Abstract
BACKGROUND: Maternal serum IgG antibody against Porphyromonas gingivalis is an indicator of both periodontitis and adverse pregnancy outcomes. This study aims to evaluate the anti-P. gingivalis IgG and IgG subclasses1-4 in threatened preterm labour (TPL) patients and their association with small for gestational age (SGA). METHODS: Serum, saliva and subgingival plaque samples were collected from 47 TPL patients compared with 48 healthy pregnant women. The amount of P. gingivalis was measured in saliva and plaque using real-time polymerase chain reaction. The serum anti-P. gingivalis IgG titre and anti-P. gingivalis subclasses IgG 1-4 concentration were measured using enzyme-linked immunosorbent assay. RESULTS: The amount of anti-P. gingivalis IgG-1 was significantly lower in the TPL group than in the healthy group. Fourteen subjects delivered SGA infants in the TPL group. The pocket probing depth (PPD), clinical attachment loss, PPD ≥ 5 mm%, amount of P. gingivalis in plaque, anti-P. gingivalis IgG and anti-P. gingivalis IgG-4 were significantly higher in the TPL-SGA group than in the TPL-normal weight group. Moreover, logistic regression analysis revealed the detection frequency of P. gingivalis in plaque and placenta weight were significantly correlated with SGA in TPL. In the receiver operating characteristic curve analysis, an amount of P. gingivalis in plaque ≥ 86.45 copies showed a sensitivity of 0.786 and a specificity of 0.727 (AUC 0.792) for predicting SGA in TPL. CONCLUSION: Lower anti-P. gingivalis IgG-1 amounts are related to TPL, while higher anti-P. gingivalis IgG and IgG-4 are related with SGA in TPL. Further, greater colonisation of P. gingivalis in plaque might increase the risk of SGA and can be useful in prediction of SGA in TPL.