Limited relationship between cervico-vaginal fluid cytokine profiles and cervical shortening in women at high risk of spontaneous preterm birth

INSIGHT-2: mechanistic studies into pregnancy complications and their impact on maternal and child health-study protocol

BACKGROUND

Pregnancy and early childhood cohorts provide a framework for investigating the complex interplay between early-life exposures and health outcomes, thereby informing prevention strategies and interventions to improve maternal and child health. In this paper, we outline the objectives, methodologies and expected contributions of INSIGHT-2, a comprehensive cohort study dedicated to advancing our understanding of pregnancy and pregnancy complications towards improving the health and well-being of mothers and their offspring.

METHODS

Over the course of 5 years, the study aims to establish a diverse cohort of 1700 pregnant women and to follow up their children up to 2 years of age. Recruitment targets participants with healthy pregnancies, preexisting conditions, and/or risk factors for pregnancy complications or later child health problems. Clinical and lifestyle data and a range of biological samples will be collected, providing a comprehensive resource for biomarker investigations and cross-sectional analyses. It is anticipated that the cohort will continue beyond this initial 5-year plan.

DISCUSSION

By gathering a wide range of biological samples and using diverse analytical techniques, this study supports broad participation, potential replication and collaboration across various sites. The extensive collection of longitudinal data and samples not only facilitates current investigations but also establishes a biobank for future research. The exploration of pre-pregnancy and pregnancy factors that may contribute to disease processes and impact fetal well-being and future health will provide a comprehensive picture of disease mechanisms in both mothers and children, facilitating the identification of biomarkers for the prediction, diagnosis, and management of pregnancy complications. Additionally, our diverse population allows for the capture of various pregnancy complications and outcomes, enhancing external validity and addressing health disparities. This comprehensive design ultimately aims to improve maternal and child health outcomes by providing a valuable longitudinal study of the relationships among the in utero environment, pregnancy management, and long-term maternal and child health, ensuring that findings are relevant and beneficial to a broader population.

Gestation-dependent increase in cervicovaginal pro-inflammatory cytokines and cervical extracellular matrix proteins is associated with spontaneous preterm delivery within 2 weeks of index assessment in South African women

Introduction

Inflammation-induced remodelling of gestational tissues that underpins spontaneous preterm birth (sPTB, delivery < 37 weeks' gestation) may vary by race and context. To explore relationships between markers of these pathological processes, we (a) characterised the cervicovaginal fluid (CVF) cytokine profiles of pregnant South African women at risk of PTB; (b) determined CVF matrix-metalloproteinase-9 (MMP-9) and its regulator tissue inhibitor of metalloproteinase-1 (TIMP-1); and (c) explored the predictive potential of these markers for sPTB.

Method of study

The concentrations of 10 inflammatory cytokines and MMP-9 and TIMP-1 were determined by ELISA in CVF samples from 47 non-labouring women at high risk of PTB. We studied CVF sampled at three gestational time points (GTPs): GTP1 (20-22 weeks, n = 37), GTP2 (26-28 weeks, n = 40), and GTP3 (34-36 weeks, n = 29) and analysed for changes in protein concentrations and predictive capacities (area under the ROC curve (AUC) and 95% confidence interval (CI)) for sPTB.

Results

There were 11 (GTP1), 13 (GTP2), and 6 (GTP3) women who delivered preterm within 85.3 ± 25.9, 51.3 ± 15.3, and 11.8 ± 7.5 (mean ± SD) days after assessment, respectively. At GTP1, IL-8 was higher (4-fold, p = 0.02), whereas GM-CSF was lower (~1.4-fold, p = 0.03) in the preterm compared with term women with an average AUC = 0.73. At GTP2, IL-1β (18-fold, p < 0.0001), IL-8 (4-fold, p = 0.03), MMP-9 (17-fold, p = 0.0007), MMP-9/TIMP-1 ratio (9-fold, p = 0.004), and MMP-9/GM-CSF ratio (87-fold, p = 0.005) were higher in preterm compared with term women with an average AUC = 0.80. By contrast, IL-10 was associated with term delivery with an AUC (95% CI) = 0.75 (0.55-0.90). At GTP3, IL-1β (58-fold, p = 0.0003), IL-8 (12-fold, p = 0.002), MMP-9 (296-fold, p = 0.03), and TIMP-1 (35-fold, p = 0.01) were higher in preterm compared with term women with an average AUC = 0.85. Elevated IL-1β was associated with delivery within 14 days of assessment with AUC = 0.85 (0.67-0.96). Overall, elevated MMP-9 at GTP3 had the highest (13.3) positive likelihood ratio for distinguishing women at risk of sPTB. Lastly, a positive correlation between MMP-9 and TIMP-1 at all GTPs (ρ ≥ 0.61, p < 0.01) for women delivering at term was only observed at GTP1 for those who delivered preterm (ρ = 0.70, p < 0.03).

Conclusions

In this cohort, sPTB is associated with gestation-dependent increase in pro-inflammatory cytokines, decreased IL-10 and GM-CSF, and dysregulated MMP-9-TIMP-1 interaction. Levels of cytokine (especially IL-1β) and ECM remodelling proteins rise significantly in the final 2 weeks before the onset of labour when sPTB is imminent. The signalling mechanisms for these ECM remodelling observations remain to be elucidated.

Comparing cervical cerclage, pessary and vaginal progesterone for prevention of preterm birth in women with a short cervix (SuPPoRT): A multicentre randomised controlled trial

BACKGROUND

Cervical cerclage, cervical pessary, and vaginal progesterone have each been shown to reduce preterm birth (PTB) in high-risk women, but to our knowledge, there has been no randomised comparison of the 3 interventions. The SuPPoRT "Stitch, Pessary, or Progesterone Randomised Trial" was designed to compare the rate of PTB <37 weeks between each intervention in women who develop a short cervix in pregnancy.

METHODS AND FINDINGS

SuPPoRT was a multicentre, open label 3-arm randomised controlled trial designed to demonstrate equivalence (equivalence margin 20%) conducted from 1 July 2015 to 1 July 2021 in 19 obstetric units in the United Kingdom. Asymptomatic women with singleton pregnancies with transvaginal ultrasound cervical lengths measuring <25 mm between 14+0 and 23+6 weeks' gestation were eligible for randomisation (1:1:1) to receive either vaginal cervical cerclage (n = 128), cervical pessary (n = 126), or vaginal progesterone (n = 132). Minimisation variables were gestation at recruitment, body mass index (BMI), and risk factor for PTB. The primary outcome was PTB <37 weeks' gestation. Secondary outcomes included PTB <34 weeks', <30 weeks', and adverse perinatal outcome. Analysis was by intention to treat. A total of 386 pregnant women between 14+0 and 23+6 weeks' gestation with a cervical length <25 mm were randomised to one of the 3 interventions. Of these women, 67% were of white ethnicity, 18% black ethnicity, and 7.5% Asian ethnicity. Mean BMI was 25.6. Over 85% of women had prior risk factors for PTB; 39.1% had experienced a spontaneous PTB or midtrimester loss (>14 weeks gestation); and 45.8% had prior cervical surgery. Data from 381 women were available for outcome analysis. Using binary regression, randomised therapies (cerclage versus pessary versus vaginal progesterone) were found to have similar effects on the primary outcome PTB <37 weeks (39/127 versus 38/122 versus 32/132, p = 0.4, cerclage versus pessary risk difference (RD) -0.7% [-12.1 to 10.7], cerclage versus progesterone RD 6.2% [-5.0 to 17.0], and progesterone versus pessary RD -6.9% [-17.9 to 4.1]). Similarly, no difference was seen for PTB <34 and 30 weeks, nor adverse perinatal outcome. There were some differences in the mild side effect profile between interventions (vaginal discharge and bleeding) and women randomised to progesterone reported more severe abdominal pain. A small proportion of women did not receive the intervention as per protocol; however, per-protocol and as-treated analyses showed similar results. The main study limitation was that the trial was underpowered for neonatal outcomes and was stopped early due to the COVID-19 pandemic.

CONCLUSIONS

In this study, we found that for women who develop a short cervix, cerclage, pessary, and vaginal progesterone were equally efficacious at preventing PTB, as judged with a 20% equivalence margin. Commencing with any of the therapies would be reasonable clinical management. These results can be used as a counselling tool for clinicians when managing women with a short cervix.

TRIAL REGISTRATION

EU Clinical Trials register. EudraCT Number: 2015-000456-15, clinicaltrialsregister.eu., ISRCTN Registry: ISRCTN13364447, isrctn.com.

The vaginal immunoproteome for the prediction of spontaneous preterm birth: A retrospective longitudinal study

Background

Preterm birth is the leading cause of neonatal morbidity and mortality worldwide. Most cases of preterm birth occur spontaneously and result from preterm labor with intact (spontaneous preterm labor [sPTL]) or ruptured (preterm prelabor rupture of membranes [PPROM]) membranes. The prediction of spontaneous preterm birth (sPTB) remains underpowered due to its syndromic nature and the dearth of independent analyses of the vaginal host immune response. Thus, we conducted the largest longitudinal investigation targeting vaginal immune mediators, referred to herein as the immunoproteome, in a population at high risk for sPTB.

