Periodontal therapy reduces the rate of preterm low birth weight in women with pregnancy-associated gingivitis

Background: One hypothesis to explain the association between periodontal disease (PD) preterm/low birth weight (PT/LBW) is that PT/LBW may be indirectly mediated through translocation of bacteria or bacterial products in the systemic circulation. Transient bacteremias occur in subjects with marginal periodontitis or with gingivitis, and it is possible that bacteria and their products may reach the placental membranes hernatogenously and provide the inflammatory effect to induce preterm labor. The effect of gingivitis as a potential risk factor for PT/LBW has still not been studied. A randomized controlled trial was undertaken to determine the effect of routine plaque control and scaling on the pregnancy outcomes in women with gingivitis. Methods: Eight hundred seventy (870) pregnant women with gingivitis, aged 18 to 42, were enrolled while receiving prenatal care in Santiago, Chile. Women were randomly assigned in a two-to-one fashion to either a treatment group (N = 580), receiving periodontal treatment before 28 weeks of gestation or to a control group (N = 290), receiving periodontal treatment after delivery. Periodontal therapy consisted of plaque control, scaling, and daily rinsing with 0.12% clorhexidine. Maintenance therapy was provided every 2 to 3 weeks until delivery, and consisted of oral hygiene instruction and supragingival plaque removal by instrumentation, as needed. The primary outcomes assessed were delivery at less than 37 weeks of gestation or an infant weighing less than 2,500 g. Results: Of the 870 women enrolled, 36 women (27 in the treatment group and nine in the control group) were excluded from the analyses for different reasons. The incidence of PT/LBW in the treatment group was 2.14% (12/560) and in the control group, 6.71% (19/283) (odds ratio [OR] 3.26; 95% confidence interval [CI] 1.56 to 6.83; P= 0.0009). Multivariate logistic regression analysis showed that, after adjusting for several known risk factors for PT/LBW, women with gingivitis were at a higher risk of PT/LBW than women who received periodontal treatment (OR 2.76; 95%Cl 1.29 to 5.88; P= 0.008). Conclusions: Periodontal treatment significantly reduced the PT/LBW rate in this population of women with pregnancy-associated gingivitis. Within the limitions of this study, we conclude that gingivitis appears to be an independent risk factor for PT/LBW for this population.