An umbrella review of systematic reviews of the evidence of a causal relationship between periodontal disease and adverse pregnancy outcomes: A position paper from the Canadian Dental Hygienists Association.

Previous position papers have confirmed associations between periodontal disease and adverse pregnancy outcomes. Causal associations have not been confirmed and have been the source of much confusion for the profession and public. AIM: To investigate whether sufficient evidence exists for a causal relationship between periodontal disease and adverse pregnancy outcomes. METHODS: The PICO question was "For adults in good general health who are diagnosed with periodontal disease, will receiving non-surgical periodontal therapy (NSPT), as compared to not receiving non-surgical periodontal therapy, lower their risk for adverse pregnancy outcomes?" Only systematic reviews (SRs) with or without meta-analyses (MAs) of randomized controlled trials published in the English language between 2007 and 2019 were included. Databases searched included PubMed, MEDLINE, EbscoHost, CINAHL, Scopus, Cochrane Registry of Systematic Reviews, and Clinical Trials Registry. Quality assessments were conducted by both authors using the PRISMA checklist. The Bradford Hill criteria were used to determine evidence for causality. RESULTS: Of 37 records retrieved for adverse pregnancy outcomes, 9 met the criteria for inclusion and were analysed. None showed that NSPT lowers the risk for adverse pregnancy outcomes. CONCLUSION: Bradford Hill criteria analysis failed to support a causal relationship between periodontal disease and adverse pregnancy outcomes based on the most current evidence available.