Methods

Vaginal swabs were collected across gestation from pregnant women who ultimately underwent term birth, sPTL, or PPROM. Cytokines, chemokines, growth factors, and antimicrobial peptides in the samples were quantified via specific and sensitive immunoassays. Predictive models were constructed from immune mediator concentrations.

Results

Throughout uncomplicated gestation, the vaginal immunoproteome harbors a cytokine network with a homeostatic profile. Yet, the vaginal immunoproteome is skewed toward a pro-inflammatory state in pregnant women who ultimately experience sPTL and PPROM. Such an inflammatory profile includes increased monocyte chemoattractants, cytokines indicative of macrophage and T-cell activation, and reduced antimicrobial proteins/peptides. The vaginal immunoproteome has improved predictive value over maternal characteristics alone for identifying women at risk for early (<34 weeks) sPTB.

Conclusions

The vaginal immunoproteome undergoes homeostatic changes throughout gestation and deviations from this shift are associated with sPTB. Furthermore, the vaginal immunoproteome can be leveraged as a potential biomarker for early sPTB, a subset of sPTB associated with extremely adverse neonatal outcomes.

Funding

This research was conducted by the Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS) under contract HHSN275201300006C. ALT, KRT, and NGL were supported by the Wayne State University Perinatal Initiative in Maternal, Perinatal and Child Health.

Predicting preterm birth within 2 weeks in asymptomatic women with a short cervix: Combined effects of cervicovaginal fluid cytokine levels and fetal fibronectin test

AIMS

To predict preterm birth (PTB) accurately, we conducted a comprehensive cytokine assay using cervicovaginal fluid (CVF) and evaluated the additive effects of cytokine levels on the fetal fibronectin (fFN) test.

METHODS

A total of 645 CVF samples were collected from 256 asymptomatic pregnant women between 24 and 35 weeks gestation, exhibiting short cervix. After selection based on specific criteria, 17 cytokines in 105 CVF samples were simultaneously measured using multiplex assay. Multivariate logistic regression analysis was performed to evaluate the association between cytokine levels and impending PTB, which is defined as PTB within 2 weeks after CVF collection. Moreover, receiver operating characteristic (ROC) analysis was performed in women with positive fFN results, which was validated using another set of 65 CVF samples.

RESULTS

In positive fFN women, the CCL2 level was significantly higher in the impending PTB group than the other group (p < 0.01) and a predictor of impending PTB (adjusted odds ratio 1.020, 95% confidence interval [95% CI] 1.003-1.038, p = 0.020). The cutoff value of CCL2 was 64.8 pg/mL (are under the curve 0.726, p = 0.004, 95% CI 0.593-0.859, sensitivity 45.2%, specificity 91.7%). Additionally, the reliable classification performance of proposed ROC model could be validated. However, measuring cytokine levels could not help in predicting impending PTB in women with negative fFN or normal labor onset in healthy-term women.

CONCLUSION

Comprehensive analysis of CVF cytokines revealed that the CCL2 level significantly improves the prediction of impending PTB in asymptomatic fFN-positive women with a short cervix, which may contribute to better clinical management.

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.

Amniotic fluid sludge is associated with earlier preterm delivery and raised cervicovaginal interleukin 8 concentrations

BACKGROUND

Preterm birth is the leading cause of global neonatal mortality. Amniotic fluid sludge, thought to indicate intra-amniotic infection, may have potential as a clinical biomarker of preterm birth risk.

OBJECTIVE

This study aimed to analyze whether the presence of amniotic fluid sludge in pregnant participants with a known short cervical length can help improve the understanding of the etiology and guide management choice.

STUDY DESIGN

This was a retrospective cohort study analyzing the effects of amniotic fluid sludge presence on the risk of preterm birth in high-risk asymptomatic pregnant participants with a short cervical length (<25 mm) at a large tertiary referral maternity center in London. Amniotic fluid sludge was detected on a routine transvaginal ultrasound scan.

RESULTS

Overall, 147 pregnant participants with a short cervical length were identified, 54 of whom had amniotic fluid sludge. Compared with pregnant participants without amniotic fluid sludge, pregnant participants with amniotic fluid sludge were more likely to have a short cervical length (19 vs 14 mm, respectively; P<.0001) and increased cervicovaginal fetal fibronectin concentrations at diagnosis (125 vs 45 ng/mL, respectively; P=.0006). Pregnant participants with amniotic fluid sludge were at increased risk of midtrimester loss and delivery before 24 weeks of gestation (relative risk, 3.4; 95% confidence interval, 1.2-10.3). Furthermore, this study showed that pregnant participants with amniotic fluid sludge have increased cervicovaginal interleukin 8 concentrations, supporting the concept of amniotic fluid sludge as an indicator of an inflammatory response to microbial invasion (P=.03). Neonatal outcomes were similar between the 2 groups.

CONCLUSION

In our cohort of high-risk asymptomatic pregnant participants with a short cervical length, the presence of amniotic fluid sludge is associated with an increased risk of delivery before 24 weeks of gestation. Moreover, pregnant participants with amniotic fluid sludge were more likely to have raised fetal fibronectin levels and inflammatory cytokines, particularly interleukin 8, in the cervicovaginal fluid, supporting the concept that amniotic fluid sludge is associated with an infective or inflammatory process. Future research should aim to further establish the clinical significance of amniotic fluid sludge presence and guide subsequent management.

Biological and pathological mechanisms leading to the birth of a small vulnerable newborn

The pathway to a thriving newborn begins before conception and continues in utero with a healthy placenta and the right balance of nutrients and growth factors that are timed and sequenced alongside hormonal suppression of labour until a mature infant is ready for birth. Optimal nutrition that includes adequate quantities of quality protein, energy, essential fats, and an extensive range of vitamins and minerals not only supports fetal growth but could also prevent preterm birth by supporting the immune system and alleviating oxidative stress. Infection, illness, undernourishment, and harmful environmental exposures can alter this trajectory leading to an infant who is too small due to either poor growth during pregnancy or preterm birth. Systemic inflammation suppresses fetal growth by interfering with growth hormone and its regulation of insulin-like growth factors. Evidence supports the prevention and treatment of several maternal infections during pregnancy to improve newborn health. However, microbes, such as Ureaplasma species, which are able to ascend the cervix and cause membrane rupture and chorioamnionitis, require new strategies for detection and treatment. The surge in fetal cortisol late in pregnancy is essential to parturition at the right time, but acute or chronically high maternal cortisol levels caused by psychological or physical stress could also trigger labour onset prematurely. In every pathway to the small vulnerable newborn, there is a possibility to modify the course of pregnancy by supporting improved nutrition, protection against infection, holistic maternal wellness, and healthy environments.

Predicting spontaneous preterm birth in asymptomatic high-risk women with cervical cerclage

OBJECTIVE

To determine the performance of the predictive markers of spontaneous preterm birth, cervicovaginal quantitative fetal fibronectin (fFN) and cervical length, in asymptomatic high-risk women with transabdominal, history-indicated or ultrasound-indicated cervical cerclage.

METHODS

This was a secondary analysis of a prospective cohort of asymptomatic high-risk women with cervical cerclage and no other prophylactic intervention (including progesterone), who attended the preterm birth clinic at a central London teaching hospital between October 2010 and September 2016. Women had either transabdominal cerclage, placed prior to conception, history-indicated cerclage, placed before 14 weeks' gestation, or ultrasound-indicated cerclage for a short cervix (< 25 mm), placed before 24 weeks. All women underwent serial cervical length assessment on transvaginal ultrasound in the second trimester (16-28 weeks), and quantitative fFN testing from 18 weeks onward. Test performance was analyzed for the prediction of spontaneous preterm birth before 30 weeks (cerclage failure), 34 weeks and 37 weeks, using receiver-operating-characteristics (ROC)-curve analysis.

RESULTS

Overall, 181 women were included in the analysis. Cervical length and fFN were strong predictors of spontaneous preterm birth before 30 weeks in women with cerclage, with areas under the ROC curve (AUC) of 0.86 (95% CI, 0.79-0.94) and 0.84 (95% CI, 0.75-0.92), respectively. Cervical length was a better predictor of preterm birth before 30 weeks in women with history-indicated compared to those with ultrasound-indicated cerclage, although both showed clinical utility (AUC, 0.96 (95% CI, 0.91-1.00) vs 0.79 (95% CI, 0.66-0.91); P = 0.01). Quantitative fFN was a strong predictor of spontaneous preterm birth before 30 weeks in women with history-indicated cerclage (AUC, 0.91 (95% CI, 0.75-1.00)) and retained clinical utility in those with ultrasound-indicated cerclage (AUC, 0.76 (95% CI, 0.64-0.89)). There were no spontaneous deliveries before 34 weeks in women with a transabdominal cerclage, so AUC was not calculated. Delivery was delayed significantly in this group (P < 0.01).

