Inflammation induced preterm labor and birth

Physical activity and circulating inflammatory markers and cytokines during pregnancy: A population-based cohort study

INTRODUCTION

Physical activity (PA) during pregnancy has numerous benefits, which may be mediated via effects on the immune system. However, supportive evidence is inconsistent and is mainly from studies in high-risk groups. We estimated the effect of PA during pregnancy on systemic inflammatory markers and cytokines in mothers recruited in the Barwon infant study.

MATERIAL AND METHODS

The Barwon infant study is a prebirth cohort of 1064 mothers recruited in the Barwon Region of Victoria, Australia. Participants reported their previous week's PA at their 28-week antenatal appointment using the International PA Questionnaire. Women were grouped into low, moderate, and high PA categories based on daily duration and weekly frequency of walking, moderate- or vigorous-intensity PA. Women reporting moderate levels of PA, consistent with current recommendations, served as the comparison group. Markers of systemic inflammation, high-sensitivity C-reactive protein (hsCRP), glycoprotein acetyls (GlycA), and 17 cytokines were measured at 28 weeks gestation and log transformed as appropriate. Regression analyses adjusted for maternal smoking, gestational diabetes mellitus, prepregnancy BMI, and household size were performed.

RESULTS

Compared to women in the moderate group (n = 371, 42%), women reporting low PA (n = 436, 50%) had 10.1% higher hsCRP (95% CI (3.7% to 16.6%), p < 0.01) while women in high PA (n = 76, 9%) had a 14% higher hsCRP (95% CI (3.1% to 24.8%), p = 0.01). Women in the high PA category had higher interleukin (IL)-4 (q = 0.03) and IL-9 (q = 0.03) levels compared to those in moderate category. Each vigorous MET minute/week was associated with lower GlycA (β = -0.004, 95% CI (-0.044 to 0.035); p = 0.03).

CONCLUSIONS

Low and high PA are each associated with higher hsCRP than moderate PA, suggesting that undertaking the recommended moderate PA during pregnancy decreases systemic inflammation. High PA affects T cell-associated cytokines during pregnancy. Evidence from our study suggests that PA can modulate the immune responses during pregnancy. Studies are now required to assess whether PA during pregnancy impacts maternal and infant clinical outcomes by modifying inflammatory responses.

Inflammatory markers in pregnancy - surprisingly stable. Mapping trajectories and drivers in four large cohorts

Adaptations of the immune system throughout gestation have been proposed as important mechanisms regulating successful pregnancy. Dysregulation of the maternal immune system has been associated with adverse maternal and fetal outcomes. To translate findings from mechanistic preclinical studies to human pregnancies, studies of serum immune markers are the mainstay. The design and interpretation of human biomarker studies require additional insights in the trajectories and drivers of peripheral immune markers. The current study mapped maternal inflammatory markers (C-reactive protein (CRP), interleukin (IL)-1β, IL-6, IL-17A, IL-23, interferon- γ ) during pregnancy and investigated the impact of demographic, environmental and genetic drivers on maternal inflammatory marker levels in four multi-ethnic and socio-economically diverse population-based cohorts with more than 12,000 pregnant participants. Additionally, pregnancy inflammatory markers were compared to pre-pregnancy levels. Cytokines showed a high correlation with each other, but not with CRP. Inflammatory marker levels showed high variability between individuals, yet high concordance within an individual over time during and pre-pregnancy. Pre-pregnancy body mass index (BMI) explained more than 9.6% of the variance in CRP, but less than 1% of the variance in cytokines. The polygenic score of CRP was the best predictor of variance in CRP (>14.1%). Gestational age and previously identified inflammation drivers, including tobacco use and parity, explained less than 1% of variance in both cytokines and CRP. Our findings corroborate differential underlying regulatory mechanisms of CRP and cytokines and are suggestive of an individual inflammatory marker baseline which is, in part, genetically driven. While prior research has mainly focused on immune marker changes throughout pregnancy, our study suggests that this field could benefit from a focus on intra-individual factors, including metabolic and genetic components.

Phenanthroline relaxes uterine contractions induced by diverse contractile agents by decreasing cytosolic calcium concentration

Uterine contractions during labor and preterm labor are influenced by a complex interplay of factors, including hormones and inflammatory mediators. This complexity may contribute to the limited efficacy of current tocolytics for preterm labor, a significant challenge in obstetrics with 15 million cases annually and approximately 1 million resulting deaths worldwide. We have previously shown that the myometrium expresses bitter taste receptors (TAS2Rs) and that their activation leads to uterine relaxation. Here, we investigated whether the selective TAS2R5 agonist phenanthroline can induce relaxation across a spectrum of human uterine contractions and whether the underlying mechanism involves changes in intracellular Ca2+ signaling. We performed experiments using samples from pregnant women undergoing scheduled cesarean delivery, assessing responses to various inflammatory mediators and oxytocin with and without phenanthroline. Our results showed that phenanthroline concentration-dependently inhibited contractions induced by PGF2α, U46619, 5-HT, endothelin-1 and oxytocin. Furthermore, in hTERT-infected human myometrial cells exposed to uterotonics, phenanthroline effectively suppressed the increase in intracellular Ca2+ concentration induced by PGF2α, U46619, oxytocin, and endothelin-1. These results suggest that the selective TAS2R5 agonist may not only significantly reduce uterine contractions but also decrease intracellular Ca2+ levels. This study highlights the potential development of TAS2R5 agonists as a new class of uterine relaxants, providing a novel avenue for improving the management of preterm labor.

Frontiers in the Etiology and Treatment of Preterm Premature Rupture of Membrane: From Molecular Mechanisms to Innovative Therapeutic Strategies

Preterm premature rupture of membranes (pPROM) poses a significant threat to fetal viability and increases the risk for newborn morbidities. The perinatal period of preterm infants affected by pPROM is often characterized by higher rates of mortality and morbidity, with associated risks of cerebral palsy, developmental delays, compromised immune function, respiratory diseases, and sensory impairments. pPROM is believed to result from a variety of causes, including but not limited to microbially induced infections, stretching of fetal membranes, oxidative stress, inflammatory responses, and age-related changes in the fetal-placental interface. Maternal stress, nutritional deficiencies, and medically induced procedures such as fetoscopy are also considered potential contributing factors to pPROM. This comprehensive review explores the potential etiologies leading to pPROM, delves into the intricate molecular mechanisms through which these etiologies cause membrane ruptures, and provides a concise overview of diagnostic and treatment approaches for pPROM. Based on available therapeutic options, this review proposes and explores the possibilities of utilizing a novel composite hydrogel composed of amniotic membrane particles for repairing ruptured fetal membranes, thereby holding promise for its clinical application.

Longitudinal intravital imaging of mouse placenta

Studying placental functions is crucial for understanding pregnancy complications. However, imaging placenta is challenging due to its depth, volume, and motion distortions. In this study, we have developed an implantable placenta window in mice that enables high-resolution photoacoustic and fluorescence imaging of placental development throughout the pregnancy. The placenta window exhibits excellent transparency for light and sound. By combining the placenta window with ultrafast functional photoacoustic microscopy, we were able to investigate the placental development during the entire mouse pregnancy, providing unprecedented spatiotemporal details. Consequently, we examined the acute responses of the placenta to alcohol consumption and cardiac arrest, as well as chronic abnormalities in an inflammation model. We have also observed viral gene delivery at the single-cell level and chemical diffusion through the placenta by using fluorescence imaging. Our results demonstrate that intravital imaging through the placenta window can be a powerful tool for studying placenta functions and understanding the placental origins of adverse pregnancy outcomes.

Investigating the association of the lifestyle of pregnant women with the rate of preterm labor

Introduction

From a long time ago, preterm birth has posed life-threatening risks due to the significant complications it causes. The present study aimed to examine how the lifestyle of pregnant women is related to the incidence of preterm birth.

Materials and Methods

For this cohort study, a total of 234 individuals with healthy and unhealthy lifestyles who visited the women's clinics of Azad University hospitals during the year 2021 were randomly selected to participate. Four criteria were utilized to build lifestyle questionnaires, which included smoking habits, physical activity levels, consumption of high-fiber foods, and sufficient sleep. According to the individuals' responses, 117 mothers who scored above 14, and 117 mothers who scored below 14 were followed up. The SPSS version 25 (SPSS Inc., Chicago, Ill., USA) was used to analyze the correlation between variables and preterm birth, employing statistical tests such as Mann-Whitney, Chi-square, and independent t-test.

Results

In this study, the mean age of the examined women was 27.11 ± 3.19. Out of the total number of babies, 133 (56.8%) were females, while 101 (43.2%) were males. The P value for the association between lifestyle and preterm birth was less than 0.0001, indicating statistical significance. The difference between the consumption of tobacco, fruits, and vegetables and sufficient sleep with preterm birth was not statistically significant (P value >0.05).

Conclusion

A healthy lifestyle can serve as an important preventive measure against preterm birth. Adequate education provided by the healthcare and treatment system plays an important role in promoting the adoption of a healthy lifestyle and benefiting from its positive outcomes.

