Prospective observational study of vaginal microbiota pre- and post-rescue cervical cerclage

Nomogram-based risk assessment for emergency cervical cerclage failure in patients with cervical insufficiency

Background

Cervical insufficiency can lead to preterm birth and neonatal mortality. Emergency cervical cerclage is a surgical intervention aimed at preventing preterm birth in patients with cervical insufficiency. However, some patients may experience cerclage failure. This study aimed to identify the risk factors associated with cerclage failure and develop a predictive nomogram model for patients with cervical insufficiency undergoing emergency cervical cerclage.

Methods

Data of 200 patients who underwent emergency cervical cerclage for cervical insufficiency were retrospectively analyzed. Patients were categorized into successful and failed groups based on their ability to take the infant home. Univariate and multivariate logistic regression analyses were performed to identify risk factors for cerclage failure. A nomogram model was developed based on multivariate logistic regression results, and its performance was assessed using receiver operating characteristic curves, calibration plots, and decision curve analysis (DCA).

Results

Univariate logistic regression analysis identified 11 potential risk factors for cerclage failure, including the presence of polycystic ovary syndrome (PCOS), vaginitis, cervical dilation, preoperative C-reactive protein, routine vaginal lavage after cervical cerclage, delivery, gestational age, extended days, chorioamnionitis, intrauterine infection, cervical laceration, and premature rupture of membranes. Multivariate logistic regression analysis revealed that PCOS, cervical dilation after cervical cerclage were independent risk factors for cerclage failure while routine vaginal lavage was a protective factor against failure. The nomogram predictive model demonstrated an area under the curve value of 0.975, indicating excellent discriminatory ability. The calibration plot showed good consistency between the nomogram predictions and actual observations. DCA demonstrated the strong clinical applicability of the nomogram.

Conclusions

This study successfully identified risk factors associated with emergency cervical cerclage failure in patients with cervical insufficiency and developed a predictive nomogram model. This model can assist clinicians in making informed decisions and accurately predicting the risk of cerclage failure in these patients.

Investigating into microbiota in the uterine cavity of the unexplained recurrent pregnancy loss patients in early pregnancy

INTRODUCTION

The majority of unexplained recurrent pregnancy loss (URPL) cases have been attributed to immune abnormalities. Inappropriate changes in microbiota could lead to immune disorders. However, the specific role of uterine cavity microbiota in URPL remains unclear, and only a limited number of related studies are available for reference.

METHODS

We utilized double-lumen embryo transfer tubes to collect uterine cavity fluid samples from pregnant women in their first trimester. Subsequently, we conducted 16S rRNA sequencing to analyze the composition and abundance of the microbiota in these samples.

RESULTS

For this study, we enlisted 10 cases of URPL and 28 cases of induced miscarriages during early pregnancy. Microbial communities were detected in all samples of the URPL group (100 %, n = 10), whereas none were found in the control group (0 %, n = 28). Among the identified microbes, Lactobacillus and Curvibacter were the two most dominant species. The abundance of Curvibacter is correlated with the number of NK cells in peripheral blood (r = -0.759, P = 0.018).

DISCUSSION

This study revealed that during early pregnancy, Lactobacillus and Curvibacter were the predominant colonizers in the uterine cavity of URPL patients and were associated with URPL. Consequently, alterations in the dominant microbiota may lead to adverse pregnancy outcomes.

Cerclage prevents ascending intrauterine infection in pregnant mice

BACKGROUND

The treatment for cervical insufficiency is cerclage surgery. Although cerclage is a common therapy for prevention of preterm birth, there is no consensus about its mechanism of efficacy. Previous investigators have hypothesized that cerclage prevents preterm birth by improving the cervical barrier to ascending infection. However, this hypothesis is difficult to study in human pregnancy.

OBJECTIVE

In a mouse model of ascending infection, we hypothesized that a cerclage improves the cervical barrier leading to decreased ascending intrauterine infection and inflammation. An abdominal cerclage was studied because a vaginal cerclage is not feasible in mice.

STUDY DESIGN

To perform an abdominal cerclage, laparotomy was performed on timed, pregnant C57BL/6 mice on gestational day 10 (E10). A 6-0 silk suture was placed around the cervix just below the junction of the 2 uterine horns. Sham controls received the same surgery, but no cerclage was placed. To track ascending infection nonpathogenic E coli K12 was genetically modified to express bioluminescence. On E15, bioluminescent E coli K12 (20 μL of 1×109 bacteria) was inoculated into the vagina. Whole-body bioluminescence imaging was performed 0.5 hours and 24 hours after inoculation. To assess intrauterine inflammation, pathogenic E coli K1 was used. On E15, bacterial inoculums of E coli K1 (20 μL of 1×104 bacteria) were vaginally administered. Samples of uterus, placenta, and fetal membranes were collected 24 hours after inoculation. Gene expression of inflammation-related proteins was compared between 3 groups: (1) sham control surgery + inoculation of phosphate-buffered saline (PBS), (2) sham control surgery + inoculation of E coli K1, and (3) cerclage surgery + inoculation of E coli K1.

RESULTS

Abdominal cerclage was well tolerated. No cases of preterm birth were seen following abdominal cerclage. Whole-body bioluminescent imaging performed 0.5 hours post inoculation showed a strong luminescence signal in the vaginal region of mice in both control and experimental groups indicating successful bacteria inoculation. Twenty-four hours after inoculation, bioluminescent signal was seen ascending into the uterine horns in all control mice. However, in mice with abdominal cerclages, no bioluminescent signal was seen after 24 hours. When the reproductive tissues were imaged separately in control mice, strong bioluminescence signal was detected in the placenta, fetal membranes, and uterus. Gene expression studies showed that cerclage significantly decreased the expression of inflammatory proteins induced by E coli K1 in the uterus, placenta, and fetal membranes.

CONCLUSION

In this mouse model of ascending intrauterine infection, abdominal cerclage prevented ascending infection of E coli. In addition, abdominal cerclage prevented expression of inflammatory cytokines in the uterus, placenta, and membranes of mice. The study provides evidence for a potential mechanism of cerclage success in human pregnancy.

Preterm birth, a consequence of immune deviation mediated hyperinflammation

Preterm birth represents a multifaceted syndrome with intricacies still present in our comprehension of its etiology. In the context of a semi-allograft, the prosperity from implantation to pregnancy to delivery hinges on the establishment of a favorable maternal-fetal immune microenvironment and a successful trilogy of immune activation, immune tolerance and then immune activation transitions. The occurrence of spontaneous preterm birth could be related to abnormalities within the immune trilogy, stemming from deviation in maternal and fetal immunity. These immune deviations, characterized by insufficient immune tolerance and early immune activation, ultimately culminated in an unsustainable pregnancy. In this review, we accentuated the role of both innate and adaptive immune reason in promoting spontaneous preterm birth, reviewed the risk of preterm birth from vaginal microbiome mediated by immune changes and the potential of vaginal microbiomes and metabolites as a new predictive marker, and discuss the changes in the role of progesterone and its interaction with immune cells in a preterm birth population. Our objective was to contribute to the growing body of knowledge in the field, shedding light on the immunologic reason of spontaneous preterm birth and effective biomarkers for early prediction, providing a roadmap for forthcoming investigations.

