title: Association between lactate in vaginal fluid and time to spontaneous onset of labour for women with suspected prelabour rupture of the membranes.
abstract: OBJECTIVE
  To assess whether lactate determination in vaginal fluid is associated with, and can predict, onset of labour for women with suspected prelabour rupture of the membranes (PROM).
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Labour ward at Soder Hospital, Stockholm, Sweden.
  
  
  METHODS
  Women with suspected PROM after 34 weeks of gestation, who later had spontaneous onset of labour (n = 179).
  
  
  METHODS
  All women underwent a speculum examination and a test for determining lactate concentration in vaginal fluid. We used logistic regression to estimate the association between lactate concentration in vaginal fluid and time to onset of labour.
  
  
  METHODS
  Time from examination to onset of labour (cervix > or =4 cm), within 24 hours and 48 hours.
  
  
  RESULTS
  The median time interval between examination and spontaneous onset of labour was 8.4 hours for women with 'high' lactate (> or =4.5 mmol/l) and 54 hours for those with 'low' lactate concentrations (<4.5 mmol/l). Among 86 women with high lactate concentrations, 76 (88%) had started labour within 24 hours compared with 20 of 93 (22%) women with low lactate concentrations (OR 27.7, 95% CI 12.2-63.3). After checking for the effect of visible amniotic fluid, the corresponding odds were still substantially increased (OR 13.5, 95% CI 5.3-34.3).
  
  
  CONCLUSIONS
  High lactate concentration (> or =4.5 mmol/l) in vaginal fluid can be used to predict whether a woman with suspected PROM will commence spontaneous onset of labour within 24 or 48 hours.
authors.affiliation: Department of Obstetrics and Gynaecology, Söder Hospital, Stockholm, Sweden. eva.itzel@telia.com
authors.forename: E
authors.initials: E
authors.lastname: Wiberg-Itzel
authors.forename: H
authors.initials: H
authors.lastname: Pettersson
authors.forename: S
authors.initials: S
authors.lastname: Cnattingius
authors.forename: L
authors.initials: L
authors.lastname: Nordstrom
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis; D001826:Body Fluids / Q000737:chemistry; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000175:diagnosis*; D006801:Humans; D007745:Labor Onset; D019344:Lactic Acid / Q000032:analysis*; D008875:Middle Aged; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D011296:Prenatal Diagnosis / Q000379:methods / Q000592:standards*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014621:Vagina / Q000737:chemistry*
chemical_list: D015415:Biomarkers; D019344:Lactic Acid