First-trimester urinary extracellular vesicles as predictors of preterm birth: an insight into immune programming

Background: The programming of innate and adaptive immunity plays a pivotal role in determining the course of pregnancy, leading to either normal term birth (TB) or preterm birth (PB) through the modulation of macrophage (M1/M2) differentiation. Extracellular vesicles (EVs) in maternal blood, harboring a repertoire of physiological and pathological messengers, are integral players in pregnancy outcomes. It is unknown whether urinary EVs (UEVs) could serve as a non-invasive mechanistic biomarker for predicting PB. Methods: This study investigated first-trimester UEVs carrying M1 messengers with altered immune programming, aiming to discern their correlation to subsequent PB. A birth cohort comprising 501 pregnant women, with 40 women experiencing PB matched to 40 women experiencing TB on the same day, was examined. First-trimester UEVs were isolated for the quantification of immune mediators. Additionally, we evaluated the UEV modulation of "trained immunity" on macrophage and lymphocyte differentiations, including mRNA expression profiles, and chromatin activation modification at histone 3 lysine 4 trimethylation (H3K4me3). Results: We found a significant elevation (p < 0.05) in the particles of UEVs bearing characteristic exosome markers (CD9/CD63/CD81/syntenin) during the first trimester of pregnancy compared to non-pregnant samples. Furthermore, UEVs from PB demonstrated significantly heightened levels of MCP-1 (p = 0.003), IL-6 (p = 0.041), IL-17A (p = 0.007), IP-10 (p = 0.036), TNFα (p = 0.004), IL-12 (p = 0.045), and IFNγ (p = 0.030) relative to those from TB, indicative of altered M1 and Th17 differentiation. Notably, MCP-1 (>174 pg/mL) exhibited a sensitivity of 71.9% and specificity of 64.6%, and MCP-1 (>174 pg/mL) and IFNγ (>8.7 pg/mL) provided a higher sensitivity (84.6%) of predicting PB and moderate specificity of 66.7%. Subsequent investigations showed that UEVs from TB exerted a significant suppression of M1 differentiation (iNOS expression) and Th17 differentiation (RORrT expression) compared to those of PB. Conversely, UEVs derived from PB induced a significantly higher expression of chromatin modification at H3K4me3 with higher production of IL-8 and TNFα cytokines (p < 0.001). Implications: This pioneering study provides critical evidence for the early detection of altered M1 and Th17 responses within UEVs as a predictor of PB and early modulation of altered M1 and Th17 polarization associated with better T-cell regulatory differentiation as a potential prevention of subsequent PB.

Polybrominated diphenyl ether (PBDE) exposure and adverse maternal and infant health outcomes: Systematic review

Polybrominated diphenyl ethers (PBDEs) are flame retardants found in ambient environment and are measured in humans. There are reports on general PBDE toxicity, including endocrine disrupting properties. Studies on adverse maternal and infant outcomes and underlying toxicity mechanisms needs to be understood. The objective of this study was to conduct a systematic review to examine the state of science on the relationship between PBDE and adverse maternal/infant health outcomes and related maternal biomarker changes. This literature review was conducted using PubMed, Scopus, Embase and Web of Science for published articles from January 2005-February 2022. Article quality was assessed using Newcastle-Ottawa Scale. Of the 1518 articles, only 54 human observational studies were screened in for this review. A second reviewer examined the validity of these articles. Reports on associations between PBDE and maternal health outcomes included gestational hypertension/preeclampsia (N = 2) and gestational diabetes mellitus/glycemic index (N = 6). Meanwhile, reports on PBDE and infant outcomes (N=32) included effects on infant birth weight, birth length and cephalic perimeter, preterm birth, fetal growth restriction and APGAR scores. Although findings on PBDE exposure and adverse infant outcomes showed inconsistencies across studies, in general, negative correlations between maternal PBDEs and infant birth weight, birth length and cephalic perimeter were seen, in few cases, after stratification by sex. Association between maternal PBDE and maternal biomarkers (N=18) suggested negative impact of PBDE exposure on markers relevant to neuro-endocrine system and inflammatory processes. The review findings identified potential associations between maternal PBDE and adverse maternal/infant health outcomes. Furthermore, PBDE-related biomarker changes suggest disturbances in maternal mechanisms relevant to endocrine disrupting properties of PBDEs. The observed study heterogeneity can be attributed to factors namely, sample size, study design and statistical analysis. Overall review findings imply the necessity for further research to validate PBDE exposure-related adverse maternal/infant health effects and to validate underlying toxicity mechanisms.

An analysis of placental chorionic villous and decidual basalis tissue immunoreactivity in patients after cesarean section due to a placenta accreta spectrum disorder and elective cesarean section followed by the depressed mood

An analysis of placental chorionic villous and decidual basalis tissue immunoreactivity in patients after cesarean section due to a placenta accreta spectrum disorder and elective cesarean section followed by a depressed mood.

RESEARCH BACKGROUND

Over the past few years, interest in investigating immune dysfunction in patients with psychiatric disorders has increased. B7-H4 is a molecule with immunosuppressive properties that seems to play a key role in establishing maternal tolerance against fetal antigens. The aim of this study was to compare the B7-H4 immunoreactivity levels in patients after cesarean section.

METHODS

Placental and decidual tissue samples were obtained from 49 women who delivered at Bielański Hospital in Warsaw between 2009 and 2015. Fifteen of the patients developed postpartum depression and 14 had a diagnosis of placenta accreta spectrum. The control group consisted of 20 healthy patients on whom cesarean section was performed due to breech presentation at term.

RESULTS

The highest levels of B7-H4 immunoreactivity were found in the placental chorionic villous and decidual basalis tissue samples of the patients who later developed postpartum depression, while the lowest levels were found in the samples of those patients with a placenta accreta spectrum disorder. The difference between the B7-H4 immunoreactivity levels of these two groups was statistically significant. The B7-H4 expression levels were statistically significantly higher in the women in the postpartum depression group than in the control group.

CONCLUSION

Postpartum depression follows a disturbance of the suppressive milieu responsible for rebalancing the maternal immune system after the initial cytotoxic activation during labor.

Elevated expression of Toll-like receptor 4 and cytokines in both serum and myometrium at term may serve as promising biomarkers for uterine activation preceding labor

Objective

Increased inflammation and cytokine levels are considered risk factors and promoters of preterm birth (PTB). However, the regulatory mechanism of pregnancy-related inflammation remains unclear. Toll-like receptor 4 (TLR4) plays a critical role in inflammatory responses in various diseases. Therefore, our study aimed to investigate whether TLR4 is involved in the inflammatory responses during uterine activation for labor, with the goal of identifying potential biomarkers for uterine activation at term.

Materials and methods

We used flow cytometry to detect TLR4 expression on CD14+ maternal blood monocytes in the first, second, and third trimesters. ELISA was employed to measure TLR4 and cytokines levels in the maternal serum of term non-labor (TNL), term labor (TL) women and LPS induced preterm labor and PBS injected controls. TLR4siRNA was transfected into the human myometrial smooth muscle cells (HMSMCs), which were subsequently treated with IL-1β. The mRNA and protein levels of TLR4, uterine contraction-related protein connexin 43 (CX43), oxytocin receptor (OTR), MAPK/NF-κB signaling pathway, and cytokines were analyzed using qRT-PCR, western blotting, and immunohistochemistry.

Results

The study revealed TLR4 expression on CD14+ maternal blood monocytes was higher in the third trimester group compared to the first and second trimester groups (p<0.001). Maternal serum concentrations of TLR4 and cytokines were significantly higher in the TL group than the TNL group (p<0.001). TLR4, OTR, CX43, activated MAPK/NF-κB expression, and cytokines levels were upregulated in TL group, and similarly significantly higher in the LPS-induced preterm group than in the control group. Using the HMSMCs we demonstrated that TLR4siRNA transfection suppressed contractility. Interfering with TLR4 expression reduced the expression of OTR, CX43, cytokines, and MAPK/NF-κB activation. There was a significant positive relationship between TLR4 expression and the inflammatory status in the myometrium. ROC analysis indicated that TLR4 and cytokines may serve as potential biomarkers for predicting uterine activation for labor.

Conclusion

Our data suggest that TLR4 and cytokines can act as stimulators of uterine activation for labor at term. Furthermore, the MAPK/NF-κB pathway appears to be one of the potential signaling pathways mediating TLR4's regulation of parturition initiation.

A Novel Predictive Machine Learning Model Integrating Cytokines in Cervical-Vaginal Mucus Increases the Prediction Rate for Preterm Birth

Preterm birth (PB) is a leading cause of perinatal morbidity and mortality. PB prediction is performed by measuring cervical length, with a detection rate of around 70%. Although it is known that a cytokine-mediated inflammatory process is involved in the pathophysiology of PB, none screening method implemented in clinical practice includes cytokine levels as a predictor variable. Here, we quantified cytokines in cervical-vaginal mucus of pregnant women (18-23.6 weeks of gestation) with high or low risk for PB determined by cervical length, also collecting relevant obstetric information. IL-2, IL-6, IFN-γ, IL-4, and IL-10 were significantly higher in the high-risk group, while IL-1ra was lower. Two different models for PB prediction were created using the Random Forest machine-learning algorithm: a full model with 12 clinical variables and cytokine values and the adjusted model, including the most relevant variables-maternal age, IL-2, and cervical length- (detection rate 66 vs. 87%, false positive rate 12 vs. 3.33%, false negative rate 28 vs. 6.66%, and area under the curve 0.722 vs. 0.875, respectively). The adjusted model that incorporate cytokines showed a detection rate eight points higher than the gold standard calculator, which may allow us to identify the risk PB risk more accurately and implement strategies for preventive interventions.