CONCLUSIONS

Cervical length and quantitative fFN retain clinical utility for the prediction of spontaneous preterm birth in women with cervical cerclage, and prediction is best in women with a history-indicated stitch. These tests can be relied upon to discriminate risk and have utility when planning clinical management with regard to treatment failure. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Elevated midtrimester maternal plasma cytokines and preterm birth in patients with cerclage

BACKGROUND

Cerclage is used for the prevention of spontaneous preterm birth; however, many patients at high risk of spontaneous preterm birth who have a cerclage in place eventually deliver before term. Although inflammation, measured by biomarkers (eg, cytokines), is a known risk factor for preterm delivery, evaluation of inflammation to determine pregnancy outcomes among patients with cerclage is poorly understood.

OBJECTIVE

We sought to examine levels of maternal plasma inflammatory cytokines in the midtrimester among asymptomatic patients with a cervical cerclage (placed for any indication, including history, ultrasound, and examination indications) to evaluate the association between cytokine levels and preterm birth.

STUDY DESIGN

This was a prospective cohort study of singleton, nonanomalous pregnancies who had a cerclage placed at <24 weeks of gestation from 2015 to 2018 at a single tertiary institution. Maternal plasma was collected perioperatively whenever possible. A custom magnetic bead Luminex cytokine assay was used to measure plasma inflammatory cytokine levels from these stored samples. The primary outcome was preterm birth at <37 weeks of gestation. A statistical cut point was calculated for each cytokine level to assess its optimal sensitivity and specificity for spontaneous preterm birth prediction. Patients were classified as having a "high" or "low" result for each cytokine based on this cut point. Receiver operating characteristic curve analysis was performed to estimate sensitivity, specificity, and positive and negative predictive values for spontaneous preterm birth prediction. Cox proportional-hazards regression modeled the association between the number of "high" inflammatory cytokines and gestational age at delivery, adjusting for confounders. Additional analyses were performed on the subgroup of patients with history-indicated cerclage and those with an ultrasound- or examination-indicated cerclage.

RESULTS

A total of 43 patients participated in this study: 20 (46.5%) had spontaneous preterm birth (median, 30.9 weeks of gestation; interquartile range, 28.4-35.0). Plasma samples were collected at a median of 0 (interquartile range, -2 to 17) days concerning cerclage placement and a median of 18 (interquartile range, 13-21) weeks of gestation. Based on the statistical cut point for each cytokine level, 7% of patients had zero, 20.9% had 1, 18.6% had 2, 20.9% had 3, and 32.6% had ≥4 "high" cytokine results. Each additional "high" cytokine level was associated with earlier delivery (hazard ratio, 1.51; 95% confidence interval, 1.25-1.81) even after controlling for ultrasound- or examination-indication for cerclage (hazard ratio, 1.73; 95% confidence interval, 0.95-3.15). The presence of ≥4 "high" cytokine levels was 70% sensitive and 74% specific for predicting spontaneous preterm birth (area under the curve, 0.846; 95% confidence interval, 0.728-0.964; positive predictive value, 70%; negative predictive value, 73.9%).

CONCLUSION

Among patients with a cervical cerclage, elevated midtrimester maternal plasma cytokine profiles were associated with subsequent preterm birth and can estimate the probability of preterm birth. Confirmation and refinement of this noninvasive panel may provide insight into improved selection of individuals who may benefit from cerclage placement and investigation of therapeutic strategies to mitigate midpregnancy inflammation.

Antenatal diagnosis of chorioamnionitis: A review of the potential role of fetal and placental imaging

Chorioamnionitis is present in up to 70% of spontaneous preterm births. It is defined as an acute inflammation of the chorion, with or without involvement of the amnion, and is evidence of a maternal immunological response to infection. A fetal inflammatory response can coexist and is diagnosed on placental histopathology postnatally. Fetal inflammatory response syndrome (FIRS) is associated with poorer fetal and neonatal outcomes. The only antenatal diagnostic test is amniocentesis which carries risks of miscarriage or preterm birth. Imaging of the fetal immune system, in particular the thymus and the spleen, and the placenta may give valuable information antenatally regarding the diagnosis of fetal inflammatory response. While ultrasound is largely limited to structural information, MRI can complement this with functional information that may provide insight into the metabolic activities of the fetal immune system and placenta. This review discusses fetal and placental imaging in pregnancies complicated by chorioamnionitis and their potential future use in achieving non-invasive antenatal diagnosis. This article is protected by copyright. All rights reserved.

Microbial-driven preterm labour involves crosstalk between the innate and adaptive immune response

There has been a surge in studies implicating a role of vaginal microbiota in spontaneous preterm birth (sPTB), but most are associative without mechanistic insight. Here we show a comprehensive approach to understand the causative factors of preterm birth, based on the integration of longitudinal vaginal microbiota and cervicovaginal fluid (CVF) immunophenotype data collected from 133 women at high-risk of sPTB. We show that vaginal depletion of Lactobacillus species and high bacterial diversity leads to increased mannose binding lectin (MBL), IgM, IgG, C3b, C5, IL-8, IL-6 and IL-1β and to increased risk of sPTB. Cervical shortening, which often precedes preterm birth, is associated with Lactobacillus iners and elevated levels of IgM, C3b, C5, C5a and IL-6. These data demonstrate a role for the complement system in microbial-driven sPTB and provide a scientific rationale for the development of live biotherapeutics and complement therapeutics to prevent sPTB.

Gaining mechanistic insight into the microbiological and immunological factors that are associated with spontaneous preterm birth is important for the development of prevention strategies. Here authors show that the complement system in conjunction with specific vaginal microbial and associated immunological changes are contributing to this condition.

Controversies in treatment practices of the mother-infant dyad at the limit of viability

In the setting of threatened extreme preterm birth, balancing maternal and fetal risks and benefits in order to choose the best available treatment options is of utmost importance. Inconsistency in treatment practices for infants born between 22 and 24 weeks of gestatotional age may account for inter-hospital variation in survival rates with and without impairment. Most importantly, non-biased and accurate information must be presented to the family as soon as extremely preterm birth is suspected, including counseling on morbidities and mortality associated with delivery at the limits of viability. This review will focus on different therapeutic medical and surgical practices available for threatened extremely preterm birth to improve fetal and maternal outcomes while highlighting the importance of patient-centered approaches.

Concentration of vaginal and systemic cytokines obtained early in pregnancy and their impact on preterm birth

OBJECTIVE

A number of factors can lead to a maternal pro-inflammatory response resulting in a spontaneous preterm birth. However, it remains unknown if an upregulation in the maternal immune system early in pregnancy leads to an increase in pro-inflammatory cytokines and ultimately preterm birth. Therefore, we hypothesize an increase in vaginal and systemic pro-inflammatory cytokines early pregnancy is associated with an increased risk of preterm birth.

STUDY DESIGN

Patients initiating prenatal care prior to 14 weeks gestation were recruited for eligibility. A vaginal swab and serum sample was obtained at the first prenatal visit and these were then stored at -80 C. Patients were then followed for their gestational age at delivery. Five patients delivering preterm (cases) were matched with ten patients delivering at term (controls) based on age, BMI, smoking status and ethnicity. The serum and vaginal swabs from the cases and controls were then analyzed for the following cytokines using a multiplex cytokine assay: GM-CSF, IL-1b, IL-6, TNFα, and Rantes.

RESULTS

A total of 116 patients were screened for eligibility and 96 of these patients had samples obtained prior to 14 weeks gestation. Of these 96, 5 had a spontaneous preterm birth and these were matched to 10 controls. There was no difference detected in the cytokine concentrations of GM-CSF, IL-1b, IL-6, TNFα, and Rantes in the serum or cervicovaginal fluid between cases and controls.

CONCLUSION

This study demonstrates there is no difference in cytokine concentrations of several pro-inflammatory cytokines in the vagina or in the serum prior to 14 weeks gestation in patients delivering preterm. Therefore, the concentration of the cytokines analyzed in this study from the vagina and serum have little predictive value on the risk of preterm birth. Further research is needed to deepen our understanding of the mechanisms leading to preterm birth.

Cervicovaginal microbiota and metabolome predict preterm birth risk in an ethnically diverse cohort

The syndrome of spontaneous preterm birth (sPTB) presents a challenge to mechanistic understanding, effective risk stratification, and clinical management. Individual associations between sPTB, self-reported ethnic ancestry, vaginal microbiota, metabolome, and innate immune response are known but not fully understood, and knowledge has yet to impact clinical practice. Here, we used multi–data type integration and composite statistical models to gain insight into sPTB risk by exploring the cervicovaginal environment of an ethnically heterogenous pregnant population (n = 346 women; n = 60 sPTB < 37 weeks’ gestation, including n = 27 sPTB < 34 weeks). Analysis of cervicovaginal samples (10–15⁺⁶ weeks) identified potentially novel interactions between risk of sPTB and microbiota, metabolite, and maternal host defense molecules. Statistical modeling identified a composite of metabolites (leucine, tyrosine, aspartate, lactate, betaine, acetate, and Ca²⁺) associated with risk of sPTB < 37 weeks (AUC 0.752). A combination of glucose, aspartate, Ca²⁺, Lactobacillus crispatus, and L. acidophilus relative abundance identified risk of early sPTB < 34 weeks (AUC 0.758), improved by stratification by ethnicity (AUC 0.835). Increased relative abundance of L. acidophilus appeared protective against sPTB < 34 weeks. By using cervicovaginal fluid samples, we demonstrate the potential of multi–data type integration for developing composite models toward understanding the contribution of the vaginal environment to risk of sPTB.

