Effects of oral probiotic supplements on vaginal microbiota during pregnancy: a randomised, double-blind, placebo-controlled trial with microbiome 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.

Exploring the Limits of Artificial Intelligence for Referencing Scientific Articles

OBJECTIVE

 To evaluate the reliability of three artificial intelligence (AI) chatbots (ChatGPT, Google Bard, and Chatsonic) in generating accurate references from existing obstetric literature.

STUDY DESIGN

 Between mid-March and late April 2023, ChatGPT, Google Bard, and Chatsonic were prompted to provide references for specific obstetrical randomized controlled trials (RCTs) published in 2020. RCTs were considered for inclusion if they were mentioned in a previous article that primarily evaluated RCTs published by the top medical and obstetrics and gynecology journals with the highest impact factors in 2020 as well as RCTs published in a new journal focused on publishing obstetric RCTs. The selection of the three AI models was based on their popularity, performance in natural language processing, and public availability. Data collection involved prompting the AI chatbots to provide references according to a standardized protocol. The primary evaluation metric was the accuracy of each AI model in correctly citing references, including authors, publication title, journal name, and digital object identifier (DOI). Statistical analysis was performed using a permutation test to compare the performance of the AI models.

RESULTS

 Among the 44 RCTs analyzed, Google Bard demonstrated the highest accuracy, correctly citing 13.6% of the requested RCTs, whereas ChatGPT and Chatsonic exhibited lower accuracy rates of 2.4 and 0%, respectively. Google Bard often substantially outperformed Chatsonic and ChatGPT in correctly citing the studied reference components. The majority of references from all AI models studied were noted to provide DOIs for unrelated studies or DOIs that do not exist.

CONCLUSION

 To ensure the reliability of scientific information being disseminated, authors must exercise caution when utilizing AI for scientific writing and literature search. However, despite their limitations, collaborative partnerships between AI systems and researchers have the potential to drive synergistic advancements, leading to improved patient care and outcomes.

KEY POINTS

· AI chatbots often cite scientific articles incorrectly.. · AI chatbots can create false references.. · Responsible AI use in research is vital..

Vulvovaginitis in pregnant women

• The balanced vaginal microbiome is the main factor defending the vaginal environment against infections. Lactobacilli play a key role in this regard, maintaining the vaginal pH within the normal range (3.8 to 4.5). •Hormonal and immune adaptations resulting from pregnancy influence changes in the vaginal microbiome during pregnancy. •An altered vaginal microbiome predisposes to human immunodeficiency virus (HIV) infection. •Bacterial vaginosis is the main clinical expression of an imbalanced vaginal microbiome. •Vulvovaginal candidiasis depends more on the host's conditions than on the etiological agent. •Trichomonas vaginalis is a protozoan transmitted during sexual intercourse. •The use of probiotics is not approved for use in pregnant women.

The effects of probiotics administration during pregnancy on preeclampsia and associated maternal, fetal, and newborn outcomes: a systematic review and meta-analysis

OBJECTIVE

This study aimed to synthesize the available evidence on probiotic administration during pregnancy for the prevention of preeclampsia and its effects on related maternal, fetal, and newborn outcomes.

DATA SOURCES

Six databases were systematically searched for eligible studies, namely Ovid MEDLINE, Embase, CINAHL, Cochrane, Global Index Medicus, and the Maternity and Infant Care Database, from inception to August 2, 2023.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials that evaluated the effects of probiotic administration on women during any stage of pregnancy were eligible for inclusion.

METHODS

The protocol was registered with the International Prospective Register of Systematic Reviews under identifier CRD42023421613. Evaluating study eligibility, extracting data, assessing risk of bias (ROB-2 tool), and rating certainty (Grading of Recommendations, Assessment, Development and Evaluations) were conducted independently by 2 authors. The primary outcomes were incidence of preeclampsia, eclampsia, and maternal mortality. A meta-analysis was performed, and the results were reported as risk ratios with 95% confidence intervals.

RESULTS

A total of 29 trials (7735 pregnant women) met the eligibility criteria. There was heterogeneity across the trials in the population of enrolled women and the type of probiotic tested (20 different strains), although most used oral administration. Probiotics may make no difference to the risk of preeclampsia (risk ratio, 1.14; 95% confidence interval, 0.84-1.53; 11 trials; 2401 women; low certainty evidence), preterm birth at <37 weeks' gestation (risk ratio, 0.93; 95% confidence interval, 0.66-1.30; 18 trials, 4016 women; low certainty evidence), or gestational age at delivery (mean difference, -0.03 weeks [≈0.2 days]; 95% confidence interval, -0.16 to 0.10 weeks [≈ -1.1 to 0.7 days]; 13 trials, 2194 women; low certainty evidence). It is difficult to assess the effects of probiotics on other secondary outcomes because the evidence was of very low certainty, however, no benefits or harms were observed.

CONCLUSION

Limited evidence suggests that probiotic supplementation does not affect the risk for preeclampsia. Further high-quality trials are needed to definitively assess the benefits and possible harms of probiotic supplementation during pregnancy. There is also a lack of data from trials that included women who were undernourished or who experienced microbial dysbiosis and for whom probiotic supplementation might be useful.

Effect of probiotics on mother-to-neonate vertical transmission of group B streptococci: A prospective open-label randomized study

BACKGROUND

Group B Streptococci (GBS) are common vaginal bacteria found in 20-30% of pregnant women and a significant cause of invasive infections in newborns. Recently, attention has been focused on the efficacy of probiotics during the perinatal period. However, the effect of probiotic intake on the mother-to-child transmission (MTCT) of GBS remains unknown.

METHODS

Pregnant women with positive GBS results from vaginal and rectal swab cultures at 35-37 weeks of gestation were randomly assigned to the probiotic group or the control group in an open-label manner at the Department of Obstetrics and Gynecology, San-ikukai Hospital, Tokyo, Japan. The probiotic group received Lactobacillus reuteri during antenatal checkups from 35 to 37-week gestation to 1 month after delivery. Rectal swabs were obtained from the newborns at 5 days and at 1 month of age. Whole-genome sequencing was performed to test for GBS strains in the mother, whose newborn carried GBS at the 1-month checkup. Multi-locus sequence typing and single nucleotide polymorphism analyses were performed to identify MTCT.

RESULTS

Overall, 67 mother-infant pairs were included, with 31 in the probiotic group and 36 in the control group. The positivity rate of GBS in newborns at 1 month of age was 10% (n = 3) in the probiotic group and 28% (n = 10) in the control group. In newborns carrying GBS at 1 month of age, genetic analysis revealed that the MTCT rate was 6% in the probiotic group and 22% in the control group, although the difference was not statistically significant (p = 0.0927).

CONCLUSION

No statistically significant difference was found; however, the consumption of L. reuteri by women with GBS-positive pregnancies may inhibit the MTCT of GBS.

The human vaginal microbiota: from clinical medicine to models to mechanisms

The composition of the vaginal microbiota is linked to numerous reproductive health problems, including increased susceptibility to infection, pregnancy complications, and impaired vaginal tissue repair; however, the mechanisms contributing to these adverse outcomes are not yet fully defined. In this review, we highlight recent clinical advancements associating vaginal microbiome composition and function with health outcomes. Subsequently, we provide a summary of emerging models employed to identify microbe-microbe interactions contributing to vaginal health, including metagenomic sequencing, multi-omics approaches, and advances in vaginal microbiota cultivation. Last, we review new in vitro, ex vivo, and in vivo models, such as organoids and humanized microbiota murine models, used to define and mechanistically explore host-microbe interactions at the vaginal mucosa.

