Predicting Spontaneous Preterm Birth Using the Immunome

Throughout pregnancy, the maternal peripheral circulation contains valuable information reflecting pregnancy progression, detectable as tightly regulated immune dynamics. Local immune processes at the maternal-fetal interface and other reproductive and non-reproductive tissues are likely to be the pacemakers for this peripheral immune "clock." This cellular immune status of pregnancy can be leveraged for the early risk assessment and prediction of spontaneous preterm birth (sPTB). Systems immunology approaches to sPTB subtypes and cross-tissue (local and peripheral) interactions, as well as integration of multiple biological data modalities promise to improve our understanding of preterm birth pathobiology and identify potential clinically actionable biomarkers.

Risk factors of early spontaneous preterm birth despite carrying a cervical pessary in singleton pregnancies with a short cervix: Development of a risk prediction model

Introduction

We aimed to identify the incidence and risk factors of spontaneous preterm birth in pessary carriers with singleton pregnancies and a short cervix in the mid-trimester of pregnancy.

Material and Methods

Patient data were obtained from the PECEP Trial. We analyzed singleton pregnancies in pessary carriers with a short cervix (≤25 mm) between 18 and 22 gestational weeks. Demographics and obstetric history were compared to identify risk factors for spontaneous preterm birth < 34 gestational weeks. Each demographic and obstetric variable was compared between spontaneous preterm birth < 34 and ≥ 34 weeks of gestation.Regression analysis was used to identify risk factors. A risk score model was generated using the odds ratio for significant factors. The risk score model and spontaneous preterm birth risk were assessed using the receiver operating characteristic curve. Perinatal outcomes were compared by risk score.

Results

Among 190 pregnant individuals, 12 (6.3%) had spontaneous preterm birth < 34 gestational weeks. In the bivariate analysis, statistically significant differences between those with and without spontaneous preterm birth were only observed for mean cervical length at diagnosis and mean cervical length after pessary placement. By multiple logistic regression analysis, maternal age (OR 0.818; 95% CI 0.69-0.97; P 0.020), cervical length at diagnosis (OR 0.560; 95% CI 0.43-0.73; P < 0.001) and smoking status (OR 7.276; 95% CI 1.02-51.80; P 0.048) remained significantly associated with spontaneous preterm birth.The ROC curve from the multiple logistic regression analysis, including cervical length, maternal age and smoking status, had an area under the curve (AUC) of 0.952 (P < 0.001). The ROC curve for the risk score model incorporating all three variables had an AUC of 0.864 (95% CI 0.77-0.96; P < 0.001). A high-risk score was predictive of spontaneous preterm birth with a sensitivity of 75%, specificity of 84%, positive predictive value of 24%, and negative predictive value of 98%.Women with a high-risk score had a significantly reduced latency to delivery and poorer neonatal outcomes than those with a low-risk score.

Conclusions

Patients at a high risk for spontaneous preterm birth despite pessary therapy may be identified using cervical length at diagnosis added to maternal age and smoking status.

Predicting Preterm Birth Using Cell-Free Ribonucleic Acid

Spontaneous preterm birth (sPTB) is a complex and clinically heterogeneous condition that remains incompletely understood, leading to insufficient interventions to effectively prevent it from occurring. Cell-free ribonucleic acid signatures in the maternal circulation have the potential to identify biologically relevant subtypes of sPTB. These could one day be used to predict and prevent sPTB in asymptomatic individuals, and to aid in prognosis and management for individuals presenting with threatened preterm labor and preterm prelabor rupture of membranes.