Granulocyte-macrophage colony-stimulating factor initiates amniotic membrane rupture and preterm birth in a mouse model

OBJECTIVE

Preterm premature rupture of membranes is associated with 30% of all preterm births. The weakening of amniotic membranes is associated with an increase in matrix metallopeptidases (MMPs) along with a decrease in their inhibitors, tissue inhibitor metallopeptidases (TIMPs). Additionally, granulocyte-macrophage colony-stimulating factor (GM-CSF) has been shown to weaken fetal membranes in-vitro. We hypothesize pregnant mice treated with GM-CSF lead to increased MMPs:TIMPs resulting in membrane rupture and preterm birth.

STUDY DESIGN

Pregnant CD-1 mice on gestational day 17 received either an intrauterine injection of GM-CSF or vehicle control. A second series of mice were administered an intrauterine injection of Lipopolysaccharide along with either anti-mouse GM-CSF or control antibody. Mice were evaluated for rupture of membranes and/or preterm birth and the uterus, amniotic fluid, and serum were collected for analysis.

RESULTS

87.5% of GM-CSF mice exhibited evidence of membrane rupture or preterm birth, compared with 0% in control mice (p < .001). Treatment with GM-CSF decreased the expression of TNFα (p < .05) while increasing the ratio of MMP2:TIMP1 (p < .05), MMP2:TIMP2 (p < .05), MMP2:TIMP3 (p < .001), MMP9:TIMP1 (p < .01), MMP9:TIMP2 (p < .05), MMP9:TIMP3 (p < .001), and MMP10:TIMP1 (p < .05). Mice treated with LPS and the GM-CSF antibody resulted in a decrease in the ratio of MMP2:TIMP1 (p < .0001) compared with controls.

CONCLUSION

These studies demonstrate GM-CSF will result in membrane rupture and preterm birth by increasing the ratio MMPs:TIMPs in our animal model. By increasing our understanding of the molecular pathways associated with GM-CSF, we may be able to develop future therapies to prevent preterm birth and reduce neonatal morbidity.

Cytokine profiling: variation in immune modulation with preterm birth vs. uncomplicated term birth identifies pivotal signals in pathogenesis of preterm birth

OBJECTIVES

To assess deviations in longitudinally measured cytokines with preterm birth (PTB).

METHODS

Prospective longitudinal study targeting 80 subjects. Phlebotomy specimens for broad panel of cytokine analysis were obtained at three time (T) intervals: first trimester (T1: 8-14 weeks' gestation), second trimester (T2: 18-22 weeks' gestation), and third trimester (T3: 28-32 weeks' gestation). Important demographics and outcomes were tracked. Data were stratified and the target groups were analyzed as follows: "Uncomplicated" (delivered ≥37 weeks) or "Preterm Birth" (<37 weeks). Generalized Linear Modeling determined rate of change T1-T3 by outcome.

RESULTS

Complete data replete with phlebotomy at all three visits were obtained on 80 women. Birth outcomes were as follows: 11 Uncomplicated Term Birth (UTB), 28 PTB, 4 low birth weight (LBW), 16 OB complications (OBC), 11 current infections (IFN), and 10 mixed complications (MC=2 or more of the above). 28 PTB were compared to 11 uncomplicated term deliveries. In both groups, T helper type 1 (TH1) cytokine (IL-1β), pleiotrophic pro-inflammatory cytokine (IL-6), and counter-regulatory cytokine (IL-10) responses decreased over gestation, but rates of change in IL-1β, IL-6, and IL-10 were significantly different. Stratification of women by smoking status additionally demonstrated significant variance in immune status over the course of pregnancy.

CONCLUSIONS

Women delivering PTB demonstrated significant differences in cytokine trajectory over pregnancy; these data further validate key role played by immune regulation in directing pregnancy outcome. Likewise, smoking impacts longitudinal trajectory of cytokines over pregnancy.

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.

Periodontal diseases and adverse pregnancy outcomes: Mechanisms

Adverse pregnancy outcomes (APOs) have been defined as (a) pre-term birth, when there is a delivery before 37 completed weeks (<259 days); (b) pre-eclampsia, which is a multisystem disorder of pregnancy characterized by maternal hypertension and proteinuria after the 20th gestational week; (c) low and very low birthweight, depending on whether the weight of the baby is less of 2500 g or <1500 g and (d) the spontaneous death of the fetus with <20 weeks (miscarriage) or between 20 and 36 weeks (stillbirth). In 2012, during the Consensus Report from the Joint EFP/AAP workshop on periodontitis and systematic diseases the role of periodontal diseases on APOs was reviewed. Some years later, this evidence has grown, and an update on the literature regarding the mechanisms related to this potential association (APOs and periodontal diseases) needs to be presented. The two major pathways (direct and indirect) already accepted in 2012 are still valid nowadays. Most evidence published in the last 5 years deals with a strong and solid evidence coming from the direct pathway while there is as scarce new evidence regarding indirect pathway. In this direct pathway, the haematological dissemination of oral microorganisms and their products, would later induce an inflammatory/Immune response in the foetal-placental unit. The most plausible route for this direct pathway is the hematogenous transmission through dental bacteremia, although not many new studies dealing with bacteremia has been performed lately.

Cervicovaginal fluid cytokines as predictive markers of preterm birth in symptomatic women

Objective

Here, we investigated whether cytokines in the cervicovaginal fluid (CVF) can be predictive markers of preterm birth (PTB).

Methods

A multi-center prospective cohort study was conducted on 59 singleton pregnant women hospitalized for preterm labor (PTL) and/or preterm premature rupture of membranes (pPROM) between 22 weeks and 36 weeks 6 days of gestation from 2014 to 2015. The levels of 13 inflammatory cytokines (macrophage inflammatory protein [MIP]-1α, MIP-1β, tumor necrosis factor [TNF]-α, interleukin [IL]-1β, IL-6, IL-8, IL-17α, granulocyte colony stimulating factor [G-CSF], IL-7, IL-4, IL-5, IL-10, and IL-13) were measured using a multiplex bead-based immunoassay and that of fetal fibronectin (fFN) was measured using enzyme-linked immunosorbent assay (ELISA). Statistical analyses were performed using Student’s t-test, Mann-Whitney U test, Pearson’s correlation, and receiver operating characteristic (ROC) curve analysis in SPSS version 20.0.

Results

Among the 13 cytokines assessed, the levels of 3 cytokines (MIP-1α, IL-6, and IL-7) were negatively correlated with gestational age at delivery (P=0.028, P=0.002, and P=0.018, respectively). Sensitivities of MIP-1α, IL-6, and IL-17α were 70%, 80%, and 75%, respectively, and their specificities were 57%, 65%, and 69%, respectively. The sensitivity and specificity of fFN were 33% and 95%, respectively.

Conclusion

In symptomatic women diagnosed with PTL and/or pPROM, cytokines from cervicovaginal fluid, especially IL-6 and IL-17α, could be better predictive markers of PTB than fFN.

Repeated Measures of Cervicovaginal Cytokines during Healthy Pregnancy: Understanding "Normal" Inflammation to Inform Future Screening

OBJECTIVE

This study aimed to describe characteristics of cervicovaginal cytokines obtained during pregnancy from women who subsequently delivered at term.

STUDY DESIGN

We used repeated measures of 20 cervicovaginal cytokines, collected on average on a monthly basis, from the second to the ninth month of gestation among 181 term pregnancies in the Mexico City Pregnancy Research on Inflammation, Nutrition, & City Environment: Systematic Analyses cohort (2009-2014). Cytokines were quantified using multiplex assay.

RESULTS

Cytokine distributions differed more between than within cytokines. Across trimesters, cytokines interleukin (IL)-1Ra, IL-1α, and IL-8 consistently had high concentrations compared with other measured cytokines. Cytokine intraclass correlation coefficients ranged from 0.41 to 0.82. Spearman's correlation coefficients among cytokine pairs varied but correlation directions were stable; 95.3% of the 190 correlation pairs remained either negative or positive across trimesters. Mean longitudinal patterns of log-transformed cytokines from Tobit regression varied across but less within cytokines.

CONCLUSION

Although mean concentrations of cervicovaginal cytokines among term pregnancies were high, they were largely stable over time. The high cytokine concentrations corroborate that pregnancy is associated with an active inflammatory state. These characterizations may serve as a baseline for comparison to other obstetric outcomes, which may be helpful in understanding deviations from normal gestational inflammation.

