Periodontal Pathogens and Preterm Birth: Current Knowledge and Further Interventions

Inflammatory mechanisms of preterm labor and emerging anti-inflammatory interventions

Preterm birth is a major public health concern, requiring a deeper understanding of its underlying inflammatory mechanisms and to develop effective therapeutic strategies. This review explores the complex interaction between inflammation and preterm labor, highlighting the pivotal role of the dysregulation of inflammation in triggering premature delivery. The immunological environment of pregnancy, characterized by a fragile balance of immune tolerance and resistance, is disrupted in preterm labor, leading to a pathological inflammatory response. Feto-maternal infections, among other pro-inflammatory stimuli, trigger the activation of toll-like receptors and the production of pro-inflammatory mediators, promoting uterine contractility and cervical ripening. Emerging anti-inflammatory therapeutics offer promising approaches for the prevention of preterm birth by targeting key inflammatory pathways. From TLR-4 antagonists to chemokine and interleukin receptor antagonists, these interventions aim to modulate the inflammatory environment and prevent adverse pregnancy outcomes. In conclusion, a comprehensive understanding of the inflammatory mechanisms leading to preterm labor is crucial for the development of targeted interventions in hope of reducing the incidence of preterm birth and improving neonatal health outcomes.

The Impact of Periodontal Disease on Preterm Birth and Preeclampsia

This review delves into the possible connection between periodontitis and negative pregnancy outcomes, such as preeclampsia and preterm birth. It highlights the potential influence of an unidentified microbial factor on preeclampsia and the effects of inflammatory responses on the rate of preterm births. Furthermore, it underscores the prevalent occurrence of oral ailments within the populace and their significant repercussions on quality of life. Hormonal fluctuations during pregnancy may exacerbate oral conditions such as pregnancy gingivitis and periodontitis, necessitating bespoke therapeutic approaches that take into account potential fetal ramifications. Periodontal disease, characterized by microbial attack and inflammatory response, results in tissue destruction and tooth loss. The oral cavity's susceptibility to bacterial colonization, which is primarily due to its role as a site for food intake, is highlighted. Furthermore, research indicates a correlation between inflammatory responses and factors such as prostaglandin E2 and IL-1β, and preterm birth. Therapeutic interventions are a focus of international research, with efforts being aimed at optimizing outcomes through larger studies involving pregnant women.

Periodontal pathogens of the interdental microbiota in a 3 months pregnant population with an intact periodontium

Steroid hormones and the oral microbiota of pregnant women both appear as cumulative risk factors for gingivitis. This cross-sectional study, using real-time PCR, investigated the composition and diversity of the microbiota in interdental spaces of 3 months pregnant women with intact periodontium according the 2018 EFP/AAP classification. Bacteria identified were belonged to the red (Porphyromonas gingivalis Treponema denticola, and Tanerella forsythia), orange (Fusobacterium nucleatum, Prevotella intermedia, Campylobacter rectus, and Parvimonas micra), and green (Eikenella corrodens and A. actinomycetencomitans) Socransky complexes. Approximatively 109.11 bacteria were counted per interdental space in pregnant women. Bacteria from the red complex represented 33.80% versus 62.81% for the orange group versus 3.39% for the green group of the total number spread over the 3 groups. Dietary habits and physical activity did not have a significant impact on interdental microbiota, although a decrease in the median amount of 9 periodontopathogens was observed when fruit and vegetable consumption increased. Pregnant women who brushed their teeth at least twice a day had lower counts of total bacteria and 9 periodontal pathogens than those who brushed less. In 3 months pregnant women at high risk of periodontal disease (>30% bleeding sites), the dendogram revealed 2 clusters of the 9 periodontopathogens. This provides further support for the "key pathogen" hypothesis, among which Porphyromonas gingivalis plays a key role, indicating that specific bacteria in limited quantities can influence the host immune system and convert the microbiota from symbiotic to dysbiotic to induce inflammatory disorder. As a result, this study reported that 3 months pregnant women with healthy periodontium had high levels of interdental bleeding and a dysbiotic microbiota with periodontal pathogens of the Socransky orange and red complexes. These subjects were therefore potentially at increased risk of developing periodontal disease and, consequently, an adverse pregnancy outcome. So, preventive oral prophylaxis measures, in particular individual interdental prophylaxis, should be implemented as soon as pregnancy is established.

