Periodontitis, a Marker of Risk in Pregnancy for Preterm Birth

There is limited evidence that periodontitis is associated with preterm birth, but why it might induce inflammation and premature termination of pregnancy remains uncertain. The investigators evaluated periodontal status in 36 women at risk of miscarriage or preterm delivery. Amniocentesis was carried out at 15-20 weeks gestation, and a full-mouth periodontal examination was done at approximately the same time. The criterion for periodontitis was at least 1 site with a probing depth of 5 mm or greater in each quadrant. The 2 sites with the deepest pockets were chosen for microbial sampling of intraoral plaque. Vaginal smears also were obtained and cytokine levels estimated in amniotic fluid samples. Chronic periodontitis was diagnosed in 20% of women delivering within the normal period and in 83% of those who had a preterm delivery and an infant with low birth weight. All women with preterm gestations had regularly received dental care. Probing depths differed significantly in the preterm and full-term cases. In no case was the amniotic fluid infected, and none of the women presented with ascending bacterial infection. Pathogens were more often present in subgingival plaque from women who delivered prematurely. Women delivering preterm had significantly higher amniotic fluid levels of the cytokines interleukin (IL)-6 and prostaglandin-E 2 (PGE 2 ), whereas levels of IL-8 were significantly higher in women delivering at term. Amniotic fluid levels of IL-6 and PGE 2 correlated significantly with colony-forming units in subgingival plaque samples. These findings indicate that chronic periodontitis can induce a primary host chorioamniotic response that increases the risk of preterm birth.