclampsia that is nearly twice as high as that of a woman whose partner does not have such a history.

In this issue of the Journal, investigators report that men who were themselves born of pregnancies complicated by preeclampsia are twice as likely to have a child who is the product of a pregnancy complicated by preeclampsia as are men who were born after a normal pregnancy.

There thus seems to be both a maternally transmitted and a paternally transmitted genetic predisposition to preeclampsia.

The ability to study this predisposition is hampered by the obvious fact that preeclampsia is a disease of pregnancy and no markers for the disorder have yet been identified in nonpregnant women, let alone men.

Women who have never born children has been confirmed as a risk factor for preeclampsia, in both large-scale epidemiologic studies and detailed clinical studies. A change of partner for a second or subsequent pregnancy causes a woman's risk to return to nearly the values associated with women who have never born children, suggesting a poorly defined immunologic contribution to the condition.

A curious but consistent finding is that women who smoke cigarettes have a lower risk of preeclampsia than women who do not smoke, even when confounders are carefully excluded. The babies of cigarette smokers are smaller than those of nonsmokers, presumably because of tobacco-related interference with the transfer of placental nutrients, and their average blood pressures are lower.

Environmental factors may also contribute to the development of preeclampsia.

For example, the high incidence of preeclampsia in many poor countries suggests that an inadequate diet may be a risk factor. The dietary inadequacies that have been proposed as relevant include deficiencies of calcium, zinc, vitamins C and E, and n-3 essential fatty acids.

The New England Journal of Medicine -- March 22, 2001 -- Vol. 344, No. 12