Microbiota dynamics, metabolic and immune interactions in the cervicovaginal environment and their role in spontaneous preterm birth

Differences in the cervicovaginal microbiota are associated with spontaneous preterm birth (sPTB), a significant cause of infant morbidity and mortality. Although establishing a direct causal link between cervicovaginal microbiota and sPTB remains challenging, recent advancements in sequencing technologies have facilitated the identification of microbial markers potentially linked to sPTB. Despite variations in findings, a recurring observation suggests that sPTB is associated with a more diverse and less stable vaginal microbiota across pregnancy trimesters. It is hypothesized that sPTB risk is likely to be modified via an intricate host-microbe interactions rather than due to the presence of a single microbial taxon or broad community state. Nonetheless, lactobacilli dominance is generally associated with term outcomes and contributes to a healthy vaginal environment through the production of lactic acid/maintenance of a low pH that excludes other pathogenic microorganisms. Additionally, the innate immunity of the host and metabolic interactions between cervicovaginal microbiota, such as the production of bacteriocins and the use of proteolytic enzymes, exerts a profound influence on microbial populations, activities, and host immune responses. These interplays collectively impact pregnancy outcomes. This review aims to summarize the complexity of cervicovaginal environment and microbiota dynamics, and associations with bacterial vaginosis and sPTB. There is also consideration on how probiotics may mitigate the risk of sPTB and bacterial vaginosis.

Limosilactobacillus reuteri in immunomodulation: molecular mechanisms and potential applications

Frequent use of hormones and drugs may be associated with side-effects. Recent studies have shown that probiotics have effects on the prevention and treatment of immune-related diseases. Limosilactobacillus reuteri (L. reuteri) had regulatory effects on intestinal microbiota, host epithelial cells, immune cells, cytokines, antibodies (Ab), toll-like receptors (TLRs), tryptophan (Try) metabolism, antioxidant enzymes, and expression of related genes, and exhibits antibacterial and anti-inflammatory effects, leading to alleviation of disease symptoms. Although the specific composition of the cell-free supernatant (CFS) of L. reuteri has not been clarified, its efficacy in animal models has drawn increased attention to its potential use. This review summarizes the effects of L. reuteri on intestinal flora and immune regulation, and discusses the feasibility of its application in atopic dermatitis (AD), asthma, necrotizing enterocolitis (NEC), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and multiple sclerosis (MS), and provides insights for the prevention and treatment of immune-related diseases.

Vaginal microbiome in obesity and its impact on reproduction

A number of reproductive outcomes have been increasingly found to be affected by the vaginal microbiota. Obesity has become a global epidemic, affecting increasing numbers of reproductive-age women, and has been shown to be a risk factor for a number of adverse female health outcomes. A healthy vaginal microbiome is characterized by Lactobacillus-dominance, in particular Lactobacillus crispatus; obesity has been found to be associated with higher diversity and a lower likelihood of Lactobacillus-dominance. In this review, we summarize the evidence on the vaginal microbiome in obese women and the impact on reproductive outcomes such as conception rates, early pregnancy, and preterm birth. We further explore the mechanisms by which obesity may result in an altered microbial composition and highlight future avenues for therapeutic targeting of the vaginal microbiota.

A Narrative Review Discussing the Obstetric Repercussions Due to Alterations of Personalized Bacterial Sites Developed within the Vagina, Cervix, and Endometrium

BACKGROUND

The reproductive tract microbiota that evolved as an integrative component has been studied intensively in the last decade. As a result, novel research, clinical opportunities, and perspectives have been derived following the close investigation of this microecological environment. This has paved the way for an update to and improvement of the management strategies and therapeutic approaches. However, obscurities, contradictions, and controversies arise regarding the ascension route from the vagina to the endometrium via the cervix, with finality in adverse obstetric outcomes.

METHODS

Starting from these considerations, we aimed to gather all existing data and information from four major academic databases (PubMed, ISI Web of Knowledge, Scopus, and ScienceDirect) published in the last 13 years (2010-2023) using a controlled vocabulary and dedicated terminology to enhance the coverage, identification, and sorting of potentially eligible studies.

RESULTS

Despite the high number of returned entries (n = 804), only a slight percentage (2.73%) of all manuscripts were deemed eligible following two rounds of evaluation. Cumulatively, a low level of Lactobacillus spp. and of other core microbiota members is mandatory, with a possible eubiosis-to-dysbiosis transition leading to an impairment of metabolic and endocrine network homeostasis. This transposes into a change in the pro-inflammatory landscape and activation of signaling pathways due to activity exerted by the bacterial lipopolysaccharides (LPSs)/endotoxins that further reflect a high risk of miscarriage in various stages. While the presence of some pathogenic entities may be suggestive of an adverse obstetric predisposition, there are still pros and cons of the role of specific strains, as only the vagina and cervix have been targeted as opposed to the endometrium, which recently started to be viewed as the key player in the vagina-cervix-endometrium route. Consequently, based on an individual's profile, diet, and regime, antibiotics and probiotics might be practical or not.

CONCLUSIONS

Resident bacteria have a dual facet and are beneficial for women's health, but, at the same time, relaying on the abundance, richness, and evenness that are definitory indexes standing as intermediaries of a miscarriage.

Orally administrated Lactobacillus gasseri TM13 and Lactobacillus crispatus LG55 can restore the vaginal health of patients recovering from bacterial vaginosis

Bacterial vaginosis (BV) is a common infection of the lower genital tract with a vaginal microbiome dysbiosis caused by decreasing of lactobacilli. Previous studies suggested that supplementation with live Lactobacillus may benefit the recovery of BV, however, the outcomes vary in people from different regions. Herein, we aim to evaluate the effectiveness of oral Chinese-origin Lactobacillus with adjuvant metronidazole (MET) on treating Chinese BV patients. In total, 67 Chinese women with BV were enrolled in this parallel controlled trial and randomly assigned to two study groups: a control group treated with MET vaginal suppositories for 7 days and a probiotic group treated with oral Lactobacillus gasseri TM13 and Lactobacillus crispatus LG55 as an adjuvant to MET for 30 days. By comparing the participants with Nugent Scores ≥ 7 and < 7 on days 14, 30, and 90, we found that oral administration of probiotics did not improve BV cure rates (72.73% and 84.00% at day 14, 57.14% and 60.00% at day 30, 32.14% and 48.39% at day 90 for probiotic and control group respectively). However, the probiotics were effective in restoring vaginal health after cure by showing higher proportion of participants with Nugent Scores < 4 in the probiotic group compared to the control group (87.50% and 71.43% on day 14, 93.75% and 88.89% on day 30, and 77.78% and 66.67% on day 90). The relative abundance of the probiotic strains was significantly increased in the intestinal microbiome of the probiotic group compared to the control group at day 14, but no significance was detected after 30 and 90 days. Also, the probiotics were not detected in vaginal microbiome, suggesting that L. gasseri TM13 and L. crispatus LG55 mainly acted through the intestine. A higher abundance of Prevotella timonensis at baseline was significantly associated with long-term cure failure of BV and greatly contributed to the enrichment of the lipid IVA synthesis pathway, which could aggravate inflammation response. To sum up, L. gasseri TM13 and L. crispatus LG55 can restore the vaginal health of patients recovering from BV, and individualized intervention mode should be developed to restore the vaginal health of patients recovering from BV.

Clinical trial registration

https://classic.clinicaltrials.gov/ct2/show/, identifier NCT04771728.

Cycle Biodynamics of Women's Microbiome in the Urinary and Reproductive Systems

The genitourinary microbiome plays a crucial role in the establishment and maintenance of urinary and reproductive health in women throughout their lives. Particularly during the reproductive stage, resident microorganisms contribute to implantation and protect against perinatal complications, including preterm birth, stillbirth, and low birth weight, while also serving as the first line of defense against pathogens that can cause infections, such as urinary tract infections and bacterial vaginosis. This review aimed to elucidate the relationship between a healthy microbiome environment and women's overall health. We examine the variability and dynamics of the microbiome during different developmental stages, ranging from the prepubertal to the postmenopausal stage. Furthermore, we explore the significance of a healthy microbiota in successful implantation and pregnancy development and investigate potential differences between women experiencing infertility. In addition, we analyze the local and systemic inflammatory responses associated with the establishment of a dysbiotic state and compare it to a condition where a healthy microbiome was established. Lastly, we present the most recent evidence regarding preventive measures, such as dietary interventions and the use of probiotics to promote and maintain a healthy microbiome, thereby ensuring comprehensive women's health. By highlighting the importance of the genitourinary microbiome in reproductive health, this review aimed to enhance this microbiome's visibility and significance in the field.