Analysis of Vaginal Microbiota Variations in the Third Trimester of Pregnancy and Their Correlation with Preterm Birth: A Case-Control Study

This study conducted a detailed analysis of the vaginal microbiota in pregnant women to explore its correlation with preterm birth (PTB) outcomes. The primary objective was to identify microbial variations associated with increased PTB risk. Secondary objectives included investigating how changes in microbial composition relate to the local immune environment and PTB. Utilizing a retrospective case-control design, the study involved pregnant women with liveborn infants between 2019 and 2023. In total, 89 women who delivered preterm and 106 term deliveries were included. Data collection focused on third-trimester vaginal cultures. Statistically significant differences were observed between the preterm and full-term groups in several areas. The median white blood cell count (10.2 × 103/mm3 vs. 7.6 × 103/mm3, p = 0.009) and neutrophil count (7.2 × 103/mm3 vs. 5.1 × 103/mm3, p < 0.001) were higher in the preterm group. Vaginal pH was also elevated in preterm births (5.6 vs. 4.4, p < 0.001), with a higher prevalence of bacterial vaginosis (29.2% vs. 12.3%, p = 0.001) as indicated by the Nugent Score. The study noted a significant association of PTB with the presence of Candida spp. (OR = 1.84, p = 0.018), Gardnerella vaginalis (OR = 2.29, p = 0.003), Mycoplasma hominis (OR = 1.97, p = 0.007), and Ureaplasma urealyticum (OR = 2.43, p = 0.001). Conversely, a reduction in Lactobacillus spp. correlated with a decreased PTB risk (OR = 0.46, p = 0.001). The study provides compelling evidence that specific vaginal microbiota components, particularly certain pathogenic bacteria and an altered Lactobacillus profile, are significantly associated with PTB risk. These findings highlight the potential of targeting microbial factors in strategies aimed at reducing PTB rates. Further research is necessary to fully understand the complex interplay between microbial dynamics, host immunity, and PTB outcomes.

Abnormal Vaginal Flora in Cervical Incompetence Patients - the Impact of Escherichia coli

The purpose of this study was to investigate the prevalence of abnormal vaginal colonization in women with cervical incompetence and to analyze its impact on obstetric and neonatal outcomes and placental inflammation. We included 138 pregnant women diagnosed with cervical incompetence and delivered in our hospital. Patients with major fetal anomaly or multifetal pregnancy were excluded. Upper vaginal culture was performed on the day of admission. A total of 60.9% (84/138) of cervical incompetence patients had abnormal bacterial colonization, and Escherichia coli (E. coli) was the most common colonized pathogen (33.3%, 46/138). The positive vaginal E. coli group had a higher rate of prior preterm birth (p = 0.021) and an earlier gestational age at which cervical incompetence was diagnosed (p < 0.01) than the negative group. The positive vaginal E. coli group had higher rates of clinical chorioamnionitis (p = 0.008) and subchorionic microabscess of the placenta (p = 0.012). Importantly, the positive vaginal E. coli group had significantly higher rates of proven early-onset neonatal sepsis (EONS) (p = 0.046), necrotizing enterocolitis (NEC) (p = 0.001), and neonatal mortality (p = 0.023). After adjusting for confounding variables, the positive vaginal E. coli group had significantly higher risk for proven EONS (OR: 3.853, 95% CI: 1.056-14.055) and NEC (OR: 12.410, 95% CI: 1.290-119.351). In conclusion, E. coli was the most common vaginal microorganism isolated from patients with cervical incompetence. Maternal vaginal E. coli colonization was associated with adverse neonatal outcomes including proven EONS and NEC and was characterized by a higher rate of placental subchorionic microabscess.

Degree of expression of inflammatory proteins in the amniotic cavity, but not prior obstetric history, is associated with the risk severity for spontaneous preterm birth after rescue cerclage for cervical insufficiency

PROBLEM

To examine whether the severity of spontaneous preterm birth (SPTB) risk after rescue cerclage for acute cervical insufficiency (CI) is linked to the degree of inflammatory response in the amniotic fluid (AF) based on the concentrations of various inflammatory proteins and prior obstetric history.

METHOD OF STUDY

We conducted a retrospective cohort study of 65 singleton pregnant women (17-25 weeks) who underwent rescue cerclage following the diagnosis of acute CI and were subjected to amniocentesis. EN-RAGE, IL-6, IL-8, and IP-10 as inflammatory mediators and kallistatin, MMP-2/8, and uPA as extracellular matrix remodeling-related molecules were assayed in the AF using ELISA. The level of each inflammatory mediator was divided into quartiles.

RESULTS

Intra-amniotic inflammation (IAI; AF IL-6 level ≥2.6 ng/mL) was independently associated with SPTB after cerclage placement. The odds of SPTB at < 32 weeks, even after adjusting for confounders, increased significantly with each increasing quartile of baseline AF levels for each inflammatory mediator (p for trend < .05). Kaplan-Meier survival curves showed that the cerclage-to-delivery intervals were significantly shorter as the quartiles of AF EN-RAGE and MMP-8 increased (log-rank test, p < .01 each). Neither previous term birth nor prior PTB was associated with SPTB risk or cerclage-to-delivery interval after rescue cerclage. Multiparous women who experience CI after term birth showed significantly elevated levels of MMP-8 and reduced kallistatin levels in the AF.

CONCLUSION

In patients with CI, SPTB risk (especially risk severity) after rescue cerclage is associated with the degree of the inflammatory response in AF as well as the presence of IAI but not with prior obstetric history.

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.

Immune-checkpoint proteins, cytokines, and microbiome impact on patients with cervical insufficiency and preterm birth

Background

Microenvironmental factors, including microbe-induced inflammation and immune-checkpoint proteins that modulate immune cells have been associated with both cervical insufficiency and preterm delivery. These factors are incompletely understood. This study aimed to explore and compare interactions among microbiome and inflammatory factors, such as cytokines and immune-checkpoint proteins, in patients with cervical insufficiency and preterm birth. In particular, factors related to predicting preterm birth were identified and the performance of the combination of these factors was evaluated.

Methods

A total of 220 swab samples from 110 pregnant women, prospectively recruited at the High-Risk Maternal Neonatal Intensive Care Center, were collected between February 2020 and March 2021. This study included 63 patients with cervical insufficiency receiving cerclage and 47 control participants. Endo- and exocervical swabs and fluids were collected simultaneously. Shotgun metagenomic sequencing for the microbiome and the measurement of 34 immune-checkpoint proteins and inflammatory cytokines were performed.

