Association between high risk for preterm birth and changes in gingiva parameters during pregnancy—a prospective cohort study

Maternal periodontitis as a risk factor for preterm birth: A cross-sectional study

Background

Preterm birth is a heterogeneous condition with multiple underlying causes, and periodontal diseases are one of them. Approximately 900000 preterm births are reported in Pakistan each year. Oral infections such as periodontitis during pregnancy are associated with adverse pregnancy outcomes such as low birth weight and preterm births. However, different studies have reported contradictory findings. We conducted a cross-sectional study to assess the association of preterm birth with oral infection in pregnancy.

Methods

We conducted a cross-sectional analytical study on 400 postpartum pregnant women in Khyber Teaching Hospital, Peshawar. Only women within the age bracket of 18‒40 years were recruited. Data were collected by an interview-based structured questionnaire. The extent and severity index were used to assess the periodontal health of participants. Frequency tables were generated, and the chi-squared test was used to determine associations between different categorical variables.

Results

The mean age of the participants was 25.8±4.9 years. Approximately 87.5% of the women had generalized periodontitis. Approximately 68% of mothers had moderate severity of periodontitis. The extent index showed no notable difference between the preterm and full-term birth groups. In contrast, the severity index displayed a statistically significant difference between the preterm and full-term birth groups.

Conclusion

The majority of women had generalized periodontitis. The severity index demonstrated a significant association between maternal periodontitis and preterm births. There was no association between the age of mothers and preterm births. Complications in pregnancy were not associated with preterm births.

Placental TLR recognition of salivary and subgingival microbiota is associated with pregnancy complications

BACKGROUND

Pre-term birth, the leading cause of neonatal mortality, has been associated with maternal periodontal disease and the presence of oral pathogens in the placenta. However, the mechanisms that underpin this link are not known. This investigation aimed to identify the origins of placental microbiota and to interrogate the association between parturition complications and immune recognition of placental microbial motifs. Video Abstract METHODS: Saliva, plaque, serum, and placenta were collected during 130 full-term (FT), pre-term (PT), or pre-term complicated by pre-eclampsia (PTPE) deliveries and subjected to whole-genome shotgun sequencing. Real-time quantitative PCR was used to measure toll-like receptors (TLR) 1-10 expression in placental samples. Source tracking was employed to trace the origins of the placental microbiota.

RESULTS

We discovered 10,007 functionally annotated genes representing 420 taxa in the placenta that could not be attributed to contamination. Placental microbial composition was the biggest discriminator of pregnancy complications, outweighing hypertension, BMI, smoking, and maternal age. A machine-learning algorithm trained on this microbial dataset predicted PTPE and PT with error rates of 4.05% and 8.6% (taxonomy) and 6.21% and 7.38% (function). Logistic regression revealed 32% higher odds of parturition complication (95% CI 2.8%, 81%) for every IQR increase in the Shannon diversity index after adjusting for maternal smoking status, maternal age, and gravida. We also discovered distinct expression patterns of TLRs that detect RNA- and DNA-containing antigens in the three groups, with significant upregulation of TLR9, and concomitant downregulation of TLR7 in PTPE and PT groups, and dense correlation networks between microbial genes and these TLRs. 70-82% of placental microbiota were traced to serum and thence to the salivary and subgingival microbiomes. The oral and serum microbiomes of PTPE and PT groups displayed significant enrichment of genes encoding iron transport, exosome, adhesion, quorum sensing, lipopolysaccharide, biofilm, and steroid degradation.

CONCLUSIONS

Within the limits of cross-sectional analysis, we find evidence to suggest that oral bacteria might translocate to the placenta via serum and trigger immune signaling pathways capable of inducing placental vascular pathology. This might explain, in part, the higher incidence of obstetric syndromes in women with periodontal disease.

The Oral Microbiome Throughout Pregnancy: A Scoping Review

INTRODUCTION

Oral health is associated with systemic health, including adverse pregnancy outcomes. Understanding the oral microbiome during pregnancy may lead to targeted interventions for prevention of adverse outcomes. The purpose of this review is to examine the literature on the oral microbiome throughout pregnancy.

METHODS

We conducted a literature search with four electronic databases for original research conducted between 2012 and 2022 that examined the oral microbiome longitudinally using 16s rRNA sequencing during pregnancy.

RESULTS

We identified six studies that examined the oral microbiome longitudinally throughout pregnancy, though comparisons of oral niches, oral microbiome measures, and findings between studies were not consistent. Three studies identified alterations in alpha diversity throughout pregnancy and two studies identified increased pathogenic bacteria during pregnancy. Three studies reported no changes in the oral microbiome throughout pregnancy, and one study identified differences in the composition of the microbiome based on socioeconomic status and antibiotic exposure. Two studies examined adverse pregnancy outcomes in association with the oral microbiome, one reporting no associations and one reported difference in community gene composition in those diagnosed with preeclampsia.

