title: Vaginal fluid pH and buffer capacity for predicting false preterm labor in Japanese women.
abstract: OBJECTIVE
  To determine the relationship between preterm labor and delivery, and the pH and buffer capacity of vaginal secretions.
  
  
  METHODS
  Between January 1, 2009 and March 31, 2012, two cohorts of patients at 22-36weeks of pregnancy were enrolled in a prospective cohort study at Nara Medical University Hospital, Japan. Patients experiencing preterm contractions and a control group of patients experiencing normal pregnancies were included. The pH and buffer capacity of vaginal secretions were measured and compared.
  
  
  RESULTS
  Of the 237 patients enrolled, 48 (20.3%) were experiencing symptoms of preterm labor and 189 (79.7%) were included in the control group. The pH was higher (P<0.001) and the buffer capacity was lower (P=0.0135) in the vaginal secretions of the patients experiencing preterm contractions compared with the control group. There was no difference in the pH and buffer capacity of the vaginal secretions of symptomatic patients who would experience preterm delivery and those who would not. Receiver operating characteristic curve analyses demonstrated that vaginal-secretion pH and buffer capacity could differentiate between patients experiencing preterm contractions and those not, but could not differentiate between patients who would experience preterm delivery and those who would not.
  
  
  CONCLUSIONS
  Vaginal-secretion pH and buffer capacity could be useful in diagnosing preterm labor; further studies are needed to determine potential practical diagnostic criteria.
authors.affiliation: Department of Obstetrics and Gynecology, Nara Medical University, Nara, Japan.
authors.forename: Taketoshi
authors.initials: T
authors.lastname: Noguchi
authors.affiliation: Department of Obstetrics and Gynecology, Nara Medical University, Nara, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Sado
authors.affiliation: Department of Obstetrics and Gynecology, Nara Medical University, Nara, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Naruse
authors.affiliation: Department of Obstetrics and Gynecology, Nara Medical University, Nara, Japan. Electronic address: hirokoba@naramed-u.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kobayashi
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007564:Japan; D007752:Obstetric Labor, Premature / Q000175:diagnosis*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies; D012372:ROC Curve; D012307:Risk Factors; D014621:Vagina / Q000378:metabolism*; D055815:Young Adult
keywords: Buffering capacity; Prediction; Preterm delivery; Preterm labor; Threatened preterm labor; Vaginal pH