Microdiversity of the vaginal microbiome is associated with preterm birth

Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality. The vaginal microbiome has been associated with PTB, yet the mechanisms underlying this association are not fully understood. Understanding microbial genetic adaptations to selective pressures, especially those related to the host, may yield insights into these associations. Here, we analyze metagenomic data from 705 vaginal samples collected during pregnancy from 40 women who delivered preterm spontaneously and 135 term controls from the Multi-Omic Microbiome Study-Pregnancy Initiative. We find that the vaginal microbiome of pregnancies that ended preterm exhibited unique genetic profiles. It was more genetically diverse at the species level, a result which we validate in an additional cohort, and harbored a higher richness and diversity of antimicrobial resistance genes, likely promoted by transduction. Interestingly, we find that Gardnerella species drove this higher genetic diversity, particularly during the first half of the pregnancy. We further present evidence that Gardnerella spp. underwent more frequent recombination and stronger purifying selection in genes involved in lipid metabolism. Overall, our population genetics analyses reveal associations between the vaginal microbiome and PTB and suggest that evolutionary processes acting on vaginal microbes may play a role in adverse pregnancy outcomes such as PTB.

Maternal saliva visfatin level in term and preterm labor: A case control study

Visfatin, a colony-enhancing factor (pre-B-cell), is an inflammatory biomarker that is secreted from a different number of cells and appears to have some proinflammatory or immune-regulating effects. The aim of this study was to compare maternal saliva visfatin levels in women with preterm and term delivery. In This case-control study, women in labor before 37 weeks of gestation were the case group (n = 40) and women in labor after 37 weeks of gestation were in control group (n = 40). The saliva of the participants was sampled and maternal saliva visfatin level was measured by ELISA test. In this study, 80 pregnant women were studied in case and control groups. The mean age of case and control group was 29.1±6.9 and 30.55±5.3 years, respectively. The results revealed that the mean maternal saliva visfatin level in the preterm group (4.75±2.2) is significantly (p = 0.001) lower than that in term birth group (6.7±3.1). The results of adjusted logistic regression revealed that after adjusting for GDM, preeclampsia, pre pregnancy BMI and weight gain, the mean of maternal saliva visfatin level in the preterm group is significantly lower than that in the term group (p = 0.026). Considering that during the term pregnancy visfatin levels increase and visfatin may play a role in initiating labor, in our study due to the high visfatin level in case group although the level of maternal saliva visfatin was lower than the control group but high levels of visfatin in the case group can represent the role of visfatin in initiating labor and due to this issue can be use the role of this adipokine for early diagnosis of preterm delivery can be used to prevent, treat and improve the prognosis of this disease. Also, this study is the first study to compare the maternal saliva visfatin level between SGA and AGA group and there is no difference between these groups.

The yield of procalcitonin and Interleukin-6 in predicting intraamniotic infection in the presence of intrapartum fever: A pilot study

Intrapartum fever (IF) accompanied by either maternal or foetal tachycardia, elevated WBC, or purulent discharge is classified as "suspected triple 1", the hallmark of intraamniotic infection (IAI). Poor specificity of the clinical diagnosis of IAI results, in retrospect, in the unnecessary treatment of most parturients and neonates. We studied the yield of specific acute phase reactants (APRs): procalcitonin, CRP, IL-6, in detecting bacterial IAI among parturients classified as "suspected triple 1" (cases) compared to afebrile parturients (controls). Procalcitonin, CRP, and IL-6 were all significantly elevated in the cases compared to the controls, yet this by itself was not sufficient for an additive effect in detecting a bacterial infection among parturients clinically diagnosed with "suspected triple 1", as demonstrated by the poor area under the receiver operating characteristic curve of all three APRs.

Microdiversity of the Vaginal Microbiome is Associated with Preterm Birth

Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality. The vaginal microbiome has been associated with PTB, yet the mechanisms underlying this association are not fully understood. Understanding microbial genetic adaptations to selective pressures, especially those related to the host, may yield new insights into these associations. To this end, we analyzed metagenomic data from 705 vaginal samples collected longitudinally during pregnancy from 40 women who delivered preterm spontaneously and 135 term controls from the Multi-Omic Microbiome Study-Pregnancy Initiative (MOMS-PI). We find that the vaginal microbiome of pregnancies that ended preterm exhibits unique genetic profiles. It is more genetically diverse at the species level, a result which we validate in an additional cohort, and harbors a higher richness and diversity of antimicrobial resistance genes, likely promoted by transduction. Interestingly, we find that Gardnerella species, a group of central vaginal pathobionts, are driving this higher genetic diversity, particularly during the first half of the pregnancy. We further present evidence that Gardnerella spp. undergoes more frequent recombination and stronger purifying selection in genes involved in lipid metabolism. Overall, our results reveal novel associations between the vaginal microbiome and PTB using population genetics analyses, and suggest that evolutionary processes acting on the vaginal microbiome may play a vital role in adverse pregnancy outcomes such as preterm birth.

