title: Early pregnancy changes in bacterial vaginosis-associated bacteria and preterm delivery.
abstract: BACKGROUND
  We evaluated the importance of measuring early vaginal levels of eight bacterial vaginosis (BV)-associated bacteria, at two points in pregnancy, and the risk of spontaneous preterm delivery (SPTD) among pregnant women and the subgroup of pregnant women with a history of preterm delivery (PTD).
  
  
  METHODS
  This prospective cohort study enrolled women at five urban obstetric practices at Temple University Hospital in Philadelphia PA. Women with singleton pregnancies less than 16 weeks gestation self-collected vaginal swabs at two points in pregnancy, prior to 16 weeks gestation and between 20-24 weeks gestation, to measure the presence and level of eight BV-associated bacteria. Women were followed-up for gestational age at delivery via medical records.
  
  
  RESULTS
  Among women reporting a prior PTD, women with higher levels of Leptotrichia/Sneathia species, BVAB1 and Mobiluncus spp., prior to 16 weeks gestation, were significantly more likely to experience a SPTD. In addition, pregnant women with a prior PTD and increasing levels of Leptotrichia/Sneathia species (aOR: 9.1, 95% CI 1.9, 42.9), BVAB1 (aOR: 16.4, 95% CI 4.3, 62.7) or Megasphaera phylotype 1 (aOR: 6.2, 95% CI 1.9, 20.6), through 24 weeks gestation, were significantly more likely to experience an SPTD. Among the overall group of pregnant women, the levels of BV-associated bacteria were not related to SPTD.
  
  
  CONCLUSIONS
  Among the group of women reporting a prior PTD, increasing levels of BVAB1, Leptotrichia/Sneathia species, and Megasphaera phylotype 1, through mid-pregnancy were related to an increased risk of SPTD.
authors.affiliation: Department of Obstetrics & Gynecology, Temple University, Philadelphia, PA; Department of Public Health, Temple University, Philadelphia, PA.
authors.forename: Deborah B
authors.initials: DB
authors.lastname: Nelson
authors.forename: Alexandra
authors.initials: A
authors.lastname: Hanlon
authors.forename: Irving
authors.initials: I
authors.lastname: Nachamkin
authors.forename: Catherine
authors.initials: C
authors.lastname: Haggerty
authors.forename: Dimitrios S
authors.initials: DS
authors.lastname: Mastrogiannis
authors.forename: Congzhou
authors.initials: C
authors.lastname: Liu
authors.forename: David N
authors.initials: DN
authors.lastname: Fredricks
mesh_terms: D000328:Adult; D015373:Bacterial Typing Techniques; D015169:Colony Count, Microbial; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D045183:Leptotrichia / Q000302:isolation & purification*; D017904:Mobiluncus / Q000302:isolation & purification*; D007752:Obstetric Labor, Premature / Q000209:etiology / Q000382:microbiology* / Q000517:prevention & control; D015143:Philadelphia; D011237:Predictive Value of Tests; D011247:Pregnancy; D047928:Premature Birth; D011446:Prospective Studies; D012307:Risk Factors; D014621:Vagina / Q000382:microbiology*; D016585:Vaginosis, Bacterial / Q000150:complications / Q000382:microbiology* / Q000517:prevention & control
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal
keywords: BVAB1; Leptotrichia/Sneathia species; Megasphaera phylotype 1; preterm delivery