title: Periodontitis and risk of preterm birth and low birthweight--a meta-analysis.
abstract: BACKGROUND
  Periodontitis and prematurity are social diseases with common risk factors. In 1996 periodontitis was proven to be a possible significant and independent risk factor of preterm birth of newborns with low body weight. Numerous studies on the influence of periodontitis on the time of birth and/or birth weight of newborns have been conducted throughout the world since, including several ones in Poland, but their results have been inconsistent. Work objective: A meta-analysis of case-control, prospective and cohort studies on the influence of periodontitis on preterm birth and low birth weight.
  
  
  METHODS
  The international and Polish bibliography bases were searched for essays on the relationship between periodontitis and preterm birth and/or low birth weight published between 1996 and 2010. All essays qualified for the meta-analysis were subjected to qualitative evaluation. The calculation of the overall odds ratio used both, fixed-effects and random-effects models (DerSimonian-Liard method). The heterogeneity of the included studies and effect of publication bias were also subjected to evaluation.
  
  
  RESULTS
  The meta-analysis included 15 case-control studies, 1 cross-sectional study and 6 cohort studies. The essays came from 4 continents: 8 from Europe (including 2 from Poland), 7 from South America, 4 from North America, and 3 from Asia. The total analysis covered 12047 pregnant women. The overall odds ratio of giving premature birth to a child with low weight for mothers with periodontitis in the model of random effects amounted to 2.35 (1.88-2.93, p < 0.0001). For low birth weight, the overall OR was 1.5 (95% Cl: 1.26-1.79, p = 0.001) for premature births--2.73 (95% CI: 2.06-3.6, p < 0.0001). A significant heterogeneity of the studies included in the meta-analysis was observed, and a significant publication bias was also demonstrated.
  
  
  CONCLUSIONS
  The hypothesis of periodontitis as an independent risk factor of preterm birth and/or low birth weight needs further verification. In order to achieve that, it is necessary to conduct more methodologically well-planned cohort and intervention studies. The need of dental care for pregnant women as an integral component of the prenatal care program remains to be an important issue.
authors.affiliation: Department of Periodontology, Wroclaw Medical University, Poland. tkonopka@stom.am.wroc.pl
authors.forename: Tomasz
authors.initials: T
authors.lastname: Konopka
authors.forename: Anna
authors.initials: A
authors.lastname: Paradowska-Stolarz
mesh_terms: D016001:Confidence Intervals; D055094:Evidence-Based Dentistry; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D016017:Odds Ratio; D010518:Periodontitis / Q000453:epidemiology*; D011044:Poland; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology*; D011256:Pregnancy Outcome / Q000453:epidemiology*; D047928:Premature Birth; D012107:Research Design; D012307:Risk Factors