Development of probiotic loaded multilayer microcapsules incorporated into dissolving microneedles for potential improvement treatment of vulvovaginal candidiasis: A proof of concept study

Vulvovaginal candidiasis (VVC) is a vaginal infection caused by abnormal growth of Candida sp., especially Candida albicans, in the vaginal mucosa. A shift in vaginal microbiota is prominent in VVC. The presence of Lactobacillus plays a vital role in maintaining vaginal health. However, several studies have reported resistance of Candida sp. against azoles drugs, which is recommended as VVC treatment. The use of L. plantarum as a probiotic would be an alternative to treat VVC. In order to exert their therapeutic activity, the probiotics needed to remain viable. Multilayer double emulsion was formulated to obtain L. plantarum loaded microcapsules (MCs), thus improving its viability. Furthermore, a vaginal drug delivery system using dissolving microneedles (DMNs) for VVC treatment was developed for the first time. These DMNs showed sufficient mechanical and insertion properties, dissolved rapidly upon insertion, facilitating probiotic release. All formulations proved non-irritating, non-toxic, and safe to apply on the vaginal mucosa. Essentially, the DMNs could inhibit the growth of Candida albicans up to 3-fold than hydrogel and patch dosage forms in ex vivo infection model. Therefore, this study successfully developed the formulation of L. plantarum-loaded MCs with multilayer double emulsion and its combination in DMNs for vaginal delivery to treat VVC.

A probiotic nanozyme hydrogel regulates vaginal microenvironment for Candida vaginitis therapy

Molecular therapeutics are limited for Candida vaginitis because they damage normal cells and tissues of vagina, aggravating the imbalance of vaginal microbiota and increasing the recurrence. To tackle this limitation, through the combination of peroxidase-like rGO@FeS₂ nanozymes [reduced graphene oxide (rGO)] with Lactobacillus-produced lactic acid and H₂O₂, a responsive hyaluronic acid (HA) hydrogel rGO@FeS₂/Lactobacillus@HA (FeLab) is developed. FeLab has simultaneous anti-Candida albicans and vaginal microbiota-modulating activities. In particular, the hydroxyl radical produced from rGO@FeS₂ nanozymes and Lactobacillus kills C. albicans isolated from clinical specimens without affecting Lactobacillus. In mice with Candida vaginitis, FeLab has obvious anti-C. albicans activity but hardly damages vaginal mucosa cells, which is beneficial to vaginal mucosa repair. Moreover, a higher proportion of Firmicutes (especially Lactobacillus) and a decrease in Proteobacteria reshape a healthy vaginal microbiota to reduce the recurrence. These results provide a combined therapeutic of nanozymes and probiotics with translational promise for Candida vaginitis therapy.

Cervicovaginal microbiome in patients with recurrent pregnancy loss

There have been few studies concerning an association between unexplained recurrent pregnancy loss (RPL) and the microbiome. A recent study including 67 patients demonstrated that an increase in Ureaplasma species in the endometrium raised the risk of miscarriage with an euploid karyotype. While endometrial sampling is invasive, cervicovaginal sampling is not. We compared vaginal and cervical microbiomes with a 16 S ribosomal RNA sequence between 88 patients with unexplained RPL and 17 healthy women with no history of miscarriage. We prospectively assessed risk factors for maternal colonization at a subsequent miscarriage without an aneuploid karyotype in patients. Cervicovaginal bacteria were dominated by Lactobacillus iners, Gardnerella vaginalis, Atopobium vaginae and Bifidobacterium breve in Japanese population. The proportions of Delftia and unknown bacteria in the cervix were significantly higher in patients with RPL than in controls. Streptococcus, Microbacterium, Delftia, Anaerobacillus and Chloroplast in the cervix were significantly higher in patients with a history of chorioamnionitis compared to the controls. The abundance of Cutibacterium and Anaerobacillus in the cervix was significantly higher in patients who had subsequently miscarried compared to those who gave birth. The miscarriage rate in patients with higher proportions of both Cutibacterium and Anaerobacillus (66.7%, 2/3) was significantly greater than that of patients who lacked these bacteria (9.2%, 6/65, adjusted odds ratio 16.90, 95% confidence interval 1.27-225.47, p = 0.032). The presence of certain bacteria could be a predictor of subsequent miscarriage without an aneuploid karyotype. The cervicovaginal microbiome might be useful for investigating a possible cause of RPL.

Preclinical Potential of Probiotic-Loaded Novel Gelatin-Oil Vaginal Suppositories: Efficacy, Stability, and Safety Studies

The current study describes a suppository base composed of aqueous gelatin solution emulsifying oil globules with probiotic cells dispersed within. The favorable mechanical properties of gelatin to provide a solid gelled structure, and the tendency of its proteins to unravel into long strings that interlace when cooled, lead to a three-dimensional structure that can trap a lot of liquid, which was exploited herein to result in a promising suppository form. The latter maintained incorporated probiotic spores of Bacillus coagulans Unique IS-2 in a viable but non-germinating form, preventing spoilage during storage and imparting protection against the growth of any other contaminating organism (self-preserved formulation). The gelatin-oil-probiotic suppository showed uniformity in weight and probiotic content (23 ± 2.481 × 10⁸ cfu) with favorable swelling (double) followed by erosion and complete dissolution within 6 h of administration, leading to the release of probiotic (within 45 min) from the matrix into simulated vaginal fluid. Microscopic images indicated presence of probiotics and oil globules enmeshed in the gelatin network. High viability (24.3 ± 0.46 × 10⁸), germination upon application and a self-preserving nature were attributed to the optimum water activity (0.593 a_w) of the developed composition. The retention of suppositories, germination of probiotics and their in vivo efficacy and safety in vulvovaginal candidiasis murine model are also reported.

Safety, tolerability, and acceptability of Lactobacillus crispatus CTV-05 (LACTIN-V) in pregnant women at high-risk of preterm birth

The vaginal microbiota is a determinant for the risk of preterm birth (PTB). Dominance of the vaginal niche by Lactobacillus crispatus associates with term delivery. This is the first observational clinical study of live vaginal biotherapeutics (Lactobacillus crispatus CTV-05 (LACTIN-V)) in pregnant women at high-risk of PTB. The primary aim was to explore safety, tolerability and acceptability of LACTIN-V in pregnancy. Women were offered a course of LACTIN-V at 14 weeks gestation for five consecutive days followed by weekly administration for six weeks. Participants were followed up at 15, 18-, 20-, 28- and 36-weeks' gestation and at delivery for assessment of adverse events, compliance and tolerability. Participants completed a questionnaire to gauge experience and acceptability. In total, 73 women were recruited, of whom eight withdrew, leaving a final cohort size of 61. Self-reported compliance to the course was high (56/60, 93%). Solicited adverse events were reported in 13 women (19%) including changes in vaginal discharge, odour, colour or consistency of urine, itching and vaginal bleeding. One unsolicited adverse event was reported as haematuria at 38 weeks gestation, but was judged to be unrelated to LACTIN-V. No serious adverse events occurred. One mild adverse event led to study withdrawal. Thirty-one women completed an experience and acceptability questionnaire. Women found LACTIN-V easy and comfortable to use and the majority (30/31, 97%) would use LACTIN-V in future pregnancies. Eight women (8/31, 26%) found the schedule of use difficult to remember. The rate of PTB <34 weeks in this cohort was 3.3% compared to 7% in a historical cohort of 2,190 women at similar background PTB risk. With satisfactory uptake and good compliance, we demonstrate that LACTIN-V is safe and accepted in pregnancy, with high tolerability. Further studies are needed to assess colonisation of Lactobacillus crispatus CTV-05 and clinical efficacy.