Immunomodulation of cytokine signalling at feto-maternal interface by microRNA-223 and -150-5p in infection-associated spontaneous preterm birth

Spontaneous preterm birth (sPTB) is a global health concern and it is the most prevalent cause of infant mortality and morbidity with occurrence rate of 5 - 18% worldwide. Studies suggest infection and infection-driven activation of inflammatory responses are the potential risk factors for sPTB. MicroRNAs (miRNAs) are thought to control the expression of several immune genes, making them crucial components of the intricate immune regulatory network and the dysregulation of miRNAs in placenta has been associated to several pregnancy-related complications. However, studies on possible role of miRNAs in immunomodulation of cytokine signalling in infection-associated sPTB are scarce. Present study aimed to investigate expression/ correlation of a few circulating miRNAs (miR-223, -150-5p, -185-5p, -191-5p), miRNA target genes and associated cytokines in sPTB women found infected with Chlamydia trachomatis/ Mycoplasma hominis/ Ureaplasma urealyticum. Non-heparinized blood and placental sample were collected from 140 sPTB and 140 term women visiting Safdarjung hospital, New Delhi (India) for conducting PCR and RT-PCR for pathogen detection and miRNA/ target gene/ cytokine expression, respectively. Common target genes of differentially expressed miRNAs were obtained from databases. The correlation between select target genes/ cytokines and serum miRNAs was determined by Spearman's rank correlation. 43 sPTB were infected with either pathogen and a significant upregulation of serum miRNAs was observed. However, miR-223 and 150-5p showed maximum fold-change (4.78 and 5.58, respectively) in PTB versus control group. IL-6ST, TGF-β R3 and MMP-14 were important target genes among 454 common targets, whereas, IL-6 and TGF-β were associated cytokines. miR-223 and 150-5p showed significant negative correlation with IL-6ST/ IL-6/ MMP-14 and positive correlation with TGF-β R3/ TGF-β. A significant positive correlation was found between IL-6ST and IL-6, TGF-β R3 and TGF-β. However, miR-185-5p and 191-5p were not significantly correlated. Although post-transcriptional validation is required, yet on the basis of mRNA findings, the study concludes that miR-223 and 150-5p are apparently of clinical importance in regulation of inflammatory processes during infection-associated sPTB.

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.

Placental histopathology, maternal characteristics and neonatal outcome in cases of preterm birth in a high-risk population in South Africa

Background. Preterm birth remains a global health concern and is one of the most common pregnancy complications associated with perinatal morbidity and mortality.Objective. To investigate placental pathology and its associations with obstetric, maternal and neonatal outcomes in the Eastern Cape region of South Africa (SA) in order to help understand its associations with preterm birth in that region. Methods. In this prospective study, placentas were collected consecutively from patients attending a public tertiary referral hospital in SA, delivering preterm (n=100; 28 - 34 weeks gestational age) and term (n=20; >36 weeks gestational age). Placentas were submitted for histopathology, and comparisons with maternal characteristics and neonatal outcomes in preterm birth were undertaken.Results. Histological analysis revealed pathology in all preterm placentas (100%), with maternal vascular malperfusion (47%) and abruptio placentae (41%) most commonly identified. Acute chorioamnionitis (21%) was associated with term births (p=0.002). Maternal characteristics and neonatal outcomes significantly associated with preterm birth included pre-eclampsia (p=0.006), neonatal respiratory distress syndrome (p=0.004) and neonatal jaundice (p=0.003). Intrauterine demise (p=0.004) and alcohol abuse (p≤0.005) were significantly associated with term delivery. The number of mothers delivering preterm who were HIV-positive was high (41%). Conclusion. The pathology identified in all preterm placentas supports the need to update institutional policies for submission of placentas from all preterm births for histopathology, particularly in countries with a high burden of preterm birth.

Reference values for interleukin-6 in the amniotic fluid of asymptomatic pregnant women

INTRODUCTION

Nowadays, proinflammatory factors are considered to play an important role in the pathophysiology of threatened preterm labor or chorioamnionitis. The aim of this study was to establish the normal reference range for interleukin-6 (IL-6) levels in the amniotic fluid and to identify factors which may alter this value.

MATERIAL AND METHODS

Prospective study in a tertiary-level center including asymptomatic pregnant women undergoing amniocentesis for genetic studies from October 2016 to September 2019. IL-6 measurements in amniotic fluid were performed using a fluorescence immunoassay with microfluidic technology (ELLA Proteinsimple, Bio Techne). Maternal history and pregnancy data were also recorded.

RESULTS

This study included 140 pregnant women. Of those, women who underwent termination of pregnancy were excluded. Therefore, a total of 98 pregnancies were included in the final statistical analysis. The mean gestational age was 21.86 weeks (range: 15-38.7) at the time of amniocentesis, and 38.6 weeks (range: 30.9-41.4) at delivery. No cases of chorioamnionitis were reported. The log₁₀ IL-6 values follow a normal distribution (W = 0.990, p = 0.692). The median, and the 5th, 10th, 90th, and 95th percentiles for IL-6 levels were 573, 105, 130, 1645, and 2260 pg/mL, respectively. The log₁₀ IL-6 values were not affected by gestational age (p = 0.395), maternal age (p = 0.376), body mass index (p = 0.551), ethnicity (p = 0.467), smoking status (p = 0.933), parity (p = 0.557), method of conception (p = 0.322), or diabetes mellitus (p = 0.381).

CONCLUSIONS

The log₁₀ IL-6 values follow a normal distribution. IL-6 values are independent of gestational age, maternal age, body mass index, ethnicity, smoking status, parity and method of conception. Our study provides a normal reference range for IL-6 levels in the amniotic fluid that can be used in future studies. We also observed that normal IL-6 values were higher in the amniotic fluid than in serum.

Proinflammatory changes in the maternal circulation, maternal-fetal interface, and placental transcriptome in preterm birth

BACKGROUND

Preterm birth remains a leading obstetrical complication because of the incomplete understanding of its multifaceted etiology. It is known that immune alterations toward a proinflammatory profile are observed in women with preterm birth, but therapeutic interventions are still lacking because of scarcity of evidence in the integration of maternal and placental interrelated compartments.

OBJECTIVE

This study aimed to obtain an integrated view of the maternal and placental contribution to preterm birth compared with normal term pregnancies for an in-depth understanding of the immune/inflammatory involvement, intending to identify novel strategies to mitigate the negative impact of inflammation.

STUDY DESIGN

We prospectively recruited 79 women with preterm or term deliveries and collected placentas for RNA sequencing, histologic analyses, and to assess levels of inflammatory mediators. Blood samples were also collected to determine the circulating immune profiles by flow cytometry and to evaluate the circulating levels of inflammatory mediators.

RESULTS

Placental transcriptomic analyses revealed 102 differentially expressed genes upregulated in preterm birth, including known and novel targets, which were highly enriched for inflammatory biological processes according to gene ontology analyses. Analysis of maternal immune cells revealed distinct profiles in preterm births vs term births, including an increased percentage of CD3^- cells and monocyte subsets and decreased CD3⁺ cells along with Th17 subsets of CD4⁺ lymphocytes. Supporting our bioinformatic findings, we found increases in proinflammatory mediators in the plasma, placenta, and fetal membranes (primarily the amnion) of women with preterm birth, such as interleukin-6 and tumor necrosis factor-α. These findings were not distinct between spontaneous and iatrogenic preterm births except at a molecular level where spontaneous preterm birth presented with an elevated inflammatory profile compared with iatrogenic preterm birth. Analysis of placental histology revealed increased structural and inflammatory lesions in preterm vs term births. We found that genes upregulated in placentas with inflammatory lesions have enrichment of proinflammatory pathways.

CONCLUSION

This work sheds light on changes within the immune system in preterm birth on multiple levels and compartments to help identify pregnancies at high risk of preterm birth and to discover novel therapeutic targets for preterm birth.

Spontaneous Preterm Birth: Elevated Galectin-3 and Telomere Shortening May Reflect a Common Pathway of Enhanced Inflammation and Senescence

Preterm delivery complicates 5-12% of pregnancies and is the primary cause of neonatal morbidity and mortality. The pathophysiology of preterm labor and parturition is not fully known, although it is probably related to inflammation and placental senescence. Telomere shortening is related to senescence and galectin-3 (Gal-3) protein is involved in cell growth, differentiation, inflammation, and fibrosis. This study examined changes in Gal-3 expression and telomere homeostasis (which represent inflammatory and stress markers) in maternal blood and placental tissue of spontaneous preterm births (SPTB) and uncomplicated, spontaneous term pregnancies (NTP) during labor. Participants included 19 women with NTP and 11 with SPTB who were enrolled during admission for delivery. Maternal blood samples were obtained along with placental tissue for Gal-3 analysis and telomere length evaluation. Gal-3 protein expression in placental tissue was increased in SPTB compared to NTP (fold change: 1.89 ± 0.36, P < 0.05). Gal-3 immunohistochemistry demonstrated strong staining in placental extravillous trophoblast tissue from SPTB. Maternal blood levels of Gal-3 protein were elevated in SPTB compared to NTP (19.3 ± 1.3 ng/ml vs. 13.6 ± 1.07 ng/ml, P = 0.001). Placental samples from SPTB had a higher percentage of trophoblasts with short telomeres (47.6%) compared to NTP (15.6%, P < 0.0001). Aggregate formation was enhanced in SPTB (7.8%) compared to NTP (1.98%, P < 0.0001). Maternal blood and placental samples from SPTB had shorter telomeres and increased Gal-3 expression compared to NTP. These findings suggest that increased senescence and inflammation might be factors in the abnormal physiology of spontaneous preterm labor.

