Oral microflora and pregnancy: a systematic review and meta-analysis

Untangling Associations of Microbiomes of Pregnancy and Preterm Birth

This review illuminates the complex interplay between various maternal microbiomes and their influence on preterm birth (PTB), a driving and persistent contributor to neonatal morbidity and mortality. Here, we examine the dynamics of oral, gastrointestinal (gut), placental, and vaginal microbiomes, dissecting their roles in the pathogenesis of PTB. Importantly, focusing on the vaginal microbiome and PTB, the review highlights (1) a protective role of Lactobacillus species; (2) an increased risk with select anaerobes; and (3) the influence of social health determinants on the composition of vaginal microbial communities.

Differences in maternal subgingival microbiome between preterm and term births: The MOHEPI study

AIM

Periodontitis is a potential risk factor for preterm birth (PTB) in women; however, the causal relationship or the exact mechanism remain unknown. This study aimed to compare the oral microbiome features of mothers with full-term birth (FTB) with those who had preterm delivery.

METHODS

This study prospectively enrolled 60 women (30 mothers with PTB and 30 mothers with FTB), and subgingival plaque samples were collected and analysed by metagenomic 16S rDNA sequencing. Clinical measurements, including periodontal probing depth, clinical attachment level, modified gingival index (mGI) and plaque index, were performed to determine the periodontal state of the participants. Medical and obstetric data were collected as well.

RESULTS

Among the periodontal measurements, mGI score, reflecting the level of gingival inflammation, exhibited a statistically significant association with PTB (adjusted odds ratio 2.705, 95% confidence interval 1.074-6.811, p = .035). When subgroup analysis was conducted based on mean mGI scores (mGI ≥ 2, high inflammation [HI] versus mGI < 2, low inflammation [LI]), microbiome analysis revealed clear distinctions in microbial compositions between PTB and FTB mothers in both the HI and LI groups. Especially in the HI group, alpha diversity exhibited a decreasing trend in PTB mothers compared to FTB mothers. Beta diversity also revealed significant differences between the two groups. In Linear Discriminant Analysis Effect Size analysis, certain anaerobic taxa, including the genera Spirochaetes, Treponema and Porphyromonas, were relatively abundant in the FTB/HI group, whereas the PTB/HI group showed a high abundance of the order Actinomycetales. Network analysis showed that the FTB/HI had relatively stronger connectivity in microbial composition than the PTB/HI group. Dysbiosis ratio of plaque microbiome, in terms of periodontitis, was significantly lower in PTB/HI group compared to FTB/HI group.

CONCLUSION

The compositions of maternal subgingival microbiomes differed between PTB and FTB mothers in both the high and low levels of gingival inflammation groups. In the presence of high level of gingival inflammation, dysbiosis in plaque microbiome, in terms of periodontitis, was decreased in PTB mothers compared to FTB mothers.

Salivary Metabolites Produced by Oral Microbes in Oral Diseases and Oral Squamous Cell Carcinoma: A Review

In recent years, salivary metabolome studies have provided new biological information and salivary biomarkers to diagnose different diseases at early stages. The saliva in the oral cavity is influenced by many factors that are reflected in the salivary metabolite profile. Oral microbes can alter the salivary metabolite profile and may express oral inflammation or oral diseases. The released microbial metabolites in the saliva represent the altered biochemical pathways in the oral cavity. This review highlights the oral microbial profile and microbial metabolites released in saliva and its use as a diagnostic biofluid for different oral diseases. The importance of salivary metabolites produced by oral microbes as risk factors for oral diseases and their possible relationship in oral carcinogenesis is discussed.

Adverse childhood experiences and dental cleaning during pregnancy: Findings from the North and South Dakota PRAMS, 2017-2021

OBJECTIVE

Research demonstrates that adverse childhood experiences (ACEs)-that is, experiences of abuse, neglect, and household dysfunction-are related to lower preventive dental care utilization in childhood and adolescence. However, limited research has explored the connection between ACEs and preventive dental care utilization in adulthood, and no research has examined this relationship during pregnancy. The current study extends existing research by investigating the relationship between ACEs and dental cleaning and dental care utilization during pregnancy among a sample of women who delivered live births in North Dakota and South Dakota.

METHODS

Data are from the 2017 to 2021 Pregnancy Risk Assessment Monitoring System (PRAMS) in North Dakota and South Dakota (n = 7391). Multiple logistic regression is used to examine the relationship between the number of ACEs (0, 1, 2, 3 or 4 or more) and dental cleaning during pregnancy.

RESULTS

Relative to respondents with 0 ACEs, those with 4 or more ACEs were significantly less likely to report having dental care during pregnancy (OR = 0.757, 95% CI = 0.638, 0.898). By racial and ethnic background, the results showed that the significant associations are concentrated among White and Native American respondents.

CONCLUSIONS

The results suggest that exposure to 4 or more ACEs is associated with a significantly lower likelihood of dental cleaning during pregnancy among women who delivered a live birth in North Dakota and South Dakota. Further investigations are necessary to understand the mechanisms underlying the relationship between ACEs and dental cleaning during pregnancy and replicate the findings in other geographic contexts.

Medicinal herbs, especially Hibiscus sabdariffa, inhibit oral pathogenic bacteria

OBJECTIVES

Medicinal herbs are plants with potential medicinal and health benefits. In recent years, they are being increasingly used as a treatment alternative owing to their effectiveness against various diseases. In this study, we investigated the inhibitory effects of 15 medicinal herbs on causative bacteria for dental caries and periodontal disease.

METHODS

This study evaluated the effects of the extracts of 15 medicinal herbs on growth and biofilm formation in five oral pathogenic bacterial strains. The herbs were processed into extracts, and bacterial strains were cultured. Then, bacterial growth and biofilm formation were assessed using various methods. Finally, the extract of the herb Hibiscus sabdariffa (hibiscus) was analyzed using high-performance liquid chromatography.