Lactobacilli and Their Probiotic Effects in the Vagina of Reproductive Age Women

In the present narrative review, the probiotic effects of vaginal Lactobacillus spp. are described in detail, covering the importance of the differential production of lactic acid, the lactic acid D/L isoforms, the questionable in vivo effect of hydrogen peroxide, as well as bacteriocins and other core proteins produced by vaginal Lactobacillus spp. Moreover, the microbe–host interaction is explained with emphasis on the vaginal mucosa. To understand the crucial role of Lactobacillus spp. dominance in the vaginal microbiota, different dysbiotic states of the vagina are explained including bacterial vaginosis and aerobic vaginitis. Finally, this review takes on the therapeutic aspect of live lactobacilli in the context of bacterial vaginosis. Until recently, there was very low-quality evidence to suggest that any probiotic might aid in reducing vaginal infections or dysbiosis. Therefore, clinical usage or over the counter usage of probiotics was not recommended. However, recent progress has been made, moving from probiotics that are typically regulated as food supplements to so-called live biotherapeutic products that are regulated as medical drugs. Thus, recently, a phase 2b trial using a Lactobacillus crispatus strain as a therapeutic add-on to standard metronidazole showed significant reduction in the recurrence of bacterial vaginosis by 12 weeks compared to placebo. This may constitute evidence for a brighter future where the therapeutic use of lactobacilli can be harnessed to improve women’s health.

Impact of Lactobacillus crispatus-containing oral and vaginal probiotics on vaginal health: a randomised double-blind placebo controlled clinical trial

Health of reproductive tract is tightly associated with balance of microbial communities in this area. Bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC) represent common disturbances of vaginal communities. Vaginal discharge due to BV or VVC is a very frequent reason for visiting gynaecologist. We aimed to evaluate the impact of the novel evidence-based probiotics on BV and VVC patients. The study group included 89 BV and 93 VVC patients (aged 18-50 years) who were recruited into randomised double-blind placebo-controlled two-arm parallel trial. The patients of each diagnosis group received oral or vaginal probiotic capsules, or placebo capsules during 3 months. A probiotic capsule contained two (DSM32717 and DSM32720, in case of BV) or three (DSM32720, DSM32718 and DSM32716, in case of VVC) Lactobacillus crispatus strains. Vaginal, intestinal and general health was monitored weekly by questionnaire. Blood analyses were done in the beginning and at the end of trial. Vaginal samples were collected monthly, microscopic and molecular analyses were performed. The study revealed that both oral and vaginal capsules reduced the signs and symptoms in BV patients. Remarkable improvement was noted in Nugent score, amount and smell of discharge, but also in itching/irritation. Consumption of vaginal probiotics significantly increased the lactobacilli counts in their vagina while mean proportion of some BV-related bacteria decreased. In VVC patients, both oral and vaginal capsules lowered the combined score of two most important symptoms, amount of discharge and itching/irritation. In conclusion, the novel formulations of evidence-based well-focused probiotic L. crispatus strains are effective against BV and VVC being suitable for both vaginal and oral administration. Clinical trial registration: ISRCTN34840624, BioMed Central.

The Importance of the Microbiota in Shaping Women’s Health—The Current State of Knowledge

According to current knowledge, a properly colonized human microbiota contributes to the proper functioning of the body. The composition of the natural flora changes depending on age, health, living conditions, and the use of antimicrobial agents: antibiotics, disinfectants, and some cosmetics. The human body is diversely populated with microorganisms and undergoes constant changes under the influence of various factors, and its proper composition is extremely important for the proper functioning of the body. Given the above, it was decided that we would review current scientific research that explains the cause–effect relationship between the composition of microorganisms populating the human body and health, focusing on women’s health. As a result, an overview paper was prepared based on 109 scientific sources from 2009–2022. Special attention was paid to the most recent scientific studies of the last five years, which account for more than 75% of the cited sources.

Host and Microbiome Interplay Shapes the Vaginal Microenvironment

The female reproductive tract harbors a unique microbiome, especially the vagina. The human vaginal microbiome exhibits a low diversity and is dominated by Lactobacillus species, compared to the microbiome of other organs. The host and vaginal microbiome mutually coexist in the vaginal microenvironment. Host cells provide Lactobacillus glycogen as an energy source, and Lactobacillus produce lactic acid, which lowers vaginal pH thereby preventing growth of other bacteria. Bacterial vaginosis can modulate host immune systems, and is frequently associated with various aspects of disease, including sexually transmitted infection, gynecologic cancer, and poor pregnancy outcomes. Because of this, numerous studies focused on the impact of the vaginal microbiome on women`s health and disease. Furthermore, numerous epidemiologic studies also have demonstrated various host factors regulate the vaginal microbiome. The female reproductive tract undergoes constant fluctuations due to hormonal cycle, pregnancy, and other extrinsic factors. Depending on these fluctuations, the vaginal microbiome composition can shift temporally and dynamically. In this review, we highlight the current knowledge of how host factors modulate vaginal microbiome composition and how the vaginal microbiome contributes to maintaining homeostasis or inducing pathogenesis. A better understanding of relationship between host and vaginal microbiome could identify novel targets for diagnosis, prognosis, or treatment of microbiome-related diseases.

Potential pathobionts in vaginal microbiota are affected by fish oil and/or probiotics intervention in overweight and obese pregnant women

New means to stabilize the microbial balance during pregnancy could benefit maternal health. Our objectives were to investigate in overweight/obese pregnant women 1) the impact of long-chain polyunsaturated fatty acids (fish oil) and/or probiotics on the vaginal microbiota, 2) its relation to gestational diabetes mellitus (GDM) and 3) its interaction with vaginal active matrix metalloproteinase-8 (aMMP-8) and serum high sensitivity C-reactive protein (hsCRP) and phosphorylated insulin-like growth factor-binding protein-1 (phIGFBP-1), IGFBP-1 and aMMP-8. The women were allocated to fish oil + placebo, probiotics + placebo, fish oil + probiotics and placebo + placebo-groups, from early pregnancy onwards (fish oil: 1.9 g docosahexaenoic acid and 0.22 g eicosapentaenoic acid; probiotics: Lacticaseibacillus rhamnosus HN001 (formerly Lactobacillus rhamnosus HN001) and Bifidobacterium animalis ssp. lactis 420, 10¹⁰ colony-forming units each). Vaginal and serum samples (early pregnancy, n = 112; late pregnancy, n = 116), were analyzed for vaginal microbiota using 16S rRNA gene amplicon sequencing and vaginal aMMP-8 and serum hsCRP, aMMP-8, phIGFBP-1 and IGFBP-1 by immunoassays. GDM was diagnosed from a 2-h 75 g OGTT. ClinicalTrials.gov, NCT01922791. The intervention exerted effects on many low-abundant bacteria. Compared to the placebo-group, there was a lower abundance of potential pathobionts, namely Ureaplasma urealyticum in the fish oil-group, Ureaplasma, U. urealyticum and Prevotella disiens in the probiotics-group, Dialister invisus and Prevotella timonensis in the fish oil + probiotics-group. Moreover, probiotics decreased the abundance of a few potential pathobionts during pregnancy. Many bacteria were related to GDM. The vaginal aMMP-8 level correlated significantly with α-diversity and inversely with two Lactobacillus species. Dietary interventions, especially probiotics, may have beneficial effects on the vaginal microbiota during pregnancy.

Probiotics Properties: A Focus on Pregnancy Outcomes

A healthy microbiome plays an important role in the prevention of illness and maintenance of overall health, including reproductive health. Although the therapeutic advantages of probiotics have been shown to run across multiple organ systems, their role in pregnancy is not well explored. The aim of this review is to highlight the potential advantages and adverse effects of probiotics in pregnancy. Data were collected from the literature over the past decade using PubMed, Medline, Google Scholar, Ovid, Scopus, and Science Direct. A total of 40 articles were utilized in this review. Collected data indicated that prenatal and post-natal supplementation with lactobacilli alone or lactobacilli with Bifidobacterium spp. seems to be protective. Probiotics may improve insulin resistance and consequently reduce the risk of gestational diabetes. Probiotics may also reduce anxiety and depression by influencing brain activity. Additionally, they interfere with vaginal flora to make it friendlier to beneficial bacteria, and enhance anti-inflammatory or reduce pro-inflammatory cytokines. They may also decrease eczema in breastfed infants and prevent allergic reactions by downregulating Th2 responses to specific allergens from mid to late gestation. Leveraging the cervicovaginal microbiota could promote a number of positive pregnancy-related health outcomes. Caution should be exercised in the selection, dosing, and monitoring of probiotics administration. More comprehensive randomized clinical trials are needed to reach a more meaningful evidence-based clinical knowledge.

