DIAGNOSING GESTATIONAL HYPERTENSION AND PREECLAMPSIA WITH THE 24-HOURMEAN OF BLOOD-PRESSURE

The use of ambulatory blood pressure monitoring has provided a method of blood pressure assessment that may compensate for some of the limit ations of isolated measurements. Here we aim to examine prospectively the effectiveness of the commonly used 24-hour mean as a potential scr eening test for the identification of gestational hypertension and pre eclampsia. We analyzed 503 blood pressure series from 71 healthy pregn ant women and 256 series from 42 women who developed gestational hyper tension or preeclampsia. Forty-eight-hour blood pressure monitoring wa s done once every 4 weeks after the first obstetric consultation. Sens itivity and specificity of the 24-hour mean of blood pressure were com puted for each trimester of pregnancy by comparing distributions of va lues obtained for healthy and complicated pregnancies, without assumin g an a priori threshold for diagnosing gestational hypertension on the basis of mean blood pressure. Sensitivity ranges from 31.8% for diast olic blood pressure in the second trimester to 84.1% for systolic bloo d pressure in the third trimester. However, specificity is as low as 6 .9% for diastolic blood pressure in the first trimester. The positive predictive value does not reach 55% for any variable in any trimester. The higher relative risk was consistently obtained for systolic blood pressure (4.9 in the third trimester). Despite the highly statistical ly significant differences in blood pressure found between healthy and complicated pregnancies in all trimesters, the daily mean of blood pr essure does not provide a proper and stable individualized test for di agnosing hypertensive complications in pregnancy. Other indexes obtain ed from the blood pressure series have been shown, however, to identif y early in pregnancy those women who subsequently will develop gestati onal hypertension or preeclampsia, rendering ambulatory blood pressure monitoring a useful, but still costly, technique in pregnancy.