DALLAS, Jan. 16 - A new, highly sensitive test based on blood pressure monitoring can detect late-pregnancy complications such as high blood pressure and preeclampsia a full 23 weeks before symptoms occur, Spanish researchers report in this month's Hypertension: Journal of the American Heart Association.
An elevated blood pressure during pregnancy, called gestational hypertension, can cause convulsions in the mother and growth failure in the baby. High blood pressure, swelling and protein in the urine characterize preeclampsia, which occurs in about 7 percent of pregnant women and is a leading cause of pregnancy-related death.
"With this monitoring, 96 percent of the women who eventually develop pregnancy-induced high blood pressure and preeclampsia can be diagnosed during the first half of pregnancy -- long before problems arise," says Ramon C. Hermida, Ph.D., director of bioengineering and chronobiology laboratories, University of Vigo, Spain.
The study involved 48-hour blood pressure monitoring of 152 pregnant women every four weeks. Blood pressures were taken every 60 minutes during the night and every 30 minutes during the day. The readings were then compared to previous readings of women with normal pregnancies. In the first trimester, the test accurately diagnosed 93 percent of the 60 women who later developed pregnancy-induced high blood pressure or preeclampsia. This rose to 99 percent by the third trimester.
The test does not require monthly monitoring during pregnancy, which was done during the study to validate the test. "The risk for gestational hypertension can be detected after the first session of monitoring for 48 hours," says Hermida. Monitoring costs and sleep disturbances may limit the use of this as a routine test for all pregnant women, he says. "However, the test may be worthwhile in high-risk pregnancies, which include women with a family history of preeclampsia or who have a multiple pregnancy." Other factors that put women at high risk include obesity, high blood pressure or cardiovascular disease before pregnancy.
The previous standard for pregnant women at risk for pregnancy-induced high blood pressure or preeclampsia was blood pressures of 140/90 millimeters of mercury or the detection of protein in the urine. The new monitoring additionally examines lower blood pressures in women and fluctuations between activity and rest during different trimesters. This allows diagnosis before blood pressure becomes elevated.
In a normal pregnancy, blood pressure slowly decreases over the first
half and then gradually increases over the second half. In pregnancy-induced
high blood pressure or preeclampsia, the blood pressure initially is in the
normal range, but is still higher than in women with normal pregnancies.
Media advisory: Dr. Hermida can be reached at 011-348 681-2148 or 348-180-7011;
fax 011-348-681-2116. (Please do not publish telephone numbers.)
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