The association between Porphyromonas gingivalis-specific maternal serum IgG and low birth weight

Background: In Alabama, low birth weight (LBW) infants are about 20 times m ore likely to die before their first birthday compared to normal birth weig ht infants. While the rate of LBW has been consistently higher among Africa n Americans compared to whites, there has been a gradual increase in LBW fo r both African Americans and whites over the last 15 years. In an attempt t o identify modifiable risk factors for LBW, we have previously reported tha t a pregnant woman's poor periodontal health may be an independent risk fac tor for low birth weight. Methods: A predominantly African American and socioeconomically homogeneous group of 448 women was followed from the second trimester of their first p regnancy. Thirty-nine LBW cases were observed at the end of follow-up. Usin g 17 preterm LBW cases and 63 randomly selected controls from the above coh ort, the periodontal pathogen-specific maternal serum IgG levels during the second trimester of pregnancy were evaluated in relation to birth weight o f the infant, while controlling for known risk factors for LBW. Results: Porphyromonas gingivalis (P.g.)-specific maternal serum IgG levels were higher in the LBW group (mean 58.05, SE = 20.00 mug/ml) compared to t he normal birth weight (NBW) group (mean 13.45, SE = 3.92 mug/ml; P = 0.004 ). Women with higher levels of Pg.-specific IgG had higher odds of giving b irth to LBW infants (odds ratio [OR] = 4.1; 95% confidence interval [CI] fo r odds ratio = 1.3 to 12.8). This association remained significant after co ntrolling for smoking, age, IgG levels against other selected periodontal p athogens, and race. Conclusions: Low birth weight deliveries were associated with a higher mate rnal serum antibody level against P gingivalis at mid-trimester.