RESULTS

Incubation of bacteria with the herbal extracts showed that hibiscus exerted a significant inhibitory effect on all the oral pathogenic bacterial strains evaluated in this study. In addition, the pigment delphinidin-3-sambubioside, which is found in hibiscus extract, was identified as a particularly important inhibitory component.

CONCLUSIONS

These results lay the ground work for the potential development of novel therapeutic or preventive agents against dental caries and periodontal disease, two major oral diseases.

Oral Manifestations in Pregnant Women: A Systematic Review

Background: The period of pregnancy is characterized by a multitude of diverse changes that exert a notable impact on the oral cavity of women. During this gestational phase, patients necessitate tailored oral care and specific recommendations to preempt and address potential oral diseases. This systematic review aimed to perform a detailed analysis of the research studies that focused on the oral manifestations observed in pregnant women. Methods: A meticulous search was conducted in the databases Medline, Scopus, and Scielo by employing the following search terms: ((pregnant OR pregnancy)) AND (("oral manifestation*") OR ("oral health")). Articles that were published between 2013 and 2023 and written in English or Spanish and studies that scrutinized oral manifestations in pregnant women and included a diagnosis conducted by a qualified dentist were selected; we excluded articles published before 2013, articles that could not be accessed in full text, studies whose patients were not pregnant women at the time of the study, studies where patients were selected because they had a specific disease, studies where the clinical examination was not performed by a dentist, and articles written in languages other than English or Spanish. Subsequently, the risk of bias in the chosen articles was assessed in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) scale. Results: A total of 20 studies were included in the analysis, following the exclusion and inclusion criteria. These studies were categorized as cross-sectional, cohort, longitudinal, or case-control. Various oral manifestations in pregnant women were examined, with five studies comparing these manifestations with those observed in nonpregnant women. Conclusions: The most prevalent oral manifestations associated with pregnancy encompass dental caries, periodontitis, gingivitis, pyogenic granuloma, and candidiasis. Nonetheless, less common lesions may also emerge during the course of pregnancy.

Oral Pyogenic Granuloma: A Narrative Review

Pyogenic granuloma (PG) is a benign vascular lesion found predominantly in the oral cavity. Characterized by rapid growth and propensity to bleed, PG presents diagnostic challenges due to its similarity and alarming proliferation. This narrative review synthesizes current knowledge on the epidemiology, etiopathogenesis, clinical manifestations, and management of oral PG, with emphasis on recent advances in diagnostic and therapeutic approaches. The epidemiology of the injury is meticulously analyzed, revealing a higher incidence in women and a wide range of ages of onset. It delves into the etiopathogenesis, highlighting the uncertainty surrounding the exact causal factors, although historical attributions suggest an infectious origin. It exhaustively analyzes the clinical and histopathological aspects of oral PG, offering information on its various presentations and the importance of an accurate diagnosis to guide effective treatment. It details treatment strategies, emphasizing the personalized approach based on individual patient characteristics. This comprehensive review consolidates current knowledge on oral PG, highlighting the need for further research to clarify its pathogenesis and optimize treatment protocols.

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.

Altered Oral Nitrate Reduction and Bacterial Profiles in Hypertensive Women Predict Blood Pressure Lowering Following Acute Dietary Nitrate Supplementation

BACKGROUND

The efficacy of dietary nitrate supplementation to lower blood pressure (BP) in pregnant women is highly variable. We aimed to investigate whether differences in oral microbiota profiles and oral nitrate-reducing capacity may explain interindividual differences in BP lowering following nitrate supplementation.

METHODS

Participants recruited for this study were both pregnant and nonpregnant women, with or without hypertension (n=55). Following an overnight fast, plasma, saliva, and tongue scraping samples were collected for measurement of nitrate/nitrite concentrations, oral NaR (nitrate reductase) activity, and microbiota profiling using 16S rRNA gene sequencing. Baseline BP was measured, followed by the administration of a single dose of dietary nitrate (400 mg nitrate in 70 mL beetroot juice). Post-nitrate intervention, plasma and salivary nitrate/nitrite concentrations and BP were determined 2.5 hours later.

RESULTS

Women with hypertension had significantly lower salivary nitrite concentrations (P=0.006) and reduced abundance of the nitrate-reducing taxa Veillonella(P=0.007) compared with normotensive women. Oral NaR activity was not significantly different in pregnant versus nonpregnant women (P=0.991) but tended to be lower in hypertensive compared with normotensive women (P=0.099). Oral NaR activity was associated with both baseline diastolic BP (P=0.050) and change in diastolic BP following acute nitrate intake (P=0.01, adjusted for baseline BP).

CONCLUSIONS

The abundance and activity of oral nitrate-reducing bacteria impact both baseline BP as well as the ability of dietary nitrate supplementation to lower BP. Strategies to increase oral nitrate-reducing capacity could lower BP and enhance the efficacy of dietary nitrate supplementation, in pregnancy as well as in nonpregnant adults.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03930693.

The Complicated Relationship of Short-Chain Fatty Acids and Oral Microbiome: A Narrative Review

The human oral microbiome has emerged as a focal point of research due to its profound implications for human health. The involvement of short-chain fatty acids in oral microbiome composition, oral health, and chronic inflammation is gaining increasing attention. In this narrative review, the results of early in vitro, in vivo, and pilot clinical studies and research projects are presented in order to define the boundaries of this new complicated issue. According to the results, the current research data are disputable and ambiguous. When investigating the role of SCFAs in human health and disease, it is crucial to distinguish between their local GI effects and the systemic influences. Locally, SCFAs are a part of normal oral microbiota metabolism, but the increased formation of SCFAs usually attribute to dysbiosis; excess SCFAs participate in the development of local oral diseases and in oral biota gut colonization and dysbiosis. On the other hand, a number of studies have established the positive impact of SCFAs on human health as a whole, including the reduction of chronic systemic inflammation, improvement of metabolic processes, and decrease of some types of cancer incidence. Thus, a complex and sophisticated approach with consideration of origin and localization for SCFA function assessment is demanded. Therefore, more research, especially clinical research, is needed to investigate the complicated relationship of SCFAs with health and disease and their potential role in prevention and treatment.