Effect of Oral Probiotic Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 on the Vaginal Microbiota, Cytokines and Chemokines in Pregnant Women

Spontaneous preterm birth is associated with vaginal microbial dysbiosis. As certain strains of lactobacilli help restore homeostasis in non-pregnant women, the goal was to determine the effect of Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 administered orally, twice daily for 12 weeks on the vaginal microbiota, cytokines and chemokines of low-risk pregnant women. A double-blind, placebo-controlled, randomized trial comparing probiotic lactobacilli to placebo daily was performed in 86 asymptomatic pregnant women who had an Intermediate or Bacterial Vaginosis Nugent score at 13 weeks. After drop outs, 32 women receiving probiotics and 34 receiving placebo completed the study. The Nugent score returned to normal in 30% of the women in both groups at 28 weeks and was maintained until 35 weeks. The majority of subjects had normal pregnancy outcomes. Ninety-three bacterial species were detected at 13 weeks, with Lactobacillus iners, Lactobacillus crispatus, Gardnerella vaginalis and Atopobium vaginae being the most abundant across pregnancy. There was no difference in the Shannon diversity index between the probiotic and placebo groups at 13, 28 or 35 weeks. Almost all subjects consumed fermented foods and many of the organisms in the vagina are also known to be present in fermented foods. Interleukin-4 in the placebo group and Interleukin-10 in both probiotic and placebo groups increased slightly at 28 weeks but were not different at 35 weeks when compared to 13 weeks. In conclusion, this study showed no adverse issues resulting from 12 week use of probiotic Lactobacillus strains GR-1 and RC-14 during pregnancy in women at low risk for premature birth. The vaginal microbiota demonstrated flux irrespective of this oral probiotic administration.

Pharmacokinetics of vaginal progesterone in pregnancy

BACKGROUND

Characterization of pharmacokinetics is lacking for vaginal progesterone in pregnancy. Dosing of vaginal progesterone for preterm birth prevention has been empirical. Owing to pregnancy-related changes in vaginal and uterine blood flow, hepatic metabolism, renal clearance, and endogenously elevated serum progesterone, studies outside of pregnancy may not be applicable. The lack of the pharmacokinetics profile of vaginally administered progesterone in pregnancy limits the ability to define the exposure-response relationship needed to optimize dosing, which has implications for its use in research and clinical care regarding management of short cervix, prevention of recurrent preterm birth, and prevention of recurrent miscarriage.

OBJECTIVE

This was a study to establish the feasibility of using serum progesterone to establish basic pharmacokinetic parameters of vaginal progesterone in pregnancy for preterm birth prevention.

STUDY DESIGN

This is a prospective study of 6 low-risk singletons at 18 0/7 to 23 6/7 weeks' gestation with body mass index 20-40. Exclusion criteria were current vaginitis, abnormal Pap smear, prescription medication use, cervical length ≤25 mm, prior preterm birth, and contraindication to progesterone. Participants received a single dose of 200 mg micronized vaginal progesterone and serum progesterone levels were evaluated every 2 hours from 0 to 12 hours and then 24 hours post dose. Primary outcome was concentration/time profile of serum progesterone.

RESULTS

Median (range) maternal age was 27 (21.5-33.3) years, median body mass index was 26.5 (23.3-29.0) kg/m², and median gestational age was 22.9 (21.0-23.4) weeks. Median baseline serum progesterone was 47 (40-52) ng/mL, median peak concentration was 54 (48-68) ng/mL, and median time to peak was 12 (4-15) hours. There was a trend in rising serum progesterone over baseline with a median change in peak concentration of 11 ng/mL and interquartile range of 2-22. Median percent change from baseline was an increase by 24% (interquartile range, 4%-53%). However, there was no clear elimination phase and the median area under the curve was 112 ng*h/mL with an interquartile range of -43 to 239.

CONCLUSION

Unlike in nonpregnant individuals, administration of vaginal progesterone in pregnant individuals only minimally impacts systemic exposure. There is a limited trend of rising serum progesterone over baseline levels, with significant inter-individual variability. Serum progesterone is unlikely to be a good candidate for establishing pharmacokinetics or dosing of vaginal progesterone in pregnancy for preterm birth prevention.

Predictive value of cervical cytokine, antimicrobial and microflora levels for pre-term birth in high-risk women

Spontaneous preterm birth (sPTB, delivery <37 weeks gestation), accounts for approximately 10% of births worldwide; the aetiology is multifactorial with intra-amniotic infection being one contributing factor. This study aimed to determine whether asymptomatic women with a history of sPTB or cervical surgery have altered levels of inflammatory/antimicrobial mediators and/or microflora within cervical fluid at 22-24 weeks gestation. External cervical fluid was collected from women with history of previous sPTB and/or cervical surgery at 22-24 weeks gestation (n = 135). Cytokine and antimicrobial peptides were measured on a multiplex platform or by ELISA. qPCR was performed for detection of 7 potentially pathogenic bacterial species. IL-8 and IL-1β levels were lower in women who delivered preterm compared to those who delivered at term (IL-8 P = 0.02; IL-1β P = 0.04). There were no differences in elafin or human beta defensin-1 protein levels between the two groups. Multiple bacterial species were detected in a higher proportion of women who delivered preterm than in those who delivered at term (P = 0.005). Cervical fluid IL-8 and IL-1β and microflora have the potential to be used as biomarkers to predict sPTB in high risk women.

Compartmentalisation of the inflammatory response following aneurysmal subarachnoid haemorrhage

INTRODUCTION

There is some evidence to suggest that a systemic and central nervous system (CNS) inflammatory response occurs following aneurysmal subarachnoid haemorrhage (aSAH) which may be related to the pathophysiology of early brain injury and delayed ischaemic neurological deficit (DIND). The aim of this study was to measure inflammatory mediator levels in plasma and cerebrospinal fluid (CSF) in the days following aSAH and to determine their association with aSAH, DIND and clinical outcome.

MATERIAL AND METHODS

Plasma and CSF samples were obtained prospectively from patients with aSAH on days 1-3, 5, 7 and 9 and profiled for interleukin (IL)-1α, IL-1β, IL-4, IL-6, IL-8, IL-10, IL-15, IL-17, IL-18, macrophage chemotactic protein (MCP)-1, vascular endothelial growth factor (VEGF) and tumour necrosis factor (TNF)-α. Plasma and CSF samples from non-aSAH patients undergoing spinal anaesthesia were used as controls.

RESULTS

The CSF levels of all cytokines investigated except for IL-1α were significantly higher in aSAH compared to controls in the first seven days of ictus. CSF levels of IL-1α (p = 0.014), IL-18 (p = 0.016), IL-6 (p = 0.0006) and IL-8 (p = 0.006) showed significant increases in the days following aSAH. Conversely IL-17 demonstrated a decrease. In particular, IL-4 was higher in the CSF of patients who had DIND at all time-points (p = 0.032). Plasma IL-6 and IL-8 levels were higher, and IL-1α levels lower, than controls at most time-points. All mediators demonstrated persistent elevation in the CSF compared to plasma apart from IL-1α and IL-18 which followed the opposite trend. Day 3 plasma IL-6 levels predicted poor outcome at six months (Exp(B) 1.12 1.03-1.22, P = 0.012), although this association was lost in the second analysis incorporating Fisher grade, WFNS grade and age.

CONCLUSION

The post aSAH inflammatory response peaks on days 5-7 post ictus and remains largely compartmentalised within the CNS. IL-4 may have a particular association with DIND although its precise role in the pathophysiology of the disorder remains unclear. IL-6 predicted poor outcome but not independently of clinical grade, suggesting that it may be a surrogate marker of early brain injury.

Neutrophil elastase in cervical fluid in women with short cervical length

OBJECTIVE

The aim of the study was to determine the relationships between short cervical length (CL) and levels of cervical fluid neutrophil elastase (NE), secretory leukocyte protease inhibitor (SLPI), and interleukin 8 (IL-8) in the second trimester of pregnancy of women who underwent ultrasound-indicated cervical cerclage.

MATERIALS AND METHODS

CL of <25 mm or cervical funneling were included in the short CL group (n = 26) and the normal CL group (n = 22) included women who had CL of ≥25 mm and had no cervical funneling in women between 17 + 0 and 24 + 6 weeks of gestation. Levels of NE, SLPI, and IL-8 were measured by using enzyme-linked immunosorbent assay kits. Mann-Whitney U tests and Spearman's correlation analysis were used for statistical analyses.

RESULTS

Compared with the normal CL group, the short CL group had significantly higher median NE levels (P < 0.001) and higher, though not significant, median IL-8 levels by approximately three times (2107.0 vs. 798.3 pg/mL, P = 0.132). The median SLPI levels in cervical fluid was similar between the two groups (107.6 vs. 103.2 ng/mL, P = 0.499). Short CL had a significant correlations with cervical fluid NE levels (r = -0.475, P = 0.001).

CONCLUSION

Increased cervical fluid NE associated with cervical shortening in second trimester of pregnancy, whereas cervical fluid SLPI had constant levels.

Block of Granulocyte-Macrophage Colony-Stimulating Factor Prevents Inflammation-Induced Preterm Birth in a Mouse Model for Parturition

OBJECTIVE

A multitude of factors promotes inflammation in the reproductive tract leading to preterm birth. Macrophages peak in the cervix prior to birth and their numbers are increased by the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF). We hypothesize GM-CSF is produced from multiple sites in the genital tract and is a key mediator in preterm birth.