Healthy Vaginal Microbiota and Influence of Probiotics Across the Female Life Span

Vaginal microbiota plays a central role in women’s health and reproduction. Vaginal microbiota is dynamic and shaped by hormonal shifts in each stage of a woman’s life from pre-puberty to postmenopause. Current research has mainly focused on vaginal bacterial and fungal members of the community and emphasized their role in disease. However, the impact of balanced vaginal microbiota on health and its interaction with the host is yet poorly understood. High abundance of vaginal lactobacilli is most strongly associated with health, but the concept of health may vary as vaginal dysbiosis may be asymptomatic. Furthermore, there is a lot of variation between ethnic groups in terms of dominating vaginal bacteria. Probiotic lactobacilli could be a safe and natural means to balance and maintain healthy vaginal microbiota. Research evidence is accumulating on their role in supporting women’s health throughout life. This review describes the current literature on vaginal microbiota, the major factors affecting its composition, and how the communities change in different life stages. Furthermore, we focused on reviewing available literature on probiotics and their impact on vaginal microbiota and health.

Myo-inositol nutritional supplement for prevention of gestational diabetes (EMmY): a randomised, placebo-controlled, double-blind pilot trial with nested qualitative study

OBJECTIVES

To determine the feasibility and acceptability of conducting a randomised trial on the effects of myo-inositol in preventing gestational diabetes in high-risk pregnant women.

DESIGN

A multicentre, double-blind, placebo-controlled, pilot randomised trial with nested qualitative evaluation.

SETTING

Five inner city UK National Health Service hospitals PARTICIPANTS: Multiethnic pregnant women at 12⁺⁰ and 15⁺⁶ weeks' gestation with risk factors for gestational diabetes.

INTERVENTIONS

2 g of myo-inositol or placebo, both included 200 µg folic acid, twice daily until delivery.

PRIMARY OUTCOME MEASURES

Rates of recruitment, randomisation, adherence and follow-up.

SECONDARY OUTCOME MEASURES

Glycaemic indices (including homoeostatic model assessment-insulin resistance HOMA-IR), gestational diabetes (diagnosed using oral glucose tolerance test at 28 weeks and by delivery), maternal, perinatal outcomes, acceptability of intervention and costs.

RESULTS

Of the 1326 women screened, 58% (773/1326) were potentially eligible, and 27% (205/773) were recruited. We randomised 97% (198/205) of all recruited women (99 each in intervention and placebo arms) and ascertained outcomes in 90% of women (178/198) by delivery. The mean adherence was 52% (SD 44) at 28 weeks' and 34% (SD 41) at 36 weeks' gestation. HOMA-IR and serum insulin levels were lower in the myo-inositol vs placebo arm (mean difference -0.6, 95% CI -1.2 to 0.0 and -2.69, 95% CI -5.26 to -0.18, respectively). The study procedures were acceptable to women and healthcare professionals. Women who perceived themselves at high risk of gestational diabetes were more likely to participate and adhere to the intervention. The powder form of myo-inositol and placebo, along with nausea in pregnancy were key barriers to adherence.

CONCLUSIONS

A future trial on myo-inositol versus placebo to prevent gestational diabetes is feasible. The intervention will need to be delivered in a non-powder form to improve adherence. There is a signal for efficacy in reducing insulin resistance in pregnancy with myo-inositol.

TRIAL REGISTRATION NUMBER

ISRCTN48872100.

Towards a deeper understanding of the vaginal microbiota

The human vaginal microbiota is a critical determinant of vaginal health. These communities live in close association with the vaginal epithelium and rely on host tissues for resources. Although often dominated by lactobacilli, the vaginal microbiota is also frequently composed of a collection of facultative and obligate anaerobes. The prevalence of these communities with a paucity of Lactobacillus species varies among women, and epidemiological studies have associated them with an increased risk of adverse health outcomes. The mechanisms that drive these associations have yet to be described in detail, with few studies establishing causative relationships. Here, we review our current understanding of the vaginal microbiota and its connection with host health. We centre our discussion around the biology of the vaginal microbiota when Lactobacillus species are dominant versus when they are not, including host factors that are implicated in shaping these microbial communities and the resulting adverse health outcomes. We discuss current approaches to modulate the vaginal microbiota, including probiotics and vaginal microbiome transplants, and argue that new model systems of the cervicovaginal environment that incorporate the vaginal microbiota are needed to progress from association to mechanism and this will prove invaluable for future research.

Is prenatal diet associated with the composition of the vaginal microbiome?

BACKGROUND

The vaginal microbiome has been associated with adverse pregnancy outcomes, but information on the impact of diet on microbiome composition is largely unexamined.

OBJECTIVE

To estimate the association between prenatal diet and vaginal microbiota composition overall and by race.

METHODS

We leveraged a racially diverse prenatal cohort of North Carolina women enrolled between 1995 and 2001 to conduct this analysis using cross-sectional data. Women completed food frequency questionnaires about diet in the previous 3 months and foods were categorised into subgroups: fruits, vegetables, nuts/seeds, whole grains, low-fat dairy, sweetened beverages and red meat. We additionally assessed dietary vitamin D, fibre and yogurt consumption. Stored vaginal swabs collected in mid-pregnancy were sequenced using 16S taxonomic profiling. Women were categorised into three groups based on predominance of species: Lactobacillus iners, Lactobacillus miscellaneous and Bacterial Vaginosis (BV)-associated bacteria. Adjusted Poisson models with robust variance estimators were run to assess the risk of being in a specific vagitype compared to the referent. Race-stratified models (Black/White) were also run.

RESULTS

In this study of 634 women, higher consumption of dairy was associated with increased likelihood of membership in the L. crispatus group compared to the L. iners group in a dose-dependent manner (risk ratio quartile 4 vs. 1: 2.01, 95% confidence interval 1.36, 2.95). Increased intake of fruit, vitamin D, fibre and yogurt was also associated with increased likelihood of membership in L. crispatus compared to L. iners, but only among black women. Statistical heterogeneity was only detected for fibre intake. There were no detected associations between any other food groups or risk of membership in the BV group.

CONCLUSIONS

Higher consumption of low-fat dairy was associated with increased likelihood of membership in a beneficial vagitype, potentially driven by probiotics.

The emerging potential of microbiome transplantation on human health interventions

The human microbiome has been the subject of intense research over the past few decades, in particular as a promising area for new clinical interventions. The microbiota colonizing the different body surfaces are of benefit for multiple physiological and metabolic processes of the human host and increasing evidence suggests an association between disturbances in the composition and functionality of the microbiota and several pathological conditions. This has provided a rationale for beneficial modulation of the microbiome. One approach being explored for modulating the microbiota in diseased individuals is transferring microbiota or microbiota constituents from healthy donors via microbiome transplantation. The great success of fecal microbiome transplantation for the treatment of Clostridioides difficile infections has encouraged the application of this procedure for the treatment of other diseases such as vaginal disorders via transplantation of vaginal microbiota, or of skin pathologies via the transplantation of skin microbiota. Microbiome modulation could even become a novel strategy for improving the efficacy of cancer therapies. This review discusses the principle, advantages and limitations of microbiome transplantation as well as different clinical contexts where microbiome transplantation has been applied.

Effects of Pro/Prebiotics Alone over Pro/Prebiotics Combined with Conventional Antibiotic Therapy to Treat Bacterial Vaginosis: A Systematic Review

BACKGROUND

Bacterial vaginosis (BV), caused by an imbalance in the vaginal microbiota, can be treated and prevented by probiotics. Pregnant women with BV can experience premature labor and spontaneous abortions. Probiotics and prebiotics promote the proliferation of beneficial microorganisms, alter the composition of the vaginal microbiota, and prevent intravaginal infections in postmenopausal women. In addition to reducing infection symptoms, pre/probiotics can also help prevent vaginal infections.

