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23-05-2012 | Genetics | Article

Gum disease could impede pregnancy


Free abstract

MedWire News: Periodontal disease could hinder women's ability to conceive, shows research, although the mechanism underlying the effect remains unclear.

The finding derives from a subanalysis of the Smile study, a multicenter randomized controlled trial of treatment for peridontal disease in midpregnancy.

A team led by Roger Hart (The University of Western Australia, Perth) analyzed data on 3416 trial participants who had conceived spontaneously, 1014 (29.7%) of whom had periodontal disease.

In all, 146 women took 12 months or longer to conceive. Periodontal disease was significantly more prevalent in these women than in those who conceived more quickly, at 34.9% versus 25.7%, Hart et al found.

Further analysis revealed that the average time to conceive was 7.1 months in women with periodontal disease versus 5.0 months in those without such disease, also a significant difference.

When women were stratified by race, periodontal disease was found to be significantly more prevalent in non-Caucasian than Caucasian women, at 41.4% versus 23.8%.

Furthermore, in non-Caucasians but not in Caucasians, the presence of periodontal disease was a significant independent predictor for trying to conceive for more than 12 months, at an odds ratio of 1.15.

The three other independent predictors for this outcome were older age, overweight (body mass index >25 kg/m2), and smoking.

In their discussion, Hart et al propose two hypotheses to explain the link between periodontal disease and difficulty conceiving.

First, several inflammatory conditions are known to have a negative impact on conception and fertility, possibly mediated by an effect of proinflammatory cytokines on the endometrium.

The fact that the association between gum disease and reduced fertility was observed only in non-Caucasian women could suggest that this group is "immunologically different from Caucasian women and therefore more susceptible to periodontal disease and its systemic consequences," write the authors.

The second hypothesis proposes a genetic basis for interindividual differences in infectious disease manifestations. Some people are hyper-responders, potentially mounting excessive inflammatory responses that can lead to tissue damage, while others are hyporesponders and are predisposed to overwhelming infection.

Several lines of evidence indicate that people with a hyper-responsive immune system are at increased risk for periodontal disease; similarly, hyper-responsive women may have an impaired ability to conceive. "Immunological mechanisms have been thought to play a role in reproductive problems such as recurrent miscarriage, infertility, and implantation failure," note the authors.

They conclude in Human Reproduction: "Our study suggests that periodontal disease is potentially a further modifiable risk factor influencing the time to conception in non-Caucasian women. As this condition is easily treated, couples trying to conceive may consider attending for a dental health check prior to attempting to conceive."

MedWire ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2012

By Joanna Lyford

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