Inflammatory Molecules Responsible for Length Shortening and Preterm Birth

It is estimated that inflammation at the placental-maternal interface is directly responsible for or contributes to the development of 50% of all premature deliveries. Chorioamnionitis, also known as the premature rupture of the amniotic membrane in the mother, is the root cause of persistent inflammation that preterm newborns experience. Beyond contributing to the onset of early labor, inflammation is a critical element in advancing several conditions in neonates, including necrotizing enterocolitis, retinopathy of prematurity, bronchopulmonary dysplasia, intraventricular hemorrhage, retinopathy of prematurity and periventricular leukomalacia. Notably, the immune systems of preterm infants are not fully developed; immune defense mechanisms and immunosuppression (tolerance) have a delicate balance that is easily upset in this patient category. As a result, premature infants are exposed to different antigens from elements such as hospital-specific microbes, artificial devices, medications, food antigens and hypoxia/hyperoxia. This has detrimental implications for preterm deliveries of less than 28 weeks because they have not yet evolved the mechanisms to tolerate maternal and self-antigens.

Term and Preterm Birth Initiation Is Associated with the Macrophages Shifting to M1 Polarization in Gestational Tissues in Mice

Inflammation in gestational tissues plays critical role in parturition initiation. We sought to investigate the leukocyte infiltration and cytokine profile in uterine tissues to understand the inflammation during term and preterm labor in the mouse model. Preterm birth was induced by the administration of lipopolysaccharide (LPS) or RU38486. The populations of leukocytes were determined by flow cytometry. Macrophages were the largest population in the myometrium and decidua in late gestation. The macrophage population was significantly changed in the myometrium and decidua from late pregnancy to term labor and significantly changed at LPS- and RU386-induced preterm labor. Neutrophils, T cells, and NKT cells were increased in LPS- and RU38486-induced preterm labor. The above changes were accompanied by the increased expression of cytokines and chemokines. In late gestation, M2 macrophages were the predominant phenotype in gestational tissues. M1 macrophages significantly increased in these tissues at term and preterm labor. IL-6 and NLRP3 expression was significantly increased in macrophages at labor, supporting that macrophages exhibit proinflammatory phenotypes. NLRP3 inflammasome inhibitor MCC950 mainly suppressed macrophage infiltration in the myometrium at term labor and preterm labor. Our data suggest that the M1 polarization of macrophages contributes to inflammation linked to term and preterm labor initiation in gestational tissues.

Diverticulitis during pregnancy: A review of the reported cases

BACKGROUND

Diverticular disease of the colon represents a common clinical condition in the western world. Its prevalence increases with age and only 5% of cases occur in adults younger than 40 years of age, making it a rare condition during pregnancy. The aim of this review was to provide an overview of the reported cases of diverticulitis during pregnancy.

METHODS

We conducted a systematic review of the literature based on preferred reporting items for systematic review and meta-analysis (PRISMA) guidelines. We searched three different electronic databases namely PubMed, Scopus and Web of Science from inception to December 2021. Literature search and data extraction were completed in duplicates.

RESULTS

The initial search yielded 564 articles from which 12 were finally included in our review. Ten articles were case reports and two were observational studies. The mean age of the cases was 34 years. The presenting complain was provided for 11 cases. The majority of the patients (10/11, 91%) presented with abdominal pain located mainly on the left (6/11, 55%) or right (4/11, 36%) iliac fossa. The most common diagnostic modality used for the diagnosis of the condition was ultrasonography in nine cases (9/12, 75%) followed by magnetic resonance imaging (MRI) in two cases (2/12, 17%). In spite of clinical and radiological evaluation, the initial diagnosis was inaccurate in seven cases (7/12, 58%). The therapeutic approach was available for 11 cases and it was based on the administration of intravenous antibiotics in six cases (6/11, 55%) and surgical management in five cases (5/11, 45%). Data for the type of delivery was provided in nine studies with five patients (5/9, 56%) delivering vaginally and four patients (4/9, 44%) delivering with cesarean section.

CONCLUSION

As advanced maternal age becomes more common, the frequency of diverticulitis in pregnancy may increase. Although available guidelines do not exist, the clinical awareness, early recognition of the disorder, using diagnostic modalities such as ultrasound and MRI, and rapid therapeutic approach with antibiotics, may improve maternal and neonatal outcomes.

Differential Expression of Endogenous Retroviruses and Inflammatory Mediators in Female and Male Offspring in a Mouse Model of Maternal Immune Activation

Maternal infections during pregnancy and the consequent maternal immune activation (MIA) are the major risk factors for autism spectrum disorder (ASD). Epidemiological evidence is corroborated by the preclinical models in which MIA leads to ASD-like behavioral abnormalities and altered neuroinflammatory profiles, with an increase in pro-inflammatory cytokines and microglial markers. In addition to neuroinflammatory response, an abnormal expression of endogenous retroviruses (ERVs) has been identified in neurodevelopmental disorders and have been found to correlate with disease severity. Our aim was to evaluate the transcriptional profile of several ERV families, ERV-related genes, and inflammatory mediators (by RT real-time PCR) in mouse offspring of both sexes, prenatally exposed to polyinosinic:polycytidylic acid (Poly I:C), a synthetic double-stranded RNA molecule targeting TLR-3 that mimics viral maternal infection during pregnancy. We found that prenatal exposure to Poly I:C deregulated the expression of some ERVs and ERV-related genes both in the prefrontal cortex (PFC) and hippocampus, while no changes were detected in the blood. Interestingly, sex-related differences in the expression levels of some ERVs, ERV-related genes, and inflammatory mediators that were higher in females than in males emerged only in PFC. Our findings support the tissue specificity of ERV and ERV-related transcriptional profiles in MIA mice.

Associations between pro-inflammatory cytokines and fatigue in pregnant women

Background

Fatigue is one of the most prevalent symptoms among pregnant women. In patients with various diseases, pro-inflammatory cytokines are associated with fatigue; however, such associations are unknown in pregnant women.

Objectives

The objective of this study was to examine the associations between pro-inflammatory cytokines and prenatal fatigue.

Methods

A cross-sectional study was conducted on 271 pregnant Chinese women in their third trimester of pregnancy. Patient-reported Outcome Measurement Information System (PROMIS) was used to evaluate women's prenatal fatigue. Using enzyme-linked immunosorbent assay (ELISA), the serum concentrations of four pro-inflammatory cytokines, including tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), interleukin 6 (IL-6) and interleukin 8 (IL-8), were measured. The data was analyzed by correlation analysis and general linear regression analysis.

Results

In this sample, the mean (standard deviation) of fatigue scores was 51.94 (10.79). TNF-α (r = 0.21, p < 0.001), IL-6 (r = 0.134, p = 0.027) and IL-8 (r = 0.209, p = 0.001) were positively correlated to prenatal fatigue, although IL-1β was not. TNF-α (β = 0.263, p < 0.001), along with sleep quality (β = 0.27, p < 0.001) and depression (β = 0.376, p < 0.001) independently predicted prenatal fatigue.

Conclusions

TNF-α was identified as an independent biomarker for prenatal fatigue in our study. Reducing pro-inflammatory cytokines may be a unique method for lowering prenatal fatigue and, consequently, enhancing mother and child health.

Impact of gestational hypertension and pre-eclampsia on preterm birth in China: a large prospective cohort study

OBJECTIVE

To investigate the impact of gestational hypertension and pre-eclampsia on preterm birth.

DESIGN

The data were collected from the China-US Collaborative Project for Neural Tube Defect Prevention; this was a large population-based cohort study.

SETTING AND PARTICIPANTS

We selected participants registered in two southern provinces, for whom we had exact information on gestational blood pressure and pregnancy outcomes, and who were not affected by chronic hypertension. In total, 200 103 participants were recruited from 1993 to 1995.

OUTCOME MEASURES

Preterm birth was defined as a singleton pregnancy and birth before 37 gestational weeks.

RESULTS

The incidences of gestational hypertension and pre-eclampsia were 5.47% and 5.44%, respectively, for women who gave birth at full term, and 5.63% and 7.33%, respectively, for those who gave birth preterm. After adjusting for potential confounders, the risk ratios (RRs) of preterm birth in women with gestational hypertension and pre-eclampsia were 1.04 (95% CI 0.98 to 1.11) and 1.39 (95% CI 1.25 to 1.55), respectively. The associations were stronger for early-onset (<28 weeks of gestation) gestational hypertension (adjusted RR=2.13, 95% CI 1.71 to 2.65) and pre-eclampsia (adjusted RR=8.47, 95% CI 5.59 to 12.80).

CONCLUSIONS

Pre-eclampsia was associated with a higher risk of preterm birth. The early-onset gestational hypertension and pre-eclampsia were associated with more severe risks than late-onset conditions.

Interleukin-33 regulates the endoplasmic reticulum stress of human myometrium via an influx of calcium during initiation of labor

Background:

Inflammation is currently recognized as one of the major causes of premature delivery. As a member of the interleukin-1β (IL-1β) family, interleukin-33 (IL-33) has been shown to be involved in normal pregnancy as well as a variety of pregnancy-related disorder. This study aims to investigate the potential function of IL-33 in uterine smooth muscle cells during labor.

Methods:

Myometrium samples from term pregnant (≥37 weeks gestation) women were either frozen or cells were isolated and cultured. Immunohistochemistry and western blotting were used to assess the distribution of IL-33. Cultured cells were incubated with lipopolysaccharide (LPS) to mimic inflammation as well as in the presence of 4μ8C (IRE1 inhibitor III) to block endoplasmic reticulum (ER) stress and BAPTA-AM, a calcium chelator.

