Studies suggest an association between maternal periodontal disease and pre-eclampsia.
In this systematic review, several types of infections are identified and investigated: urinary tract infection, periodontal disease, Chlamydia pneumoniae infection, HIV infection, malaria and other persistent bacterial and viral infections. Separate analyses were conducted for each of them. This summary review will only focus on the link between pre-eclampsia and periodontitis, which was just a part of the original systematic review.


METHODS
MEDLINE, EMBASE, POPLINE, CINAHL, LILACS (all from inception to June 30, 2007), proceedings of international meetings on pre-eclampsia, bibliography of the retrieved articles, reviews, chapters in standard textbooks on hypertension in pregnancy, and contact with investigators involved in the field were used to identify relevant studies. No language restrictions were imposed.


METHODS
Cohort, case-control or cross-sectional studies with original data that evaluated the association between maternal periodontal disease and pre-eclampsia were included. Cases were defined as women suffering from hypertension plus proteinuria, after 20 weeks' gestation.


METHODS
Data were extracted from each study according to design, geographic location, sample size, gestational age when periodontal disease was diagnosed, definition and severity of pre-eclampsia, confounding factors controlled for, temporality of the association, and report of dose-response gradient. Studies included in the systematic review were also included in the meta-analysis if they reported Odds Ratio (OR) or Relative Risk (RR) estimates with their 95% Confidence Intervals (CIs), or provided the information necessary to calculate them. Results from different reports were combined to produce a pooled OR according to the Mantel-Haenszel method, using both fixed- and random-effects models. Heterogeneity was quantified with I(2) statistics. Studies were also quality assessed.


RESULTS
Seven case-control studies and 2 cohort studies evaluated the association between periodontal disease and pre-eclampsia. Six studies, representing a total of 3420 women (493 pre-eclamptic and 2927 non-pre-eclamptic control women) were pooled for meta-analysis. Women with evidence of periodontal disease during pregnancy had a 1.76 fold higher risk of pre-eclampsia compared with women without periodontal disease (OR, 1.76, 95% CI: 1.43-2.18).


CONCLUSIONS
Periodontal disease during pregnancy is associated with an increased risk of pre-eclampsia. More studies are required to verify this as well as to explore whether or not such relationship is causal and, if so, the mechanisms involved.
Vergnes
Jean-Noel
JN
Toulouse Dental Hospital, Dental Department of Epidemiology, and Unit on Perinatal and Women's Health, Institut National de la Santé et de la Recherche Médicale, U149, Paris, France.