The Salivary Microbiome During Pregnancy: Associations With Clinical and Sociodemographic Characteristics

PURPOSE

Poor oral health has been associated with adverse pregnancy outcomes, and the oral microbiome may play a role in these mechanisms. We aimed to examine the salivary microbiome for alterations in diversity or relative abundance throughout pregnancy and its associations with adverse pregnancy outcomes and sociodemographic characteristics.

STUDY DESIGN AND METHODS

We conducted an ancillary study from a previous cohort study of 37 women during their second and third trimesters of pregnancy using preexisting, participant-collected salivary samples to examine the oral microbiome using 16S rRNA sequencing.

RESULTS

The salivary microbiome demonstrated stability throughout pregnancy, as there were no significant differences in alpha or beta diversity. Individuals who were diagnosed with preeclampsia had differences in beta diversity at the genus level (F = 2.65, df = 1, P = .015). There were also differences in beta diversity at the species level in Hispanic individuals compared with non-Hispanic individuals (F = 1.7183, df = 1, P = .04).

CONCLUSION

The salivary microbiome demonstrated stability throughout the second and third trimesters but may be different in Hispanics or those diagnosed with preeclampsia. As such, clinical providers need to demonstrate culturally competent care during pregnancy and continue to educate women about the importance of oral healthcare during the perinatal period. Future research is needed to examine the mechanisms associated with oral microbiome dysbiosis in Hispanic women during pregnancy and in women with preeclampsia.

The Oral Microbiome and Cross-Kingdom Interactions during Pregnancy

Pregnancy initiates a temporary transition in the maternal physiological state, with a shift in the oral microbiome and a potential increase in frequency of oral diseases. The risk of oral disease is higher among populations of Hispanic and Black women and those with lower socioeconomic status (low SES), demonstrating a need for intervention within these high-risk populations. To further our understanding of the oral microbiome of high-risk pregnant women, we characterized the oral microbiome in 28 nonpregnant and 179 pregnant low-SES women during their third trimester living in Rochester, New York. Unstimulated saliva and supragingival plaque samples were collected cross-sectionally, followed by assessment of the bacterial (16S ribosomal RNA) and fungal (18S ITS) microbiota communities. Trained and calibrated dentists performed oral examinations to determine the number of decayed teeth and plaque index. Initially, plaque from 28 nonpregnant women and 48 pregnant women were compared; these data showed significant differences in bacterial abundances based on pregnancy status. To further our understanding of the oral microbiome within the pregnant population, we next examined the oral microbiome within this population based on several variables. Streptococcus mutans, Streptococcus oralis, and Lactobacillus were associated with a greater number of decayed teeth. The composition of fungal communities differed between plaque and saliva, demonstrating 2 distinct "mycotypes" that were represented by a greater abundance of Candida in plaque and Malassezia in saliva. Veillonella rogosae, a common oral bacterium, was negatively associated with both plaque index and salivary Candida albicans colonization by culture data. This was further emphasized by in vitro inhibition of C. albicans by V. rogosae. Identification of interactions between the bacterial or fungal oral communities revealed that V. rogosae was positively associated with the oral commensal Streptococcus australis and negatively with the cariogenic Lactobacillus genus, suggesting V. rogosae as a potential biomarker of a noncariogenic oral microbiome.

Oral microbiome and preterm birth

Background

The etiology of preterm birth (PTB) is heterogeneous and not yet well known. Maternal periodontal disease has been investigated for decades and is a known risk factor for adverse pregnancy outcomes. However, no particular bacterial species or higher taxonomic order has been found as causative of PTB, leading to studies of the whole oral microbiome. In order to determine if and how the composition of the oral microbiome is associated with PTB, we performed a large case-control study including women with term (TB) and PTB.

Methods

We compared oral microbiomes in PTB to TB, to examine differences in the microbial richness, diversity, and differential abundance of specific taxa. We obtained oral swab samples from 152 Caucasian pregnant women who were classified as either PTB (≤36 6/7 weeks, n = 61) or TB (≥38 0/7 weeks, n = 91) in exclusion of any other major medical or obstetric conditions. The oral microbiomes of these women were characterized by 16S ribosomal RNA (rRNA) gene sequencing of the V3-V4 region on the MiSeq platform.

Results

The dominant microorganisms at the phylum level in all pregnant women regardless of birth week outcomes as belonging to Firmicutes, Proteobacteria, Bacteroidetes, Fusobacteria, and Actinobacteria. The phyla Firmicutes and Bacteroidetes were relatively more abundant in women with a PTB than in women with a TB, while Proteobacteria was less prevalent in women with a PTB. At the genus level, Veillonella, Prevotella, and Capnocytophaga were enriched in the PTB, and while many of the members of these genera could not be resolved to the species level, Veillonella massillensis was shown to be increased in the PTB group.

Conclusion

We identified the genera Veillonella, Prevotella, and Capnocytophaga in the maternal oral microbiome as being associated with PTB independently of clinically apparent infection, uterine anomalies, and other pregnancy complications, including placenta previa, and placental abruption. The clarification of the role of those taxa in the etiology of PTB merits further research.

Evaluation of the periodontal disease on oral microorganisms during pregnancy: A systematic review and meta-analysis

Background and Aim

In the present study, the potential changes of oral microbes during pregnancy were investigated by examining the findings of the previous studies and comprehensively examining their results. The relationship between oral microorganisms and birth outcomes and adverse labor outcomes was investigated; to provide sufficient evidence. The purpose of the present study was to evaluate periodontal disease in oral microorganisms during pregnancy.