Results:

LPS reduced the expression of nuclear IL-33 in a time-limited manner and induced ER stress. However, knockdown of IL-33 increased LPS-induced calcium concentration, ER stress and phosphorylation of nuclear factor kappa-B (NF-κB), and P38 mitogen-activated protein kinase (P38 MAPK). In addition, siRNA IL-33 further stimulates LPS enhanced cyclooxygenase-2 (COX-2) expression via NF-κB and p38 pathways. IL-33 expression was decreased in the nucleus with the onset of labor. LPS-induced ER stress and increased expression of the labor-associated gene, COX-2, as well as IL-6 and IL-8 in cultured myometrial cells. IL-33 also increased COX-2 expression, but after it was knocked down, the stimulating effect of LPS on calcium was enhanced. 4μ8C also inhibited the expression of COX-2 markedly. The expression of calcium channels on the membrane and intracellular free calcium ion were both increased which was accompanied by phosphorylated NF-κB and p38.

Conclusions:

These data suggest that IL-33 may be involved in the initiation of labor by leading to stress of the ER via an influx of calcium ions in human uterine smooth muscle cells.

Funding:

This study was supported by grants from the National Natural Science Foundation of China (No. 81300507).

The landscape of circular RNA in preterm birth

Background

Preterm birth (PTB) is a multifactorial syndrome that seriously threatens the health of pregnant women and babies worldwide. Recently, circular RNAs (circRNAs) have been understood as important regulators of various physiological and pathological processes. However, the expression pattern and potential roles of circRNAs in PTB are largely unclear.

Methods

In this study, we extracted and analyzed the circRNA expression profiles in maternal and fetal samples of preterm and term pregnancies, including maternal plasma, maternal monocytes, myometrium, chorion, placenta, and cord blood. We identified the circRNAs which is associated with PTB in different tissues and explored their relationships from the perspective of the overall maternal-fetal system. Furthermore, co-expression analysis of circRNAs and mRNAs, target microRNAs (miRNAs), and RNA-binding proteins (RBPs), provided new clues about possible mechanisms of circRNA function in PTB. In the end, we investigated the potential special biofunctions of circRNAs in different tissues and their common features and communication in PTB.

Results

Significant differences in circRNA types and expression levels between preterm and term groups have been proved, as well as between tissues. Nevertheless, there were still some PTB-related differentially expressed circRNAs (DECs) shared by these tissues. The functional enrichment analysis showed that the DECs putatively have important tissue-specific biofunctions through their target miRNA and co-expressed mRNAs, which contribute to the signature pathologic changes of each tissue within the maternal-fetal system in PTB (e.g., the contraction of the myometrium). Moreover, DECs in different tissues might have some common biological activities, which are mainly the activation of immune-inflammatory processes (e.g., interleukin1/6/8/17, chemokine, TLRs, and complement).

Conclusions

In summary, our data provide a preliminary blueprint for the expression and possible roles of circRNAs in PTB, which lays the foundation for future research on the mechanisms of circRNAs in PTB.

Microbiota of the Pregnant Mouse: Characterization of the Bacterial Communities in the Oral Cavity, Lung, Intestine, and Vagina through Culture and DNA Sequencing

Mice are frequently used as animal models for mechanistic studies of infection and obstetrical disease, yet characterization of the murine microbiota during pregnancy is lacking. The objective of this study was to characterize the microbiotas of distinct body sites of the pregnant mouse—vagina, oral cavity, intestine, and lung—that harbor microorganisms that could potentially invade the murine amniotic cavity, thus leading to adverse pregnancy outcomes. The microbiotas of these body sites were characterized through anoxic, hypoxic, and oxic culture as well as through 16S rRNA gene sequencing. With the exception of the vagina, the cultured microbiotas of each body site varied by atmosphere, with the greatest diversity in the cultured microbiota appearing under anoxic conditions. Only cultures of the vagina were comprehensively representative of the microbiota observed through direct DNA sequencing of body site samples, primarily due to the predominance of two Rodentibacter strains. Identified as Rodentibacter pneumotropicus and Rodentibacter heylii, these isolates exhibited predominance patterns similar to those of Lactobacillus crispatus and Lactobacillus iners in the human vagina. Whole-genome sequencing of these Rodentibacter strains revealed shared genomic features, including the ability to degrade glycogen, an abundant polysaccharide in the vagina. In summary, we report body site-specific microbiotas in the pregnant mouse with potential ecological parallels to those of humans. Importantly, our findings indicate that the vaginal microbiotas of pregnant mice can be readily cultured, suggesting that mock vaginal microbiotas can be tractably generated and maintained for experimental manipulation in future mechanistic studies of host vaginal-microbiome interactions.

IMPORTANCE Mice are widely utilized as animal models of obstetrical complications; however, the characterization of the murine microbiota during pregnancy has been neglected. Microorganisms from the vagina, oral cavity, intestine, and lung have been found in the intra-amniotic space, where their presence threatens the progression of gestation. Here, we characterized the microbiotas of pregnant mice and established the appropriateness of culture in capturing the microbiota at each site. The high relative abundance of Rodentibacter observed in the vagina is similar to that of Lactobacillus in humans, suggesting potential ecological parallels. Importantly, we report that the vaginal microbiota of the pregnant mouse can be readily cultured under hypoxic conditions, demonstrating that mock microbial communities can be utilized to test the potential ecological parallels between microbiotas in human and murine pregnancy and to evaluate the relevance of the structure of these microbiotas for adverse pregnancy outcomes, especially intra-amniotic infection and preterm birth.

Uterine Fibroids Causing Preterm Birth: A New Pathophysiological Hypothesis on the Role of Fibroid Necrosis and Inflammation

According to recent studies and observations in clinical practice, uterine fibroids increase the risk of preterm birth. There are several theories on the pathogenesis of preterm birth in the presence of fibroids. One theory proclaims that fibroid necrosis leads to preterm birth, though pathophysiological mechanisms have not been described. Necrotic tissue secretes specific cytokines and proteins and we suggest these to be comparable to the inflammatory response leading to spontaneous preterm birth. We hypothesize that fibroid necrosis could induce preterm parturition through a similar inflammatory response. This new hypothesis generates novel perspectives for future research and the development of preventative strategies for preterm birth. Moreover, we emphasize the importance of the recognition of fibroids and especially fibroid necrosis by clinicians during pregnancy.

Associations of GNAS and RGS Gene Polymorphisms with the Risk of Ritodrine-Induced Adverse Events in Korean Women with Preterm Labor: A Cohort Study

Ritodrine, a β2-adrenergic receptor agonist, is among most commonly prescribed tocolytic agents. This study aimed to evaluate the associations of single nucleotide polymorphisms in GNAS, RGS2, and RGS5 with the risk of ritodrine-induced adverse events (AEs) and develop a risk scoring system to identify high-risk patients. This is the prospective cohort study conducted at the Ewha Woman’s University Mokdong Hospital between January 2010 and October 2016. Pregnant women were included if they were treated with ritodrine for preterm labor with regular uterine contractions (at least 3 every 10 min) and cervical dilation. A total of 6, 3, and 5 single nucleotide polymorphisms (SNPs) of GNAS, RGS2, and RGS5 genes were genotyped and compared in patients with and without ritodrine-induced AEs. A total of 163 patients were included in this study. After adjusting confounders, GNAS rs3730168 (per-allele odds ratio (OR): 2.1; 95% confidence interval (95% CI): 1.0–4.3) and RGS2 rs1152746 (per-allele OR: 2.6, 95% CI: 1.1–6.5) were significantly associated with ritodrine-induced AEs. According to the constructed risk scoring models, patients with 0, 1, 2, 3, 4, and 5 points showed 0%, 13%, 19%, 31%, 46%, and 100% risks of AEs. This study suggested that GNAS and RGS2 polymorphisms could affect the risk of AEs in patients treated with ritodrine.

Syncytin-1 nonfusogenic activities modulate inflammation and contribute to preeclampsia pathogenesis

Maternal cellular and humoral immune responses to the allogeneic fetoplacental unit are a normal part of pregnancy adaptation. Overactive or dysregulated immune responses that often manifest as inflammation are considered a key element for the development of preeclampsia. Infiltration and activation of macrophages, nature killer cells, and T lymphocytes are frequently observed in the decidua and placenta associated with preeclampsia. In addition to local inflammation, systemic inflammatory changes including increased levels of TNF-α and interleukins (ILs) are detected in the maternal circulation. Syncytin-1 is an endogenous retroviral envelope protein that mediates the fusion of trophoblasts to form syncytiotrophoblasts, a cellular component carrying out most of placental barrier, exchange, and endocrine functions. In addition to these well-defined fusogenic functions that are known for their close association with preeclampsia, multiple studies indicated that syncytin-1 possesses nonfusogenic activities such as those for cell cycle and apoptosis regulation. Moreover, syncytin-1 expressed by trophoblasts and various types of immune cells may participate in regulation of inflammation in preeclamptic placenta and decidua. This review concentrates on the triangular relationship among inflammation, syncytin-1 nonfusogenic functions, and preeclampsia pathogenesis. Data regarding the reciprocal modulations of inflammation and poor vascularization/hypoxia are summarized. The impacts of syncytin-A (the mouse counterpart of human syncytin-1) gene knockout on placental vascularization and their implications for preeclampsia are discussed. Syncytin-1 expression in immune cells and its significance for inflammation are analyzed in the context of preeclampsia development. Finally, the involvements of syncytin-1 nonfusogenic activities in neuroinflammation and multiple sclerosis are compared to findings from preeclampsia.

