Systemic Antibody Responses in Pregnant Women: The OPT Trial

Recent studies suggest a relationship between periodontal disease in expectant women and adverse pregnancy outcomes including preeclampsia, preterm delivery, and low birthweight infants.  OBJECTIVE: The OPT Trial was designed to determine if non-surgical periodontal treatment in 2^nd trimester pregnant women decreases the risk of preterm birth.  METHODS: At four centers, 823 women with periodontitis (13-16 weeks of gestation) were randomized into treatment (periodontal therapy prior to 21 weeks, Tx) or control (same therapy after delivery, C) groups. Serum samples were obtained at baseline (13-16 weeks gestation) and at 29-32 weeks gestation and IgG antibody levels to 7 periodontal pathogens determined. Associations were explored between IgG levels and demographics, baseline and post-treatment periodontal status, and pregnancy outcomes.  RESULTS:  Significant differences were noted in antibody levels to Pg, Aa, Cr, Pi, and Td among the 4 centers at baseline (p<0.0001).  However, IgG levels did not differ significantly between Tx and C groups at baseline or 29-32 weeks. Antibody levels were generally positively associated with baseline measures of periodontitis, were significantly positively correlated with age (p<0.003) and significantly different among racial/ethnic groups (Hispanics>Blacks>Caucasians). The centers differed significantly in the fraction of treatment-group patients having a positive response to periodontal therapy (range 16-79%).  Women with preterm and term deliveries did not differ significantly in antibody levels to this battery of bacteria. CONCLUSIONS:  These findings demonstrate significant variation in serum antibody to oral bacteria among a population of pregnant women with periodontitis. Antibody levels differed among enrollment centers and racial/ethnic groups, and by maternal age.  There did not appear to be an association of antibody levels or changes related to birth outcomes or response to therapy, although the variations across centers in antibody levels and therapeutic outcomes complicate interpreting these relationships. Supported by NIDCR U01 DE014338.