Periodontal Health and Fertility: Is there any Relationship?

Varun S¹ and Bharti J²*

¹Public Health Dentistry, Rayat Behra Dental College, India

²Department of Obstetrics & Gynaecology, Post Graduate Institute of Medical Education and Research, India

*Corresponding author: Joshi Bharti, Department of Obstetrics and Gynecology, Old Nehru Hospital, Post Graduate Institute of Medical Education and Research Chandigarh, India

Received: October 12, 2016; Accepted: November 27, 2016; Published: November 24, 2016

Abstract

Periodontal disease is a chronic microbial infection of gums and surrounding tissues. The host response to bacterial infection results in overproduction of cytokines and other inflammatory markers which has been held responsible for various systemic conditions like diabetes, respiratory disease, adverse pregnancy outcomes and cardiovascular events. In recent years few studies have thrown light on the association of periodontitis with infertility and concluded that there could be possible association between periodontal disease and woman’s chance of conception and effectiveness of infertility treatment. The evaluation of periodontal clinical parameters within IVF programme is a new field of research with limited information. Furthermore, effect of bacteriospermia secondary to periodontal disease resulting in decreased sperm motility or count or increased sperm apoptosis remain to be determined as only few studies have mentioned about these effects. Nevertheless, the confirmation of real association of periodontal disease with male and female infertility requires further prospective randomized trials and interventional studies. There is a need of coherent approach between gynaecologists and dentists to verify the existing relation which may establish the background for need of periodontal treatment upon diagnosis before embarking on infertility treatment.

Keywords: Periodontal disease; Infertility; Association; Periodontitis; Fertility

Introduction

Periodontitis is a chronic inflammatory disorder of gums & surrounding tissues caused by specific microorganisms resulting in progressive destruction of the periodontal ligament and alveolar bone with pocket formation, recession or both. The clinical feature that distinguishes periodontitis from gingivitis is the presence of clinically detectable attachment loss. Gingivitis is milder reversible inflammation of the soft tissues around teeth while periodontitis is severe form of periodontal disease resulting in the destruction of the alveolar bone supporting structures & soft tissues [1]. Oral health is gaining lot of importance in recent times and has been associated with almost all the disease states of the body i.e. Respiratory, cardiovascular diabetes and adverse pregnancy outcomes [2-5]. Infertility affects around 15% of the couples worldwide and can be due to many factors like tubal, ovulatory or male factor. Around 30% of cases of infertility are unexplained. Till date little is known about the effect of periodontal disease on reproductive function and evidence to support a link between periodontitis and subfertility is still emerging. In the last few years focus of researchers has been on the role of periodontitis in infertility. Whether oral health status plays any part in subfertility of the partners, was the question in our mind. With this hypothesis that fertility is compromised in people with chronic dental diseases, we searched the literature and reviewed the studies published till now in this article.

Methodology

Various studies published so far were searched and review was carried out to verify the existing research about the association between periodontal diseases and female infertility, and the biological rationale for such relation. After a judicious literature investigation, it is possible to state that there is insufficient evidence to confirm the association until now. More studies proposing to investigate that relation are, thus, necessary.

Evidence of effect of periodontal diseases on female fertility

The term infertility is defined as failure of a woman to conceive after one year of unprotected intercourse. Regarding the effect of periodontal disease on the female fertility, it has been interpreted that gram negative bacteraemia resulting from periodontal inoculous incites the immune mechanism and triggers the overproduction of pro-inflammatory markers like tumour necrosis factor alpha (TNF-a), interferon gamma (IFN-g) and interleukin 1 beta (IL-1b) etc [6]. This has been strongly supported by various studies identifying that even subclinical infection significantly affects conception rate. Significant failure rate in achieving pregnancy despite the fact that there has been appreciable progress in the knowledge and techniques to treat infertility has recently raised concern regarding the role of periodontal disease in infertility [7-10]. The question arises whether the chronic infection from periodontal disease directly affects endometrium or influences the effectiveness of hormonal therapy used to treat infertility or indirectly associated with other subclinical infections causing infertility [11,12]. The answer to the above seems to be difficult but the possible mechanisms supported by available literature may be due to local endometrial effect or other mechanism which is not clear. Collective evidence so far suggest that successful treatment of periodontal disease have led to improvement in endothelial and vascular function and reduction in the level of inflammatory markers.

Endometrial effect of periodontitis is corroborated by several studies [13-16]. This has been explained in similar fashion to other inflammatory conditions such as hydrosalpinges, endometritis and polycystic ovarian syndrome in which it is hypothesized that negative influence on conception relates in part to an endometrial effect. A cross-sectional study aimed to explore the relation between time to conceive and periodontitis by Nwhator, et al. [17] concluded that there is significant association between periodontal disease and conception time. He further suggested that women of reproductive age group should have periodic dental checkup and maintain good oral hygiene.