Materials and Methods

All articles were published between January 2011 and January 2023 in international databases, including PubMed, Scopus, Science Direct, and Embase. To answer the research questions, the Google Scholar search engine employed the PECO strategy. STATA.V17 software was used to analyze the data.

Results

Two hundred and eighteen studies were found in the initial search; 63 full texts were reviewed; and finally, 14 articles were included in the analysis. The mean differences in salivary S. mutans carriage before and after prenatal dental treatment were 0.92 (MD; 95 CI [0.57, 1.27], P > 0.05). The odds ratio of association between perinatal mortality and periodontal treatment was -0.88 (OR; 95 CI [-2.53, 0.76], P > 0.05) and the odds ratio of association between pre-term birth and periodontal treatment was -0.31 (OR; 95 CI [-0.70, 0.09], P > 0.05). There was a statistically significant relationship between birth weight and periodontal treatment during pregnancy.

Conclusion

According to the present meta-analysis, periodontal treatment can reduce the odds ratio of perinatal mortality and pre-term birth by 88% and 31%, respectively. High association of microorganisms between pregnancy and postpartum requires further study.

Relevance for Patients

In the findings of the present study, it is observed that during pregnancy, there is a direct relationship between periodontal disease with low birth weight, perinatal mortality, and pre-term delivery; however, the high association of microorganisms between pregnancy and postpartum requires further study. Oral microforms are reported to be affected in pregnant women, and they should take extra care of their mouth and teeth. Sufficient and strong evidence can help to improve the health outcomes of mothers and children.

Adverse Pregnancy Outcomes and Maternal Periodontal Disease: An Overview on Meta-Analytic and Methodological Quality

This umbrella review aims to appraise the methodological quality and strength of evidence on the association between maternal periodontitis and adverse pregnancy outcomes (APOs). PubMed, CENTRAL, Web-of-Science, LILACS, and Clinical Trials were searched until February 2023, without date or language restrictions. Two authors independently screened studies, extracted data, performed the risk-of-bias analysis, and estimated the meta-analytic strengths and validity and the fail-safe number (FSN). A total of 43 SRs were identified, of which 34 conducted meta-analyses. Of the 28 APOs, periodontitis had a strong association with preterm birth (PTB), low birth weight (LBW), and gestational diabetes mellitus (GDM), PTB and LBW showed all levels of strength, and pre-eclampsia showed only suggestive and weak strength. Regarding the consistency of the significant estimates, only 8.7% were likely to change in the future. The impact of periodontal treatment on APOs was examined in 15 SRs, 11 of which conducted meta-analyses. Forty-one meta-analyses were included and showed that periodontal treatment did not have a strong association with APOs, although PTB revealed all levels of strength and LBW showed only suggestive and weak evidence. Strong and highly suggestive evidence from observational studies supports an association of periodontitis with a higher risk of PTB, LBW, GDM, and pre-eclampsia. The effect of periodontal treatment on the prevention of APOs is still uncertain and requires future studies to draw definitive and robust conclusions.

Prevalence, Severity of Extension, and Risk Factors of Gingivitis in a 3-Month Pregnant Population: A Multicenter Cross-Sectional Study

The scope of this study was to assess the prevalence, severity of extension, and risk factors of gingivitis among pregnant women. In this cross-sectional study, 220 nulliparous women at 3 months of pregnancy were recruited in 2022 at the first obstetrical visit in Dakar, Senegal. Demographic characteristics, lifestyle habits, prenatal clinical status, and oral clinical parameters were recorded. Multivariable logistic regression modeling was used to assess relationships between gingivitis and risk factors. Eighty-eight percent of women had gingivitis, 15% were classified as moderate and 73% as severe. A total of 66.7% (95% CI [28.8-92.1]) of the sites had bleeding on interdental brushing. The odds for gingivitis decreased significantly for women consuming more than five portions of fruits and vegetables per day (OR = 0.15; 95% CI [0.03-0.66]) and increased in women who had a professional activity (OR = 6.75; 95% CI [1.27-35.87]) and high education. Concomitantly, the percentage of dental plaque (OR = 131.6; 95% CI [10.80-1619.71] and the severity of clinical attachment loss (OR = 7.70; 95% CI [3.16-18.92]) were important risk factors. Inverse associations were observed with increasing body mass index (OR = 0.76; 95% CI [0.63-0.93]). Our results underline that gingivitis cases and bleeding were particularly high among 3-month pregnant women. Literacy and adequate oral hygiene actions to modify behaviors and to achieve meticulous biofilm disorganization could make a favorable change in the gingival health outcome. Additionally, further research is necessary to precisely determine the role of biofilm-induced gingivitis and systemic-induced gingivitis in improving gingival conditions.

The oral microbiota and gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is one of the most frequent endocrine conditions during pregnancy. GDM is linked to adverse pregnancy outcomes and has implications for maternal health. Studies have demonstrated the link between pathogenic periodontal bacteria, glycemic control, and the risk of diabetes. The objective of the current study is to perform a mini-review of the available literature on the potential changes in the oral microbiota of women with GDM. The review was conducted by two independent reviewers (LLF and JDC). Indexed electronic databases (PubMed/Medline, Cochrane Library, Web of Science, and Scopus) were searched, including articles published in English and Portuguese. A manual search was also performed to identify related articles. The oral microbial community of pregnant women with GDM is unique from that of healthy pregnant women. The majority of the alterations found in the oral microbiota of women with GDM point to a pro-inflammatory environment with high levels of bacteria associated with periodontitis (Prevotella, Treponema, anaerobic bacteria) and a depletion of bacteria associated with periodontal health maintenance (Firmicutes, Streptococcus, Leptotrichia). More well-designed studies differentiating between pregnant women with good oral health and those with periodontitis are needed to ascertain which differences are due to GDM or periodontitis.

