Aim: To update the available evidence on the impact of periodontal disease on adverse pregnancy
outcomes (APOs). 

Material and methods: Observational studies (cross-sectional, case-control, and cohort design) on the
effect of periodontitis on pregnancy outcome, published after May 2012, were identified
through electronic databases and hand-searched journals. Findings were summarised by evidence
tables, using the PRISMA statement. Quality of the included studies was evaluated through the
Newcastle-Ottawa scale. Meta-analysis was performed with a random approach when feasible. 

Results: Results were divided for the following pregnancy outcomes: low birth weight (LBW), preterm
birth (PTB), preterm low birth weight (PTLBW), and pre-eclampsia (PE). A total of 35 studies have been
included in the update, although some of these have been included in more than one category. The
overall synthesis, drawn from 108 studies, indicated that there might be some association between
APOs and periodontitis. However, the strength of this association is extremely limited and hampered
by the wide heterogeneity in terms of methods, design, and result interpretation. In fact, a nearly
equal number of manuscripts that did not indicate association was found in each of the sub-sets
analysed.

 Conclusions: There is still no clear evidence to support the association between maternal periodontal
disease and adverse pregnancy outcomes.