The Implication of Aquaporin-9 in the Pathogenesis of Preterm Premature Rupture of Membranes

OBJECTIVE

This study aimed to detect aquaporin-9 (AQP9) concentrations in the serum of patients with preterm premature rupture of membranes (PPROM) and compare them with the healthy control group with intact membranes.

MATERIAL AND METHODS

We conducted this prospective case-control study from January 2020 to June 2020. Of the 80 pregnant patients included in the study, we enrolled 42 singleton pregnant patients with PPROM as the study group and 43 healthy gestational age-, and body mass index (BMI)-matched healthy pregnant women with intact fetal membranes as the control group. We compared demographic and clinical characteristics, complete blood count and biochemical parameters, and serum AQP9 concentrations of the participants. We constructed an ROC curve to illustrate the sensitivity and specificity performance characteristics of AQP9 and calculated a cutoff value by using the Youden index.

RESULTS

Maternal serum AQP-9 concentrations were significantly higher in patients with PPROM (804.46±195.63 pg/mL) compared to the healthy pregnant women in the control group (505.97±68.89 pg/mL, p<0.001). When we examine the area under the ROC curve (AUC), the AQP-9 value can be reflected as a statistically significant parameter for diagnosing PPROM. According to the Youden index, a 654.78 pg/mL cut-off value of AQP-9 can be utilized to diagnose PPROM with 80.5% sensitivity and 100% specificity.

CONCLUSION

Maternal serum AQP9 concentrations were significantly higher in PPROM patients than healthy pregnant women with an intact membrane. We suggest that AQP9 might be an essential biomarker of the inflammatory process and energy homeostasis in PPROM.

Inflammation and Preterm Birth: A Systematic Review

Inflammatory mechanisms have a critical role in parturition, which results from a gathering of different stimuli that collectively initiate labour. In fact, a sophisticated interaction occurs between contractile and immuno-inflammatory pathways, whereby proinflammatory amplification is intensified by collaborative connections between cells, ligands, and tissues. Preterm birth (PTB) is one of the major challenges of modern obstetrics and still lacks an efficient treatment. Therefore, the scientific research of modern therapies is warranted. This systematic review aims to provide an overview of recent research into inflammation and PTB. The main inclusion criterion was articles concerning birth and inflammation, and searches were performed in the electronic databases MEDLINE, Embase, Scopus, Web of Science and Cochrane Library, from 2017 to 2021. A literature search from all databases yielded 1989 results which, applying the specified eligibility criteria, resulted in the 16 articles included in this review. Delivery is the consequence of an inequity between maternal inflammation and hormonal-driven uterine quiescence. Studies show that the distinction between term and preterm labour could consist of a pre-existing disproportion of decidual inflammatory signalling, or an unusual stimulus eliciting inflammatory pathways, comparable to both. Thus, controlling inflammation could be hopeful for detaining PTB.

Identification of a novel gene signature in second-trimester amniotic fluid for the prediction of preterm birth

Preterm birth affects approximately 5% to 7% of live births worldwide and is the leading cause of neonatal morbidity and mortality. Amniotic fluid supernatant (AFS) contains abundant cell-free nucleic acids (cfNAs) that can provide genetic information associated with pregnancy complications. In the current study, cfNAs of AFS in the early second-trimester before the onset of symptoms of preterm birth were analyzed, and we compared gene expression levels between spontaneous preterm birth (n = 5) and term birth (n = 5) groups using sequencing analysis. Differential expression analyses detected 24 genes with increased and 6 genes with decreased expression in the preterm birth group compared to term birth. Upregulated expressions of RDH14, ZNF572, VOPP1, SERPINA12, and TCF15 were validated in an extended AFS sample by quantitative PCR (preterm birth group, n = 21; term birth group, n = 40). Five candidate genes displayed a significant increase in mRNA expression in immortalized trophoblast HTR-8/SVneo cell with H₂O₂ treatment. Moreover, the expression of five candidate genes was increased to more than twofold by pretreatment with lipopolysaccharide in HTR-8/SVneo cells. Changes in gene expression between preterm birth and term birth is strongly correlated with oxidative stress and infection during pregnancy. Specific expression patterns of genes could be used as potential markers for the early identification of women at risk of having a spontaneous preterm birth.

Assisted Reproductive Technology Treatment, the Catalyst to Amplify the Effect of Maternal Infertility on Preterm Birth

OBJECTIVE

To identify the influence of different infertility causes and assisted reproductive technology (ART) treatment on perinatal outcomes and clarify the relationship between the maternal pathophysiological changes and artificial interventions.

METHODS

A total of 1,629 fertile women and 27,112 infertile women with sole infertility causes were prospectively recruited from July 2014 to December 2017, and 9,894 singletons were finally enrolled into the study. Pregnancies with more than one cause of infertility and/or multiple births were excluded. According to the causes of infertility and the exposure of ART treatment, the participants were divided into four groups, namely, fertile naturally conceived (NC) group, infertile NC group, female factor ART group, and male factor ART group. Perinatal outcomes, including gestational age of delivery (GA), birth weight (BW), preterm birth (PTB), low birth weight (LBW), small for gestational age (SGA), and large for gestational age (LGA), were compared among groups. Logistic regression was performed for the adjustment of several covariates.

RESULTS

The birth outcomes of the infertile NC group and fertile NC group, female factor ART group, and infertile NC group were comparable. Compared to the fertile NC group, the female factor ART group had a shorter GA (39.0 ± 1.6 vs. 39.3 ± 1.5 weeks, BW: P < 0.05). An interaction test showed that ART treatment had an interaction on the effect of female infertility on GA (P = 0.023). The female factor ART group also had a higher risk of PTB (OR 1.56, 95% CI 1.18-2.07) and LGA (OR 1.27, 95% CI 1.10-1.47) compared to the fertile NC group. The risk of PTB was increased for tubal factor ART (OR 1.49, 95% CI 1.12-2.00), ovulatory dysfunction ART (OR 1.87, 95% CI 1.29-2.72), and unexplained infertility ART (OR 1.88, 95% CI 1.11-3.17). The risk of LGA was increased for tubal factor ART (OR 1.28, 95% CI 1.11-1.48) and ovulatory dysfunction ART (OR 1.27, 95% CI 1.03-1.57).

CONCLUSIONS

Our findings indicated that ART treatment could amplify the adverse effect of female infertility on neonates. Women with tubal factor infertility, ovulatory dysfunction, and unexplained infertility have a higher risk of PTB after ART treatment. Thus, clinicians should be vigilant in such patients and provide corresponding prevention strategies before and during pregnancy.

15-Deoxy-Delta-12,14-prostaglandin J2 modulates pro-labour and pro-inflammatory responses in human myocytes, vaginal and amnion epithelial cells

BACKGROUND

Prematurity is the leading cause of childhood death under the age of five. The aetiology of preterm birth is multifactorial; however, inflammation and infection are the most common causal factors, supporting a potential role for immunomodulation as a therapeutic strategy. 15-Deoxy-Delta-12,14-prostaglandin J2 (15dPGJ2) is an anti-inflammatory prostaglandin and has been shown to delay lipopolysaccharide (LPS) induced preterm labour in mice and improve pup survival. This study explores the immunomodulatory effect of 15dPGJ2 on the transcription factors NF-κB and AP-1, pro-inflammatory cytokines, and contraction associated proteins in human cultured myocytes, vaginal epithelial cell line (VECs) and primary amnion epithelial cells (AECs).

METHODS

Cells were pre-incubated with 32µM of 15dPGJ2 and stimulated with 1ng/mL of IL-1β as an in vitro model of inflammation. Western immunoblotting was used to detect phosphorylated p-65 and phosphorylated c-Jun as markers of NF-κB and AP-1 activation, respectively. mRNA expression of the pro-inflammatory cytokines IL-6, IL-8, and TNF-α was examined, and protein expression of COX-2 and PGE2 were detected by western immunoblotting and ELISA respectively. Myometrial contractility was examined ex-vivo using a myograph.

RESULTS

15dPGJ2 inhibited IL-1β-induced activation of NF-κB and AP-1, and expression of IL-6, IL-8, TNF-α, COX-2 and PGE2 in myocytes, with no effect on myometrial contractility or cell viability. Despite inhibiting IL-1β-induced activation of NF-κB, expression of IL-6, TNF-α, and COX-2, 15dPGJ2 led to activation of AP-1, increased production of PGE2 and increased cell death in VECs and AECs.

CONCLUSION

We conclude that 15dPGJ2 has differential effects on inflammatory modulation depending on cell type and is therefore unlikely to be a useful therapeutic agent for the prevention of preterm birth.

The role of inflammation in the pathogenesis of perinatal depression and offspring outcomes

The role of inflammation in the pathogenesis of depression is becoming increasingly apparent, but its role in perinatal depression is less well-studied. Pregnancy and the postpartum are characterised by distinct and changing inflammatory profiles throughout, which makes the study of depression-related alterations in this period complex. This review presents literature discussing a role for the immune system in both antenatal and postnatal depression. Furthermore, literature investigating the role of the maternal immune system on breast milk composition and offspring immunological and behavioural outcomes is discussed, before concluding with suggestions for future work as this developing field grows.