Recurrent Pregnancy Loss Etiology, Risk Factors, Diagnosis, and Management. Fresh Look into a Full Box

Recurrent pregnancy loss is a complex health challenge with no universally accepted definition. Inconsistency in definitions involves not only the number of spontaneous abortions (two or three) that are accepted for recurrent pregnancy loss but the types of pregnancy and gestational age at miscarriage. Due to the heterogeneity of definitions and criteria applied by international guidelines for recurrent pregnancy loss, the true incidence of recurrent miscarriage, which is reported to range from 1% to 5%, is difficult to estimate. Moreover, the exact etiology of recurrent pregnancy loss remains questionable; thus, it is considered a polyetiological and multifactorial condition with many modifiable and non-modifiable factors involved. Even after thoroughly evaluating recurrent pregnancy loss etiology and risk factors, up to 75% of cases remain unexplained. This review aimed to summarize and critically analyze accumulated knowledge on the etiology, risk factors, relevant diagnostic options, and management approach to recurrent pregnancy loss. The relevance of various factors and their proposed roles in recurrent pregnancy loss pathogenesis remains a matter of discussion. The diagnostic approach and the management largely depend on the etiology and risk factors taken into consideration by a healthcare professional as a cause of recurrent miscarriage for a particular woman or couple. Underestimation of social and health consequences of recurrent pregnancy loss leads to compromised reproductive health and psychological well-being of women after miscarriage. Studies on etiology and risk factors for recurrent pregnancy loss, especially idiopathic, should be continued. The existing international guidelines require updates to assist clinical practice.

Clinical chorioamnionitis: where do we stand now?

Intraamniotic infection is an infection resulting in the inflammation of any combination of the amniotic fluid, the placenta, the fetus itself, the fetal membranes, umbilical cord, or the decidua. In the past, an infection of the amnion and chorion or both was dubbed chorioamnionitis. In 2015, a proposal was made by an expert panel that, instead of clinical chorioamnionitis, the name intrauterine inflammation or infection or both be used, abbreviated as Triple I or simply IAI. However, the abbreviation IAI did not gain popularity, and this article uses the term chorioamnionitis. Chorioamnionitis may arise prior to, during, or following labor. It can present as a chronic, subacute, or acute infection. Its clinical presentation is generally referred to as acute chorioamnionitis. The treatment of chorioamnionitis varies widely across the world due to different bacterial causes and the absence of sufficient evidence to support a specific treatment regimen. There are limited randomized controlled trials that have evaluated the superiority of antibiotic regimens for treating amniotic infections during labor. This lack of evidence-based treatment suggests that the current choice of antibiotics is based on limitations in existing research, rather than absolute science. Chorioamnionitis cannot be cured by antibiotic therapy alone without delivery, and therefore it is necessary to make a decision according to the guidelines for induction of labor or acceleration of delivery. When a diagnosis is suspected or established, it is therefore necessary to apply broad-spectrum antibiotics according to the protocol used by each country, and to continue with them until delivery. A commonly recommended first-line treatment for chorioamnionitis is a simple regimen consisting of amoxicillin or ampicillin and once-daily gentamicin. Available information is not sufficient to indicate the best antimicrobial regimen to treat this obstetric condition. However, the evidence that is currently available suggests that patients with clinical chorioamnionitis, primarily women with a gestational age of 34 weeks or more and those in labor, should receive treatment with this regime. However, antibiotic preferences may vary based on local policy, clinician experience and knowledge, bacterial reasons for the infection, antimicrobial resistance patterns, maternal allergies, and drug availability.