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.

[Developments in Research on the Relationship Between Porphyromonas gingivalis and Non-Oral Diseases]

Porphyromonas gingivalis ( P. gingivalis) is a common periodontal pathogen. Recently, there has been increasing evidence suggesting that P. gingivalis is not only a common pathogen in the oral cavity, but is also closely associated with non-oral diseases, including inflammatory bowel disease, cancer, cardiovascular diseases, Alzheimer's disease, rheumatoid arthritis, diabetes mellitus, premature birth and non-alcoholic hepatitis, etc. Herein, we reviewed the developments in recent years in research on the relationship between P. gingivalis, a periodontal pathogen, and non-oral diseases, which will help determine whether P. gingivalis could be used as an auxiliary diagnostic biomarker or a potential therapeutic target for these non-oral diseases, thus contributing to the development of treatment strategies for the relevant diseases.

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.

Inflammatory Response in Oral Biofilm during Pregnancy: A Systematic Review

Understanding the inflammatory response in oral biofilm during pregnancy and its association with oral and maternal health is essential for identifying biomarker patterns that may serve as markers of pregnancy-related complications. We aimed to conduct a systematic review of the available literature to assess: (1) inflammatory responses in oral biofilm during pregnancy, (2) the association between inflammatory responses in oral biofilm during pregnancy and maternal, oral or systemic conditions, (3) changes in the response of inflammatory biomarkers found in the oral biofilm during different pregnancy stages, and (4) the value of other risk factors such as nutrition and lifestyle. PubMed, Web of Science and Cochrane Library were systematically searched from inception until April 2022. From 5441 records, 39 studies were included for qualitative assessment. The oral biofilm in pregnant women was associated with increased inflammatory biomarkers when compared to non-pregnant women. Levels of inflammatory biomarkers in the oral biofilm were found to be highest in pregnant women with systemic conditions. Increased inflammatory biomarkers in the oral biofilm were also associated with worse oral health outcomes. Given the importance of nutrition and lifestyle for pregnancy and oral health outcomes and the fact that these factors were largely excluded in the included studies, future research should consider a holistic view of the mother during pregnancy to capture physiological, hormonal, immunologic, and metabolic changes in the context of inflammatory responses.

Maternal Obesity and Gut Microbiota Are Associated with Fetal Brain Development

Obesity in pregnancy induces metabolic syndrome, low-grade inflammation, altered endocrine factors, placental function, and the maternal gut microbiome. All these factors impact fetal growth and development, including brain development. The lipid metabolic transporters of the maternal-fetal-placental unit are dysregulated in obesity. Consequently, the transport of essential long-chain PUFAs for fetal brain development is disturbed. The mother’s gut microbiota is vital in maintaining postnatal energy homeostasis and maternal-fetal immune competence. Obesity during pregnancy changes the gut microbiota, affecting fetal brain development. Obesity in pregnancy can induce placental and intrauterine inflammation and thus influence the neurodevelopmental outcomes of the offspring. Several epidemiological studies observed an association between maternal obesity and adverse neurodevelopment. This review discusses the effects of maternal obesity and gut microbiota on fetal neurodevelopment outcomes. In addition, the possible mechanisms of the impacts of obesity and gut microbiota on fetal brain development are discussed.

Cohort profile: the Swedish Maternal Microbiome project (SweMaMi) - assessing the dynamic associations between the microbiome and maternal and neonatal adverse events

PURPOSE

The Swedish Maternal Microbiome (SweMaMi) project was initiated to better understand the dynamics of the microbiome in pregnancy, with longitudinal microbiome sampling, shotgun metagenomics, extensive questionnaires and health registry linkage.

PARTICIPANTS

Pregnant women were recruited before the 20th gestational week during 2017-2021 in Sweden. In total, 5439 pregnancies (5193 unique women) were included. For 3973 pregnancies (73%), samples were provided at baseline, and for 3141 (58%) at all three timepoints (second and third trimester and postpartum). In total, 38 591 maternal microbiome samples (vaginal, faecal and saliva) and 3109 infant faecal samples were collected. Questionnaires were used to collect information on general, reproductive and mental health, diet and lifestyle, complemented by linkage to the nationwide health registries, also used to follow up the health of the offspring (up to age 10).

FINDINGS TO DATE

The cohort is fairly representative for the total Swedish pregnant population (data from 2019), with 41% first-time mothers. Women with university level education, born in Sweden, with normal body mass index, not using tobacco-products and aged 30-34 years were slightly over-represented.

FUTURE PLANS

The sample and data collection were finalised in November 2021. The next steps are the characterisation of the microbial DNA and linkage to the health and demographic information from the questionnaires and registries. The role of the microbiome on maternal and neonatal outcomes and early-childhood diseases will be explored (including preterm birth, miscarriage) and the role and interaction of other risk factors and confounders (including endometriosis, polycystic ovarian syndrome, diet, drug use). This is currently among the largest pregnancy cohorts in the world with longitudinal design and detailed and standardised microbiome sampling enabling follow-up of both mothers and children. The findings are expected to contribute greatly to the field of reproductive health focusing on pregnancy and neonatal outcomes.

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.

Racial and oral health disparity associated with perinatal oral health care utilization among underserved US pregnant women

OBJECTIVE

The study aims to identify specific determinants of dental care utilization during the perinatal period (prenatal and 1-year postnatal) among underserved US women residing in Upstate New York.

METHOD AND MATERIALS

The prospective cohort study included 186 low-income US pregnant women. Demographic-socioeconomic parameters and medical-dental conditions were obtained from questionnaires, electronic medical-dental records, and dental examinations. Multivariate regression analyses were used to assess factors associated with perinatal dental care utilization. As an exploratory effort, a separate logistic model assessed factors associated with adverse birth outcomes.

