title: Vaginal Microbiota in Pregnancy: Evaluation Based on Vaginal Flora, Birth Outcome, and Race.
abstract: OBJECTIVE
  This study aims to evaluate vaginal microbiota differences by bacterial vaginosis (BV), birth timing, and race, and to estimate parameters to power future vaginal microbiome studies.
  
  
  METHODS
  Previously, vaginal swabs were collected at 21 to 25 weeks (stored at -80°C), and vaginal smears evaluated for BV (Nugent criteria). In a blinded fashion, 40 samples were selected, creating 8 equal-sized groups stratified by race (black/white), BV (present/absent), and birth timing (preterm/term). Samples were thawed, DNA extracted, and prepared. Polymerase chain reaction (PCR) with primers targeting the 16S rDNA V4 region was used to prepare an amplicon library. PCR products were sequenced and analyzed using quantitative insight into microbial ecology; taxonomy was assigned using ribosomal database program classifier (threshold 0.8) against the modified Greengenes database.
  
  
  RESULTS
  After quality control, 97,720 sequences (mean) per sample, single-end 250 base-reads, were analyzed. BV samples had greater microbiota diversity (p < 0.05)-with BVAB1, Prevotella, and unclassified genus, Bifidobacteriaceae family (all p < 0.001) more abundant; there was minimal content of Gardnerella or Mobiluncus. Microbiota did not differ by race or birth timing, but there was an association between certain microbial clusters and preterm birth (p = 0.07). To evaluate this difference, 159 patients per group are needed.
  
  
  CONCLUSIONS
  There are differences in the vaginal microbiota between patients with and without BV. Larger studies should assess the relationship between microbiota composition and preterm birth.
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Center for Women's Reproductive Health, Birmingham, Alabama.
authors.forename: Akila
authors.initials: A
authors.lastname: Subramaniam
authors.affiliation: Biomedical Informatics, Center for Clinical and Translational Sciences, Birmingham, Alabama.
authors.forename: Ranjit
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Center for Women's Reproductive Health, Birmingham, Alabama.
authors.forename: Suzanne P
authors.initials: SP
authors.lastname: Cliver
authors.affiliation: Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: Degui
authors.initials: D
authors.lastname: Zhi
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Center for Women's Reproductive Health, Birmingham, Alabama.
authors.forename: Jeff M
authors.initials: JM
authors.lastname: Szychowski
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Center for Women's Reproductive Health, Birmingham, Alabama.
authors.forename: Adi
authors.initials: A
authors.lastname: Abramovici
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Center for Women's Reproductive Health, Birmingham, Alabama.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Biggio
authors.affiliation: Biomedical Informatics, Center for Clinical and Translational Sciences, Birmingham, Alabama.
authors.forename: Elliot J
authors.initials: EJ
authors.lastname: Lefkowitz
authors.affiliation: Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: Casey
authors.initials: C
authors.lastname: Morrow
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Center for Women's Reproductive Health, Birmingham, Alabama.
authors.forename: Rodney K
authors.initials: RK
authors.lastname: Edwards
mesh_terms: D000293:Adolescent; D000328:Adult; D000407:Alabama; D004275:DNA, Ribosomal / Q000302:isolation & purification; D005260:Female; D006801:Humans; D064307:Microbiota; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D017422:Sequence Analysis, DNA; D014621:Vagina / Q000382:microbiology*; D016585:Vaginosis, Bacterial / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D004275:DNA, Ribosomal