DIURNAL BLOOD-PRESSURE DIFFERENCE IN THE ASSESSMENT OF PREECLAMPSIA

Objective: To evaluate diurnal variation in blood pressure (BP) in nor mal gravidas and those with preeclampsia, using ambulatory BP monitori ng. Methods: A cross-sectional comparative observational study was per formed in three teaching hospital maternity units. Twenty-four normote nsive and 24 preeclamptic women who were similar in age, weight, and m ean duration of gestation (35 weeks) were studied. Diurnal variation a nd BP measurement were assessed using ambulatory BP monitors validated for use in pregnancy and for which normal reference ranges for pregna ncy have been derived. Results: At night, the BP fall was less in pree clamptic women than in normotensive women. The day-night BP difference decreased as average BP rose (diastolic gradient = -0.54 [95% confide nce interval (CI) -0.77 to -0.31], systolic gradient = -0.36 [95% CI - 0.58 to -0.14], where gradient denotes a unit increase in BP leading t o an increase or decrease in the day-night difference). Conclusion: Th e decrease in day-night BP difference observed in preeclampsia is inve rsely related to average BP. This blunting of the day-night BP differe nce may be a useful adjunctive measure of disease severity in preeclam psia.