Association between Chronic Gingivitis and Cancer: A Retrospective Cohort Study of 19,782 Outpatients from the United Kingdom

Purpose: Recent data argue for the involvement of inflammatory and infectious diseases in cancer development. However, clinical data on the association between chronic gingivitis and cancer have been less conclusive. Here, we systematically evaluated the cancer incidence in a population-based cohort of outpatients with chronic gingivitis from the United Kingdom. Methods: 9891 patients with chronic gingivitis and an identical number of people without gingivitis matched by age, gender, index year, and the Charlson Comorbidity Index were identified from the Disease Analyzer database (IQVIA) between January 2000 and December 2016. Cox regression models were used to study the association between gingivitis and cancer. Results: The probability of cancer was significantly higher among patients with diagnosed chronic gingivitis compared to non-gingivitis individuals (HR = 1.36, 95% CI = 1.15–1.62). In cancer site-stratified analyses, we observed a trend towards higher rates of cancer in almost all cancers (breast cancer, lymphoid system cancer, digestive tract cancers, skin cancer); however, a significant association was only observed for prostate cancer (HR: 3.38; 95% CI: 1.57–7.27). Notably, the largest increase in cancer rates was observed in male patients (HR: 1.46, 95% CI: 1.13–1.89) between 41 and 60 years old (HR: 1.74, 95% CI: 1.30–2.32). Conclusions: Our data suggest that chronic gingivitis represents an important risk factor for the development of cancer. Therefore, in the context of patient dental care, awareness should be raised to refer gingivitis patients to existing screening programs, especially for prostate cancer. Moreover, the consistent treatment of gingivitis could potentially have a positive impact on the morbidity of certain cancers.

Maternal Periodontal Status as a Factor Influencing Obstetrical Outcomes

Background and Objectives: Preterm birth as a complex phenomenon is influenced by numerous endogenic and exogenic factors, although its exact cause often remains obscure. According to epidemiological studies, maternal periodontal diseases, in addition to affecting general health, can also cause adverse pregnancy outcomes. Nonetheless, the existing results in the literature regarding this topic remain controversial. Consequently, our study aimed to determine the connection between poor maternal periodontal status and neonatal birth weight. Materials and Methods: A total of 111 primigravida-primiparous pregnant, healthy women underwent a periodontal examination in the second trimester of their pregnancies. Probing depth (PD) and bleeding on probing (BOP) were determined, and based on these diagnostic measurements, the patients were divided into three subgroups according to their dental status: healthy (H, n = 17), gingivitis (G, n = 67), and periodontitis (P, n = 27). Results: Considering that poor maternal oral status is an influencing factor for obstetrical outcomes, the presence of PD and BOP (characterized by the sulcus bleeding index, SBI) was evaluated. In the case of P, defined as PD ≥ 4 mm in at least one site and BOP ≥ 50% of the teeth, a significant correlation between BOP and a low neonatal birth weight at delivery (p = 0.001) was found. An analysis of the relationship between SBI and gestational age (GA) at the time of the periodontal examination in the different dental status groups showed a significant correlation between these parameters in the G group (p = 0.04). Conclusions: Our results suggest that a worse periodontal status during pregnancy may negatively affect obstetrical outcomes, especially the prematurity rate and newborn weight. Therefore, the importance of periodontal screening to prevent these complications is undeniable.

Female reproductive tract-organ axes

The female reproductive tract (FRT) and remote/versatile organs in the body share bidirectional communication. In this review, we discuss the framework of the "FRT-organ axes." Each axis, namely, the vagina-gut axis, uterus-gut axis, ovary-gut axis, vagina-bladder axis, vagina-oral axis, uterus-oral axis, vagina-brain axis, uterus-brain axis, and vagina-joint axis, is comprehensively discussed separately. Each axis could be involved in the pathogenesis of not only gynecological diseases but also diseases occurring apart from the FRT. Although the microbiota is clearly a key player in the FRT-organ axes, more quantitative insight into the homeostasis of the microbiota could be provided by host function measurements rather than current microbe-centric approaches. Therefore, investigation of the FRT-organ axes would provide us with a multicentric approach, including immune, neural, endocrine, and metabolic aspects, for understanding the homeostatic mechanism of women's bodies. The framework of the FRT-organ axes could also provide insights into finding new therapeutic approaches to maintain women's health.

