BACKGROUND Periodontal diseases are a common group of conditions that cause inflammation and destruction to the supporting structures of the teeth. When it is found during pregnancy, it may lead to adverse pregnancy outcomes. Hence an attempt has been made to investigate the relationship between periodontal disease and adverse pregnancy outcomes among pregnant women attending a maternity hospital in Aligarh city. METHODS Screening of periodontal disease was carried out on 604 eligible pregnant women aged 20-35 yrs. from the maternity ward of Aligarh district hospital. Patients with four or more sites with pocket depth 4 mm or higher, and clinical attachment loss 3 mm or higher at the same site with presence of bleeding on probing were diagnosed as having periodontitis in this study. A sample of 604 subjects was enrolled in the study out of which 104 were lost to follow-up. Of the remaining 503 subjects, 250 with periodontitis were in the exposed group and 253 with healthy periodontium were in the non-exposed group. Patients were followed up to the date of delivery. Primary outcomes were measured. Simple and multiple logistic regression analyses were used to assess the association between periodontal disease and adverse pregnancy outcomes. RESULTS Significant difference has been reported between maternal periodontitis and adverse pregnancy outcomes but logistic regression analysis showed a weak association between periodontitis and poor pregnancy outcomes. CONCLUSIONS The results of this study showed that there is some role of periodontitis as an independent risk factor for causing adverse pregnancy outcomes.