U Physician, Part of New England Journal of Medicine Study, Says Eclampsia Likely Not Caused by Lack of Blood Flow

U Physician, Part of New England Journal of Medicine Study, Says Eclampsia Likely Not Caused by Lack of Blood Flow

Feb 6, 2003 5:00 PM

Eclampsia, the condition that causes some pregnant women to experience life-threatening seizures, is less likely to have been caused by a lack of blood flow in the brain than has been commonly thought.

An international group of researchers, led by University of Utah professor of obstetrics and gynecology Michael A. Belfort, M.D., Ph.D, reached that conclusion in a study of 1,650 pregnant women who received two different drugs to prevent eclamptic seizures. The group published its findings in the January 23 edition of The New England Journal of Medicine.

The researchers studied women with severe preeclampsia, a condition marked by high blood pressure and protein in the urine. Left untreated, preeclampsia can lead to eclampsia, which strikes once every 2,000 to 3,000 births.

For the trial, which took place from 1995 to 2000, the researchers studied outcomes in pregnant women who received nimodipine with those given magnesium sulfate to prevent seizures. The study was unblinded, meaning the women and researchers knew who was receiving nimodipine (819 women) and who was getting magnesium sulfate (831).

Nimodipine, a drug that prevents blood vessels from constricting, was used to treat eclampsia under the hypothesis that eclamptic seizures are induced by a lack of blood flow in the brain. But after comparing nimodipine with magnesium sulfate (similar to epsom salts), the researchers found 21 preeclamptic pregnant women who received nimodipine suffered seizures, while seven who received magnesium sulfate experienced seizures. Women who received nimodipine were even more likely to suffer a seizure after giving birth.

The results led the researchers to believe that eclamptic seizures probably are not caused by lack of blood flow, but may be the result of a sudden increase in blood pressure in the brain that may lead to swelling, and occasionally hemorrhage.

"We are now able to say with reasonable certainty that the most common form of eclampsia is probably not caused by vasospasm or ischemia and is much more likely to be the result of overperfusion of the brain rather than underperfusion," Belfort said.

The results may lead researchers in new directions to prevent and treat eclampsia.

U.S. doctors have used magnesium sulfate to treat eclampsia and preeclampsia for 30 years, but physicians in other parts of the world have not yet embraced the treatment, Belfort said.

Along with Belfort, the study included researchers from the University of Cape Town, South Africa; the University of Texas Medical Branch, Galveston; and the University of Texas School of Public Health, Houston.

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