The bidirectional relationship between periodontal disease and pregnancy via the interaction of oral microorganisms, hormone and immune response

Periodontal disease has been suggested to be linked to adverse pregnancy outcomes such as preterm birth, low birth weight, and preeclampsia. Adverse pregnancy outcomes are a significant public health issue with important clinical and societal repercussions. This article systematically reviews the available epidemiological studies involving the relationship between periodontal disease and adverse pregnancy outcomes over the past 15 years, and finds a weak but independent association between adverse pregnancy outcomes and periodontal disease. The bidirectional association and the potential mechanisms are then explored, focusing on three possible mechanisms: inflammatory reaction, oral microorganisms and immune response. Specifically, elevated systemic inflammation and increased periodontal pathogens with their toxic products, along with a relatively suppressed immune system may lead to the disruption of homeostasis within fetal-placental unit and thus induce adverse pregnancy outcomes. This review also explains the possible mechanisms around why women are more susceptible to periodontal disease. In conclusion, pregnant women are more likely to develop periodontal disease due to hormonal changes, and periodontal disease has also been suspected to increase the incidence of adverse pregnancy outcomes. Therefore, in order to lessen the risk of adverse pregnancy outcomes, both obstetricians and dentists should pay attention to the development of periodontal diseases among women during pregnancy.

Gain a Baby Lose a Tooth-Is There an Association between Periodontitis and Preterm Birth?

Preterm birth serves as one of the leading causes of neonatal mortality worldwide. The underlying mechanisms that contribute to preterm birth are not yet fully understood. However, an association between periodontitis and preterm birth has been proposed. The periodontal status and presence of periodontal pathogens in women with different birth outcomes have been previously examined. However, varying definitions of periodontitis and different microbiological methods make their interpretation challenging. The aim of this case-control study on women with and without preterm birth was to investigate their periodontal status using the current classification system for periodontal diseases. Moreover, differences in the periodontal microbiome of the study participants were investigated. Therefore, we collected data on oral and periodontal parameters in 77 puerperal women divided into two groups based on gestational age at delivery: 33 patients with preterm birth (PTB, <37 weeks) and 44 patients with term birth (TB, >37 weeks). These data included pocket probing depth (PPD), clinical attachment loss (CAL), bleeding on probing (BOP), gingival-bleeding index, DMFT index, and gynecologic and dental history. In addition, their oral microbiome was explored. Median CAL and percentage PPD ≥ 4 mm were significantly higher in the PTB group than in the TB group (p = 0.0128 and p = 0.047, respectively). Birth weight was significantly higher in periodontally healthy women than in those with gingivitis (p = 0.0078) or periodontitis (p = 0.0127). The periodontal microbiome differed significantly between groups. Our results are underlining the possible association between periodontitis and preterm delivery. Women with periodontitis had babies with significantly lower birth weights. The microbiome varied between the groups.

Periodontal disease in pregnancy and adverse pregnancy outcomes: Progress in related mechanisms and management strategies

Periodontal disease is an inflammatory and destructive disease of tissues supporting the tooth. A large number of studies have confirmed that periodontal pathogens and their metabolites can lead to adverse pregnancy outcomes in direct or indirect ways. Adverse pregnancy outcomes, such as preterm birth, low birth weight, and pre-eclampsia, have a serious impact on human reproductive health. In recent years, although the level of global medical technology has gradually improved, the incidence of adverse pregnancy outcomes has not declined and is still a global public health problem. The purpose of this review is to summarize the current data on periodontal disease in pregnancy and adverse pregnancy outcomes, including the association between periodontal disease and adverse pregnancy outcomes, the pathogenic mechanism related to this association, the efficacy of different nutrition supplements for both periodontal disease and adverse pregnancy outcomes and the effect of providing periodontal treatment on the occurrence of adverse pregnancy outcomes, to provide guidance for the prevention and treatment of adverse pregnancy outcomes in clinical practice.