MATERIALS AND METHODS

A systematic review was conducted on studies from 2010 to 2020 to determine the efficacy of pre/probiotics on the treatment of BV in pregnant and nonpregnant women. The databases Medline, Scopus, Embase, and Google Scholar were systematically searched using the following keywords: "bacterial vaginosis," "probiotics," "prebiotics," and "synbiotics."

RESULTS

A total of 1,871 articles were found in the initial search, and 24 clinical trials were considered eligible. In studies comparing the effects of pre/probiotics and placebos with or without antibiotic therapy in patients with BV, significant differences in clinical outcomes were observed. Probiotics reduced the levels of IL-1β and IL-6, as well as the overall Nugent score and Amsel's criteria for restitution of a balanced vaginal microbiota. In addition, probiotics can reduce the vaginal colonization of Group B streptococci among pregnant women. In subjects treated with probiotics, BV cure rates were higher than those in subjects treated with antibiotics. There were no additional adverse events.

CONCLUSION

Pre/probiotic regimens, when used for BV treatment, are usually safe and can exhibit long-term and short-term benefits. In order to prove the benefits of pre/probiotics in BV treatment, additional high-quality research is required.

Influence of Maternal Microbiome and Inflammatory Response in Preterm Birth: Recent Aspects of the Prevention of Preterm Birth

Preterm birth (PTB) is a global health issue and one of the most challenging problems affecting 12.9 million births worldwide. PTB is a multi-etiological disease and remains incompletely understood. The major cause of PTB is infection or inflammation and disruption of the vaginal microbiome, which affects the maternal immunologic response leading to PTB. The vaginal microbiome composition changes by a shift in the community are typically dominated by Lactobacillus during pregnancy. There are complex interactions between the maternal microbiome in pregnancy and the development of PTB, therefore, researchers have struggled to connect the maternal microbiome with the dysregulation of the maternal immune response in cases of PTB. The host microbiome affects alterations of the microorganisms with external stimuli such as disease, nutrition, immunity, and behavior. In this review, we discuss the complex association between the maternal microbiome and the risk of PTB and also focus on recent aspects of the prevention of PTB.

Number and quality of randomized controlled trials in obstetrics published in the top general medical and obstetrics and gynecology journals

BACKGROUND

There has been an increasing number of randomized controlled trials published in obstetrics and maternal-fetal medicine to reduce biases of treatment effect and to provide insights on the cause-effect of the relationship between treatment and outcomes.

OBJECTIVE

This study aimed to identify obstetrical randomized controlled trials published in top weekly general medical journals and monthly obstetrics and gynecology journals, to assess their quality in reporting and identify factors associated with publication in different journals.

STUDY DESIGN

The 4 weekly medical journals with the highest 2019 impact factor (New England Journal of Medicine, The Lancet, The Journal of the American Medical Association, and British Medical Journal), the top 4 monthly obstetrics and gynecology journals with obstetrics-related research (American Journal of Obstetrics & Gynecology, Ultrasound in Obstetrics & Gynecology, Obstetrics & Gynecology, and the British Journal of Obstetrics and Gynaecology), and the American Journal of Obstetrics & Gynecology Maternal-Fetal Medicine were searched for obstetrical randomized controlled trials in the years 2018 to 2020. The primary outcome was the number of obstetrical randomized controlled trials published in the obstetrics and gynecology journals vs the weekly medical journals and the percentage of trials published, overall and per journal. The secondary outcomes included the proportion of positive vs negative trials overall and per journal and the assessment of the study characteristics of published trials, including quality assessment criteria.

RESULTS

Of the 4024 original research articles published in the 9 journals during the 3-year study period, 1221 (30.3%) were randomized controlled trials, with 137 (11.2%) randomized controlled trials being in obstetrics (46 in 2018, 47 in 2019, and 44 studies in 2020). Furthermore, 33 (24.1%) were published in weekly medical journals, and 104 (75.9%) were published in obstetrics and gynecology journals. The percentage of obstetrical randomized controlled trials published ranged from 1.5% to 9.6% per journal. Overall, 34.3% of obstetrical trials were statistically significant or "positive" for the primary outcome. Notably, 24.8% of the trials were retrospectively registered after the enrollment of the first study patient. Trials published in the 4 weekly medical journals enrolled significantly more patients (1801 vs 180; P<.001), received more often funding from the federal government (78.8% vs 35.6%; P<.001), and were more likely to be multicenter (90.9% vs 42.3%; P<.001), non-United States based (69.7% vs 49.0%; P=.03), and double blinded (45.5% vs 18.3%; P=.003) than trials published in the obstetrics and gynecology journals. There was no difference in study type (noninferiority vs superiority) and trial quality characteristics, including pretrial registration, ethics approval statement, informed consent statement, and adherence to the Consolidated Standards of Reporting Trials guidelines statement between studies published in weekly medical journals and studies published in obstetrics and gynecology journals.

CONCLUSION

Approximately 45 trials in obstetrics are being published every year in the highest impact journals, with one-fourth being in the weekly medical journals and the remainder in the obstetrics and gynecology journals. Only about a third of published obstetrical trials are positive. Trials published in weekly medical journals are larger, more likely to be funded by the government, multicenter, international, and double blinded. Quality metrics are similar between weekly medical journals and obstetrics and gynecology journals.

Probiotic lactobacilli in formulas and hygiene products for the health of the urogenital tract

Lactobacilli are the predominant microorganisms of the healthy human vagina. A novel alternative for the prevention and treatment of female urogenital tract infections (UGTI) is the inclusion of these microorganisms as active pharmaceutical ingredients in probiotic formulas, and more recently in female hygienic products. Probiotics are defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” A list of requirements must be considered during the development of probiotic product/formula for the female urogenital tract (UGT). This review aims to resume the requirements, probiotic characteristics, and clinical trial applied to determine the effect of probiotic and potentially probiotic strains on different woman’s physiological and pathological conditions, and in preterm birth prevention. A revision of female hygienic products available in the world market is included, together with novel studies applying nanotechnology for Lactobacillus incorporation in hygienic products. Further studies and well‐designed clinical trials are urgently required to complement the current knowledge and applications of probiotics in the female UGT. The use of probiotic formulas and products will improve and restore the ecological equilibrium of the UGT microbiome to prevent and treat UGTI in women under different conditions.

The reproductive tract microbiota in pregnancy

The reproductive tract microbiota plays a crucial role in maintenance of normal pregnancy and influences reproductive outcomes. Microbe–host interactions in pregnancy remain poorly understood and their role in shaping immune modulation is still being uncovered. In this review, we describe the composition of vaginal microbial communities in the reproductive tract and their association with reproductive outcomes. We also consider strategies for manipulating microbiota composition by using live biotherapeutics, selective eradication of pathogenic bacteria with antibiotics and vaginal microbiota transplantation. Finally, future developments in this field and the need for mechanistic studies to explore the functional significance of reproductive tract microbial communities are highlighted.

Non-Lactobacillus dominance of the vagina is associated with reduced live birth rate following IVF/ICSI: a propensity score-matched cohort study

PURPOSE

Whether the dominant status of vaginal Lactobacillus is associated with IVF/ICSI outcomes.

METHODS

This is a propensity score-matched retrospective cohort study consists of 2285 women undergoing their first fresh autologous IVF cycles. We divided the patients into the Lactobacillus-dominant group and non-Lactobacillus-dominant group based on the abundance of Lactobacillus in Gram-stained vaginal smear examined by microscopy. We compared IVF outcomes between the two groups. We matched Lactobacillus-dominant women with non-Lactobacillus-dominant women by propensity score (PS) to reduce the impact of confounding factors. We evaluated the effect of vaginal Lactobacillus on live birth using univariate and multivariate analysis models. We also conducted interaction and stratified analyses.