STUDY DESIGN

Ectocervical, endocervical, and amniotic fluid mesenchymal stem cells were treated with lipopolysaccharide (LPS), and the concentration and expression of GM-CSF was measured. Pregnant CD-1 mice on gestational day 17 received LPS and an intravenous injection of either anti-mouse GM-CSF or control antibody. After 6 hours, the preterm birth rate was recorded.

RESULTS

Treatment with LPS increased the GM-CSF concentration and messenger RNA expression after 24 hours in all 3 cell lines ( P < .01). Mice treated with LPS and the GM-CSF antibody had a preterm birth rate of 25%, compared to a 66.7% preterm birth rate in controls, within 6 hours ( P < .05, χ²). Treatment with the anti-mouse GM-CSF antibody decreased the concentration of GM-CSF in the mouse serum ( P < .01) but did not alter the number of macrophages or collagen content in the cervix.

CONCLUSION

These studies demonstrate that GM-CSF is produced from multiple sites in the genital tract and that treatment with an antibody to GM-CSF prevents preterm birth. Curiously, the anti-mouse GM-CSF antibody did not decrease the number of macrophages in the cervix. Further research is needed to determine whether antibodies to GM-CSF can be utilized as a therapeutic agent to prevent preterm birth.

Vaginal progesterone is as effective as cervical cerclage to prevent preterm birth in women with a singleton gestation, previous spontaneous preterm birth, and a short cervix: updated indirect comparison meta-analysis

BACKGROUND

An indirect comparison meta-analysis published in 2013 reported that both vaginal progesterone and cerclage are equally efficacious for preventing preterm birth and adverse perinatal outcomes in women with a singleton gestation, previous spontaneous preterm birth, and a sonographic short cervix. The efficacy of vaginal progesterone has been challenged after publication of the OPPTIMUM study. However, this has been resolved by an individual patient-data meta-analysis (Am J Obstet Gynecol. 2018;218:161-180).

OBJECTIVE

To compare the efficacy of vaginal progesterone and cerclage in preventing preterm birth and adverse perinatal outcomes in women with a singleton gestation, previous spontaneous preterm birth, and a midtrimester sonographic short cervix.

DATA SOURCES

MEDLINE, EMBASE, LILACS, and CINAHL (from their inception to March 2018); Cochrane databases, bibliographies, and conference proceedings.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials comparing vaginal progesterone to placebo/no treatment or cerclage to no cerclage in women with a singleton gestation, previous spontaneous preterm birth, and a sonographic cervical length <25 mm.

STUDY APPRAISAL AND SYNTHESIS METHODS

Updated systematic review and adjusted indirect comparison meta-analysis of vaginal progesterone vs cerclage using placebo/no cerclage as the common comparator. The primary outcomes were preterm birth <35 weeks of gestation and perinatal mortality. Pooled relative risks (RRs) with 95% confidence intervals were calculated.

RESULTS

Five trials comparing vaginal progesterone vs placebo (265 women) and 5 comparing cerclage vs no cerclage (504 women) were included. Vaginal progesterone, compared to placebo, significantly reduced the risk of preterm birth <35 and <32 weeks of gestation, composite perinatal morbidity/mortality, neonatal sepsis, composite neonatal morbidity, and admission to the neonatal intensive care unit (RRs from 0.29 to 0.68). Cerclage, compared to no cerclage, significantly decreased the risk of preterm birth <37, <35, <32, and <28 weeks of gestation, composite perinatal morbidity/mortality, and birthweight <1500 g (RRs from 0.64 to 0.70). Adjusted indirect comparison meta-analyses did not show statistically significant differences between vaginal progesterone and cerclage in the reduction of preterm birth or adverse perinatal outcomes.

CONCLUSION

Vaginal progesterone and cerclage are equally effective for preventing preterm birth and improving perinatal outcomes in women with a singleton gestation, previous spontaneous preterm birth, and a midtrimester sonographic short cervix. The choice of treatment will depend on adverse events and cost-effectiveness of interventions and patient/physician's preferences.

Mid-gestational changes in cervicovaginal fluid cytokine levels in asymptomatic pregnant women are predictive markers of inflammation-associated spontaneous preterm birth

OBJECTIVES

Perturbation of the choriodecidual space before the onset of spontaneous preterm birth (sPTB) could lead to a concomitant rise in both cervicovaginal fluid (CVF) cytokine and fetal fibronectin (FFN), and assessing the concentrations of both markers could improve the prediction of sPTB (delivery before 37 completed weeks of gestation). Therefore, we prospectively determined mid-trimester changes in CVF cytokine and FFN concentrations, and their predictive capacity for sPTB in asymptomatic pregnant women.

STUDY DESIGN

CVF collected at 20+0-22+6 weeks (n = 47: Preterm-delivered = 22, Term-delivered = 25) and 26+0-28+6 weeks (n = 50: Preterm-delivered = 17, Term-delivered = 33) from 63 asymptomatic pregnant women at risk of sPTB were examined. Cytokine and FFN concentrations were determined by multiplexed bead-based immunoassay and 10Q Rapid analysis (Hologic, MA, USA) respectively. The 20+0-22+6/26+0-28+6 weeks ratios of cytokines and FFN concentrations were compared between preterm- and term-delivered women using Receiver Operating Characteristics curves to predict sPTB. Also, bacterial 16S rDNA from 64 samples (20+0-22+6 weeks n = 36, 26+0-28+6 weeks n = 28) was amplified by polymerase chain reaction to determine associations between vaginal microflora, cytokine and FFN concentrations.

RESULTS

Changes in RANTES and IL-1β concentrations between 20+0-22+6 and 26+0-28+6 weeks, expressed as a ratios, were predictive of sPTB, RANTES (AUC = 0.82, CI = 0.62-0.94) more so than IL-1β (AUC = 0.71, CI = 0.53-0.85) and FFN (not predictive). Combining these markers (AUC = 0.83, CI = 0.63-0.95) showed similar predictive capacity as RANTES alone. FFN concentrations at 26+0-28+6 weeks correlated with IL-1β (r = 0.4, P = 0.002) and RANTES (r = 0.3, P = 0.03). In addition, there was increased prevalence of vaginal anaerobes including Bacteroides, Fusobacterium and Mobiluncus between gestational time points in women who experienced sPTB compared to the term women (P = 0.0006).

CONCLUSIONS

CVF RANTES and IL-1β in mid-trimester of pregnancy correlate with quantitative FFN. The levels of CVF RANTES and IL-1β decline significantly in women who deliver at term unlike women who deliver preterm. This observation suggests that sPTB may be characterised by sustained choriodecidual inflammation and may have clinical value in serial screening for sPTB if confirmed by larger studies.

Cervical cerclage placement decreases local levels of proinflammatory cytokines in patients with cervical insufficiency

BACKGROUND

Cervical insufficiency is characterized by premature, progressive dilation and shortening of the cervix during pregnancy. If left unattended, this can lead to the prolapse and rupture of the amniotic membrane, which usually results in midtrimester pregnancy loss or preterm birth. Previous studies have shown that proinflammatory cytokines such as interleukin-1β, interleukin-6, interleukin-8, and tumor necrosis factor alpha are up-regulated in normal parturition but are also associated with preterm birth. Studies evaluating such markers in patients with cervical insufficiency have evaluated only their diagnostic potential. Even fewer studies have studied them within the context of cerclage surgery.

OBJECTIVES(S)

The objective of the study was to evaluate the impact of local and systemic inflammatory markers on the pathogenesis of cervical insufficiency and the effect of cerclage surgery on the local immune microenvironment of women with cervical insufficiency.

STUDY DESIGN

We recruited 28 pregnant women (12-20 weeks' gestation) diagnosed with insufficiency and referred for cerclage surgery and 19 gestational age-matched normal pregnant women as controls. Serum and cervicovaginal fluid samples were collected before and after cerclage surgery and during a routine checkup for normal women and analyzed using a targeted 13-plex proinflammatory cytokine assay.

RESULTS

Before surgery, patients with cervical insufficiency had higher levels of interleukin-1β, interleukin-6, interleukin-12, monocyte chemoattractant protein-1 and tumor necrosis factor alpha in cervicovaginal fluid compared to controls, but after surgery, these differences disappeared. No differences were found in serum of insufficiency versus control women. In patients with insufficiency, the levels of interleukin-1β, interleukin-6, interleukin-8, monocyte chemoattractant protein-1, and interferon gamma in cervicovaginal fluid declined significantly after cerclage compared with before intervention, but these changes were not detected in serum.

CONCLUSION

Compared with normal women, patients with cervical insufficiency have elevated levels of proinflammatory cytokines in cervicovaginal fluid but not in serum, suggesting a dysregulation of the local immune environment. Cerclage intervention led to a significant decline in these proinflammatory cytokines, suggesting that cerclage may help reduce local inflammation in cervical insufficiency.

The cytokine network in women with an asymptomatic short cervix and the risk of preterm delivery

PROBLEM

To characterize the amniotic fluid (AF) inflammatory-related protein (IRP) network in patients with a sonographic short cervix (SCx) and to determine its relation to early preterm delivery (ePTD).

METHOD OF STUDY

A retrospective cohort study included women with a SCx (≤25 mm; n=223) who had amniocentesis and were classified according to gestational age (GA) at diagnosis and delivery (ePTD <32 weeks of gestation).