Results

First, we demonstrated that immune-checkpoint proteins, the key immune-regulatory molecules, could be measured in endocervical and exocervical samples. Secondly, we identified significantly different microenvironments in cervical insufficiency and preterm birth, with precise cervical locations, to provide information about practically useful cervical locations in clinical settings. Finally, the presence of Moraxella osloensis (odds ratio = 14.785; P = 0.037) and chemokine CC motif ligand 2 levels higher than 73 pg/mL (odds ratio = 40.049; P = 0.005) in endocervical samples were associated with preterm birth. Combining M. osloensis and chemokine CC motif ligand 2 yielded excellent performance for predicting preterm birth (area under the receiver operating characteristic curve = 0.846, 95% confidence interval = 0.733-0.925).

Conclusion

Multiple relationships between microbiomes, immune-checkpoint proteins, and inflammatory cytokines in the cervical microenvironment were identified. We focus on these factors to aid in the comprehensive understanding and therapeutic modulation of local microbial and immunologic compositions for the management of cervical insufficiency and preterm birth.

The efficacy of emergency cervical cerclage in singleton and twin pregnancies: a systematic review with meta-analysis

OBJECTIVE

An emergency (rescue) cervical cerclage can be offered to pregnant women presenting with dilatation and prolapsed membranes in the second trimester of pregnancy because of cervical insufficiency. This study aimed to investigate the effectiveness of an emergency cerclage in both singleton and twin pregnancies in the prevention of extreme premature birth.

DATA SOURCES

We performed a systematic literature search in PubMed and Embase from inception to June 2022 for transvaginal cervical emergency cerclages.

STUDY ELIGIBILITY CRITERIA

All studies on transvaginal cervical emergency cerclages with at least 5 patients and reporting survival were included.

METHODS

Included studies were assessed for quality and risk of bias with an adjusted Quality In Prognosis Studies tool. Random-effects meta-analyses and meta-regressions were performed for the primary outcome: survival.

RESULTS

Our search yielded 96 studies, incorporating 3239 women, including 14 studies with an expectant management control group, incorporating 746 women. Overall survival after cervical emergency cerclage was 74%, with a fetal survival of 88% and neonatal survival of 90%. Singleton and twin pregnancies showed similar survival, with a pregnancy prolongation of 52 and 37 days and a gestational age at delivery of 30 and 28 weeks, respectively. Meta-regression analyses indicated a significant inverse association between mean gestational age at diagnosis and pregnancy prolongation and no association between dilatation or gestational age at diagnosis and gestational age at delivery. Compared with expectant management, emergency cerclage significantly increased overall survival by 43%, fetal survival by 17% and neonatal survival by 22%, along with a significant pregnancy prolongation of 37 days and reduction in delivery at <28 weeks of gestation of 55%. These effects were more profound in singleton pregnancies than in twin pregnancies.

CONCLUSION

This systematic review indicates that, in pregnancies threatened by extreme premature birth because of cervical insufficiency, emergency cerclage leads to significantly higher survival, accompanied by significant pregnancy prolongation and reduction in delivery at <28 weeks of gestation, compared with expectant management. The mean gestational age at delivery was 30 weeks, independent of dilatation or gestational age at diagnosis. Survival was similar for singleton and twin pregnancies, implying that emergency cerclage should be considered in both.

Growing threat of extended-spectrum β-lactamase-producing Enterobacteriaceae colonisation in high-risk pregnancies: A cross-sectional study

OBJECTIVE

To investigate the epidemiological changes in extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) vaginal colonisation in pregnant women deemed at high risk, and to identify independent risk factors. Further, the differences in perinatal outcomes according to maternal ESBL-E vaginal colonisation were analysed.

DESIGN

Cross-sectional study.

SETTING

Republic of Korea.

POPULATION

A cohort of 1460 women admitted to our high-risk pregnancy unit between 14⁺⁰ and 36⁺⁶  weeks of gestation.

METHODS

The trend of changes in the association of ESBL-E vaginal colonisation from January 2010 to December 2020 was analysed. The main outcomes were analysed over the study period and ESBL-E vaginal colonisation.

MAIN OUTCOME MEASURES

Rate of ESBL-E vaginal colonisation, risk factors for ESBL-E vaginal colonisation and perinatal outcomes.

RESULTS

The ESBL-E vaginal colonisation rate has tended to increase over the past 11 years, which was attributed to a significantly higher proportion of ESBL-producing Escherichia coli. Cerclage (RR 3.7, 95% CI 2.19-6.40) and prior antibiotic treatment (RR 4.0, 95% CI 2.44-6.54) were found as independent risk factors for ESBL-E vaginal colonisation. Earlier gestational age at delivery and higher proven early-onset neonatal sepsis (EONS) rate were observed in the ESBL-E-positive group.

CONCLUSIONS

The ESBL-E vaginal colonisation rate in pregnant patients at high risk has increased over the past decade, and the independent risk factors for colonisation are cerclage and prior antibiotic treatment. Additionally, maternal ESBL-E vaginal colonisation is associated with higher rates of proven EONS.

Vaginal Microbiota and Pregnancy Outcomes of Patients with Conization Histories

Background: One of the major risks of preterm birth is a history of conization. However, the risk of infection due to this procedure is still not well known. Using next-generation sequencing, we aimed to reveal the influence of conization on vaginal microbiota in the following pregnancy, and their relationship between spontaneous preterm birth (sPTB). Methods: We conducted a prospective cohort study including 133 pregnant patients, of whom 25 had conization histories and 108 did not. Vaginal microbiome samples were collected using swabs by an obstetrician upon inclusion in the first trimester and during delivery. V1-V2 of the 16S rRNA gene were amplified and analyzed to identify the bacteria. Results: The conization group had a significantly lower delivery week (34 weeks vs. 36 weeks, p = 0.003) and higher sPTB rate (64% vs. 8.3%, p ≤ 0.001) than the control group. In the conization group, alpha (Chao 1, p = 0.02; phylogenetic diversity whole tree, p = 0.04) and beta diversity (permutational multivariate analysis of variance test, p = 0.04) of the vaginal microbiota was significantly higher during delivery in patients who delivered preterm than in those who delivered term. Community-state type IV in the first trimester was significantly associated with sPTB (overall odds ratio 3.80, 95% confidence interval 1.33-10.8, p = 0.01). Conclusions: Conization is a risk factor for sPTB. Increased risk of sPTB in patients after conization may belong to the vulnerable defense mechanism, due to the shortened cervix and decreased cervical mucus.

Effects of emergency/nonemergency cervical cerclage on the vaginal microbiome of pregnant women with cervical incompetence

Background

Evaluation of the therapeutic effects of cerclage on preterm birth (PTB) caused by cervical incompetence remains challenging. The vaginal microbiome is associated with preterm births. Thus, this study aimed to analyse the vaginal microbiota of patients with cervical incompetence, explore the relationship between the composition of the vaginal microbiota before cervical cerclage and at term delivery, and assess the effect of cervical cerclage on the vaginal microbiota.