The answer to the fundamental question that periodontal infection not only affect reproductive potential but also alters success and treatment outcome of infertility has barely been explored [18,19].

Effect of periodontal health on infertility treatment

Haytec, et al. [18] compared the women receiving ovulation induction drugs either oral or injectable with control group and made reference regarding the impact of medication (ovulation induction drugs) on gingival tissues. The findings of the study revealed significant increase in gingival inflammation in medication group. There was also statistically significant increase in gingival volume and bleeding tendency on probing and duration of medication was .almost three months. Potential mechanism for this is increased level of estrogen and progesterone by the usage of ovulation induction drugs. Therefore effective plaque treatment and constant periodontal monitoring should be considered to minimize the effect of periodontal infection on the success of infertility treatment [20]. Transient elevation of inflammatory markers have been shown after periodontal treatment so, it is advisable to wait for few weeks before seeking fertility intervention [21,22]. Hart reported that magnitude of negative influence of periodontal disease on time to conceiving was of the same order as obesity. A large cohort of women who were taking part in “SMILE study” were followed and analyzed information on conceiving time and pregnancy outcomes [23,24]. This was the first report to suggest that periodontal disease may be one of the modifiable risk factor limiting conception and therefore infertile couples may consider dental health checkup before embarking on infertility treatment.

Endometriosis is an important cause of infertility and possible association between periodontal disease and endometriosis was investigated by cross-sectional survey over a period of 5 years [10]. Author concluded that women with self-reported endometriosis had significantly (57%) higher odds of having both gingivitis and periodontitis relative to not having periodontal disease, compared with women without self-reported endometriosis, when controlling for other relevant factors.

The evaluation of periodontal clinical parameters within IVF programme is a new field of research and this fact was first investigated by Pavlatou [25]. Sixty women undergoing IVF were recruited in the study and various indices i.e., Gingival index, bleeding on probing, plaque levels were recorded for all participants before and after IVF. It was observed that aggravation of gingival inflammation was found after hormonal administration as IVF programme and poor periodontal status before IVF was associated with more failures. Whether this increased gingival inflammation affects the final fertilization of ova needs further investigation.

Few years later in another investigation by same author regarding possible effect of periodontal status on effectiveness of IVF concluded that maternal dental status not only gets affected by hormonal treatment but also may determine the success of IVF [26,27].

Evidence of effect of periodontal diseases on male fertility

Male factor is responsible for about 40% cases of infertility and endocrine function or testicular abnormalities are the main attributable causes. The first study evaluating possible association of men’s infertility with poor oral health involved 36 men with bacteriospermia who were resistant to antibiotic therapy [28]. They were segregated into experimental and control group and after six months semen analysis of experimental group showed significant improvement in all semen parameters. This observation of positive correlation of male factor infertility with periodontal disease is supported by many studies [17,29,30]. High level of bacteriospermia and increased inflammatory markers secondary to periodontitis leading to Oligospermia, inhibiting sperm motility and inducing sperm apoptosis are the proposed aetiologies for male infertility [10]. A study by Klinger, et al. postulated that periodontal pockets lead to decreased sperm motility and increase risk of male infertility.

Pitfalls in literature

Most of the studies in literature mention about difficulty in ruling out all confounders and many are limited by small number of sample size. In a study by Nwhator, et al. [17] effect of stress and evaluation of spouse was not considered, which could be a possible cause of infertility. Author has also acknowledged that prevalence of other fertility related variables like fibroid, PCOS, obesity and tubal disease also may have affected the result. Hart, et al. [15] found positive correlation of periodontal disease with infertility in Non causcian women only and this only reflects positive correlation with conceiving time not with infertility. This could be because of different immunogenicity in different races. A good number of studies support that people with increased immunogenicity are more susceptible to periodontal diseases [31-33] and on the other hand various immunological mechanisms are held responsible for poor reproductive performance and adverse obstetric outcomes. It is clear from recent reports that modulation of immunogenicity leads to increase chance of conception [34,35]. Most of the studies are observational or cross sectional surveys.

Most of the studies establishing correlation between periodontal disease and male infertility remain unadjusted for smoking, diabetes, alcohol and heart disease [17,29,31,36-38]. In a study by Haytec, et al. [18] although gingival inflammation was significantly increased in experimental group but this did not determine that whether it was in healthy or diseased peridontium. So additional prospective studies taking into account the confounders are required to establish real association between periodontal disease and infertility.

Periodontal diseases are multifactorial and due to many different periodontal diseases definitions the comparison among them is still a challenge [39-45]. Experimental animal model studies may benefit by the ability to control the highest number of variables potentially affecting the outcomes studied (Table 1).