title: The vaginal microbiota of pregnant women who subsequently have spontaneous preterm labor and delivery and those with a normal delivery at term.
abstract: BACKGROUND
  This study was undertaken to determine whether the vaginal microbiota of pregnant women who subsequently had a spontaneous preterm delivery is different from that of women who had a term delivery.
  
  
  RESULTS
  This was a nested case-control study of pregnant women who had a term delivery (controls) and those who had a spontaneous preterm delivery before 34 weeks of gestation (cases). Samples of vaginal fluid were collected longitudinally and stored at -70°C until assayed. A microbial survey using pyrosequencing of V1-V3 regions of 16S rRNA genes was performed. We tested the hypothesis of whether the relative abundance of individual microbial species (phylotypes) was different between women who had a term versus preterm delivery. A suite of bioinformatic and statistical tools, including linear mixed effects models and generalized estimating equations, was used. We show that: 1) the composition of the vaginal microbiota during normal pregnancy changed as a function of gestational age, with an increase in the relative abundance of four Lactobacillus spp., and decreased in anaerobe or strict-anaerobe microbial species as pregnancy progressed; 2) no bacterial taxa differed in relative abundance between women who had a spontaneous preterm delivery and those who delivered at term; and 3) no differences in the frequency of the vaginal community state types (CST I, III, IV-B) between women who delivered at term and those who delivered preterm were detected.
  
  
  CONCLUSIONS
  The bacterial taxa composition and abundance of vaginal microbial communities, characterized with 16S rRNA gene sequence-based techniques, were not different in pregnant women who subsequently delivered a preterm neonate versus those who delivered at term.
authors.affiliation: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA ; Department of Obstetrics and Gynecology, University of Michigan, 1500 East Medical Center Drive, Ann Arbor, MI 48109, USA ; Department of Epidemiology and Biostatistics, Michigan State University, Room B601, 909 Fee Road, East Lansing, MI 48824, USA.
authors.forename: Roberto
authors.initials: R
authors.lastname: Romero
authors.affiliation: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA ; Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 540 E Canfield St, Detroit, MI 48201, USA.
authors.forename: Sonia S
authors.initials: SS
authors.lastname: Hassan
authors.affiliation: Institute for Genome Sciences, University of Maryland School of Medicine, 801 West Baltimore Street, Baltimore, MD 21201, USA ; Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W Baltimore St #480, Baltimore, MD 21201, USA.
authors.forename: Pawel
authors.initials: P
authors.lastname: Gajer
authors.affiliation: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA.
authors.forename: Adi L
authors.initials: AL
authors.lastname: Tarca
authors.affiliation: Institute for Genome Sciences, University of Maryland School of Medicine, 801 West Baltimore Street, Baltimore, MD 21201, USA.
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Fadrosh
authors.affiliation: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA ; Hutzel Women's Hospital, Detroit Medical Center, 3990 John R, Detroit, MI 48201, USA.
authors.forename: Janine
authors.initials: J
authors.lastname: Bieda
authors.affiliation: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA.
authors.forename: Piya
authors.initials: P
authors.lastname: Chaemsaithong
authors.affiliation: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA.
authors.forename: Jezid
authors.initials: J
authors.lastname: Miranda
authors.affiliation: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA ; Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 540 E Canfield St, Detroit, MI 48201, USA ; Hutzel Women's Hospital, Detroit Medical Center, 3990 John R, Detroit, MI 48201, USA.
authors.forename: Tinnakorn
authors.initials: T
authors.lastname: Chaiworapongsa
authors.affiliation: Institute for Genome Sciences, University of Maryland School of Medicine, 801 West Baltimore Street, Baltimore, MD 21201, USA ; Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W Baltimore St #480, Baltimore, MD 21201, USA.
authors.forename: Jacques
authors.initials: J
authors.lastname: Ravel
keywords: Histologic chorioamnionitis; Infection-induced preterm delivery; Prematurity; Vaginal flora; Vaginal microbiome