title: Vaginally obtained amniotic fluid samples in the diagnosis of subclinical chorioamnionitis.
abstract: BACKGROUND
  Preterm birth is often caused by infection or inflammation. High concentration of lactate dehydrogenase and low concentration of glucose in amniotic fluid obtained by amniocentesis are associated with subclinical chorioamnionitis. We evaluated amniotic fluid lactate dehydrogenase and glucose concentrations in relation to histologic chorioamnionitis in vaginally obtained samples.
  
  
  METHODS
  In a prospective study, vaginally obtained amniotic fluid samples were collected from 53 women with preterm prelabor rupture of membranes at 23(+4) to 34(+5) weeks of gestation at University Hospital, Helsinki, Finland. Amniotic fluid lactate dehydrogenase and amniotic fluid glucose were measured by immunochemiluminometric assays. Histopathologic examination of placenta was performed. The main outcome measure was histologic chorioamnionitis.
  
  
  RESULTS
  Median concentration of vaginally obtained amniotic fluid lactate dehydrogenase was higher in women with histologic chorioamnionitis than in women without (1400 IU/L vs. 784.5 IU/L, p = 0.005). By receiver operating characteristics curve the optimal cut-off for amniotic fluid lactate dehydrogenase in relation to histologic chorioamnionitis was 1029 IU/L (sensitivity 65%, specificity 69%, positive predictive value 83% and negative predictive value 46%). Amniotic fluid lactate dehydrogenase concentrations showed striking fluctuation in repeat samples. Amniotic fluid glucose concentrations did not differ among women with or without histologic chorioamnionitis (0 mmol/L vs. 0.65 mmol/L, p = 0.20).
  
  
  CONCLUSIONS
  Elevated amniotic fluid lactate dehydrogenase was associated with histologic chorioamnionitis, but decreased amniotic fluid glucose was not. However, the clinical value of vaginally obtained amniotic fluid lactate dehydrogenase is limited because of high sample-to-sample variability. Better biomarkers for optimal timing of delivery in women with preterm prelabor rupture of membranes are needed.
authors.affiliation: Department of Obstetrics and Gynecology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
authors.forename: Tarja
authors.identifier: http://orcid.org/0000-0002-7203-4416
authors.initials: T
authors.lastname: Myntti
authors.affiliation: Department of Obstetrics and Gynecology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
authors.forename: Leena
authors.identifier: http://orcid.org/0000-0003-4507-6917
authors.initials: L
authors.lastname: Rahkonen
authors.affiliation: Department of Obstetrics and Gynecology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
authors.forename: Minna
authors.identifier: http://orcid.org/0000-0001-5493-8588
authors.initials: M
authors.lastname: Tikkanen
authors.affiliation: Department of Obstetrics and Gynecology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
authors.forename: Jorma
authors.identifier: http://orcid.org/0000-0003-4775-606X
authors.initials: J
authors.lastname: Paavonen
authors.affiliation: Department of Obstetrics and Gynecology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
authors.forename: Vedran
authors.identifier: http://orcid.org/0000-0001-5230-1698
authors.initials: V
authors.lastname: Stefanovic
mesh_terms: D000328:Adult; D000653:Amniotic Fluid / Q000737:chemistry*; D002821:Chorioamnionitis / Q000175:diagnosis*; D005260:Female; D005322:Premature Rupture of Fetal Membranes; D005387:Finland; D005947:Glucose / Q000032:analysis*; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000032:analysis*; D011247:Pregnancy; D011446:Prospective Studies; D014621:Vagina
chemical_list: D007770:L-Lactate Dehydrogenase; D005947:Glucose
keywords: Amniotic fluid; glucose; histologic chorioamnionitis; lactate dehydrogenase; subclinical chorioamnionitis; vaginally obtained amniotic fluid sample