title: Limited accuracy of the hyperbaric index, ambulatory blood pressure and sphygmomanometry measurements in predicting gestational hypertension and preeclampsia.
abstract: OBJECTIVE
  The aim of this study was to validate the hyperbaric index (HBI) for first trimester prediction of preeclampsia and gestational hypertension.
  
  
  METHODS
  Participants were low-risk and high-risk nulliparous women and high-risk multiparous women, and were recruited between April 2004 and June 2006. At a gestational age of 9 weeks (range 8-11 weeks), blood pressure (BP) was measured first by sphygmomanometry and thereafter by ambulatory BP measurement (ABPM) for 48 h. The first 90 low-risk women who had an uneventful pregnancy formed the reference group for calculation of a time-specified tolerance interval with 90% confidence limits. In the validation group, consisting of the remaining women, the HBI was calculated as the time-specified BP excess over this tolerance limit for SBP, DBP and mean arterial pressure.
  
  
  RESULTS
  The validation group contained 101 women. Fifteen women developed preeclampsia and 13 developed gestational hypertension. For preeclampsia, the maximum HBI had the best predictive capacity with a sensitivity of 73% and a specificity of 86%. However, the difference with standard ABPM measurement or sphygmomanometry was small with a sensitivity between 75 and 73% and a specificity between 86 and 95%. The predictive efficacy for gestational hypertension was poor with all methods (sensitivity between 54 and 77%, specificity between 41 and 78%).
  
  
  CONCLUSIONS
  Standardized sphygmomanometry, ABPM measurement and the HBI calculated from 48-h ABPM had a comparable, restricted predictive efficacy. The high predictive value of HBI as observed in earlier studies could not be reproduced.
authors.affiliation: Department of Obstetrics and Gynaecology, Academic Medical Center, Amsterdam, The Netherlands. k.c.vollebregt@amc.uva.nl
authors.forename: Karlijn Corien
authors.initials: KC
authors.lastname: Vollebregt
authors.forename: Janneke
authors.initials: J
authors.lastname: Gisolf
authors.forename: Ilja
authors.initials: I
authors.lastname: Guelen
authors.forename: Kees
authors.initials: K
authors.lastname: Boer
authors.forename: Gert
authors.initials: G
authors.lastname: van Montfrans
authors.forename: Hans
authors.initials: H
authors.lastname: Wolf
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory / Q000379:methods*; D005260:Female; D005865:Gestational Age; D006801:Humans; D006973:Hypertension / Q000175:diagnosis* / Q000503:physiopathology; D010298:Parity; D011225:Pre-Eclampsia / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011247:Pregnancy; D018566:Pregnancy, High-Risk; D011446:Prospective Studies; D015203:Reproducibility of Results; D019722:Sphygmomanometers