RESULTS

The results demonstrated unmet oral health needs among the underserved US pregnant women residing in Upstate New York. Despite an average of 2.7 ± 3.6 untreated decayed teeth per person during pregnancy, only 39.3% and 19.9% utilized prenatal and 1-year postnatal dental care, respectively. Previous dental care utilization was a notable factor contributing to a higher uptake of perinatal dental care at a subsequent period. Prenatal dental care utilization was significantly lower among African American women (odds ratio 0.43 [95% CI 0.19, 0.98], P = .04) and positively associated with dental caries severity (OR 2.40 [1.09, 5.12], P = .03). Postnatal utilization was associated with caries severity (OR 4.70 [1.73, 12.74], P = .002) and prevalent medical conditions (hypertension, diabetes mellitus, and emotional conditions). Pregnant women who achieved prenatal caries-free status had a lower odds of experiencing adverse birth outcomes; however, this was an insignificant finding due to limited adverse birth cases.

CONCLUSION

Racial and oral health disparity is associated with perinatal oral health care utilization among underserved US pregnant women in New York. While both prenatal and postnatal dental care utilization was positively associated with oral health status, specifically, postnatal utilization was driven by existing medical conditions such as emotional condition, hypertension, and diabetes mellitus. The results add to existing information on inherent barriers and postulated needs to improve access to perinatal oral care, thereby informing statewide recommendations to maximize utilization. Considering this is a geographically restricted population, the findings are particularly true to this cohort of underserved pregnant women. However, future more robust studies are warranted to assess effective strategies to further improve perinatal dental care utilization among underserved pregnant women.

Diversity of the gut, vaginal and oral microbiome among pregnant women in South Africa with and without pre-eclampsia

Background

Changes in microbial communities are a known characteristic of various inflammatory diseases and have been linked to adverse pregnancy outcomes, such as preterm birth. However, there is a paucity of information regarding the taxonomic composition and/or diversity of microbial communities in pre-eclampsia. The aim of this study was to determine the diversity of the gut, vaginal and oral microbiome in a cohort of South African pregnant women with and without pre-eclampsia. The diversity of the gut, vaginal and oral microbiome was determined by targeted next generation sequencing (NGS) of the V3 and V4 region of the 16S rRNA gene on the Illumina MiSeq platform.

Results

In this study population, pre-eclampsia was associated with a significantly higher alpha diversity (P = 0.0472; indicated by the Shannon index) in the vaginal microbiome accompanied with a significant reduction in Lactobacillus spp. (P = 0.0275), compared to normotensive pregnant women. Lactobacillus iners was identified as the predominant species of the vaginal microbiome in both cohorts. High inter-individual variation in alpha diversity was observed in the gut and oral microbiome in both cohorts. Although differences in the relative abundance of bacteria at all phylogenetic levels were observed, overall microbial composition of the gut, oral and vaginal microbiome was not significantly different in the pre-eclampsia cohort compared to the normotensive cohort.

Conclusion

Collectively, a reduction of Lactobacillus spp., and predominance of L. iners in pregnant women with pre-eclampsia could suggest an unstable vaginal microbiome that might predispose pregnant women to develop pre-eclampsia. The lack of significant structural changes in the gut, oral and vaginal microbiome does not suggest that the characterized communities play a role in pre-eclampsia, but could indicate a characteristic unique to the study population. The current study provided novel information on the diversity of the gut, oral and vaginal microbiome among pregnant women in South Africa with and without pre-eclampsia. The current study provides a baseline for further investigations on the potential role of microbial communities in pre-eclampsia.

Bibliometric Analysis of the Global Scientific Production on Oral Health during Pregnancy

AIM

To analyze the bibliometric characteristics of the global scientific production indexed in Scopus on oral health during pregnancy.

MATERIALS AND METHODS

Cross-sectional study with bibliometric methodology, using scientific publications indexed in Scopus as a unit of analysis. For the search, MESH terms, Boolean operators ("AND" and "OR"), and search topics (TITLE and ABSTRACT) were used. SciVal was the tool selected for the analysis of bibliometric parameters.

RESULTS

Most of the articles were published in Q1 (30.2%) and Q2 (29.6%) quartile journals. The country with the most scientific publications was the United States (451 articles), while Spain had only 14 publications. The University of Sydney, with 16 articles, was the most productive institution and the one with the most citations per publication was Saveetha University (19.7). The author with the most articles and citations related to the topic was George Ajesh with 13 and 136, respectively. Johnson Marre had the highest impact (15.1) and expected citations with respect to the global average (FWCI: 2.49).

CONCLUSIONS

The scientific production on oral health in pregnancy has increased, with a greater preference by authors for scientific journals in the Q1 and Q2 quartile. The United States is the country with the most publications, although Australia has a greater number of institutions among the most productive.

CLINICAL SIGNIFICANCE

The clinical relevance could be addressed later in relation to oral health during pregnancy, however, analyzing the bibliometric characteristics of the global scientific production is essential to understand the dynamics of scientific publications on this topic.