Inverse association between maternal serum concentrations of trace elements and risk of spontaneous preterm birth: a nested case-control study in China

Few studies have evaluated the joint effect of trace elements on spontaneous preterm birth (SPTB). This study aimed to examine the relationships between the individual or mixed maternal serum concentrations of Fe, Cu, Zn, Se, Sr and Mo during pregnancy, and risk of SPTB. Inductively coupled plasma MS was employed to determine maternal serum concentrations of the six trace elements in 192 cases with SPTB and 282 controls with full-term delivery. Multivariate logistic regression, weighted quantile sum regression (WQSR) and Bayesian kernel machine regression (BKMR) were used to evaluate the individual and joint effects of trace elements on SPTB. The median concentrations of Sr and Mo were significantly higher in controls than in SPTB group (P < 0·05). In multivariate logistic regression analysis, compared with the lowest quartile levels of individual trace elements, the third- and fourth-quartile Sr or Mo concentrations were significantly associated with reduced risk of SPTB with adjusted OR (aOR) of 0·432 (95 CI < 0·05). In multivariate logistic regression analysis, compared with the lowest quartile levels of individual trace elements, the third- and fourth-quartile Sr or Mo concentrations were significantly associated with reduced risk of SPTB with adjusted aOR of 0·432 (95 % CI 0·247, 0·756), 0·386 (95 % CI 0·213, 0·701), 0·512 (95 % CI 0·297, 0·883) and 0·559 (95 % CI 0·321, 0·972), respectively. WQSR revealed the inverse combined effect of the trace elements mixture on SPTB (aOR = 0·368, 95 % CI 0·228, 0·593). BKMR analysis confirmed the overall mixture of the trace elements was inversely associated with the risk of SPTB, and the independent effect of Sr and Mo was significant. Our findings suggest that the risk of SPTB decreased with concentrations of the six trace elements, with Sr and Mo being the major contributors.

Molybdenum Concentration and the Risk of Spontaneous Preterm Birth: A Nested Case-Control Study - Beijing Municipality, China, 2018-2020

What is already known about this topic?

The level of molybdenum (Mo) in a mother's urine has been linked to the growth rate of the fetus and the blood pressure levels in children.

What is added by this report?

We evaluated the variations in maternal plasma Mo concentrations throughout pregnancy and their potential association with the risk of spontaneous preterm birth (SPB).

What are the implications for public health practice?

Future research must determine the Mo levels in pregnant women across various regions in China. Moreover, particular attention needs to be given to the potential increase in Mo concentration throughout pregnancy and its possible adverse impacts on the health of both the mother and the fetus.

Development and validation of a nomogram for individualized prediction of spontaneous extremely preterm birth at < 28 weeks in twin pregnancy: a retrospective cohort study

PURPOSE

To develop a nomogram to predict spontaneous preterm birth at < 28 weeks in pregnant women with twin pregnancies.

METHODS

We retrospectively studied the medical records of twin-pregnancy women with asymptomatic cervical dilation or cervical shortening between December 2015 to February 2022 in two hospitals. Data from one center was used to develop the model and data from the other was used to evaluate the model.

RESULTS

A total of 270 twin pregnancies were enrolled in the study. We incorporated 4 items (cervical length, cervical dilation, C-reactive protein and the use of cerclage) to build the 28-week nomogram with satisfactory discrimination and calibration when applied to the validation sets. The C index for the 28-week nomogram in the development and external cohort was 0.88 (95% CI, 0.84-0.93) and 0.89 (95% CI, 0.80-0.98), respectively. The nomogram reached a sensitivity of 70.70%, specificity of 97.10%, positive predicted value of 95.61% and negative predicted value of 78.77%. Moreover, the decision curve analysis indicated that the nomogram showed positive clinical benefit.

CONCLUSION

We developed and validated a nomogram with good performance in predicting individual risk of spontaneous preterm birth at < 28 in twin pregnancy.

Development and validation of a prediction model on spontaneous preterm birth in twin pregnancy: a retrospective cohort study

BACKGROUND

This study was conducted to develop and validate an individualized prediction model for spontaneous preterm birth (sPTB) in twin pregnancies.

METHODS

This a retrospective cohort study included 3845 patients who gave birth at the Chongqing Maternal and Child Health Hospital from January 2017 to December 2022. Both univariable and multivariable logistic regression analyses were performed to find factors associated with sPTB. The associations were estimated using the odds ratio (OR) and the 95% confidence interval (CI). Model performance was estimated using sensitivity, specificity, accuracy, area under the receiver operating characteristic curve (AUC) and decision curve analysis (DCA).

