title: Pregnancy's stronghold on the vaginal microbiome.
abstract: OBJECTIVE
  To assess the vaginal microbiome throughout full-term uncomplicated pregnancy.
  
  
  METHODS
  Vaginal swabs were obtained from twelve pregnant women at 8-week intervals throughout their uncomplicated pregnancies. Patients with symptoms of vaginal infection or with recent antibiotic use were excluded. Swabs were obtained from the posterior fornix and cervix at 8-12, 17-21, 27-31, and 36-38 weeks of gestation. The microbial community was profiled using hypervariable tag sequencing of the V3-V5 region of the 16S rRNA gene, producing approximately 8 million reads on the Illumina MiSeq.
  
  
  RESULTS
  Samples were dominated by a single genus, Lactobacillus, and exhibited low species diversity. For a majority of the patients (n = 8), the vaginal microbiome was dominated by Lactobacillus crispatus throughout pregnancy. Two patients showed Lactobacillus iners dominance during the course of pregnancy, and two showed a shift between the first and second trimester from L. crispatus to L. iners dominance. In all of the samples only these two species were identified, and were found at an abundance of higher than 1% in this study. Comparative analyses also showed that the vaginal microbiome during pregnancy is characterized by a marked dominance of Lactobacillus species in both Caucasian and African-American subjects. In addition, our Caucasian subject population clustered by trimester and progressed towards a common attractor while African-American women clustered by subject instead and did not progress towards a common attractor.
  
  
  CONCLUSIONS
  Our analyses indicate normal pregnancy is characterized by a microbiome that has low diversity and high stability. While Lactobacillus species strongly dominate the vaginal environment during pregnancy across the two studied ethnicities, observed differences between the longitudinal dynamics of the analyzed populations may contribute to divergent risk for pregnancy complications. This helps establish a baseline for investigating the role of the microbiome in complications of pregnancy such as preterm labor and preterm delivery.
authors.affiliation: Department of Surgical Research, Mayo Clinic, Rochester, Minnesota, United States of America.
authors.forename: Marina R S
authors.initials: MR
authors.lastname: Walther-António
authors.affiliation: Department of Surgical Research, Mayo Clinic, Rochester, Minnesota, United States of America; Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
authors.forename: Patricio
authors.initials: P
authors.lastname: Jeraldo
authors.affiliation: Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
authors.forename: Margret E
authors.initials: ME
authors.lastname: Berg Miller
authors.affiliation: Department of Animal and Range Sciences, Montana State University, Bozeman, Montana, United States of America.
authors.forename: Carl J
authors.initials: CJ
authors.lastname: Yeoman
authors.affiliation: Genomic Medicine Group, J. Craig Venter Institute, Rockville, Maryland, United States of America.
authors.forename: Karen E
authors.initials: KE
authors.lastname: Nelson
authors.affiliation: Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America; Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
authors.forename: Brenda A
authors.initials: BA
authors.lastname: Wilson
authors.affiliation: Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America; Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
authors.forename: Bryan A
authors.initials: BA
authors.lastname: White
authors.affiliation: Department of Surgical Research, Mayo Clinic, Rochester, Minnesota, United States of America; Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America; Department of Physiology and Biomedical Engineering, Mayo College, Rochester, Minnesota, United States of America.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Chia
authors.affiliation: Obstetrics and Gynecology, Mayo Clinic, Rochester, Minnesota, United States of America.
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Creedon
mesh_terms: D000328:Adult; D004269:DNA, Bacterial; D005260:Female; D006801:Humans; D007778:Lactobacillus / Q000235:genetics*; D064307:Microbiota / Q000235:genetics*; D011247:Pregnancy; D014621:Vagina / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial