title: Diurnal blood pressure difference in the assessment of preeclampsia.
abstract: OBJECTIVE
  To evaluate diurnal variation in blood pressure (BP) in normal gravidas and those with preeclampsia, using ambulatory BP monitoring.
  
  
  METHODS
  A cross-sectional comparative observational study was performed in three teaching hospital maternity units. Twenty-four normotensive and 24 preeclamptic women who were similar in age, weight, and mean duration of gestation (35 weeks) were studied. Diurnal variation and BP measurement were assessed using ambulatory BP monitors validated for use in pregnancy and for which normal reference ranges for pregnancy have been derived.
  
  
  RESULTS
  At night, the BP fall was less in preeclamptic women than in normotensive women. The day-night BP difference decreased as average BP rose (diastolic gradient = -0.54 [95% confidence 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 to an increase or decrease in the day-night difference).
  
  
  CONCLUSIONS
  The decrease in day-night BP difference observed in preeclampsia is inversely related to average BP. This blunting of the day-night BP difference may be a useful adjunctive measure of disease severity in preeclampsia.
authors.affiliation: Department of Obstetrics and Gynaecology, University of Leicester, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Halligan
authors.forename: A
authors.initials: A
authors.lastname: Shennan
authors.forename: P C
authors.initials: PC
authors.lastname: Lambert
authors.forename: M
authors.initials: M
authors.lastname: de Swiet
authors.forename: D J
authors.initials: DJ
authors.lastname: Taylor
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D009200:Myocardial Contraction / Q000502:physiology; D011225:Pre-Eclampsia / Q000503:physiopathology*; D011247:Pregnancy