RESULTS

A total of 1313 and 564 cases were included in the training and testing sets, respectively. In the training set, univariate and multivariate logistic regression analysis indicated that age ≥ 35 years (OR, 2.28; 95% CI 1.67-3.13), pre-pregnancy underweight (OR, 2.36; 95% CI 1.60-3.47), pre-pregnancy overweight (OR, 1.67; 95% CI 1.09-2.56), and obesity (OR, 10.45; 95% CI, 3.91-27.87), nulliparity (OR, 0.58; 95% CI 0.41-0.82), pre-pregnancy diabetes (OR, 5.81; 95% CI 3.24-10.39), pre-pregnancy hypertension (OR, 2.79; 95% CI 1.44-5.41), and cervical incompetence (OR, 5.12; 95% CI 3.08-8.48) are independent risk factors for sPTB in twin pregnancies. The AUC of the training and validation set was 0.71 (95% CI 0.68-0.74) and 0.68 (95% CI 0.64-0.73), respectively. And then we integrated those risk factors to construct the nomogram.

CONCLUSIONS

The nomogram developed for predicting the risk of sPTB in pregnant women with twins demonstrated good performance. The prediction nomogram serves as a practical tool by including all necessary predictors that are readily accessible to practitioners.

Prenatal per- and polyfluoroalkyl substances (PFAS) exposure in relation to preterm birth subtypes and size-for-gestational age in the LIFECODES cohort 2006-2008

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals widely used in consumer and industrial products. Numerous studies have linked prenatal PFAS exposures to increased risks of adverse pregnancy outcomes such as preterm birth (PTB) and small-for-gestational age (SGA).However, limited evidence is available for the effects of PFAS on PTB subtypes and large-for-gestational age (LGA).

OBJECTIVE

To examine the associations of PFAS with PTB [overall, placental (pPTB), spontaneous (sPTB)], BW Z-score, and size-for-gestational age (SGA, LGA).

METHODS

Our nested case-control study included 128 preterm cases and 373 term controls from the LIFECODES cohort between 2006 and 2008 (n = 501). Plasma concentrations of nine PFAS were measured in early pregnancy samples. Logistic regression was used to assess individual PFAS-birth outcome associations, while Bayesian Kernel Machine Regression (BKMR) was used to evaluate the joint effects of all PFAS. Effect modification by fetal sex was examined, and stratified analyses were conducted to obtain fetal sex-specific estimates.

RESULTS

Compared to term births, the odds of pPTB were higher from an interquartile range increase in perfluorodecanoic acid (PFDA) (OR = 1.60, 95% CI: 1.00-2.56), perfluorononanoic acid (PFNA) (OR = 1.67, 95% CI: 1.06-2.61), and perfluoroundecanoic acid (PFUA) (OR = 1.77, 95% CI: 1.00-3.12), with stronger associations observed in women who delivered males. BKMR analysis identified PFNA as the most important PFAS responsible for pPTB (conditional PIP = 0.78), with increasing ORs at higher percentiles of PFAS mixture. For LGA, positive associations were observed with PFDA and perfluorooctanoic acid in females only, and with PFUA in males only. BKMR analysis showed increasing, but null effects of PFAS mixture on LGA.

CONCLUSIONS

The effect of prenatal exposure to single and multiple PFAS on PTB and LGA depended on fetal sex. Future studies should strongly consider examining PTB subtypes and sex-specific effects of PFAS on pregnancy outcomes.

Residential greenspace counteracts PM2.5 on the risks of preterm birth subtypes: A multicenter study

BACKGROUND

The association between residential greenspace and preterm birth (PTB) risk remained inconclusive. The PTB subtypes have been ignored and the effect of co-exposure of PM2.5 on PTB risk is still unclear.

OBJECTIVE

To investigate the independent, interactive, and mixed effects of residential greenspace and PM2.5 on the risk of PTB subtypes.

METHODS

A total of 19,900 singleton births from 20 hospitals in Shanghai, China, from 2015 to 2017 were included. The Normalized Difference Vegetation Index (NDVI) within 500 m and 1000 m buffers of the maternal residence and a combined geoscience-statistical model-derived PM2.5 and its six components were used as the exposure measures. PTB (<37 completed weeks of gestation) were divided into early PTB (24-33 weeks) vs. late PTB (34-36 weeks) and into spontaneous PTB (sPTB), preterm premature rupture of the fetal membranes (PPROM), and iatrogenic PTB. Multivariable logistic regression models were applied to assess the independent and interactive effects of NDVI and PM2.5 on PTB in each trimester. The quantile g-computation approach was employed to explore the mixture effect of PM2.5 components and greenspace across the pregnancy and to determine the main contributors.

