title: Risk of preterm delivery in relation to vaginal bleeding in early pregnancy.
abstract: OBJECTIVE
  To examine the relationship between vaginal bleeding during early pregnancy and preterm delivery.
  
  
  METHODS
  Study subjects (N=2678) provided information regarding socio-demographic, biomedical, and lifestyle characteristics. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI).
  
  
  RESULTS
  Any vaginal bleeding in early pregnancy was associated with a 1.57-fold increased risk of preterm delivery (95% CI: 1.16-2.11). Vaginal bleeding was most strongly related with spontaneous preterm labor (OR=2.10) and weakly associated with preterm premature rupture of membrane (OR=1.36) and medically induced preterm delivery (OR=1.32). As compared to women with no bleeding, those who bled during the first and second trimesters had a 6.24-fold increased risk of spontaneous preterm labor; and 2-3-fold increased risk of medically induced preterm delivery and preterm premature rupture of membrane, respectively.
  
  
  CONCLUSIONS
  Vaginal bleeding, particularly bleeding that persists across the first two trimesters, is associated with an increased risk of preterm delivery.
authors.affiliation: Department of Epidemiology, Multidisciplinary International Research Training Program, University of Washington, School of Public Health and Community Medicine, Seattle, WA 98195, USA.
authors.forename: Rydhwana
authors.initials: R
authors.lastname: Hossain
authors.forename: Tenecia
authors.initials: T
authors.lastname: Harris
authors.forename: Vitool
authors.initials: V
authors.lastname: Lohsoonthorn
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Williams
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007752:Obstetric Labor, Premature; D016017:Odds Ratio; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D014592:Uterine Hemorrhage