Methods

Patients (n = 30) underwent cerclage performed by the same surgical team. Vaginal swabs were obtained pre-surgery and seven days post-surgery. A gestational age-matched cohort of healthy pregnant women (n = 20) (no particular abnormality during pregnancy, delivery at term) was used as the control group and sampled during a comparable pregnancy. All collected vaginal swabs were analysed by 16S rRNA gene sequencing.

Results

When comparing the healthy control and cervical cerclage groups, the enriched microorganism in the healthy controls was G. Scardovia, and the enriched microorganism of the cerclage was G. Streptococcus. α diversity was significantly increased in patients who received cerclage with preterm delivery compared with those with full-term delivery, and the enriched microorganism was F. Enterococcus. A comparison before and after nonemergency cerclage suggested that the enriched microorganisms were G. Lactobacillus and F. Lactobacillaceae before surgery. After nonemergency cerclage, the enriched microorganisms were F. Enterobacteriaceae and C. Gammaproteobacteria. Vaginal microbiota diversity significantly increased, and the proportion of women with Lactobacillus spp.-depleted microbiomes increased after emergency cerclage. Significant differences in β diversity were found between the groups. Before the emergency cerclage, the enriched microorganisms were G. Lactobacillus, O. Alteromonadales, and P. Firmicutes. After emergency cerclage, the enriched microorganisms were P. Actinobacteria, C. Actinobacteria, P. Proteobacteria, F. Bifidobacteriaceae, O. Bifidobacteriales, G. Gardnerella, and G. Veillonella.

Conclusion

Cerclage (particularly emergency cerclage) may alter the vaginal microbiota by increasing microbiota diversity, decreasing vaginal Lactobacillus abundance, and increasing the abundance of pathogenic bacteria that are not conducive to pregnancy maintenance, thereby affecting surgical efficacy. Therefore, the role of the vaginal microbiome should be considered when developing treatment strategies for pregnant women with cervical incompetence.

Clinical trial registration

https://www.chictr.org.cn, identifier ChiCTR2100046305.

Maternal Baseline Risk Factors for Abnormal Vaginal Colonisation among High-Risk Pregnant Women and the Association with Adverse Pregnancy Outcomes: A Retrospective Cohort Study

Abnormal vaginal colonisation can lead to adverse pregnancy outcomes such as preterm birth through intra-amniotic inflammation. Despite the concern, little is known about its risk factors and impact in pregnant women at high-risk for spontaneous preterm birth. Thus, we conducted this single-centre retrospective cohort study including 1381 consecutive women who were admitted to the high-risk pregnancy unit. The results of vaginal culture at admission were categorised according to the colonising organism: bacteria (Gram-negative or -positive) and genital mycoplasmas. Maternal baseline socioeconomic, and clinical characteristics, as well as pregnancy, delivery, and neonatal outcomes were compared according to the category. Maternal risk factors for Gram-negative colonisation included advanced maternal age, increased pre-pregnancy BMI, a greater number of past spontaneous abortions, earlier gestational age at admission, and IVF. Gram-positive colonisation was likewise associated with earlier gestational age at admission. Genital mycoplasmal colonisation was associated with a greater number of past induced abortions, a lower level of education completed, and a lower rate of multifetal pregnancy and IVF. The neonates from mothers with Gram-negative colonisation had a greater risk of NICU admission, proven early onset neonatal sepsis, and mortality. However, not Gram-positive bacteria or genital mycoplasma was directly associated with adverse pregnancy outcomes.

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

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

Alterations in the vaginal microbiota of patients with preterm premature rupture of membranes

Background

Preterm premature rupture of membranes (PPROM) is a common pregnancy complication. Yet, the main cause of PPROM remains poorly understood. In this study, we used 16S rRNA gene sequencing technology to identify the differences in vaginal microbiota between pregnant women with PPROM and those who delivered at term.

Methods

Vaginal samples were collected from 48 patients with PPROM and 54 age- and gestational age-matched pregnant women who delivered at term (controls). The vaginal microbiota of the two groups was compared using 16S rRNA gene sequencing of the V3-V4 regions.

Results

The vaginal microbial composition of the PPROM group was significantly different from that of the control group. Our results showed that the diversity of vaginal microbiota in patients with PPROM increased compared with controls. The relative abundance of Lactobacillus iners, Gardnerella vaginalis, Prevotella bivia, Ochrobactrum sp., Prevotella timonensis, and Ureaplasma parvum were more abundant in patients with PPROM, while Lactobacillus crispatus and Lactobacillus gasseri were more abundant in controls. Ochrobactrum sp., Prevotella timonensis, and Gardnerella vaginalis, could serve as biomarkers for PPROM. Finally, we proposed several metabolic pathways, including PWY-6339, PWY-6992, and PWY-7295.

Conclusion

PPROM is characterized by vaginal microbial dysbiosis. The dysbiotic vaginal microbiota signatures in patients with PPROM include a higher bacterial diversity, decreased autochthonous bacteria, and increased pathogenic bacteria. These results may be beneficial for developing biomarkers for screening and early diagnosis of PPROM and may provide effective preventative treatments.

Second trimester short cervix is associated with decreased abundance of cervicovaginal lipid metabolites

BACKGROUND

A short cervix is a risk factor for preterm birth. The molecular drivers of a short cervix remain elusive. Metabolites may function as mediators of pathologic processes.

OBJECTIVE

We sought to determine if a distinct cervicovaginal metabolomic profile is associated with a short cervix (<25 mm) to unveil the potential mechanisms by which premature cervical remodeling leads to a short cervix.

STUDY DESIGN

This was a secondary analysis of a completed prospective pregnancy cohort. Cervicovaginal fluid was obtained between 20 and 24 weeks' gestation. The participants selected for metabolomic profiling were frequency-matched by birth outcome and cervicovaginal microbiota profile. This analysis included 222 participants with cervical length measured. A short cervix was defined as one having length <25 mm, as measured by transvaginal ultrasound. Unpaired t-tests were performed with a Bonferroni correction for multiple comparisons.

RESULTS

There were 27 participants with a short cervix, and 195 with normal cervical length. Of the 637 metabolites detected, 26 differed between those with a short cervix and those with normal cervical lengths; 22 were decreased, of which 21 belonged to the lipid metabolism pathway (all P<.000079). Diethanolamine, erythritol, progesterone, and mannitol or sorbitol were increased in the cases of short cervix. Among participants with Lactobacillus-deficient microbiota, only diethanolamine and mannitol or sorbitol differed between short cervix (n=17) and normal cervical length (n=75), both increased.

CONCLUSION

A short cervix is associated with decreased cervicovaginal lipid metabolites, particularly sphingolipids. This class of lipids stabilizes cell membranes and protects against environmental exposures. Increased diethanolamine-an immunostimulatory xenobiotic-is associated with a short cervix. These observations begin to identify the potential mechanisms by which modifiable environmental factors may invoke cell damage in the setting of biological vulnerability, thus promoting premature cervical remodeling in spontaneous preterm birth.