CLINICAL IMPLICATIONS

There is limited research on the composition of the oral microbiome throughout pregnancy. There may be alterations in the oral microbiome during pregnancy such as increased relative abundance of pathogenic bacteria. Socioeconomic status, antibiotic use, and education may contribute to differences in the microbiome composition over time. Clinicians should evaluate oral health and educate on the importance of oral health care during the prenatal and perinatal time period.

Microbiome Changes in Pregnancy Disorders

The human microbiota comprises all microorganisms, such as bacteria, fungi, and viruses, found within a specific environment that live on our bodies and inside us. The last few years have witnessed an explosion of information related to the role of microbiota changes in health and disease. Even though the gut microbiota is considered the most important in maintaining our health, other regions of the human body, such as the oral cavity, lungs, vagina, and skin, possess their own microbiota. Recent work suggests a correlation between the microbiota present during pregnancy and pregnancy complications. The aim of our literature review was to provide a broad overview of this growing and important topic. We focused on the most significant changes in the microbiota in the four more common obstetric diseases affecting women's health. Thus, our attention will be focused on hypertensive disorders, gestational diabetes mellitus, preterm birth, and recurrent miscarriage. Pregnancy is a unique period in a woman's life since the body undergoes different adaptations to provide an optimal environment for fetal growth. Such changes also involve all the microorganisms, which vary in composition and quantity during the three trimesters of gestation. In addition, special attention will be devoted to the potential and fundamental advances in developing clinical applications to prevent and treat those disorders by modulating the microbiota to develop personalized therapies for disease prevention and tailored treatments.

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.

Relationship between Periodontal Condition of the Pregnant Woman with Preterm Birth and Low Birth Weight

The aim of this study was to determine the association between the mother’s periodontal condition and perinatal complications, such as preterm birth (PTB) and/or low birth weight (LBW), in a cohort of women in Valencia, Spain. Other related factors, such as tobacco, were also analysed. A prospective cohort study was carried out in a sample of 102 women with a single foetus and ages ranging between 18 and 42 years. Sociodemographic and obstetric variables, caries status, percentage of bleeding, clinical attachment loss (CAL), and probing pocket depth (PPD) data have been collected and analysed. The mean age was 32.4 years, and the BMI was normal. The average weight of new-borns (NB) was 3034 g. A total of 9.8% of the women smoked during their pregnancy. Bleeding percentage was 16.43% (SD 14.81%) and PPDs > 3 mm 8.8 (SD 11.08). The mean of CAL > 0 mm was 1.14 (SD 2.83). The frequency of PTB and LBW was 26%. No statistically significant differences were found between probing depth > 3 mm or CAL > 1 mm, with PTB and/or LBW. Periodontal disease in the mother was not statistically significantly related to either PTB or LBW. Tobacco use during pregnancy showed a statistical significance linked to LBW, but not with PTB.

Inflammatory factors, genetic variants, and predisposition for preterm birth

Preterm birth is a major clinical and public health challenge, with a prevalence of 11% worldwide. It is the leading cause of death in children younger than 5 years old and represents 70% of neonatal deaths and 75% of neonatal morbidity. Despite the clinical and public health significance, this condition's etiology is still unclear, and most of the cases are spontaneous. There are several known preterm birth risk factors, including inflammatory diseases and the genetic background, although the underlying molecular mechanisms are far from understood. The present review highlights the research advances on the association between inflammatory-related genes and the increased risk for preterm delivery. The most associated genetic variants are the TNFα rs1800629, the IL1α rs17561, and the IL1RN rs2234663. Moreover, many of the genes discussed in this review are also implicated in pathologies involving inflammatory or autoimmune systems, such as periodontal disease, bowel inflammatory disease, and autoimmune rheumatic diseases. This review presents evidence suggesting a common genetic background to preterm birth, autoimmune and inflammatory diseases susceptibility.

Oral microbiome and pregnancy: A bidirectional relationship

The oral cavity contains the second most complex microbial population within the human body, with more than 700 bacterial organisms. Recent advances in Next Generation Sequencing technology have unraveled the complexities of the oral microbiome and provided valuable insights into its role in health and disease. The human oral microbiome varies dramatically during the different stages of life, including pregnancy. The total viable microbial counts in pregnant women are known to be higher compared to non-pregnant women, especially in the first trimester of pregnancy. A balanced oral microbiome is vital for a healthy pregnancy, as perturbations in the oral microbiome composition can contribute to pregnancy complications. On the other hand, physiological changes and differences in hormonal levels during pregnancy, increase susceptibility to various oral diseases such as gingivitis and periodontitis. A growing body of evidence supports the link between the composition of the oral microbiome and adverse pregnancy outcomes such as preterm birth, preeclampsia, low birth weight among others. This review aims to summarize the dynamics of oral microbiome during pregnancy and to discuss the relationship between a dysbiotic oral microbiome and pregnancy complications.