Oral Microbiome Profiles and Inflammation in Pregnant Women Who Used Orthodontic Appliances

It is common for women to undergo orthodontic treatment during pregnancy, especially through the use of fixed orthodontic devices. In changing the oral microbiome profile, it is crucial to increase the immune responses of pregnant women using fixed orthodontics; however, changes in the microbiomes of pregnant women with orthodontic appliances can be adjusted. Therefore, we aimed to conduct research on the oral cavity microbiome profiles, specifically IL-6 and TNF-α, of pregnant women using fixed orthodontic appliances. We proposed an observational analysis of 30 third-trimester pregnant women. OHI-S was recorded, saliva collection was performed using the passive drool method for IL-6 and TNF-α, and analysis and mucosal swabs were used to determine the oral microbiome profile. Kruskal−Wallis and post hoc Bonferroni tests were used to identify any significant differences with values of p < 0.05. Of these pregnant women, those with orthodontic appliances developed 10 types of bacteria at similar levels (>80%) from the genera Streptococcus, Lactobacillus, and Veillonella. There was no difference between the oral microbiomes of the control group and the pregnant women with a history of orthodontic appliance use. While the level of TNF-α in the women with orthodontic appliances was higher compared with the control group who had never used orthodontic appliances (p < 0.05), there was no difference in the IL-6 levels. The IL-6 and microbiome profile produced normal results, so the use of orthodontic appliances during pregnancy should be allowed with conditions. Pregnant women with orthodontic appliances must keep the oral cavity clean and their appliances well-maintained to avoid oral problems.

Identification of the specific microbial community compositions in saliva associated with periodontitis during pregnancy

OBJECTIVE

To identify the specific microbial community compositions in saliva associated with periodontitis during pregnancy.

MATERIALS AND METHODS

Unstimulated saliva samples were collected from 53 pregnant women during weeks 24-28 of gestation, and the V3-V4 regions of the 16S rRNA gene were amplified from isolated saliva DNA and sequenced. Phylum-, genus-, and species-level taxonomic compositions were separately compared between subjects with (n = 12) and without (n = 41) periodontitis.

RESULTS

Taxa were selected using the random forest algorithm to distinguish subjects with periodontitis at each taxonomic level, and principal component biplots were constructed to visualize the composition of selected taxa in each subject. The genus-level biplot indicated that 44 subjects clustered around the origin. The prevalence of periodontitis was significantly higher among subjects outside the cluster compared with subjects inside the cluster (6/9 [67%] vs. 6/44 [14%], respectively; p = 0.002). Subjects outside the cluster also had significantly decreased abundance of Neisseria and increased abundances of several putative periodontopathic genera. Phylum- and species-level biplots failed to discriminate subjects with periodontitis more efficiently than the genus-level biplot.

CONCLUSIONS

The specific taxonomic composition of the saliva microbiota in pregnant women with periodontitis could be clearly identified at the genus level.

CLINICAL RELEVANCE

The formula developed based on the present findings, (%Treponema + %Tannerella + %Filifactor + %Anaeroglobus)/%Neisseria, can be used to predict periodontitis during pregnancy with sensitivity and specificity values of 0.67 (8/12) and 0.95 (39/41), respectively.

Reduced Abundance of Nitrate-Reducing Bacteria in the Oral Microbiota of Women with Future Preeclampsia

The oral microbiota can contribute to the regulation of blood pressure by increasing the availability of nitric oxide through the reduction of nitrate to nitrite, which can be converted into nitric oxide in the stomach and then enter the circulation. It is unclear if the composition of the oral microbiota is different between women who do and do not develop preeclampsia. This study aimed to compare the composition of the buccal microbiota just prior to the development of symptoms at 36 weeks gestation in 12 women who developed late-onset preeclampsia and 24 matched women who remained normotensive throughout pregnancy by 16S rRNA gene amplicon sequencing. The abundance of the nitrate-reducing Veillonella spp V. parvula and V. dispar and a subunit of nitrate reductase narH was compared using real-time PCR. The abundance of bacteria was correlated with maternal blood pressure and dietary intake of nitrate-containing vegetables. The results showed that the abundance of nitrate-reducing bacteria including Veillonella, specifically V. parvula, and Prevotella was reduced in women who developed preeclampsia. Veillonella but not Prevotella abundance was negatively correlated with maternal blood pressure. The dietary intake of nitrate-containing vegetables did not differ between the groups and was not correlated with the abundance of Veillonella. There was no difference in the abundance of the nitrate reductase subunit narH between the groups. These results suggest that the abundance of nitrate-reducing bacteria is reduced in the oral microbiota of women who later develop preeclampsia, indicating a potential pathway for prevention.

Microbiome alterations in women with gestational diabetes mellitus and their offspring: A systematic review

AIMS

Gestational diabetes mellitus (GDM) is a metabolic disorder that might predispose pregnant women to develop type 2 Diabetes Mellitus or lead to severe adverse outcomes in their offspring. One of the factors that have been thought to be involved in the pathology behind this disorder is the microbiome. In this systematic review, we comprehensively review the documents regarding the microbiota alterations in different tracts of pregnant women with GDM and their offspring.

METHODS

A comprehensive search was conducted in major databases including MEDLINE (PubMed), Scopus, and Web of sciences up to August 2021. Data on the demographics, methodology, and microbiome alterations were extracted and classified according to the type of microbiome in pregnant women with GDM and their offspring. The quality of studies was assessed using the Newcastle-Ottawa Scale (NOS).

RESULTS

In 49 articles which were retrieved, the findings were variable on the level of changes in alpha and beta diversity, enrichment or depletion in phyla, genera, species and OTUs, in each microbiome type. Although there were some inconsistencies among the results, a pattern of significant alterations was seen in the gut, oral, vaginal microbiome of women with GDM and gut, oral, and placental microbiome of their offspring.

CONCLUSION

Even though the alteration of the microbiome of the different tracts was seen in the cases of GDM, the inconsistency among the studies prevents us from identifying unique pattern. However, the results seem promising and further studies that overcome the confounding factors related to the demographics and methodology are needed.

