title: The coagulation system in placental insufficiency: a study in the fetal circulation.
abstract: OBJECTIVE
  To examine the hypothesis that Doppler-defined umbilical placental insufficiency is associated with intravascular coagulation in the fetal circulation.
  
  
  METHODS
  A prospective, descriptive, single centre study.
  
  
  METHODS
  The University of Sydney, Department of Obstetrics at Westmead Hospital.
  
  
  METHODS
  Ninety-one infants were classified on the basis of the systolic:diastolic (SD) ratio of the umbilical artery flow velocity waveforms into severe (SD > 99.9th centile), moderate (SD > 95th centile) or control groups.
  
  
  METHODS
  Blood was collected from the umbilical vein at delivery.
  
  
  METHODS
  The coagulation variables measured were the plasma concentrations of thrombin-antithrombin, fibrinopeptide A and fibrinogen, the antithrombin III activity, the prothrombin time and the activated partial thromboplastin time.
  
  
  RESULTS
  There were no differences in activated partial thromboplastin time, antithrombin III activity, fibrinopeptide A or thrombin-antithrombin complex concentrations between fetuses with placental insufficiency and those with no placental disease. Fetuses with severe and moderate placental insufficiency had a statistically significant prolongation of their mean prothrombin time compared to controls (23.7 +/- 0.8, 23.6 +/- 1.6, and 19.9 +/- 0.6 s, respectively). Infants in the severe group had a lower plasma fibrinogen concentration than control fetuses (1.66 +/- 0.09 and 1.94 +/- 0.09 g/l, respectively). The activated partial thromboplastin time and antithrombin III activity were both highly dependent on gestational age.
  
  
  CONCLUSIONS
  These results do not support the hypothesis that Doppler-defined umbilical placental insufficiency is associated with activation of coagulation in the fetal circulation.
authors.affiliation: Department of Obstetrics and Gynaecology, University of Sydney, Westmead Hospital, Australia.
authors.forename: G R
authors.initials: GR
authors.lastname: Wilcox
authors.forename: B J
authors.initials: BJ
authors.lastname: Trudinger
authors.forename: T
authors.initials: T
authors.lastname: Exner
mesh_terms: D000990:Antithrombin III / Q000032:analysis; D001777:Blood Coagulation; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005340:Fibrinogen / Q000032:analysis; D005344:Fibrinopeptide A / Q000032:analysis; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D010314:Partial Thromboplastin Time; D010927:Placental Insufficiency / Q000097:blood*; D011247:Pregnancy; D011446:Prospective Studies; D011517:Prothrombin Time; D016216:Ultrasonography, Prenatal
chemical_list: D005344:Fibrinopeptide A; D000990:Antithrombin III; D005340:Fibrinogen