Effectiveness of Alcohol-free Mouth Rinse Containing Essential Oils and Fluoride as an Oral Hygiene Adjunct among Pregnant Thai Women: A Randomized Clinical Trial

Aim:

This 3-month, double-blind, two-center, parallel, randomized controlled clinical trial compared the improvement of oral hygiene status from alcohol-free essential oils (EO) with 0.05% fluoride mouthwash to the control (0.05% fluoride mouthwash).

Materials and Methods:

One hundred and fifty-four pregnant women were clinically examined to determine Modified Gingival Index (MGI), Plaque Index (PI), and Winkel Tongue Coating Index (WTCI) at baseline, 2 weeks, and 3 months by calibrated examiners. After supragingival scaling and provision of a tooth brushing method, participants were randomly assigned to daily use of alcohol-free EO or the control rinse for 30s at bedtime. Repeated measures of analysis of variance (ANOVA) were performed to assess the effectiveness of alcohol-free EO with 0.05% fluoride mouthwash on MGI, PI, and WTCI scores.

Results:

One hundred and forty subjects completed the study. The dropout rate of 9.1% (n = 14) was mainly due to loss of follow-up. At baseline, no significant differences were observed between the intervention and the control groups for MGI (1.19±0.57 vs. 1.11±0.48, P = 0.371), PI (1.53±0.56 vs. 1.47±0.48, P = 0.439), and WTCI (0.88±0.48 vs. 0.88±0.50, P = 0.990). There was a statistically significant reduction of MGI, PI, and WTCI scores over time (P < 0.001). However, no significant differences were observed for between-group comparisons for all measured indices at any time point. No adverse effect was reported in either group.

Conclusion:

At the end of 3-month period, improvement of oral hygiene of pregnancy women in this study was evidence. However, the use of alcohol-free EO mouthwash as supplements to the daily oral hygiene did not provide a significant improvement in terms of plaque, gingival, and tongue coating indices.

Risk of preterm birth associated with maternal gingival inflammation and oral hygiene behaviours in rural Nepal: a community-based, prospective cohort study

OBJECTIVES

Observational studies have identified associations between periodontitis and adverse pregnancy outcomes, but randomised controlled trials evaluating the efficacy of periodontal therapy have yielded inconsistent results. Few studies have explored relationships between gingival inflammation and these outcomes or been conducted in rural, low-income communities, where confounding risk factors differ from other settings.

METHODS

We conducted a community-based, prospective cohort study with the aim of estimating associations between the extent of gingival inflammation in pregnant women and incidence of preterm birth in rural Nepal. Our primary exposure was gingival inflammation, defined as bleeding on probing (BOP) ≥10%, stratified by BOP <30% and BOP ≥30%. A secondary exposure, mild periodontitis, was defined as ≥2 interproximal sites with probing depth (PD) ≥4 mm (different teeth) or one site with PD ≥5 mm. Our primary outcome was preterm birth (<37 weeks gestation). We used Poisson regression to model this relationship, adjusting for potential confounders.

RESULTS

Of 1394 participants, 554 (39.7%) had gingival inflammation, 54 (3.9%) mild periodontitis and 197 (14.1%) delivered preterm. In the adjusted regression model, increasing extent of gingival inflammation was associated with a non-significant increase in risk of preterm birth (BOP ≥30% vs no BOP: adjusted relative risk (aRR) 1.37, 95% CI: 0.81 to 2.32). A secondary analysis, stratifying participants by when in pregnancy their oral health status was assessed, showed an association between gingival inflammation and preterm birth among women examined in their first trimester (BOP ≥30% vs no BOP: aRR 2.57, 95% CI: 1.11 to 5.95), but not later in pregnancy (BOP ≥30% vs no BOP: aRR 1.05, 95% CI: 0.52 to 2.11).

CONCLUSIONS

Gingival inflammation in women examined early in pregnancy and poor oral hygiene behaviours were risk factors for preterm birth. Future studies should evaluate community-based oral health interventions that specifically target gingival inflammation, delivered early in or before pregnancy, on preterm birth.

TRIAL REGISTRATION NUMBER

Nepal Oil Massage Study, NCT01177111.