RESULTS

Compare to the Lactobacillus-dominant group, the biochemical pregnancy rate (50.12% vs. 57.61%, P = 0.03), clinical pregnancy rate (40.98% vs. 50.82%, P < 0.01), and live birth rate (31.83% vs. 41.22%, P < 0.01) were significantly lower in the non-Lactobacillus-dominant group, the preclinical pregnancy loss rate (18.22% vs. 11.79%, P = 0.05) and preterm birth rate (33.09% vs. 21.59%, P = 0.02) were significantly higher in the non-Lactobacillus-dominant group. However, the miscarriage rate (18.86% vs. 15.67%, P = 0.40) and ectopic pregnancy rate (1.41% vs.1.64%, P = 0.78) were similar between the two groups. Loss dominance of Lactobacillus in the vagina was an independent risk factor for live birth (OR 0.66, 95% CI 0.50-0.88).

CONCLUSIONS

Loss dominance of Lactobacillus in the vagina negatively affects IVF outcomes by decreasing the chances of pregnancy and live birth, increasing risks of preclinical pregnancy loss and preterm birth.

Impact of maternal nutrition in viral infections during pregnancy

Other than being a physiological process, pregnancy is a condition characterized by major adaptations of maternal endocrine and metabolic homeostasis that are necessary to accommodate the fetoplacental unit. Unfortunately, all these systemic, cellular, and molecular changes in maternal physiology also make the mother and the fetus more prone to adverse outcomes, including numerous alterations arising from viral infections. Common infections during pregnancy that have long been recognized as congenitally and perinatally transmissible to newborns include toxoplasmosis, rubella, cytomegalovirus, and herpes simplex viruses (originally coined as ToRCH infections). In addition, enterovirus, parvovirus B19, hepatitis virus, varicella-zoster virus, human immunodeficiency virus, Zika and Dengue virus, and, more recently, coronavirus infections including Middle Eastern respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS) infections (especially the novel SARS-CoV-2 responsible for the ongoing COVID-19 pandemic), constitute relevant targets for current research on maternal-fetal interactions in viral infections during pregnancy. Appropriate maternal education from preconception to the early postnatal period is crucial to promote healthy pregnancies in general and to prevent and/or reduce the impact of viral infections in particular. Specifically, an adequate lifestyle based on proper nutrition plans and feeding interventions, whenever possible, might be crucial to reduce the risk of virus-related gestational diseases and accompanying complications in later life. Here we aim to provide an overview of the emerging literature addressing the impact of nutrition in the context of potentially harmful viral infections during pregnancy.

Probiotic Lacticaseibacillus rhamnosus GR-1 and Limosilactobacillus reuteri RC-14 as an Adjunctive Treatment for Bacterial Vaginosis Do Not Increase the Cure Rate in a Chinese Cohort: A Prospective, Parallel-Group, Randomized, Controlled Study

The purpose of this study was to evaluate the effectiveness of metronidazole and oral probiotics adjunct to metronidazole in the treatment of bacterial vaginosis (BV). One hundred and twenty-six Chinese women with BV were enrolled in this parallel, controlled trial, and were randomly assigned into two study arms: the metronidazole group, which was prescribed metronidazole vaginal suppositories for 7 days, and the adjunctive probiotic group, which received Lacticaseibacillus rhamnosus GR-1 and Limosilactobacillus reuteri RC-14 orally for 30 days as an adjunct to metronidazole. Clinical symptoms and Nugent scores at the initial visit, 30 days and 90 days were compared. There was no significant difference of the 30-day total cure rate between the adjunctive probiotic group (57.69%) and the metronidazole group (59.57%), with an odds ratio (OR) of 0.97 (95% confidence interval (CI), 0.70 to 1.35, p-value = 0.04), or of the 90-day total cure rate (36.54% vs. 48.94%, OR, 0.75; 95% CI, 0.47 to 1.19; p-value = 0.213). Also, no significant difference of the vaginal and faecal microbial diversity and structure between the two groups at 0, 30 or 90 days were shown based on 16S rRNA sequences. The probiotic species were rarely detected in either the vaginal microbiota or the faecal microbiota after administration which may revealed the cause of noneffective of oral probiotics. No serious adverse effects were reported in the trial. The study indicated that oral probiotic adjunctive treatment did not increase the cure rate of Chinese BV patients compared to metronidazole.

Cervicovaginal microbiome dynamics after taking oral probiotics

The vaginal microbiota is less complex than the gut microbiota, and the colonization of Lactobacillus in the female vagina is considered to be critical for reproductive health. Oral probiotics have been suggested as promising means to modulate vaginal homeostasis in the general population. In this study, 60 Chinese women were followed for over a year before, during, and after treatment with the probiotics Lactobacillus rhamnosus GR-1 and Lactobacillusreuteri RC-14. Shotgun metagenomic data of 1334 samples from multiple body sites did not support a colonization route of the probiotics from the oral cavity to the intestinal tract and then to the vagina. Our analyses enable the classification of the cervicovaginal microbiome into a stable state and a state of dysbiosis. The microbiome in the stable group steadily maintained a relatively high abundance of Lactobacilli over 1 year, which was not affected by probiotic intake, whereas in the dysbiosis group, the microbiota was more diverse and changed markedly over time. Data from a subset of the dysbiosis group suggests this subgroup possibly benefited from supplementation with the probiotics, indicating that probiotics supplementation can be prescribed for women in a subclinical microbiome setting of dysbiosis, providing opportunities for targeted and personalized microbiome reconstitution.

Maternal microbiome in preeclampsia pathophysiology and implications on offspring health

Preeclampsia is a devastating hypertensive pregnancy disorder that currently affects 2%–8% of pregnancies worldwide. It is associated with maternal and fetal mortality and morbidity and adverse health outcomes both in mom and offspring beyond pregnancy. The pathophysiology is not completely understood, and there are no approved therapies to specifically treat for the disease, with only few therapies approved to manage symptoms. Recent advances suggest that aberrations in the composition of the microbiome may play a role in the pathogenesis of various diseases including preeclampsia. The maternal and uteroplacental environments greatly influence the long‐term health outcomes of the offspring through developmental programming mechanisms. The current review summarizes recent developments on the role of the microbiome in adverse pregnancy outcomes with a focus on preeclampsia. It also discusses the potential role of the maternal microbiome in fetal programming; explores gut‐targeted therapeutics advancement and their implications in the treatment of preeclampsia.

Implications of the vaginal microbiome and potential restorative strategies on maternal health: a narrative review

The vaginal microbiome undergoes dramatic shifts before and throughout pregnancy. Although the genetic and environmental factors that regulate the vaginal microbiome have yet to be fully elucidated, high-throughput sequencing has provided an unprecedented opportunity to interrogate the vaginal microbiome as a potential source of next-generation therapeutics. Accumulating data demonstrates that vaginal health during pregnancy includes commensal bacteria such as Lactobacillus that serve to reduce pH and prevent pathogenic invasion. Vaginal microbes have been studied as contributors to several conditions occurring before and during pregnancy, and an emerging topic in women's health is finding ways to alter and restore the vaginal microbiome. Among these restorations, perhaps the most significant effect could be preterm labor (PTL) prevention. Since bacterial vaginosis (BV) is known to increase risk of PTL, and vaginal and oral probiotics are effective as supplemental treatments for BV prevention, a potential therapeutic benefit exists for pregnant women at risk of PTL. A new method of restoration, vaginal microbiome transplants (VMTs) involves transfer of one women's cervicovaginal secretions to another. New studies investigating recurrent BV will determine if VMTs can safely establish a healthy Lactobacillus-dominant vaginal microbiome. In most cases, caution must be taken in attributing a disease state and vaginal dysbiosis with a causal relationship, since the underlying reason for dysbiosis is usually unknown. This review focuses on the impact of vaginal microflora on maternal outcomes before and during pregnancy, including PTL, gestational diabetes, preeclampsia, and infertility. It then reviews the clinical evidence focused on vaginal restoration strategies, including VMTs.

