title: Platelet count may predict abnormal bleeding time among pregnant women with hypertension and preeclampsia.
abstract: BACKGROUND
  Anesthesiologists often require laboratory data to estimate the bleeding risk among hypertensive pregnant women prior to administering regional anesthesia. Many rely on the bleeding time (BT) in making this determination. We examined whether the platelet count can adequately predict BT among a group of hypertensive parturients.
  
  
  METHODS
  This retrospective subgroup analysis, taken from a cohort of 2,051 hypertensive pregnant women, comprises 87 individuals who underwent both a BT and platelet count prior to delivery. We calculated the correlation between the platelet count and BT at three platelet cut-off points with respect to prolonged BT of eight minutes or more.
  
  
  RESULTS
  There was a significant negative correlation between platelet count at delivery and BT [r= -0.45, 95% confidence interval (CI) -0.26 to -0.60; P <0.0001]. All three platelet cut-off points had a sensitivity of less than 66% with negative predictive values below 75% for an abnormal BT. A platelet count > or =75 x 109/L [corrected] was specific for the presence of an abnormal BT (specificity 97.8%, 95% CI 91.7-100.0), with a positive predictive value of 95.5% (95% CI 83.1-100.0) and a positive likelihood ratio of 24 (95% CI 3.3-168).
  
  
  CONCLUSIONS
  In a group of hypertensive parturients, the platelet count appears to be very specific for predicting a prolonged BT The platelet count may aid the anesthesiologist in determining the risk of bleeding from regional anesthesia. Given the study's potential for bias future research is needed to validate these findings.
authors.affiliation: Department of Obstetrics and Gynecology, St Joseph's Hospital and McMaster University, Hamilton, Ontario, Canada. rorymcdonagh@hotmail.com
authors.forename: R J
authors.initials: RJ
authors.lastname: McDonagh
authors.forename: J G
authors.initials: JG
authors.lastname: Ray
authors.forename: R F
authors.initials: RF
authors.lastname: Burrows
authors.forename: E A
authors.initials: EA
authors.lastname: Burrows
authors.forename: M J
authors.initials: MJ
authors.lastname: Vermeulen
mesh_terms: D000328:Adult; D001760:Bleeding Time; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000150:complications*; D007231:Infant, Newborn; D010976:Platelet Count; D011225:Pre-Eclampsia / Q000097:blood / Q000150:complications*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000628:therapy*; D012189:Retrospective Studies