Characterization of cervical canal and vaginal bacteria in pregnant women with cervical incompetence

Vaginal and cervical canal bacteria are associated with women’s health and pregnancy outcomes. Here, we compared their composition and characteristics in 37 reproductive-aged Chinese women including 24 pregnant women with cervical incompetence (vaginal and cervical canal bacteria formed Groups A and B, respectively) and 13 healthy pregnant women (vaginal and cervical canal bacteria formed Groups C and D, respectively) using high-throughput sequencing of the V4 region of 16S rRNA gene. The results of alpha and beta diversity analysis, respectively, indicated no statistical differences between Groups A and B (p = 0.32, 0.06), nor Groups B and D (p = 0.69, 0.74); however, differences were found between Groups C and D (p = 0.02, 0.01) and between Groups A and C (p = 0.04, 0.02). PLS-DA analysis showed that the individuals from each group were irregularly distributed according to their clade. Lactobacillus, Bifidobacterium and Ureaplasma were the dominant genera in all groups. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSts) analysis identified 31 Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologs associated with the bacterial communities from the four groups, including membrane transport, folding, sorting and degradation, xenobiotics biodegradation and metabolism, and nucleotide metabolism. We further determined relationships between pregnancy outcomes (Apgar scores) and certain bacterial species. A significant positive correlation was found between Apgar scores and Actinomyces neuii and Anoxybacillus flavithermus in the vagina and cervical canal of pregnant women with cervical incompetence while Bacteroides plebeius, Bifidobacterium pseudopodium and Staphylococcus petrasii in the cervical canal displayed negative correlations with Apgar scores. Moreover, Clostridium fimetarium, Methanobacterium congolense, Pseudomonas chlororaphis, and Psychrobacter nivimaris in the vagina were negatively correlated with Apgar scores. These bacteria may serve as potential biomarkers, however, additional research is warranted to verify their role in clinical outcomes.

Antifungal Susceptibility of Candida albicans Isolated from Tongue and Subgingival Biofilm of Periodontitis Patients

The subgingival biofilm, as the most complex microbial community, has been proven to be reservoir of Candida spp. The main concept of this study was to investigate if there is a difference between the sensitivity of Candida albicans (C. albicans) isolated from tongue and subgingival areas of periodontitis patients to antifungal agents. The aim of the study was to determine: (1) the distribution of different Candida species in the tongue and subgingival samples of periodontitis patients; (2) the susceptibility of Candida albicans strains from tongue and subgingival biofilm to the effects of commonly used antifungal agents: fluconazole, amphotericin B and itraconazole; (3) the correlation between the susceptibility of Candida albicans and clinical periodontal parameters. Tongue and subgingival biofilm samples of periodontitis subjects (N = 163) were examined. Susceptibility was tested when the same Candida species was isolated from both sites (17 subjects). Candida spp. were isolated in 23.3% of tongue and 21.5% of the subgingival samples. All isolates were susceptible to amphotericin B, while 64.71% of tongue and 52.94% of subgingival isolates were susceptible to fluconazole. A low frequency of itraconazole susceptibility was observed for tongue (17.64%) and subgingival isolates (11.76%). The correlations between full-mouth plaque score and Minimal Inhibitory Concentration (MIC) for tongue isolates were strongly positive for all antimycotics. Positive correlation was also observed between moderate periodontal destruction and MICs for tongue and subgingival isolates. The susceptibility of C. albicans to antifungals correlate with oral hygiene and moderate periodontal destruction. There is no difference in antifungal susceptibility between tongue and subgingival isolates.

Effect of Oral Prophylactic Measures on the Occurrence of Pre-Eclampsia (OP-PE) in High-Risk Pregnant Women: A Cluster Randomized Controlled Trial

Pre-eclampsia (PE), a pregnancy-specific hypertensive disorder, characterized by the development of placental endothelial dysfunction, remains a major source of maternal and perinatal morbidity and mortality, especially in low- and middle-income settings. Periodontal disorders during pregnancy, and particularly periodontal pathogens, may be related to the risk of PE. Standard oral hygiene methods, based mainly on the joint use of toothbrushes and interdental brushes, reduce periodontal inflammatory risk and modulate the dysbiosis of the oral microbiome. The aim of this trial is to compare the PE outcomes in high-risk pregnant women receiving oral prophylactic measures to a control group. This trial is designed as a two-arm, parallel, cluster randomized controlled trial with the antenatal obstetric clinic as the unit of randomization and an allocation ratio of 1:1. The pregnant women will be included at 3 months of pregnancy and will be followed throughout the pregnancy. The primary outcome measure will be the incidence of PE from a baseline during the pregnancy. Secondary outcomes measures will include changes from the baseline in quantification of the pathogenic bacterial load of the interdental microbiota, the severity scores of periodontal indicators, and the incidence of adverse perinatal outcomes. This trial should demonstrate that the implementation of daily oral hygiene reduces oral dysbiosis, the incidence of periodontal disease, and the risk of PE.