[Effect of oral Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 on vaginal Group B Streptococcus colonization and vaginal microbiome in late pregnancy]

OBJECTIVE

To explore the effects of intervention with oral probiotic Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 on vaginal Group B Streptococcus (GBS) colonization, pregnancy outcome and vaginal microbiome in GBS-positive women in the third trimester of pregnancy.

METHODS

This study were conducted among 155 women in the third trimester of pregnancy with positive results of GBS culture in the Outpatient Department of Zhujiang Hospital from March to November, 2019. After excluding 32 patients who received lactobacillus intervention for less than 2 weeks or underwent postpartum GBS retesting, the women were divided into oral probiotics intervention group (60 cases) and non-intervention group (63 cases). According to the results of GBS retesting, the 60 women in the intervention group were divided into GBS-negative group (18 cases) and persistent GBS-positive group (42 cases). At the end of the intervention, the rates of negative GBS culture result were calculated and the pregnancy outcomes were compared. From 5 women randomly selected from the intervention group, samples of vaginal secretions were collected before and after the intervention for amplicon sequencing and bioinformatics analysis.

RESULTS

At the end of the intervention, the GBS-negative rate in the intervention group was 30% (18/60), as compared with 23% (3/13) in the non-intervention group. Probiotic intervention significantly reduced the incidence of premature rupture of membranes (P < 0.05) and reduced the use of antibiotics during pregnancy (P < 0.05). OTU analysis of the vaginal secretions suggested probiotic intervention decreased the total sequence number and GBS sequence number, increased the species composition, and significantly decreased GBS abundance (P < 0.05). Probiotics intervention also significantly decreased the species abundance of Enterococcus, Staphylococcus and Streptococcus in the vaginal flora (P < 0.05).

CONCLUSIONS

Intervention with oral probiotics can reduce vaginal GBS colonization in late pregnancy and improve the pregnancy outcome. Lactobacillus is capable of reducing the abundance of GBS and other pathogenic bacteria to improve the microbiome of vaginal flora.

Protocol for probiotic therapy vs placebo for preterm prelabour rupture of membranes to prolong pregnancy duration (Pro-PPROM) trial

BACKGROUND

Preterm prelabour rupture of membranes (PPROM) is a common preterm birth antecedent. Preterm infants experience increased adverse newborn outcome risks. Infection is a risk factor for early birth in PPROM. Current management is antibiotic therapy, antenatal corticosteroids and to plan delivery at 37 weeks gestation. The microbiota and probiotics are potentially protective and may improve outcomes.

AIMS

The primary aim is to evaluate whether oral probiotic therapy (Lactobacillus fermentum CECT5716) administered during PPROM between 24 and 34 weeks gestation prolongs pregnancy duration. The secondary aim is to evaluate maternal and neonatal outcomes.

MATERIALS AND METHODS

This is a pragmatic, multicentre, double-blind, placebo-controlled randomised controlled trial in Australia. The population will be women with a singleton pregnancy and PPROM less than 34 weeks gestation. The intervention will be an oral probiotic therapy compared with a placebo control. The primary outcome will be the proportion of women still pregnant at seven days following PPROM. One-to-one randomisation will occur within 24 h of PPROM. The trial is powered (80%, alpha = 0.05) to detect an absolute percentage increase in the primary outcome of 30%, (from expected rate of 20% up to 50%).

DISCUSSION

This trial will provide evidence for the effectiveness of the probiotic in prolonging pregnancy duration. Findings will inform the feasibility of a larger trial to examine the effect of oral probiotics on clinically important maternal and neonatal outcomes in PPROM.

Menstrual symptoms and risk of preterm birth: A population-based longitudinal study

OBJECTIVES

To examine the prospective association between menstrual symptoms before pregnancy and preterm birth.

METHODS

Secondary analysis of data from 14 247 young Australian women born between 1973 and 1978 who participated in a longitudinal, population-based cohort study between 1996 and 2015. Women were first surveyed at 18-23 years, and seven waves of data were collected at roughly three-yearly intervals. At each survey, women were asked about "severe period pain," "heavy periods," and "irregular periods" within the last 12 months. From 2009 onward, information on their children was collected, including birth dates and preterm birth (<37 weeks). Logistic regression using generalized estimating equations was used to examine prospective associations between self-reported menstrual symptoms before pregnancy and risk of preterm birth.

RESULTS

Data from 6615 mothers who had 12 337 live singleton births were available for analysis. Among all births, women reporting severe period pain (adjusted odds ratio [aOR] 1.34 [95% CI 1.10-1.62]) or heavy periods (1.25 [1.02-1.53]) before pregnancy had higher odds of preterm birth. However, in analyses stratified by birth order, only severe period pain (2.05 [1.41-2.99]), heavy periods (1.77 [1.23-2.55]), or irregular periods (1.58 [1.10-2.28]) before a second or subsequent birth were associated with an increased risk of preterm birth.

CONCLUSIONS

Severe period pain, heavy periods, and irregular periods before a second or subsequent birth may be associated with preterm birth.

The pregnancy microbiome and preterm birth

Preterm birth is a global health concern and continues to contribute to substantial neonatal morbidity and mortality despite advances in obstetric and neonatal care. The underlying aetiology is multi-factorial and remains incompletely understood. In this review, the complex interplay between the vaginal microbiome in pregnancy and its association with preterm birth is discussed in depth. Advances in the study of bacteriology and an improved understanding of the human microbiome have seen an improved awareness of the vaginal microbiota in both health and in disease.

Use of a vaginal probiotic suppository and antibiotics to influence the composition of the endometrial microbiota

The aim of the present study was to determine the status of the endometrial microbiota in patients with repeated implantation failure (RIF) and to assess treatment strategies for nondominant Lactobacillus (NLD) cases. A total of 392 patients with RIF were enrolled in this prospective cohort study (UMIN-CTR 000038582) and underwent endometrial microbiota analysis. Patients diagnosed with NLD were treated with a combination of oral and vaginal probiotics or oral prebiotics and antibiotics. The outcome was evaluated through re-analysis of the endometrial microbiota following treatment, and the results are presented as cure rates. NLD represented 44.9 % of the total endometrial microbiota in patients with RIF. The most commonly detected bacterium was Gardnerella vaginalis. The cure rates in the oral probiotics + oral prebiotics, antibiotics, oral probiotics + oral prebiotics + antibiotics, vaginal probiotic suppository, and vaginal probiotic suppository + antibiotics groups were 29.5, 33.33, 33.33, 43.6, and 78.6 %, respectively. Significant improvements were noted in the vaginal probiotic suppository + antibiotics group. Moreover, we revealed that approximately half of patients with RIF had NLD. Thus, the combination of a vaginal probiotic suppository and antibiotics may represent an effective treatment for NLD cases.

Laboratory Analysis Techniques for the Perinatal Microbiome: Implications for Studies of Probiotic Interventions

The microbiome is composed of many organisms and is impacted by an intricate exchange between genetics and environmental factors. The perinatal microbiome influences both the developing fetus and the pregnant person. The purpose of this article is to describe the tests that are currently available for laboratory analysis of the perinatal microbiome in relationship to probiotic interventions. This article focuses on the bacterial component of the microbiome. Although adverse outcomes associated with the perinatal microbiome have been studied, a comprehensive understanding of the physiologic perinatal microbiome is still emerging. Early efforts to influence the perinatal microbiome through probiotics are currently under investigation. Unique terminology is defined, and the microbial composition of perinatal microbiota is summarized. The outcomes of studies of antenatal probiotics are summarized. Microbiome testing and analysis are defined and compared. Implications for perinatal care and probiotics research are presented.

Dysbiosis and Prematurity: Is There a Role for Probiotics?

Healthy microbiota is a critical mediator in maintaining health and it is supposed that dysbiosis could have a role in the pathogenesis of a number of diseases. Evidence supports the hypothesis that maternal dysbiosis could act as a trigger for preterm birth; aberrant colonization of preterm infant gut might have a role in feeding intolerance and pathogenesis of necrotizing enterocolitis. Despite several clinical trials and meta-analyses, it is still not clear if modulation of maternal and neonatal microbiota with probiotic supplementation decreases the risk of preterm birth and its complications.