Twenty-four-hour automated blood pressure monitoring as a predictor of preeclampsia

OBJECTIVE: The purpose of this study was to determine the predictive ability of parameters of 24-hour ambulatory blood pressure monitoring for the development of preeclampsia or gestational hypertension in women who are already considered at risk for these disorders.

STUDY DESIGN: One hundred twenty-two pregnant women who were considered high risk for the development of preeclampsia underwent 24-hour ambulatory blood pressure monitoring between 18 and 30 weeks gestation, while their condition was normotensive according to routine mercury sphygmomanometry. One hundred sixty-four healthy primigravid women who were considered at usual risk for preeclampsia underwent the same tests as a parallel study. Routine blood pressure, awake and sleep average blood pressure, and 24-hour mean average blood pressure were entered into multiple logistic regression as predictors of either preeclampsia or gestational hypertension; significant variables were then tested by a series of receiver operator curves.

RESULTS: Eight percent of usual risk and 45% of high risk women experienced the development of preeclampsia or gestational hypertension. In both groups, the average routine mercury blood pressure and awake, sleeping, and 24-hour ambulatory blood pressure monitoring-derived blood pressure were significantly higher in women who later experienced the development of preeclampsia or gestational hypertension. In usual risk women, 24-hour systolic blood pressure of >or=115 mm Hg and sleeping systolic blood pressure of >or=106 mm Hg were predictive of later preeclampsia or gestational hypertension, but sensitivities were low (77% and 54%, respectively). In high risk women, sleeping diastolic blood pressure of >or=62 mm Hg and sleeping mean arterial pressure of >or=79 mm Hg were predictive of preeclampsia or gestational hypertension, but again sensitivities were low (70% and 65%, respectively).

CONCLUSION: Awake and sleeping blood pressure are higher in midpregnancy in women who later experience the development of preeclampsia or gestational hypertension. Twenty-four-hour ambulatory blood pressure monitoring provides a noninvasive method of selecting some of these women, but this test has a sensitivity no better than that of other predictive tests, even in women at high risk for preeclampsia.