title: Periodontal disease and adverse pregnancy outcomes: a systematic review.
abstract: BACKGROUND
  Recent studies suggest that periodontal disease, as a source of subclinical and persistent infection, may induce systemic inflammatory responses that increase the risk of adverse pregnancy outcomes.
  
  
  OBJECTIVE
  To examine the existing evidence on the relationship between periodontal disease and adverse pregnancy outcomes.
  
  
  METHODS
  Published studies identified via searches of the MEDLINE, EMBASE, CINAHL, and Current Contents full-text databases.
  
  
  METHODS
  We identified and selected observational studies (i.e. case-control, cross-sectional, and cohort) and nonrandomised controlled studies or randomised controlled trials that examined periodontal disease as a risk factor for adverse pregnancy outcomes.
  
  
  METHODS
  Odds ratios (OR) or risk ratios (RR) were extracted or calculated from the studies' data. We calculated pooled effect size for two clinical controlled trials but not for the observational studies due to the heterogeneity in definitions for periodontal disease and adverse pregnancy outcomes across studies.
  
  
  RESULTS
  Twenty-five studies (13 case-control, 9 cohort, and 3 controlled trials) were identified. The studies focused on preterm low birthweight, low birthweight, preterm birth, birthweight by gestational age, miscarriage or pregnancy loss, and pre-eclampsia. Of the chosen studies, 18 suggested an association between periodontal disease and increased risk of adverse pregnancy outcome (ORs ranging from 1.10 to 20.0) and 7 found no evidence of an association (ORs ranging from 0.78 to 2.54). Three clinical trial studies suggest that oral prophylaxis and periodontal treatment can lead to a 57% reduction in preterm low birthweight (pooled RR 0.43; 95% CI 0.24-0.78) and a 50% reduction in preterm births (RR 0.5; 95% CI 0.20-1.30).
  
  
  CONCLUSIONS
  Periodontal disease may be associated with an increased risk of adverse pregnancy outcome. However, more methodologically rigorous studies are needed for confirmation.
authors.affiliation: Department of Epidemiology, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112, USA. xxiong@tulane.edu
authors.forename: X
authors.initials: X
authors.lastname: Xiong
authors.forename: P
authors.initials: P
authors.lastname: Buekens
authors.forename: W D
authors.initials: WD
authors.lastname: Fraser
authors.forename: J
authors.initials: J
authors.lastname: Beck
authors.forename: S
authors.initials: S
authors.lastname: Offenbacher
mesh_terms: D000022:Abortion, Spontaneous / Q000209:etiology; D005260:Female; D005317:Fetal Growth Retardation / Q000209:etiology; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D010510:Periodontal Diseases / Q000150:complications*; D011225:Pre-Eclampsia / Q000209:etiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000209:etiology*; D011256:Pregnancy Outcome; D047928:Premature Birth / Q000209:etiology