Abnormal vaginal flora and spontaneous preterm birth in high-risk singleton pregnancies with cervical cerclage

OBJECTIVE

To investigate abnormal vaginal and suture-based bacterial flora for associations with spontaneous preterm birth in high-risk singleton pregnancies with an ultrasound-indicated or emergency cervical cerclage.

MATERIALS AND METHODS

A retrospective study of 196 singleton pregnancies with an ultrasound-indicated or emergency cerclage at the Royal Women's Hospital, Australia, from 2004 to 2018. High vaginal swabs were collected regularly between 14 and 26 weeks' gestation, including pre- and post-cerclage insertion, and sent for microscopy and culture. Cervical suture was cultured upon removal. Primary outcomes were spontaneous preterm birth <37, <34 and <30 weeks.

RESULTS

43.4% (85/196) of women delivered preterm. The acquisition and persistence of vaginal Escherichia coli following cerclage insertion were independently associated with spontaneous preterm birth <37 weeks (p = .0225, p = .0477). Escherichia coli growth from the cervical suture upon removal was associated with spontaneous preterm birth <34 weeks (p = .0458). The acquisition of vaginal mixed anaerobes post-cerclage was independently associated with spontaneous preterm birth <34 weeks (p = .0480).

CONCLUSION

For singleton pregnancies with an ultrasound-indicated or emergency cerclage, the presence of vaginal or suture-based Escherichia coli following cerclage insertion yields increased risk of cerclage failure and spontaneous preterm birth.

Effects of vaginal microecology and immunity on the pregnancy outcome of cervical cerclage

Objective

To investigate the effects of vaginal microecology and immune status on the pregnancy outcome of cervical cerclage.

Methods

The clinical data of 125 patients with cervical incompetence who underwent transvaginal cervical cerclage in our hospital from January 2018 to January 2021 were collected, based on which the associations of vaginal microecology and related immune cytokines (IL-1β, IL-6, IL-8 and TNF-α) with the cervical cerclage outcome were explored.

Results

All of the 125 patients had singleton pregnancies, who were aged 20–43 years, with a mean of (32.34 ± 5.17) years. The surgery was successful in 104 patients (full-term delivery or survival of premature infants), while unsuccessful in 21 patients (late miscarriage or death of premature infants), revealing a success rate of 83.20%. There were 70 full-term deliveries, 34 premature deliveries (28 survived while 6 died), and 15 late miscarriages. Univariate analysis revealed statistically significant differences in the timing of surgery, gestational age of cerclage, preoperative cervical canal length, genital tract infections and preoperative invasive procedures between the successful and unsuccessful groups (P < 0.05). Insignificant differences were found in the pre-pregnancy body mass index (BMI) (P > 0.05). According to the multivariate analysis results, cerclage timing and genital tract infections were independent risk factors for postoperative pregnancy failure (P < 0.05). The pathogen detection rates in the two groups of pregnant women were analyzed, finding significantly higher incidence of bacterial vaginosis (BV) in the unsuccessful group than in the successful group (P < 0.05). Inter-group comparison revealed that the positive rates for vaginal microenvironmental factors (LE, NAG, SNA, H₂O₂ and pH) were all significantly higher in the unsuccessful group than in the successful group (P < 0.05). Besides, the immune cytokine levels in the cervicovaginal secretions were also all significantly higher in the unsuccessful group than in the successful group (P < 0.05).

Conclusion

The pregnancy outcome of patients undergoing cervical cerclage is associated with the imbalance of vaginal microecology and the levels of IL-1β, IL-6, IL-8 and TNF-α in cervicovaginal secretions.

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.

A non-optimal cervicovaginal microbiota in pregnancy is associated with a distinct metabolomic signature among non-Hispanic Black individuals

Biomechanical and molecular processes of premature cervical remodeling preceding spontaneous preterm birth (sPTB) likely result from interactions between the cervicovaginal microbiota and host immune responses. A non-optimal cervicovaginal microbiota confers increased risk of sPTB. The cervicovaginal space is metabolically active in pregancy; microbiota can produce, modify, and degrade metabolites within this ecosystem. We establish that cervicovaginal metabolomic output clusters by microbial community in pregnancy among Black individuals, revealing increased metabolism within the amino acid and dipeptide pathways as hallmarks of a non-optimal microbiota. Few differences were detected in metabolomic profiles when stratified by birth outcome. The study raises the possibility that metabolites could distinguish women with greater risk of sPTB among those with similar cervicovaginal microbiota, and that metabolites within the amino acid and carbohydrate pathways may play a role in this distinction.

Direct on-swab metabolic profiling of vaginal microbiome host interactions during pregnancy and preterm birth

The pregnancy vaginal microbiome contributes to risk of preterm birth, the primary cause of death in children under 5 years of age. Here we describe direct on-swab metabolic profiling by Desorption Electrospray Ionization Mass Spectrometry (DESI-MS) for sample preparation-free characterisation of the cervicovaginal metabolome in two independent pregnancy cohorts (VMET, n = 160; 455 swabs; VMET II, n = 205; 573 swabs). By integrating metataxonomics and immune profiling data from matched samples, we show that specific metabolome signatures can be used to robustly predict simultaneously both the composition of the vaginal microbiome and host inflammatory status. In these patients, vaginal microbiota instability and innate immune activation, as predicted using DESI-MS, associated with preterm birth, including in women receiving cervical cerclage for preterm birth prevention. These findings highlight direct on-swab metabolic profiling by DESI-MS as an innovative approach for preterm birth risk stratification through rapid assessment of vaginal microbiota-host dynamics.

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.

Vancomycin-Resistant Enterococci and Extended-Spectrum β-Lactamase-Producing Bacterial Colonization of the Cervix after Emergency Cerclage: Is It Safe?

Antimicrobial resistance is currently becoming a global threat to human health. We performed a retrospective study on patients who underwent emergency cerclage between January 2016 and December 2018 at the Dongsan Medical Center. Cervical culture was first performed before surgery to confirm that there was no infection and was repeated on days 1, 4, and 7 after surgery. A total of 85 pregnant women underwent emergency cerclage. Among them, six patients had vancomycin-resistant enterococci (VRE) colonization in the cervix after cerclage, and 23 patients developed extended-spectrum β-lactamase (ESBL)-producing bacterial colonization in the cervix. The average gestational age at delivery was lower in the VRE group. Neonatal death was also significantly higher in the VRE group. The rate of occurrence of early-onset sepsis was also higher in the VRE group, and both VRE and ESBL-producing bacterial colonization cases in which early-onset sepsis occurred resulted in neonatal death. The prognosis of cervical VRE colonization after cervical surgery was poor, whereas the prognosis of ESBL-producing bacterial colonization in the cervix did not differ significantly from that of the control group. However, careful neonatal treatment is required considering that early-onset sepsis is fatal to the newborn.