RESULTS

(i) In women with a SCx ≤ 22 1/7 weeks, the concentration of most IRPs increased as the cervix shortened; those with ePTD had a higher rate of increase in MIP-1α, MCP-1, and IL-6 concentrations than those delivering later; and (ii) the concentration of most IRPs and the correlation between several IRP pairs were higher in the ePTD group than for those delivering later.

CONCLUSION

Women with a SCx at 16-22 1/7 weeks have a unique AF cytokine network that correlates with cervical length at diagnosis and GA at delivery. This network may aid in predicting ePTD.

Cervical stitch (cerclage) for preventing preterm birth in singleton pregnancy

BACKGROUND

Cervical cerclage is a well-known surgical procedure carried out during pregnancy. It involves positioning of a suture (stitch) around the neck of the womb (cervix), aiming to give mechanical support to the cervix and thereby reduce risk of preterm birth. The effectiveness and safety of this procedure remains controversial. This is an update of a review last published in 2012.

OBJECTIVES

To assess whether the use of cervical stitch in singleton pregnancy at high risk of pregnancy loss based on woman's history and/or ultrasound finding of 'short cervix' and/or physical exam improves subsequent obstetric care and fetal outcome.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (30 June 2016) and reference lists of identified studies.

SELECTION CRITERIA

We included all randomised trials of cervical suturing in singleton pregnancies. Cervical stitch was carried out when the pregnancy was considered to be of sufficiently high risk due to a woman's history, a finding of short cervix on ultrasound or other indication determined by physical exam. We included any study that compared cerclage with either no treatment or any alternative intervention. We planned to include cluster-randomised studies but not cross-over trials. We excluded quasi-randomised studies. We included studies reported in abstract form only.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trials for inclusion. Two review authors independently assessed risk of bias and extracted data. We resolved discrepancies by discussion. Data were checked for accuracy. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

This updated review includes a total of 15 trials (3490 women); three trials were added for this update (152 women). Cerclage versus no cerclageOverall, cerclage probably leads to a reduced risk of perinatal death when compared with no cerclage, although the confidence interval (CI) crosses the line of no effect (RR 0.82, 95% CI 0.65 to 1.04; 10 studies, 2927 women; moderate quality evidence). Considering stillbirths and neonatal deaths separately reduced the numbers of events and sample size. Although the relative effect of cerclage is similar, estimates were less reliable with fewer data and assessed as of low quality (stillbirths RR 0.89, 95% CI 0.45 to 1.75; 5 studies, 1803 women; low quality evidence; neonatal deaths before discharge RR 0.85, 95% CI 0.53 to 1.39; 6 studies, 1714 women; low quality evidence). Serious neonatal morbidity was similar with and without cerclage (RR 0.80, 95% CI 0.55 to 1.18; 6 studies, 883 women; low-quality evidence). Pregnant women with and without cerclage were equally likely to have a baby discharged home healthy (RR 1.02, 95% CI 0.97 to 1.06; 4 studies, 657 women; moderate quality evidence).Pregnant women with cerclage were less likely to have preterm births compared to controls before 37, 34 (average RR 0.77, 95% CI 0.66 to 0.89; 9 studies, 2415 women; high quality evidence) and 28 completed weeks of gestation.Five subgroups based on clinical indication provided data for analysis (history-indicated; short cervix based on one-off ultrasound in high risk women; short cervix found by serial scans in high risk women; physical exam-indicated; and short cervix found on scan in low risk or mixed populations). There were too few trials in these clinical subgroups to make meaningful conclusions and no evidence of differential effects. Cerclage versus progesteroneTwo trials (129 women) compared cerclage to prevention with vaginal progesterone in high risk women with short cervix on ultrasound; these trials were too small to detect reliable, clinically important differences for any review outcome. One included trial compared cerclage with intramuscular progesterone (75 women) which lacked power to detect group differences. History indicated cerclage versus ultrasound indicated cerclageEvidence from two trials (344 women) was too limited to establish differences for clinically important outcomes.

AUTHORS' CONCLUSIONS

Cervical cerclage reduces the risk of preterm birth in women at high-risk of preterm birth and probably reduces risk of perinatal deaths. There was no evidence of any differential effect of cerclage based on previous obstetric history or short cervix indications, but data were limited for all clinical groups. The question of whether cerclage is more or less effective than other preventative treatments, particularly vaginal progesterone, remains unanswered.

The role of predictive vaginal biomarkers in women with cervical cerclage

Cervical cerclage is currently one of the primary methods of treatment for cervical insufficiency (CI). Identifying methods in order to selectively apply cerclage may allow us to further limit unnecessary procedures. In this regard, a limited number of inflammatory and extracellular matrix biomarkers measurable non-invasively at the level of the cervix have been examined. In this review we summarize the current research on the use of cervical biomarkers in predicting cerclage failure and propose potential objectives for future research.

Biomarkers of spontaneous preterm birth: a systematic review of studies using multiplex analysis

OBJECTIVE

Despite decades of research on risk indicators of spontaneous preterm birth (PTB), reliable biomarkers are still not available to screen or diagnose high-risk pregnancies. Several biomarkers in maternal and fetal compartments have been mechanistically linked to PTB, but none of them are reliable predictors of pregnancy outcome. This systematic review was conducted to synthesize the knowledge on PTB biomarkers identified using multiplex analysis.

MATERIALS AND METHODS

Three electronic databases (PubMed, EMBASE and Web of Science) were searched for studies in any language reporting the use of multiplex assays for maternal biomarkers associated with PTB published from January 2005 to March 2014.

RESULTS

Retrieved citations (3631) were screened, and relevant studies (33) were selected for full-text reading. Ten studies were included in the review. Forty-two PTB-related proteins were reported, and RANTES and IL-10 (three studies) followed by MIP-1β, GM-CSF, Eotaxin, and TNF-RI (two studies) were reported more than once in maternal serum. However, results could not be combined due to heterogeneity in type of sample, study population, assay, and analysis methods.

CONCLUSION

By this systematic review, we conclude that multiplex assays are a potential technological advancement for identifying biomarkers of PTB, although no single or combination of biomarkers could be identified to predict PTB risk.

Myometrial cytokines and their role in the onset of labour

Human labour is an inflammatory event, physiologically driven by an interaction between hormonal and mechanical factors and pathologically associated with infection, bleeding and excessive uterine stretch. The initiation and communicators of inflammation is still not completely understood; however, a key role for cytokines has been implicated. We summarise the current understanding of the nature and role of cytokines, chemokines and hormones and their involvement in signalling within the myometrium particularly during labour.

Rationale and design of SuPPoRT: a multi-centre randomised controlled trial to compare three treatments: cervical cerclage, cervical pessary and vaginal progesterone, for the prevention of preterm birth in women who develop a short cervix

BACKGROUND

Clinically, once a woman has been identified as being at risk of spontaneous preterm birth (sPTB) due to a short cervical length, a decision regarding prophylactic treatment must be made. Three interventions have the potential to improve outcomes: cervical cerclage (stitch), vaginal progesterone and cervical pessary. Each has been shown to have similar benefit in reduction of sPTB, but there have been no randomised control trials (RCTs) to compare them.

METHODS

This open label multi-centre UK RCT trial, will evaluate whether the three interventions are equally efficacious to prevent premature birth in women who develop a short cervix (<25 mm on transvaginal ultrasound). Participants will be asymptomatic and between 14+0 and 23+6 weeks' gestation in singleton pregnancies. Eligible women will be randomised to cervical cerclage, Arabin pessary or vaginal progesterone (200 mg once daily) (n = 170 women per group). The obstetric endpoints are premature birth rate <37 weeks' of gestation (primary), 34 weeks and 30 weeks (secondary outcomes) and short-term neonatal outcomes (a composite of death and major morbidity). It will also explore whether intervention success can be predicted by pre-intervention biomarker status.

DISCUSSION

Preterm birth is the leading cause of perinatal morbidity and mortality and a short cervix is a useful way of identifying those most at risk. However, best management of these women has presented a clinical conundrum for decades. Given the promise offered by cerclage, Arabin pessary and vaginal progesterone for prevention of preterm birth in individual trials, direct comparison of these prophylactic interventions is now essential to establish whether one treatment is superior. If, as we hypothesise, the three interventions are equally efficacious, this study will empower women to make a choice of treatments based on personal preference and quality of life issues also explored by the study. Our exploratory analysis into whether the response to intervention is related to the pre-intervention biomarker status further our understanding of the pathophysiology of spontaneous preterm birth and help focus future research questions.

TRIAL REGISTRATION

EudraCT Number: 2015-000456-15 . Registered 11th March 2015.