Change of pace: How developmental tempo varies to accommodate failed provision of early needs

The interplay of genes and environments (GxE) is a fundamental source of variation in behavioral and developmental outcomes. Although the role of developmental time (T) in the unfolding of such interactions has yet to be fully considered, GxE operates within a temporal frame of reference across multiple timescales and degrees of biological complexity. Here, we consider GxExT interactions to understand adversity-induced developmental acceleration or deceleration whereby environmental conditions hasten or hinder children's development. To date, developmental pace changes have been largely explained through a focus on the individual: for example, how adversity "wears down" aging biological systems or how adversity accelerates or decelerates maturation to optimize reproductive fitness. We broaden such theories by positing shifts in developmental pace in response to the parent-child dyad's capacity or incapacity for meeting children's early, physiological and safety needs. We describe empirical evidence and potential neurobiological mechanisms supporting this new conceptualization of developmental acceleration and deceleration. We conclude with suggestions for future research on the developmental consequences of early adverse exposures.

Changes of Lipoxin A4 and the Anti-inflammatory Role During Parturition

Parturition is the physiological process of newborn birth; more and more evidences show that parturition is closely related to the occurrence and resolution of inflammation. However, the inflammatory media and the mechanism are not very clear during parturition. Here, we investigate the inflammatory event during human parturition and in mouse model. We found that the pro-inflammatory cytokines (IL-6, IL-8, and IL-1β) and cells (neutrophil and macrophage) are decreased in pregnant women in labor and in mouse labor model. Mechanistically, increased stress stimulates the high-level adrenaline production in labor. Then, adrenaline upregulates the expression of 12/15-LOX (lipoxygenase) to produce more lipoxin A4 (LXA4), which is an inflammation inhibitor. Thus, LXA4 promotes the elimination of inflammation during labor to protect the body from excessive inflammatory damages. In addition, using BOC-2, the inhibitor of LXA4 receptor could reboot the pro-inflammatory cytokines. Our study indicates that LXA4 is induced by adrenaline in labor and appropriate interference of this pathway may be a potential strategy to regulate the inflammatory process in parturition.

IL-27 Mediates Pro-Inflammatory Effects via the ERK Signaling Pathway During Preterm Labor

Preterm labor (PTL) is a multifactorial syndrome that results in birth prior to 37 weeks of gestation. However, the specific molecular mechanisms underlying this condition have yet to be elucidated. Previous research demonstrated that the abnormal expression of IL-27, and its receptors, played a role in the pathophysiology of preterm labor. In the present study, we established a Lipopolysaccharide (LPS)-stimulated, infection-induced, preterm mouse model based on wild-type C57BL/6 mice and WSX-1^-/-C57BL/6 mice. WSX-1 knockdown led to a significant delay in birth by 11.32 ± 2.157h. In addition, compared with wild-type C57B/6 mice, the expression levels of IFN-γ, IL-1β, IL-6, TNF-α, and CXCL10, in the fetal membrane and myometrium of WSX-1^-/-mice were significantly lower, particularly in the myometrium. We also confirmed similar pro-inflammatory effects arising from IL-27 in human amniotic cell line (WISH) and human myometrial smooth muscle cell line (HMSMC). Once stimulated by LPS, the pro-inflammatory action exhibited a synergistic effect and appeared to be time-dependent. Finally, we demonstrated that LY3214996, an inhibitor of the ERK pathway, significantly inhibited the pro-inflammatory effect mediated by IL-27. Overall, our data confirmed that the inflammatory effect mediated by the IL-27/IFN-r/ERK axis is involved in preterm labor. Our findings, therefore, provide an enhancement in our etiological understanding of the mechanisms underlying PTL.

Cytokine Patterns in Maternal Serum From First Trimester to Term and Beyond

Pregnancy implies delicate immunological balance between two individuals, with constant changes and adaptions in response to maternal capacity and fetal demands. We performed cytokine profiling of 1149 longitudinal serum samples from 707 pregnant women to map immunological changes from first trimester to term and beyond. The serum levels of 22 cytokines and C-reactive protein (CRP) followed diverse but characteristic trajectories throughout pregnancy, consistent with staged immunological adaptions. Eotaxin showed a particularly robust decrease throughout pregnancy. A strong surge in cytokine levels developed when pregnancies progressed beyond term and the increase was amplified as labor approached. Maternal obesity, smoking and pregnancies with large fetuses showed sustained increase in distinct cytokines throughout pregnancy. Multiparous women had increased cytokine levels in the first trimester compared to nulliparous women with higher cytokine levels in the third trimester. Fetal sex affected first trimester cytokine levels with increased levels in pregnancies with a female fetus. These findings unravel important immunological dynamics of pregnancy, demonstrate how both maternal and fetal factors influence maternal systemic cytokines, and serve as a comprehensive reference for cytokine profiles in normal pregnancies.

Iatrogenic factors contributed to the high rate of preterm birth in a community hospital

BACKGROUND

Preterm birth (PTB) rates have been increased significantly in recent years, mostly due to obstetric intervention. This study presents the incidence of PTB in community hospitals by assessing the association between pregnancy complications and iatrogenic PTB.

METHODS

A total of 6,693 pregnancies were enrolled in the Wuxi Maternity and Child Health Care Hospital of Nanjing Medical University. They were divided into two groups (<35 and ≥35 years of age) to examine the effect of maternal age on PTB. Binary logistic and multiple linear regression analyses were used to assess the relationship between PTB and pregnancy complications.

RESULTS

This study provided the incidence of PTB and found that PP, PROM, and ICP increased the risk of PTB, indicating that pregnancy complications have led to the iatrogenic PTB and contributed to the high rate of PTB, especially in the group of advanced-age pregnant women. The prevalence of PTB was 9.53%. Placenta previa (PP), premature rupture of membranes (PROM), and intrahepatic cholestasis of pregnancy (ICP) were significantly associated with PTB. Among all the risk factors, hypertension, disease in pregnancy, premature PROM, and PP were observed as independent key factors for iatrogenic PTBs. In the advanced-age group, PP and pPROM increased the risk of PTB.

CONCLUSIONS

It is often necessary to terminate a pregnancy in community hospitals to balance the safety of the fetus and the maternal comorbid symptoms, which has led to nosocomial premature delivery. Therefore, high-risk pregnancies should be carefully evaluated and comprehensively treated with caution to balance the preterm rate and the safety of the pregnant woman and fetus, and the pros and cons of the outcomes, which has brought a challenge to an obstetrician to reduce the proportion of iatrogenic PTB.

Effects of ambient temperature on the risk of preterm birth in offspring of adolescent mothers in rural henan, China

BACKGROUND

A number of studies have explored the association between ambient temperature and preterm birth (PTB), but rarely among adolescent mothers.

OBJECTIVES

To estimate the effects of ambient temperature on the risk of PTB and gestational age of newborns delivered by adolescent mothers in rural areas of Henan province.

METHODS

We obtained 5394 medical records of adolescent mothers with results of pre-pregnancy physical examination and pregnancy outcomes from the National Free Preconception Health Examination Project (NFPHEP) in Henan province. Meteorological information was obtained from the China Meteorological Data Sharing Service System. Individual exposure levels were evaluated with an inverse distance-weighted model. A multiple logistic regression model and multiple linear regression model were used to estimate the effects of ambient temperature on the risk of PTB and gestational age, respectively. Stratified and interaction analyses were also performed.

RESULTS

Of newborns in this study, 3.45% (186/5394) were PTB. Mean, maximum and minimum temperature during the entire pregnancy, especially the last 1-4 weeks of pregnancy, were positively associated with the risk of PTB and negatively associated with gestational age (P < 0.05). Nevertheless, a masking effect was observed that gestational age was positively associated with ambient temperature during the first trimester of pregnancy, due to the strongly inverse correlation between ambient temperature during the early and late stages of pregnancy. Stratified analyses showed that increasing temperature during the last 1-4 weeks of pregnancy increased the risk of PTB and decreased gestational age in newborns born in the cold season (P < 0.05). Furthermore, interaction analyses showed that birth season modified the effects of temperature on the gestational age (P_interaction < 0.10).

CONCLUSIONS

Elevated ambient temperature can decrease gestational age and increase the risk of PTB in offspring of adolescent mothers in rural areas. The birth season may modify the effects of temperature on gestational age.

Elevated inflammatory mediators from the maternal-fetal interface to fetal circulation during labor

BACKGROUND

Elevated cytokines, like IL-1βand IL-6, are known to contribute to the pathogenesis of labor. However, the change of inflammatory mediators in maternal-fetal interface to fetal circulation is obscure.

STUDY DESIGN AND METHODS

We investigated the changes of inflammatory cytokines, chemokines and macrophage in maternal-fetal interface tissues and fetal circulation of women in labor vs. non-labor. Human myometrium, placenta, decidua, fetal membrane and umbilical blood were obtained from in-labor and non-in-labor women who eventually delivered live, singleton infants at term (>37 weeks gestation) by elective caesarean section. Luminex was used to measure the level of cytokines (TNF-α, IL-1β, IL-6, IL-8) and chemokines (MCP-1, GM-CSF, MIP-1α, MIP-1β) in each sample (tissue and umbilical blood). Macrophage infiltration was demonstrated by immunohistochemistry.

RESULTS

During labor, the level of cytokines TNF-α, IL-1β, IL-6 and IL-8 and chemokine MCP-1 and MIP-1β in myometrium is significantly higher (p < 0.05), than those obtained from non-laboring patients. This increase coincides with the influx of macrophage into the myometrium. In addition, IL-1β and IL-8 (p < 0.05) are also up regulated in fetal membrane during labor compared to non-labor. The cytokines do not change significantly in placenta and decidua tissue. In fetal circulation, IL-6 (p < 0.05) is up regulated in umbilical vein blood in labor group. IL-8 (p = 0.08) in umbilical vein also show an increasing trend during labor.

