title: Evidence grade associating periodontitis to preterm birth and/or low birth weight: I. A systematic review of prospective cohort studies.
abstract: OBJECTIVE
  The aims of this systematic review (SR) were to evaluate the association between maternal periodontitis and preterm birth (PB) and/or low birth weight (LBW), and the methodological quality of prospective cohort studies conducted for such a purpose.
  
  
  METHODS
  MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched up to and including October 2010 to identify prospective studies on the association of periodontitis with PB and/or LBW. Search was conducted by two independent reviewers. The methodological quality of the observational studies was assessed using a specially designed methodological tool. Random effects meta-analyses were conducted thoroughly.
  
  
  RESULTS
  Search strategy identified 1680 potentially eligible articles, of which 12 prospective studies were included. One cohort study had their data reported in two articles. Of the 11 studies, 10 showed a high methodological quality and one a medium methodological quality. Nine studies (81.8%) found an association between periodontitis and PB and/or LBW. Meta-analysis showed a significant risk of preterm delivery for pregnant women with periodontitis [risk ratio (RR): 1.70 (95% confidence interval (CI): 1.03, 2.81)] and a significant risk for LBW [RR: 2.11 (95% CI: 1.05, 4.23)] or PB/LBW [RR: 3.57 (95% CI: 1.87, 6.84)], as well as a high and unexplained degree of heterogeneity between studies.
  
  
  CONCLUSIONS
  Although this SR found a consistent association between periodontitis and PB and/or LBW, this finding should be treated with great caution until the sources of heterogeneity can be explained.
authors.affiliation: Department of Stomatology, Division of Periodontics, School of Dentistry, University of São Paulo, São Paulo, Brazil. chambrone@usp.br
authors.forename: Leandro
authors.initials: L
authors.lastname: Chambrone
authors.forename: Mariana Rocha
authors.initials: MR
authors.lastname: Guglielmetti
authors.forename: Cláudio Mendes
authors.initials: CM
authors.lastname: Pannuti
authors.forename: Luiz Armando
authors.initials: LA
authors.lastname: Chambrone
mesh_terms: D015331:Cohort Studies; D055094:Evidence-Based Dentistry; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D010518:Periodontitis / Q000150:complications*; D011247:Pregnancy; D047928:Premature Birth / Q000209:etiology*; D011446:Prospective Studies; D012107:Research Design / Q000592:standards