Periodontal disease and pregnancy outcomes

Routine specialist pregnancy care involved an initial meeting to discuss quitting smoking and set a quit date, followed by 4 weekly telephone calls, and free nicotine replacement therapy for 10 weeks.

Periodontal disease is common with the worldwide prevalence of gingivitis varying between 50% to 90% for all adults worldwide. Severe periodontitis is estimated to affect >10% of the world’s population and more than 45% of US adults over 3O years of age had (mainly) moderately sever periodontitis.  Studies suggest periodontal disease rates during pregnancy to range from 11-100%.   While a number of studies have suggested an association between adverse pregnancy outcomes (pre-eclampsia, preterm delivery and low birth weight) and periodontal disease others have not.

The aim of this systematic overview was to perform a comprehensive synthesis of findings from systematic reviews assessing the link between periodontal disease and a broad range of adverse pregnancy outcomes, focusing on interpreting findings from the highest- quality reviews.

Methods 

Searches were conducted in the Cochrane Database of Systematic Reviews, Medline EMBASE, World Health Organization Global Health Library and Google Scholar databases. PROSPERO was searched for unpublished, ongoing, and recently completed systematic reviews.

Systematic reviews that searched several databases and included prospective/retrospective cohort studies, cross-sectional studies, and/or case- control or nested case-control studies comparing pregnancy outcomes and periodontal disease (gingivitis or periodontitis) were considered. Two reviewers independently selected studies abstracted data and assessed risk of bias using the AMSTAR (Assessment of Multiple Systematic Reviews) checklist.  No meta-analysis was performed, because of the overlap of primary studies in the meta-analyses included in the review. Findings are described in tabular and narrative format.

Results

  • 23 reviews reporting on a total of 120 studies were included.
  • The number of primary studies in the reviews ranged from 3-45.
  • No reviews reported about the association between periodontal disease and maternal or perinatal mortality.
  • 17 reviews considered association between periodontal disease and preterm birth, 7 performed a meta-analysis. The reviews included a total of 70 primary studies with a high degree of overlap (CCA= 11.6%).
  • 9 reviews reported on periodontal disease and pre-eclampsia, 5 performed a meta-analysis (In total 23 primary studies CCA= 30.4%)
  • 16 reviews reported
on the association between periodontal disease and low birth weight, 6 performed a meta-analysis (In total 48 primary studies CCA= 20.8%)
  • 17 reviews investigated the association between periodontal disease and preterm low birth weight,
7 performed a meta-analysis (In total 51 primary studies CCA= 10%) Bases on the systematic reviews with the lowest risk of bias for each outcomes positive associations positive associations between periodontal disease and pregnancy outcomes are shown in the table below along with the estimated population- attributable fractions.
Relative risk (RR) or odds ratio (OR) and 95% CI No of studies No of participants Est. population- attributable fractions
Preterm birth RR =1.6 (1.3 to 2.0) 17 6,741 5% to 38%
Low birth weight RR =1.7 (1.3 to 2.1) 10 5,693 6% to 41%
Pre-eclampsia OR =2.2 (1.4 to 3.4) 15 5,111 10%
to 55%
Preterm LBW RR =3.4 (1.3 to 8.8) 4 2,263 17.9%
 to 70.6%

Conclusions

The authors concluded: –

Given the evidence presented in this comprehensive overview of systematic reviews, we propose that the association between periodontal disease and
various common and severe adverse pregnancy outcomes is now sufficiently established for the field to start moving beyond conducting additional primary epidemiologic studies and systematic reviews in this area. There is now a need to focus on elucidating the mechanisms underlying the link between periodontal disease and adverse pregnancy outcomes to inform the development of targeted therapies and preventive strategies.

Comments

While this well conducted overview helpfully draws together the large number of systematic review that have been conducted on this topic there are still important concerns regarding the quality of the primary studies on which these reviews are based.  Two important issues are highlighted by the authors themselves; the failure of many of the primary studies to consistently report confounders (for example smoking, socioeconomic
status, maternal age, and ethnicity) this could lead to an overestimation of the association measures between periodontal disease and adverse pregnancy outcomes; variation with the definition of periodontal disease used in primary studies with only 3 systematic reviews actually reporting a definition.  Concerns relating to the quality of the primary studies included in these reviews highlight the need to interpret the finding of this overview with caution.  It is also worth highlighting as do the author of the overview that, association does not confer causality.

In relation to this it is worth noting that a recent Cochrane review (Dental Elf – 19th Jun 2017) assessing the impact of treating periodontal disease on pregnancy outcomes included 15 randomised trials concluding:

It is not clear if periodontal treatment during pregnancy has an impact on preterm birth (low-quality evidence). There is low-quality evidence that periodontal treatment may reduce low birth weight (< 2500 g), however, our confidence in the effect estimate is limited. There is insufficient evidence to determine which periodontal treatment is better in preventing adverse obstetric outcomes. Future research should aim to report periodontal outcomes alongside obstetric outcomes.

Links

Primary paper

L.A. Daalderop, B.V. Wieland, K. Tomsin, L. Reyes, B.W. Kramer, S.F. Vanterpool, and J.V. Been. Periodontal Disease and Pregnancy Outcomes: Overview of Systematic Reviews  JDR Clinical & Translational Research Article first published online: September 25, 2017.

Original review protocol on PROSPERO

Published review protocol

Other references

Dental Elf – 19th Jun 2017

Periodontal treatment during pregnancy-no evidence of impact on preterm birth

 

Dental Elf – 30th Sep 2015

Periodontal treatment and adverse pregnancy outcomes

 

 

 

 

 

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Derek Richards

Derek Richards is a specialist in dental public health, Director of the Centre for Evidence-Based Dentistry and Specialist Advisor to the Scottish Dental Clinical Effectiveness Programme (SDCEP) Development Team. He is a former editor of the Evidence-Based Dentistry Journal, the chief blogger for the Dental Elf website and a past president of the British Association for the Study of Community Dentistry. He has been involved with a wide range of evidence-based initiatives both nationally and internationally since 1994. Retired from the NHS he is currently a part-time senior lecturer at Dundee Dental School.

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