As periodontal disease progresses, inflammatory mediators are released systemically. In addition, some data suggests that genetic polymorphisms can predispose their carriers to react strongly to these bacterial toxins. These three cytokines are known to be abnormally elevated in preterm deliveries and induce labor when given to animals. When correcting for known risk factors of premature, low-birthweight deliveries, scientists found that periodontitis emerged as the leading factor. It increased seven-fold the odds of this pregnancy complication among 124 women whose periodontal health was assessed the day after they gave birth.
Preterm births account for two thirds of all infant mortality in developed countries.
Survivors can suffer neurological problems or respiratory distress. Paquette's group first tested their model by chronically infecting pregnant hamsters with the oral pathogen Porphyromonas gingivalis. Their pups were smaller than those of the control animals. Then the scientists induced periodontitis in pregnant hamsters through their diet. These animals also had abnormally small pups, as well as increased levels of TNF-alpha and PGE 2 in their amniotic fluid.