Acute chorioamnionitis complicated with symmetrical peripheral gangrene

OBJECTIVE

Symmetrical peripheral gangrene (SPG) is an uncommon but important clinical syndrome. We present a case of acute chorioamnionitis complicated with SPG.

CASE REPORT

A 33-year-old female (gravida 5, para 2) was admitted with preterm premature rupture of membranes (PPROM) at 20 weeks and four days of gestation. She received cervical cerclage four days ago. Seven days after the diagnosis of PPROM, she developed fever, tachypnea and tachycardia. Termination of pregnancy was decided for clinical diagnosis of sepsis. After the abortus was born, gangrene change on the nose was noticed. Afterwards, this patient developed acrocyanosis of extremities. SPG developed following sepsis with intravascular disseminated coagulation (DIC). After intensive care, the patient underwent hyperbaric oxygen therapy and fasciectomy of the left forearm.

CONCLUSION

We suggest awareness of SPG associated with acute chorioamnionitis. Early recognition of SPG, multidisciplinary care, and treatment of its underlying conditions are the mainstays of management.

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 a Nonoptimal Cervicovaginal Microbiota and Psychosocial Stress on Recurrent Spontaneous Preterm Birth

OBJECTIVE

While select cervicovaginal microbiota and psychosocial factors have been associated with spontaneous preterm birth, their effect on the risk of recurrence remains unclear. It is also unknown whether psychosocial factors amplify underlying biologic risk. This study sought to determine the effect of nonoptimal cervicovaginal microbiota and perceived stress on the risk of recurrent spontaneous preterm birth.

STUDY DESIGN

This was a secondary analysis of a prospective pregnancy cohort, Motherhood and Microbiome. The Cohen's Perceived Stress Scale (PSS-14) was administered and cervical swabs were obtained between 16 and 20 weeks of gestation. PSS-14 scores ≥30 reflected high perceived stress. We analyzed cervicovaginal microbiota using 16S rRNA sequencing and classified microbial communities into community state types (CSTs). CST IV is a nonoptimal cervicovaginal microbial community characterized by anaerobes and a lack of Lactobacillus. The final cohort included a predominantly non-Hispanic Black population of women with prior spontaneous preterm birth who had recurrent spontaneous preterm birth or term birth and had stress measurements (n = 181). A subanalysis was performed in the subset of these women with cervicovaginal microbiota data (n = 74). Multivariable logistic regression modeled adjusted associations between CST IV and recurrent spontaneous preterm birth, high stress and recurrent spontaneous preterm birth, as well as high stress and CST IV.

RESULTS

Among the 181 women with prior spontaneous preterm birth, 45 (24.9%) had high perceived stress. We did not detect a significant association between high stress and recurrent spontaneous preterm birth (adjusted odds ratio [aOR] 1.67, 95% confidence interval [CI]: 0.73-3.85). Among the 74 women with prior spontaneous preterm birth and cervicovaginal microbiota analyzed, 29 (39.2%) had CST IV; this proportion differed significantly among women with recurrent spontaneous preterm birth (51.4%) compared with women with term birth (28.2%) (p = 0.04). In models adjusted for race and marital status, the association between CST IV and recurrent spontaneous preterm birth persisted (aOR 3.58, 95% CI: 1.25-10.24). There was no significant interaction between stress and CST IV on the odds of spontaneous preterm birth (p = 0.328). When both stress and CST IV were introduced into the model, their associations with recurrent spontaneous preterm birth were slightly stronger than when they were in the model alone. The aOR for stress with recurrent spontaneous preterm birth was 2.02 (95% CI: 0.61-6.71) and for CST IV the aOR was 3.83 (95% CI: 1.30-11.33). Compared to women with neither of the two exposures, women with both high stress and CST IV had the highest odds of recurrent spontaneous preterm birth (aOR = 6.01, 95% CI: 1.002-36.03).

CONCLUSION

Among a predominantly non-Hispanic Black cohort of women with a prior spontaneous preterm birth, a nonoptimal cervicovaginal microbiota is associated with increased odds of recurrent spontaneous preterm birth. Adjustment for perceived stress may amplify associations between CST IV and recurrent spontaneous preterm birth. Identification of modifiable social or behavioral factors may unveil novel nonpharmacologic interventions to decrease recurrent spontaneous preterm birth among women with underlying biologic risk.

KEY POINTS

· CST IV, a nonoptimal microbiota, is associated with increased odds of recurrent spontaneous preterm birth.. · Adjustment for perceived stress amplified associations between CST IV and recurrent spontaneous preterm birth.. · Identification of modifiable psychosocial factors may unveil novel nonpharmacologic interventions to decrease recurrent preterm birth..

Vaginal Microbiome in Preterm Rupture of Membranes

There is an association between vaginal microbiota dysbiosis and preterm premature rupture of membranes (PPROM). In PPROM, reduced Lactobacillus spp abundance is linked to the emergence of high-risk vaginal microbiota, close to the time of membrane rupture. Although PPROM itself can change vaginal microbial composition, antibiotic therapy profoundly effects community structure. Erythromycin may have a beneficial effect in women deplete in Lactobacillus spp but damages a healthy microbiome by targeting Lactobacillus spp. Increased rates of chorioamnionitis and early-onset neonatal sepsis are associated with vaginal microbiota dysbiosis close to the time of delivery.

Association of Cerclage with Composite Adverse Outcomes among Women Delivered at 36 Weeks or Later

OBJECTIVE

This study aimed to compare the maternal and neonatal adverse outcomes among singletons delivered at 36 weeks or later with cerclage during index pregnancy versus those without cerclage.

STUDY DESIGN

This retrospective cohort study utilized the U.S. vital statistics datasets from 2011 to 2013. Inclusion criteria were women with nonanomalous singletons, with and without cerclage placement, without diabetes or hypertensive disorders, and delivered at 36 to 41 weeks. The coprimary outcomes were composite maternal and neonatal adverse outcomes. Composite maternal adverse outcome included admission to intensive care unit, maternal transfusion, ruptured uterus, unplanned hysterectomy, or unplanned operating room procedure. Composite neonatal adverse outcome included Apgar score less than 5 at 5 minutes, assisted ventilation for more than 6 hours, neonatal seizure, birth injury, or neonatal death. Secondary outcomes were chorioamnionitis and cesarean delivery. Multivariable Poisson's regression models with error variance were used while adjusting for confounders. Adjusted relative risk (aRR) with 95% confidence intervals (CIs) were calculated.

RESULTS

Of the 8,508,228 women who met inclusion criteria, 0.2% had a cerclage and reached 36 weeks. Composite maternal (aRR: 2.04; 95% CI: 1.76-2.36) and neonatal (aRR: 1.28; 95% CI: 1.11-1.47) adverse outcomes were significantly higher among those with cerclage than those without cerclage. Chorioamnionitis (aRR: 1.47; 95% CI: 1.30-1.67) and cesarean delivery (aRR: 1.10; 95% CI: 1.08-1.12) were also significantly higher in women with cerclage than those without cerclage.