CONCLUSIONS

There are markedly elevated inflammatory mediators in maternal-fetal interface during labor. The increased maternal inflammatory factors released into the fetal circulation through placenta circulation at the time of labor. This increase coincides with the influx of macrophage into the pregnancy tissue, suggesting that the inflammatory response might play an important role in the onset of labor.

The prenatal phase of retinopathy of prematurity

AIM

To explore the current literature on prenatal inflammation-associated risk factors for retinopathy of prematurity (ROP).

METHODS

Subjective summary of selected experimental and epidemiological publications that support the authors' central hypothesis that the aetiology of ROP begins before birth.

RESULTS

Based on current evidence we suggest that, contrary to current aetiological models, the process of ROP development begins with a prephase in utero. This beginning is likely initiated by inflammatory responses that are associated with intrauterine infection.

CONCLUSION

We propose a novel aetio-pathogenetic model of ROP and suggest that the effects of postnatal exposure to inflammatory stressors (resulting from infection or hyperoxia or both) as well as those of other pre- and postnatal contributors to the complex pathogenesis of ROP might be modified by the prenatal phase of the disease.

Associations of maternal insulin resistance during pregnancy and offspring inflammation at birth and at 5 years of age: A prospective study in the Gen3G cohort

BACKGROUND

Maternal insulin resistance is associated with greater maternal inflammation during pregnancy, but its relation to inflammation in offspring remains unclear. The goal of this study was to assess the relationship of gestational insulin resistance and other glycemic markers with offspring inflammation at birth and at 5 years of age.

METHODS

We included 653 mother-child pairs from the prospective pre-birth Gen3G cohort. We examined maternal insulin and glucose levels measured during the second trimester of pregnancy, from which we derived the homeostatic model of assessment of insulin resistance (HOMA-IR) and the Matsuda index. We assessed offspring inflammation at birth and at 5 years of age by measuring plasma tumor necrosis factor-α (TNFα) concentrations. We conducted multivariable regression models to evaluate associations of each insulin and glucose marker with offspring inflammation adjusting for confounding variables.

RESULTS

Higher levels of fasting insulin were associated with lower TNFα levels at birth (-0.78, 95% CI [-1.45, -0.11]), in the fully adjusted model. We observed similar associations with the HOMA-IR and opposite direction with the Matsuda index. We did not find persistence of the association between maternal fasting insulin and offspring TNFα at 5 years of age.

CONCLUSIONS

Greater maternal insulin resistance during pregnancy was associated with lower cord blood TNFα levels in newborns. The mechanisms by which maternal insulin resistance may promote lower inflammatory levels in newborns are not fully understood and more research is needed to deepen our understanding of these mechanisms.

Amniotic fluid interleukin 6 and interleukin 8 are superior predictors of fetal lung injury compared with maternal or fetal plasma cytokines or placental histopathology in a nonhuman primate model

BACKGROUND

Intra-amniotic infection or inflammation is common in early preterm birth and associated with substantial neonatal lung morbidity owing to fetal exposure to proinflammatory cytokines and infectious organisms. Amniotic fluid interleukin 8, a proinflammatory cytokine, was previously correlated with the development of neonatal bronchopulmonary dysplasia, but whether amniotic fluid cytokines or placental pathology more accurately predicts neonatal lung pathology and morbidity is unknown. We have used a pregnant nonhuman primate model of group B Streptococcus infection to study the pathogenesis of intra-amniotic infection, bacterial invasion of the amniotic cavity and fetus, and microbial-host interactions. In this nonhuman primate model, we have studied the pathogenesis of group B Streptococcus strains with differing potential for virulence, which has resulted in a spectrum of intra-amniotic infection and fetal lung injury that affords the opportunity to study the inflammatory predictors of fetal lung pathology and injury.

OBJECTIVE

This study aimed to determine whether fetal lung injury is best predicted by placental histopathology or the cytokine response in amniotic fluid or maternal plasma.

STUDY DESIGN

Chronically catheterized pregnant monkeys (Macaca nemestrina, pigtail macaque) at 116 to 125 days gestation (term at 172 days) received a choriodecidual inoculation of saline (n=5), weakly hemolytic group B Streptococcus strain (n=5, low virulence), or hyperhemolytic group B Streptococcus strain (n=5, high virulence). Adverse pregnancy outcomes were defined as either preterm labor, microbial invasion of the amniotic cavity, or development of the fetal inflammatory response syndrome. Amniotic fluid and maternal and fetal plasma samples were collected after inoculation, and proinflammatory cytokines (tumor necrosis factor alpha, interleukin beta, interleukin 6, interleukin 8) were measured by a multiplex assay. Cesarean delivery was performed at the time of preterm labor or within 1 week of inoculation. Fetal necropsy was performed at the time of delivery. Placental pathology was scored in a blinded fashion by a pediatric pathologist, and fetal lung injury was determined by a semiquantitative score from histopathology evaluating inflammatory infiltrate, necrosis, tissue thickening, or collapse scored by a veterinary pathologist.

RESULTS

The principal findings in our study are as follows: (1) adverse pregnancy outcomes occurred more frequently in animals receiving hyperhemolytic group B Streptococcus (80% with preterm labor, 80% with fetal inflammatory response syndrome) than in animals receiving weakly hemolytic group B Streptococcus (40% with preterm labor, 20% with fetal inflammatory response syndrome) and in controls (0% preterm labor, 0% fetal inflammatory response syndrome); (2) despite differences in the rate of adverse pregnancy outcomes and fetal inflammatory response syndrome, fetal lung injury scores were similar between animals receiving the weakly hemolytic group B Streptococcus strains and animals receiving the hyperhemolytic group B Streptococcus strains; (3) fetal lung injury score was significantly correlated with peak amniotic fluid cytokines interleukin 6 and interleukin 8 but not tumor necrosis factor alpha or interleukin 1 beta; and (4) fetal lung scores were poorly correlated with maternal and fetal plasma cytokine levels and placental pathology.

CONCLUSION

Amniotic fluid interleukin 6 and interleukin 8 levels were superior predictors of fetal lung injury than placental histopathology or maternal plasma cytokines. This evidence supports a role for amniocentesis in the prediction of neonatal lung morbidity owing to intra-amniotic infection, which cannot be provided by cytokine analysis of maternal plasma or placental histopathology.

Prolactin Protects the Structural Integrity of Human Fetal Membranes by Downregulating Inflammation-induced Secretion of Matrix Metalloproteinases

Prolactin (PRL) is a pleiotropic hormone with a key role in pregnancy. In fetal membranes, PRL can regulate the secretion of pro-inflammatory factors, which induces the activation of matrix metalloproteinases (MMPs). The increase and activation of MMPs deregulate the turnover of the extracellular matrix in the fetal membranes, altering its structure and function, causing premature rupture of the membranes and preterm labor. In this work, we evaluate the effect of PRL upon the secretion of MMP-1, MMP-2, MMP-9, MMP-13, and the tissue inhibitors of metalloproteinases (TIMPs) in human fetal membranes after lipopolysaccharide (LPS) challenge. Nine fetal membranes from healthy non-laboring cesarean deliveries at term were cultured in a 2-independent chamber system and pre-treated with 250, 500, 1000 or 4000 ng/ml of PRL for 24 h, then choriodecidual region was stimulated with 500 ng/ml of LPS plus fresh PRL for 24 h. The MMPs and TIMPs secretion were quantified by ELISA, additionally MMP-2 and MMP-9 gelatinolytic activity was measured by zymography. LPS induced the MMP-9 and MMP-1 secretion, but no MMP-2 or MMP-13 in comparison with basal levels. PRL co-treatment decreased the MMP-2, MMP-9 and MMP-1 secretion induced by LPS. The active forms were present in the tissue extract, showing a response consistent with the secretion profile. TIMP-1 and TIMP-2 secretion was decreased after LPS treatment and the PRL co-treatment reverts this effect. The present results support that PRL may favor the balance between these factors involved in the structural maintenance of fetal membranes in an inflammatory event.

AACC Guidance Document on Laboratory Testing for the Assessment of Preterm Delivery

Identifying women with preterm labor who will go on to deliver prematurely is crucial to improving outcomes for mother and baby and for saving healthcare resources. Even among those with symptoms, the number of women who deliver preterm is low, and thus the low positive predictive value (PPV) and high negative predictive value (NPV) associated with available biomarkers does not substantially reduce the uncertainty of the clinical diagnosis. While there is some promise in the use of fetal fibronectin (fFN), interleukin 6 (IL-6), or placental alpha microglobulin 1 (PAMG-1) for predicting preterm birth (PTB), their use is unlikely to provide considerable clinical value in populations with a low prevalence. To provide real clinical benefit, a biomarker must demonstrate a high PPV to allow identification of the minority of symptomatic women who will deliver prematurely. As none of the currently available biomarkers exhibit this performance characteristic, we do not recommend their routine clinical use in populations with a pre-test probability of PTB of <5%. Limiting biomarker testing to only high-risk women identified on the basis of cervical length or other characteristics will increase the pre-testprobability in the tested population, thereby improving PPV. PAMG-1 is associated with a higher PPV than fFN and may show clinical utility in populations with a higher pre-test probability, but further work is required to conclusively demonstrate improved outcomes in this patient group.

Inflammatory factors, genetic variants, and predisposition for preterm birth

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