Periodontal bacterial profiles in pregnant women: Response to treatment and associations with birth outcomes in the obstetrics and periodontal therapy (OPT) study

Background: A recent clinical trial (Obstetrics and Periodontal Therapy [OPT] Study) demonstrated that periodontal therapy during pregnancy improved periodontal outcomes but failed to impact preterm birth. The present study evaluated seven target bacteria, Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia (previously T. forsythensis), Prevotella intermedia, Campylobacter rectus, and Fusobacterium nucleatum, in subgingival dental plaque of pregnant women in the OPT Study and their association with birth outcomes. Methods: Pregnant women were randomly assigned to receive periodontal treatment before 21 weeks' gestation or after delivery. Subgingival plaque was sampled at baseline (13 to 16 weeks; 6 days of gestation) and at 29 to 32 weeks. We analyzed subgingival plaque samples from women who experienced fetal loss, delivered a live preterm infant (preterm women), or delivered a full-term infant (full-term women). Samples were analyzed using quantitative polymerase chain reaction. Associations between preterm birth and bacterial counts and percentages were tested using multiple linear regression. Results: No significant differences were observed at baseline between preterm and full-term women for any measured bacterial species or group of species, after accounting for multiple comparisons. Changes in bacterial counts and proportions during pregnancy also were not associated with birth outcomes. In full-term and preterm women, periodontal therapy significantly reduced (P <0.01) counts of all target species except for A. actinomycetemcomitans. Conclusions: In pregnant women with periodontitis, non-surgical periodontal therapy significantly reduced levels of periodontal pathogens. Baseline levels of selected periodontal pathogens or changes in these bacteria resulting from therapy were not associated with preterm birth.