CONCLUSION

There is an association between increased composite maternal and neonatal adverse outcomes among women with cerclage who delivered at 36 to 41 weeks as compared with those without cerclage.

KEY POINTS

· Cerclage is associated with increased composite maternal adverse outcome in women at 36-41 weeks.. · Cerclage is associated with increased composite neonatal adverse outcome in women at 36-41 weeks.. · Increased chorioamnionitis and cesarean delivery rates are associated with cerclage in women at 36-41 weeks..

Members of Prevotella Genus Distinctively Modulate Innate Immune and Barrier Functions in a Human Three-Dimensional Endometrial Epithelial Cell Model

BACKGROUND

Prevotella species are commonly isolated from the reproductive tract of women with obstetric/gynecologic health complications. However, contributions of this genus to changes in local microenvironment are not well characterized. Our objective was to evaluate species-specific effects of Prevotella on the human endometrial epithelium.

METHODS

Thirteen Prevotella strains, originally isolated from the human oral cavity, amniotic fluid, endometrium, or vagina (including women with bacterial vaginosis), were obtained from BEI and ATCC resources. Bacteria were evaluated in silico and in vitro using human endometrial epithelial cells (EEC) grown as monolayers or a 3-dimensional (3D) model.

RESULTS

Genomic characterization illustrated metabolic and phylogenetic diversity of Prevotella genus. Among tested species, P. disiens exhibited cytotoxicity. Scanning electron microscopy analysis of the 3D EEC model revealed species-specific colonization patterns and alterations of ultracellular structures. Infection with sialidase-producing P. timonensis resulted in elongated microvilli, and increased MUC3 and MUC4 expression. Infections with Prevotella species, including P. bivia, did not result in significant proinflammatory activation of EEC.

CONCLUSIONS

Collectively, findings indicate that Prevotella species are metabolically diverse and overall not cytotoxic or overtly inflammatory in EEC; however, these bacteria can form biofilms, alter barrier properties of the endometrial epithelium, and ultimately impact colonization of secondary colonizers.

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.

Association of the vaginal microbiota with pregnancy outcomes in Chinese women after cervical cerclage

RESEARCH QUESTION

The study aimed to investigate the relationship between risk factors associated with vaginal microbiota and outcomes of cervical cerclage.

DESIGN

A retrospective cohort study of singleton pregnancies with cervical cerclage was conducted. Before cerclage, participants underwent a vaginal microbiota assay, including morphological examination and functional vaginal microecological analysis using a vaginitis multi-test kit. The chi-squared test and logistic and linear regression analyses were performed to evaluate the associations of various risk factors with maternal and neonatal outcomes.

RESULTS

Eighty-five participants were included. The mean interval between cerclage and delivery was 69.4 ± 36.7 days, and 12 (14.1%) of newborns died. A higher grade of vaginal cleanliness, a higher pH, a lower abundance of Lactobacillus spp., a higher sialidase-positive percentage, a higher positive percentage of clue cells, a higher lactobacillary grade, a higher Nugent score and a higher rate of microecological dysbiosis were significantly associated with a poor neonatal outcome and shorter cerclage to delivery intervals (P < 0.001-0.041). Furthermore, sialidase positivity was associated with the highest risk of cervical cerclage failure (odds ratio [OR] 10.469; 95% confidence interval [CI] 1.096-36.087), followed by the presence of bulging membranes (OR 6.400; 95% CI 0.428-15.641) and vaginal microbiota dysbiosis (OR 6.038; 95% CI 0.173-17.072).

CONCLUSIONS

An absence of Lactobacillus spp. and some functional factors of vaginal microbiota are potential risk factors that predict subsequent cerclage failure. These findings indicate the potential clinical utility of these factors to predict cervical cerclage failure for managing patient expectations and providing improved postoperative surveillance.

Cervicovaginal microbial communities deficient in Lactobacillus species are associated with second trimester short cervix

BACKGROUND

The cervix functions as a barrier to ascending pathogens in pregnancy. Short cervical length and lack of cervicovaginal Lactobacillus species are risk factors for spontaneous preterm birth; however, whether they interact to increase risk remains unknown.

OBJECTIVE

We sought to examine the relationship between cervicovaginal microbiota and short cervix as well as their combined impact on spontaneous preterm birth risk.

STUDY DESIGN

This was a secondary analysis of a prospective nested, case-control pregnancy study. Cervical swabs were collected between 16 and 20 weeks of gestation. Cervical length was measured per standard clinical care during a clinically indicated ultrasound at approximately 20 weeks of gestation. Cervicovaginal microbiota were analyzed with 16S ribosomal RNA gene sequencing and classified into community state types among 67 cases of spontaneous preterm birth, 47 cases of medically indicated preterm birth, and 358 cases of term births. Logistic regression was used to model associations of community state type IV, a community characterized by a paucity of Lactobacillus species and a wide array of anaerobic bacteria, and short cervix (<25 mm) as well as to model the association of a combination of short cervix and community state type IV with the odds of spontaneous preterm birth.

RESULTS

Among the 472 women in the data set, there were 38 with short cervix (8.1%) and 177 with community state type IV (37.5%). Short cervix was associated with spontaneous preterm birth (adjusted odds ratio, 15.59; 95% confidence interval, 6.77-35.92). Women with community state type IV had higher odds of short cervix (adjusted odds ratio, 2.17; 95% confidence interval, 1.04-4.53) as well as spontaneous preterm birth (adjusted odds ratio, 1.97; 95% confidence interval, 1.06-3.65). While the interaction of community state type IV and short cervix was not significant (P = .771), women with both short cervix and community state type IV (n = 20) had higher odds of spontaneous preterm birth compared with women with both normal cervical length and community state types I, II, III, or V (n = 277) (adjusted odds ratio, 21.8; 95% confidence interval, 6.78-70.2).

CONCLUSION

Community state type IV, characterized by a diverse set of strict and facultative anaerobes and a paucity of Lactobacillus species, is associated with increased odds of short cervix. Women with both community state type IV and short cervix have higher odds of spontaneous preterm birth than women with either factor alone. Determining the cascade of events leading to premature cervical shortening, including dysbiosis, may be critical in preventing spontaneous preterm birth.

Preterm neonatal immunology at the intestinal interface

Fetal and neonatal development represents a critical window for setting a path toward health throughout life. In this review, we focus on intestinal immunity, how it develops, and its implications for subsequent neonatal diseases. We discuss maternal nutritional and environmental exposures that dictate outcomes for the developing fetus. Although still controversial, there is evidence in support of an in utero microbiome. Specific well-intentioned and routine applications of antibiotics, steroids, and surgical interventions implemented before, during, and after birth skew the neonate towards pro-inflammatory dysbiosis. Shortly after birth, a consortium of maternal and environmentally derived bacteria, through cross-talk with the developing host immune system, takes center stage in developing or disrupting immune homeostasis at the intestinal interface. We also examine subsequent immunological cross-talks, which involve neonatal myeloid and lymphoid responses, and their potential impacts on health and disease such as necrotizing enterocolitis and sepsis, especially critical disease entities for the infant born preterm.