Oral Anaerobic Microflora and Pregnancy Complication

Bacterial vaginosis and periodontal diseases share very similar pathogenesis. Each of these diseases occurs when healthy microbiome changes to predominately anaerobic bacterial flora. Bacterial vaginosis is proven factor for adverse pregnancy outcomes. In recent years it has been hypothesized that infection from distant sites of the fetoplacental unit may also elicit an inflammatory response in utero. Aim: The study is designed to determine whether the presence of specific oral anaerobic bacteria in subgingival sulcus of mother increase the risk of adverse obstetric outcomes. Material and Methods: Case-control study.  Control group: 50 patients who gave birth to neonate whit normal birth weight at term. Group cases: I group - 40 pregnant women who were hospitalized with signs of preterm labor. II - 20 pregnant women, who have an ultrasound diagnosis of fetal growth retardation. Sub-gingival microbiological paper-point swab was taken in all patients. Results: The total number of isolated oral anaerobic bacteria was statistically significantly higher in the cases group compared to control group p <0.01. In our study, pregnant women who tested positive for Porphyrmonas gingivalis for 6.65 times were more likely to have preterm labor compare with pregnant women with negative oral swabs (95.0% CI: 1.38-32.11 / p <0.05), and for 2,79 times more likely to have fetus with intrauterine growth restriction (95.0% CI: 1.10-7.91 / p <0.05 Conclusions: The study confirmed the hypothesis of a statistically significant association between oral anaerobic infection and adverse pregnancy outcomes. In the future, more studies are needed to investigate the role of the microbial load, maternal immune response, pathophysiological pathway that leads to negative pregnancy outcome.  

Short-chain fatty acids during pregnancy in multiple sclerosis: A prospective cohort study

BACKGROUND AND PURPOSE

Short-chain fatty acids (SCFAs) can have pro- or anti-inflammatory properties, but their relationship with multiple sclerosis (MS) relapses during pregnancy remains unknown. This study aimed to explore SCFA profiles in MS patients during pregnancy and to assess their association with the appearance of relapses during pregnancy and postpartum.

METHODS

We prospectively included 53 pregnant MS patients and 21 healthy control women. Patients were evaluated during pregnancy and puerperium. SCFAs were measured by liquid chromatography-mass spectrometry.

RESULTS

Sixteen patients (32%) had relapses during pregnancy or puerperium, and 37 (68%) did not. All MS patients showed significant increases in acetate levels during pregnancy and the postpartum period compared to non-MS women. However, propionate and butyrate values were associated with disease activity. Their values were higher in nonrelapsing patients and remained similar to the control group in relapsing patients. The variable that best identified active patients was the propionate/acetate ratio. Ratios of <0.36 during the first trimester were associated with higher inflammatory activity (odds ratio = 165, 95% confidence interval = 10.2-239.4, p < 0.01). Most nonrelapsing patients showed values of >0.36, which were similar to those in healthy pregnant women.

CONCLUSIONS

Low propionate/acetate ratio values during the first trimester of gestation identified MS patients at risk of relapses during pregnancy and the postpartum period.

Changes in Candida albicans, Streptococcus mutans and oral health conditions following Prenatal Total Oral Rehabilitation among underserved pregnant women

Objectives

To assess the oral health condition and oral microbial outcomes from receiving an innovative treatment regimen - Prenatal Total Oral Rehabilitation (PTOR).

Methods

This prospective cohort study included 15 pregnant women in the PTOR group who had a baseline visit before PTOR and three follow-up visits (immediate after, 2 weeks and 2 months) after receiving PTOR. A historical control group of additional 15 pregnant women was matched from a separate study based on a propensity score. Along with demographic and medical background, oral health conditions and perinatal oral health literacy were assessed. Oral samples (saliva and plaque) were analyzed to identify and quantify Streptococcus mutans and Candida species by culturing-dependent and -independent methods.

Results

Significant reductions of salivary S. mutans were observed following PTOR, the effect remained until 2-month follow-up (p < 0.05). The carriage of salivary and plaque S. mutans at the 2-month visit of the PTOR group was significantly lower than that of the control group (p < 0.05). Oral health conditions reflected by BOP and PI were significantly improved upon receiving PTOR (p < 0.05). Receiving PTOR significantly improved the perinatal oral health literacy score, and the knowledge retained until 2-month follow-up (p < 0.05).

Conclusions

PTOR is associated with an improvement in oral health conditions and perinatal oral health literacy, and a reduction in S. mutans carriage, within a 2-month follow-up period. Future clinical trials are warranted to comprehensively assess the impact of PTOR on the maternal oral flora other than S. mutans and Candida, birth outcomes, and their offspring's oral health.

Nitric Oxide, Oxidative Stress and Streptococcus mutans and Lactobacillus Bacterial Loads in Saliva during the Different Stages of Pregnancy: A Longitudinal Study

Hormonal changes associated with pregnancy promote oral bacterial growth, which may affect salivary nitric oxide (NO) levels, oxidative stress (OS), and antioxidant capacity (AC). We hypothesized that caries-related bacterial load, NO level, and OS in the saliva change with advancing gestation. The aim of this study was to investigate longitudinal changes in salivary NO, OS, and AC during pregnancy and correlate them with Streptococcus mutans (SM) and Lactobacillus (LB) colonization at different stages of pregnancy. We assessed NO level by Griess method, OS by measuring malondialdehyde (MDA), AC by ABTS radicals and bacterial load by culturing SM and LB in the saliva of pregnant women (n = 96) and compared with non-pregnant women (n = 50) as well as between different stages of pregnancy. Compared with non-pregnant women, NO was 77% higher (4.73 ± 2.87 vs. 2.67 ± 1.55 µM; p < 0.001), MDA was 13% higher (0.96 ± 0.27 vs. 0.85 ± 0.22 nM; p = 0.0055), and AC was 34% lower (60.35 ± 14.33 vs. 80.82 ± 11.60%; p < 0.001) in the late third trimester. NO increased with advancing gestation, but AC and OS did not change significantly during pregnancy. SM were more abundant in pregnant women compared with non-pregnant (p = 0.0012). Pregnancy appears to have an adverse impact on oral health emphasizing the importance optimal oral healthcare during pregnancy.