In pregnant women with high blood pressure, both the top measure (systolic) and the bottom measure (diastolic) of blood pressure are important predictors of potentially serious complications, a new study suggests.

Very high systolic pressure is a better warning sign of stroke in women with preeclampsia or eclampsia than is very high diastolic pressure, researchers report. Preeclampsia, also known as toxicemia of pregnancy, is marked by high blood pressure, fluid retention and protein in the urine. If untreated, this condition may progress to eclampsia, a life-threatening complication.

“The paradigm for ob-gyns for half a century, let’s say, has been that the diastolic pressure is the most important, and that one generally doesn’t start blood pressure medications for patients with preeclampsia until the diastolic pressure reaches 110,” Dr. James N. Martin of the University of Mississippi Medical Center in Jackson told AMN Health.

“What we’re saying is that is not correct - we should be paying attention to both numbers.”

Martin and his colleagues analyzed case histories of 28 women who had a stroke associated with severe preeclampsia or eclampsia. The findings are published in the journal Obstetrics & Gynecology.

While only three of the patients had diastolic pressure of 110 mm Hg or higher immediately before having a stroke, they found, 23 of the patients had systolic blood pressures of 160 mm Hg or higher, and all had systolic pressures over 155 mm Hg.

Only three of the patients received treatment for their high blood pressure before the stroke occurred.

The next step in the research, Martin said, will be to see how effective existing drugs, such as hydralazine or labetalol, will be in keeping systolic blood pressure below 160, and whether controlling systolic blood pressure will prevent stroke.

“A lot of pregnant women get to that range and don’t have strokes,” he added. “We need to figure out why certain women do have strokes.”

Martin and his colleagues found several women in the study had also developed hemolysis, elevated liver enzymes and low platelets, or HELLP syndrome.

His group’s practice is to treat HELLP with corticosteroids, Martin noted. None of the women had these drugs in their systems at the time they suffered a stroke, suggesting that treating HELLP may be a key aspect of stroke prevention.

Women who have severe preeclampsia and eclampsia and very high systolic blood pressure (higher than 160) have an especially high risk of stroke, Martin’s group concludes. The researchers recommend that these women receive immediate and special attention, intensive care, and blood pressure treatment to reduce their stroke risk.

SOURCE: Obstetrics and Gynecology, February 2005.