Maternal periodontitis and the causes of preterm birth: the case-control Epipap study.

AIM To analyse the association between maternal periodontitis and preterm birth (<37 weeks' gestation) according to the causes of preterm birth. MATERIALS AND METHODS Epipap is a case-control multi-centre study of singleton livebirths. One thousand one hundred and eight women with preterm deliveries and 1094 with deliveries at term (> or =37 weeks) at six French maternity units were included. Periodontal examinations after delivery identified localized and generalized periodontitis. Cases were classified according to four causes of preterm birth. Polytomous logistic regression analysis was used to control for confounders (maternal age, parity, nationality, educational level, marital status, employment during pregnancy, body mass index before pregnancy, smoking status) and the examiner. RESULTS Localized periodontitis was identified in 129 (11.6%) cases and in 118 (10.8%) control women and generalized periodontitis in 148 (13.4%) and 118 (10.8%), respectively. A significant association was observed between generalized periodontitis and induced preterm birth for pre-eclampsia [adjusted odds ratio 2.46 [95% confidence intervals (95% CI)1.58-3.83]. Periodontitis was not associated with spontaneous preterm birth or preterm premature rupture of membranes or with the other causes. CONCLUSION Maternal periodontitis is associated with an increased risk of induced preterm birth due to pre-eclampsia.