Objectives: As part of the Kumamoto RAINBOW Project, a multifaceted implementation of the prevention of premature labor, we investigated pregnant women’s oral health status and assessed the validity of a self-reported periodontal disease questionnaire.

Methods: We examined the oral health status of pregnant women and asked them for subjective descriptions of symptoms of periodontitis both in the first and the second half of their pregnancy in Kumamoto Prefecture from August 2012 to January 2014. The Community Periodontal Index (CPI) was used to assess the periodontal condition, and women having periodontal pockets with depths of ≥4 mm were catecogorized as having periodontitis. The results were the scores of the self-questionnaire for periodontal disease prepared by the Japan Dental Association.

Results: Of the 9,527 pregnant women who received periodontal check- ups during the first half of pregnancy, 32 percent were diagnosed as having periodontitis. The self-questionnaire had a sensitivity of 51.2% and a specificity of 62.9% for pregnant women to predict their periodontal disease. Then, we evaluated the importance of each question by logistic regression analysis and extracted the useful items. An increased sensitivity (79.9%) was obtained with the best of the modified questionnaire.

Conclusions: To our knowledge, this is the first report of the evaluation of the usefulness of the self-reported periodontal disease questionnaire for pregnant women. The current self-questonnaire used for the general adult population was less sensitive for pregnant women. Our modified questionnaire showed an improved sensitivity for diagnosing periodontitis, but its specificity remained low. A specialized self-questionnaire for periodontal disease in pregnant women should be designed.