Emergency cerclage following a standardized protocol offers an effective and safe therapeutic option for women with high risk for prematurity - a retrospective monocentric cohort study on 130 pregnancies and 155 neonates

Objective: To present emergency cerclage (EC) as a safe and effective therapeutic option for prevention of prematurity in women with advanced cervical dilation in second-trimester pregnancy. It is focused on seemingly futile situations like cervical dilation >5 cm, bulging membranes and multifetal pregnancies. The outcomes of interest are the prolongation of pregnancy, gestational age at delivery and neonatal morbidity and mortality related to distinct risk factors.Study design: Retrospective monocentric cohort study involving 130 pregnancies (105 single and 25 twin pregnancies) and 155 neonates by using a standardized protocol. Women between 18 and 28 gestational weeks with cervical shortening of <10 mm + cervical dilation >2 cm and/or bulging membranes were included. Analyses of maternal and neonatal parameters were done by chart review.Results: The medium gestational age at delivery was 35 5/7 week with a medium interval from cerclage placement to delivery of 83 days. Overall, 46.5% (72/155) neonates were born beyond 37 weeks, extreme prematurity of less than 28 gestational weeks was observed in 14.8% (23/155), no miscarriage before 22 weeks was documented. The neonatal mortality was 1.9% (3/155). Neonatal deaths and morbidity was related to severe prematurity exclusively. The association of amnion-infection syndromes and failing therapy was significantly with respect to bulging membranes and advanced cervical dilation >5 cm.Conclusions: Even in futile cases EC can be an option to save the pregnancy and prevent severe prematurity. However, a standardized protocol is imminent for successful therapy and every indication has to be a case by case decision.

Vaginal Microbiome Signature Is Associated With Spontaneous Preterm Delivery

Background: Preterm delivery (PTD) represents an important public health and therapeutic challenge. Despite the reported link between the composition of vaginal microbiome and PTD, previous studies were inconsistent in their conclusions and utilized non-uniform designs. We performed an independent case-control study carried out on the Slovenian population, where we re-evaluated the role of the vaginal microbiome in PTD.

Methods: Vaginal microbiomes of pregnant women who delivered preterm were compared to those delivered at term to examine differences in the microbial richness, diversity, and differential abundance of specific taxa. We obtained vaginal swab samples from 155 Caucasian women who were classified as either term (≥38^0/7 weeks, n = 107) or preterm (≤36^6/7 weeks, n = 48) in exclusion of any other medical or obstetric conditions. The vaginal microbiomes of these women were characterized by 16S ribosomal RNA (rRNA) gene sequencing of the V3-V4 region on the MiSeq platform.

Results: Women who experienced PTD had a higher microbial richness (Chao1, P = 0.011) and alpha diversity (Shannon, P = 0.00059) than women with term deliveries. We report that overall vaginal microbial community composition (beta-diversity) was significantly different by delivery gestational age category (P_{WeightedUnifrac} < 0.001). Women who delivered preterm had decreased Lactobacilli spp. abundance as well as increased abundance of Gardnerella and other bacterial vaginosis (BV) and aerobic vaginitis (AV) associated genera including Atopobium, Sneathia, Gemella, Megasphaera, Dorea, Streptococcus, and Escherichia/Shigella.

Conclusions: In the present study, we provide further evidence that vaginal microbiome composition is associated with PTD.

The vaginal microbiome and preterm birth

The incidence of preterm birth exceeds 10% worldwide. There are significant disparities in the frequency of preterm birth among populations within countries, and women of African ancestry disproportionately bear the burden of risk in the United States. In the present study, we report a community resource that includes ‘omics’ data from approximately 12,000 samples as part of the integrative Human Microbiome Project. Longitudinal analyses of 16S ribosomal RNA, metagenomic, metatranscriptomic and cytokine profiles from 45 preterm and 90 term birth controls identified harbingers of preterm birth in this cohort of women predominantly of African ancestry. Women who delivered preterm exhibited significantly lower vaginal levels of Lactobacillus crispatus and higher levels of BVAB1, Sneathia amnii, TM7-H1, a group of Prevotella species and nine additional taxa. The first representative genomes of BVAB1 and TM7-H1 are described. Preterm-birth-associated taxa were correlated with proinflammatory cytokines in vaginal fluid. These findings highlight new opportunities for assessment of the risk of preterm birth.

As part of the second phase of Human Microbiome Project, the Multi-Omic Microbiome Study: Pregnancy Initiative presents a community resource to help better understand how microbiome and host profiles change throughout pregnancy as well as to identify new opportunities for assessment of the risk of preterm birth.

Prospective observational study of vaginal microbiota pre- and post-rescue cervical cerclage

OBJECTIVE

To investigate the relation between vaginal microbiota composition and outcome of rescue cervical cerclage.

DESIGN

Prospective observational study.

SETTING

Queen Charlotte's and Chelsea Hospital, London.

POPULATION

Twenty singleton pregnancies undergoing a rescue cervical cerclage.

METHODS

Vaginal microbiota composition was analysed in women presenting with a dilated cervix and exposed fetal membranes before and 10 days following rescue cervical cerclage and was correlated with clinical outcomes.

MAIN OUTCOME MEASURES

Composition of vaginal bacteria was characterised by culture-independent next generation sequencing. Successful cerclage was defined as that resulting in the birth of a neonate discharged from hospital without morbidity. Unsuccessful cerclage was defined as procedures culminating in miscarriage, intrauterine death, neonatal death or significant neonatal morbidity.

RESULTS

Reduced Lactobacillus spp. relative abundance was observed in 40% of cases prior to rescue cerclage compared with 10% of gestation age-matched controls (8/20, 40% versus 3/30, 10%, P = 0.017). Gardnerella vaginalis was over-represented in women presenting with symptoms (3/7, 43% versus 0/13, 0%, P = 0.03, linear discriminant analysis, LDA (log 10) and cases culminating in miscarriage (3/6, 50% versus 0/14, 0%, P = 0.017). In the majority of cases (10/14, 71%) bacterial composition was unchanged following cerclage insertion and perioperative interventions.

CONCLUSIONS

Reduced relative abundance of Lactobacillus spp. is associated with premature cervical dilation, whereas high levels of G. vaginalis are associated with unsuccessful rescue cerclage cases. The insertion of a rescue cerclage does not affect the underlying bacterial composition in the majority of cases.

TWEETABLE ABSTRACT

Preterm cervical dilatation associates with reduced Lactobacillus spp. Presence of Gardnerella vaginalis predicts rescue cerclage failure.