Preterm Birth Prevention Post-Conization: A Model of Cervical Length Screening with Targeted Cerclage

Women with a history of excisional treatment (conization) for cervical intra-epithelial neoplasia (CIN) are at increased risk of preterm birth, perinatal morbidity and mortality in subsequent pregnancy. We aimed to develop a screening model to effectively differentiate pregnancies post-conization into low- and high-risk for preterm birth, and to evaluate the impact of suture material on the efficacy of ultrasound indicated cervical cerclage. We analysed longitudinal cervical length (CL) data from 725 pregnant women post-conization attending preterm surveillance clinics at three London university Hospitals over a ten year period (2004-2014). Rates of preterm birth <37 weeks after targeted cerclage for CL<25mm were compared with local and national background rates and expected rates for this cohort. Rates for cerclage using monofilament or braided suture material were also compared. Of 725 women post-conization 13.5% (98/725) received an ultrasound indicated cerclage and 9.7% (70/725) delivered prematurely, <37weeks; 24.5% (24/98) of these despite insertion of cerclage. The preterm birth rate was lower for those that had monofilament (9/60, 15%) versus braided (15/38, 40%) cerclage (RR 0.7, 95% CI 0.54 to 0.94, P = 0.008). Accuracy parameters of interval reduction in CL between longitudinal second trimester screenings were calculated to identify women at low risk of preterm birth, who could safely discontinue surveillance. A reduction of CL <10% between screening timepoints predicts term birth, >37weeks. Our triage model enables timely discharge of low risk women, eliminating 36% of unnecessary follow-up CL scans. We demonstrate that preterm birth in women post-conization may be reduced by targeted cervical cerclage. Cerclage efficacy is however suture material-dependant: monofilament is preferable to braided suture. The introduction of triage prediction models has the potential to reduce the number of unnecessary CL scan for women at low risk of preterm birth.

Soluble HLA-G concentrations in maternal blood and cervical vaginal fluid of pregnant women with preterm premature rupture of membranes

OBJECTIVE

To evaluate soluble HLA-G (sHLA-G) concentrations in maternal blood serum and cervical vaginal fluid in pregnancies complicated by preterm premature rupture of membranes (PPROM) compared to controls.

STUDY DESIGN

Case-control study of 24 women with PPROM and 40 controls.

MAIN OUTCOME MEASURES

Vaginal and serum sHLA-G and IL-6 concentrations.

FINDINGS

Women with PPROM had significantly higher serum and vaginal sHLA-G concentrations compared to controls (respectively median 31.48U\ml versus 13.9U\ml p<0.001 and 1.7U\ml versus 0.1U\ml p<0.001). Vaginal expression of IL-6 was higher in PPROM cases compared to controls (respectively, median 31.19pg\ml versus 6.67pg\ml; p<0.001). Higher serum and vaginal sHLA-G were associated with both a shorter length of pregnancy and histological chorioamnionitis in the PPROM group.

CONCLUSIONS

Higher vaginal and serum sHLA-G in PPROM cases may be a sign of local and systemic inflammation.

Intra-uterine experimental infection by Ureaplasma diversum induces TNF-α mediated womb inflammation in mice

Ureaplasma diversum is an opportunistic pathogen associated with uterine inflammation, impaired embryo implantation, infertility, abortions, premature birth of calves and neonatal pneumonia in cattle. It has been suggested that the intra-uterine infection by Ureaplasma diversum can cause vascular changes that hinder the success of pregnancy. Thus, the aim of this study was to evaluate the changes of intrauterine site of A/J mice in estrus or proestrus phase inoculated with Ureaplasma diversum. The infection was monitored at 24, 48 and 72 hours by the PCR methodology to detect the Ureaplasma in the inoculation site and the profile of circulating blood cells. Morphological changes, intensity of inflammation and the production of cytokines were compared. The infected mice showed local inflammation through the production of IFN-γ and TNF-α. Ureaplasma diversum infections in the reproductive tract of studied mice seemed to be associated with the production of pro-inflammatory cytokines in uterine parenchyma. The levels of TNF-α of infected mice were dependent on the bacterial load of inoculated Ureaplasma. Uterine experimental infections by Ureaplasma diversum have not been mentioned yet and herein we presented the first report of an intrauterine infection model in mice.

A MCP-1 promoter polymorphism at G-2518A is associated with spontaneous preterm birth

Monocyte chemoattractant protein-1 (MCP-1) is an important chemokine involved in the pathogenesis of spontaneous preterm birth (SPTB). We examined whether the MCP-1 G-2518A polymorphism is associated with the risk of SPTB in a Chinese population. The MCP-1 G-2518A polymorphism was genotyped in 569 preterm singleton neonates and in 673 term neonates using polymerase chain reaction-restriction fragment length polymorphism analysis. The distribution of the MCP-1 G-2518A genotype and the allele frequencies between the SPTB patients and the controls were not significantly different in the overall sample. However, we found that the AA genotype was associated with significantly increased susceptibility to very SPTB (<32 weeks) [odds ratio (OR) 2.07; 95 % confidence interval (CI), 1.27-3.36; P = 0.005) and extremely SPTB (<28 weeks) (OR 2.74; 95 % CI, 1.10-6.72; P = 0.014) compared with -2518G-positive genotypes (GG + GA genotypes). When extremely preterm neonates and very preterm neonates were combined, the AA genotype was also significantly associated with increased susceptibility to SPTB (OR 2.23; 95 % CI, 1.40-3.54; P < 0.001). The MCP-1 G-2518A polymorphism was not associated with increased susceptibility to SPTB in patients with premature rupture of the membranes (PROM) or in those without PROM. Our findings suggest that the MCP-1 G-2518A polymorphism may plays a role in mediating the susceptibility to SPTB in the Chinese population. Knowledge of genetic factors contributing to the pathogenesis of SPTB may have implications for screening and treatment of this disorder.

Raised trappin2/elafin protein in cervico-vaginal fluid is a potential predictor of cervical shortening and spontaneous preterm birth

Early spontaneous preterm birth is associated with inflammation/infection and shortening of the cervix. We hypothesised that cervico-vaginal production of trappin2/elafin (peptidase inhibitor 3) and cathelicidin antimicrobial peptide (cathelicidin), key components of the innate immune system, are altered in women who have a spontaneous preterm birth. The aim was to determine the relationship between cervico-vaginal fluid (CVF) trappin2/elafin and cathelicidin protein concentrations with cervical length in woman at risk of spontaneous preterm birth. Trappin2/elafin and cathelicidin were measured using ELISA in longitudinal CVF samples (taken between 13 to 30 weeks' gestation) from 74 asymptomatic high risk women (based on obstetric history) recruited prospectively. Thirty six women developed a short cervix (<25 mm) by 24 weeks' and 38 women did not. Women who developed a short cervix had 2.71 times higher concentrations of CVF trappin2/elafin from 14 weeks' versus those who did not (CI 1.94–3.79, p<0.0005). CVF trappin2/elafin before 24 weeks' was 1.79 times higher in women who had a spontaneous preterm birth <37 weeks' (CI: 1.05–3.05, p = 0.034). Trappin2/elafin (>200 ng/ml) measured between 14⁺⁰–14⁺⁶ weeks' of pregnancy predicted women who subsequently developed a short cervix (n = 11, ROC area = 1.00, p = 0.008) within 8 weeks. Cathelicidin was not predictive of spontaneous delivery. Vitamin D status did not correlate with CVF antimicrobial peptide concentrations. Raised CVF trappin2/elafin has potential as an early pregnancy test for prediction of cervical shortening and spontaneous preterm birth. This justifies validation in a larger cohort.

Probiotic Lactobacillus rhamnosus GR-1 supernatant prevents lipopolysaccharide-induced preterm birth and reduces inflammation in pregnant CD-1 mice

OBJECTIVE

The objective of this study was to determine the effect of probiotic Lactobacillus rhamnosus GR-1 supernatant (GR-1 SN) on lipopolysaccharide-induced preterm birth (PTB) and outputs of cytokines, chemokines, and progesterone in pregnant CD-1 mice.

STUDY DESIGN

We compared PTB rates after intrauterine injection of lipopolysaccharide with and without previous GR-1 SN treatment. Cytokines and chemokines in the maternal plasma, myometrium, placenta, and amniotic fluid were examined with multiplex assay, and circulating maternal progesterone was measured with enzyme-linked immunoassay. Statistical significance was assessed with 2-tailed 1-way analysis of variance or analysis of variance on ranks. Fetal sex ratios in mice that delivered preterm were compared with those that delivered at term after lipopolysaccharide and GR-1 SN treatments.

RESULTS

GR-1 SN reduced lipopolysaccharide-induced PTB by 43%. GR-1 SN significantly decreased the lipopolysaccharide-induced production of interleukin (IL)-1β, -6, and -12p40, tumor necrosis factor-α, CCL4, and CCL5 in maternal plasma; IL-6, -12p70, -17, and -13 and tumor necrosis factor-α in myometrium; IL-6, -12p70, and -17 in placenta; and IL-6, tumor necrosis factor-α, CCL3, and CCL4 in amniotic fluid. Maternal plasma progesterone was reduced significantly after lipopolysaccharide injection with and without GR-1 SN pretreatment. There was no difference in fetal sex ratios between mice that delivered preterm and those that did not after lipopolysaccharide and GR-1 SN treatments.

CONCLUSION

The supernatant of probiotic L rhamnosus GR-1 attenuated lipopolysaccharide-induced inflammation and PTB in vivo. GR-1 SN may confer therapeutic benefits in the prevention of infection-associated PTB by controlling systemic and intrauterine inflammation.