Knowledge, Attitudes and Practice Behaviour of Midwives Concerning Periodontal Health of Pregnant Patients

Maternal gum disease is associated with adverse pregnancy outcomes such as preterm birth and low birthweight. This study aims to evaluate the knowledge, attitudes and practice behaviour of Australian midwives regarding the periodontal health of pregnant women to inform interprofessional antenatal care. This was an observational, cross-sectional study. We circulated an online questionnaire to Australian midwives from August 2018 to February 2019. Key outcome variables were knowledge, attitudes, and practice behaviours related to oral health. Key predictor variables were years of practice, practice location, and dental history. We summarized responses with frequency tables and assigned tallied scores for analysis using non-parametric statistical tests. 100 responses were analysed, including from rural (n = 23) and urban (n = 77) midwives. Eighty percent of midwives agreed that maternal dental care can positively affect pregnancy outcomes. Fluoridated toothpaste use (19.1%) was incorrectly answered to prevent gum disease more often than psychological stress control (7.9%), a correct answer. Rural midwives demonstrated a significantly higher knowledge score (p = 0.001) and significantly more positive practice behaviours towards oral health (p = 0.014) than urban midwives. Australian midwives have positive attitudes towards antenatal oral health but misunderstand gum disease aetiology and prevention. This study highlights areas to improve interprofessional education for optimal oral health and pregnancy outcomes.

Periodontopathogenic microbiota, infectious mechanisms and preterm birth: analysis with structural equations (cohort-BRISA)

PURPOSE

The association between periodontopathogenic microbiota and preterm birth (PTB) has been overly studied. However, the biological mechanisms involved are little known. The objective is to evaluate the effect of periodontopathogenic bacteria burden (PBB), periodontal disease and other infections during pregnancy on preterm birth (PTB), through Structural Equation Modeling.

METHODS

This was a case-control study nested in a prospective cohort called BRISA, including 330 pregnant women, 110 cases and 220 controls. This study included the following variables: cytokines interleukin-10 (IL-10) and transforming growth factor beta (TGF-β), periodontal disease, PBB, age, socioeconomic status (SES), systemic infections and PTB. The correlations between variables were analyzed using Standardized Coefficient (SC).

RESULTS

Greater PBB interfered positively with the occurrence of periodontal disease (SC: 0.027; p: 0.011), but these were not associated with the cytokines studied, nor with PTB. The lower serum levels of IL-10 (SC - 0.330; p 0.022) and TGF-β (SC - 0.612; p  < 0.001), and the presence of other systemic infections during pregnancy (SC 0.159; 0.049) explained the higher occurrence of PTB.

CONCLUSION

It is possible that only the more severe periodontal disease and other systemic infections are capable of altering the cascade of cytokines regulating the inflammatory process and have an effect on the occurrence of PTB.

Fusobacterium nucleatum Facilitates Apoptosis, ROS Generation, and Inflammatory Cytokine Production by Activating AKT/MAPK and NF-κB Signaling Pathways in Human Gingival Fibroblasts

Fusobacterium nucleatum (F. nucleatum) plays key roles in the initiation and progression of periodontitis. However, the pathogenic effect of F. nucleatum on human oral tissues and cells has not been fully evaluated. In this study, we aimed to analyze the pathogenic effects of F. nucleatum on human gingival fibroblasts (GFs) and clarify the potential mechanisms. RNA-sequencing analysis confirmed that F. nucleatum significantly altered the gene expression of GF as the stimulation time increased. Cell counting and EdU-labeling assays indicated that F. nucleatum inhibited GF proliferation and promoted cell apoptosis in a time- and dose-dependent manner. In addition, cell apoptosis, intracellular reactive oxygen species (ROS) generation, and proinflammatory cytokine production were dramatically elevated after F. nucleatum stimulation. Furthermore, we found that the AKT/MAPK and NF-κB signaling pathways were significantly activated by F. nucleatum infection and that a large number of genes related to cellular proliferation, apoptosis, ROS, and inflammatory cytokine production downstream of AKT/MAPK and NF-κB signaling pathways were significantly altered in F. nucleatum-stimulated GFs. These findings suggest that F. nucleatum inhibits GF proliferation and promotes cell apoptosis, ROS generation, and inflammatory cytokine production partly by activating the AKT/MAPK and NF-κB signaling pathways. Our study opens a new window for understanding the pathogenic effects of periodontal pathogens on the host oral system.

Inflammation induced preterm labor and birth

Preterm birth which occurs before 37 weeks gestation is one of the most common obstetrical complication in humans. After many studies, it appears that "not one answer fits all" regarding the risk factors, causes and the treatments for this syndrome. However, it is becoming more evident that one of the major risk factors is inflammation and/or infection in the fetoplacental unit. In animal models (usually consisting of mice injected with lipopolysaccharide at 14 days of gestation), IL-22 and IL-6 have been identified as factors related to preterm birth. There are some clinical tests available to determine the risk for preterm labor and delivery, which can be identified before, during early, or at mid-gestation. However, treatment of preterm birth with antibiotics so far has not been "curable" and studies using anti-inflammatory treatments are not readily available. More studies regarding causes and treatments for preterm labor and delivery in humans are necessary to prevent neonatal deaths and/or developmental abnormalities associated with this common syndrome.