title: Midtrimester bacterial vaginosis and cervical length in women at risk for preterm birth.
abstract: OBJECTIVE
  The purpose of this study was to estimate the effect of bacterial vaginosis on midtrimester cervical length in women at increased risk for recurrent spontaneous preterm birth.
  
  
  METHODS
  We conducted a secondary analysis of prerandomization data from a multicenter trial of ultrasound-indicated cerclage. Women with previous spontaneous preterm birth at <34 weeks' gestation underwent initial cervical length assessment and vaginal fluid collection at 16-21 weeks 6 days gestation. Gram stains were scored with Nugent criteria. With serial scans, the shortest cervical length was observed.
  
  
  RESULTS
  Records for 949 women had complete data. In unadjusted regression models, Nugent score (P = .003) and vaginal fluid pH (P = .008) were related inversely to cervical length. Women with bacterial vaginosis based on Nugent score ≥7 (P = .04) or pH ≥5 (P = .016) had significantly lower cervical length than unaffected women; however, all of these effects were null after covariate adjustment.
  
  
  CONCLUSIONS
  Nugent score, pH level, and bacterial vaginosis are associated inversely with cervical length; however, these relationships become null after adjustment for relevant covariates.
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA.
authors.forename: Melissa S
authors.initials: MS
authors.lastname: Mancuso
authors.forename: Dana
authors.initials: D
authors.lastname: Figueroa
authors.forename: Jeff M
authors.initials: JM
authors.lastname: Szychowski
authors.forename: Merri Maddox
authors.initials: MM
authors.lastname: Paden
authors.forename: John
authors.initials: J
authors.lastname: Owen
mesh_terms: D000328:Adult; D054791:Cervical Length Measurement; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D047928:Premature Birth; D018570:Risk Assessment; D014621:Vagina / Q000737:chemistry / Q000382:microbiology; D016585:Vaginosis, Bacterial / Q000175:diagnosis*