RESULTS

Levels of PM2.5 and greenspace were associated with increased [aOR (95%CI) ranging from 1.18 (1.07, 1.30) to 3.36 (2.45, 4.64)] and decreased risks [aORs (95%CI) ranging from 0.64 (0.53, 0.78) to 0.86 (0.73, 0.99)] of PTB subtypes, respectively. At the same PM2.5 level, higher residential greenspace was associated with lower risks, and vice versa. All these associations were more pronounced in late pregnancy. Early PTB and PPROM were the main affected subtypes, and the main drivers in PM2.5 were black carbon and ammonium.

CONCLUSIONS

Residential greenspace may mitigate the PTB risks due to PM2.5 exposure during pregnancy.

Association between light rare earth elements in maternal plasma and the risk of spontaneous preterm birth: a nested case-control study from the Beijing birth cohort study

BACKGROUND

Parental exposure to rare earth elements (REEs) could increase the risk of premature rupture of membranes, a major cause of spontaneous preterm birth (SPB). In addition, different subtypes of SPB, such as spontaneous preterm labor (SPL) and preterm premature rupture of membranes (PPROM), may have different susceptibility to environmental exposure. Therefore, we investigated the potential associations between REE exposure in different trimesters and SPB and its subtypes.

METHODS

A nested case-control study was performed. We included 244 women with SPB as cases and 244 women with full-term delivery as controls. The plasma concentrations of light REEs were measured in the first and third trimesters. Logistic regression was used to analyze the associations between single REE levels and SPB, and Bayesian kernel machine regression (BKMR) was used to analyze the mixed-exposure effect.

RESULTS

Exposure to light REEs was associated with SPB and its subtypes only in the third trimester. Specifically, the intermediate- and highest-tertile concentration groups of La and the highest-tertile concentration group of Sm were associated with an increased risk of SPL, with adjusted odds ratios (AORs) of 2.00 (95% CIs: 1.07-3.75), 1.87 (95% CIs: 1.01-3.44), and 1.82 (95% CIs: 1.00-3.30), respectively. The highest-tertile concentration group of Pr was associated with an increased risk of PPROM, with an AOR of 1.69 (95% CIs: 1.00-2.85). Similar results were also found in BKMR models.

CONCLUSIONS

La and Sm levels in plasma may be associated with the risk of SPL, and Pr levels in plasma may be associated with the risk of PPROM.

Development and validation of a nomogram to predict spontaneous preterm birth in singleton gestation with short cervix and no history of spontaneous preterm birth

Background

Spontaneous preterm birth (sPTB) stands as a leading cause of neonatal mortality. Consequently, preventing sPTB has emerged as a paramount concern in healthcare. Therefore, our study aimed to develop a nomogram, encompassing patient characteristics and cervical elastography, to predict sPTB in singleton pregnancies. Specifically, we targeted those with a short cervix length (CL), no history of sPTB, and who were receiving vaginal progesterone therapy.

Methods

A total of 568 patients were included in this study. Data from 392 patients, collected between January 2016 and October 2019, constituted the training cohort. Meanwhile, records from 176 patients, spanning November 2019 to January 2022, formed the validation cohort. Following the univariate logistic regression analysis, variables exhibiting a P-value less than 0.05 were integrated into a multivariable logistic regression analysis. The primary objective of this subsequent analysis was to identify the independent predictors linked to sPTB in the training cohort. Next, we formulated a nomogram utilizing the identified independent predictors. This tool was designed to estimate the likelihood of sPTB in singleton pregnancies, particularly those with a short CL, devoid of any sPTB history, and undergoing vaginal progesterone therapy. The C-index, Hosmer-Lemeshow (HL) test, calibration curves, decision curve analysis (DCA), and receiver operating characteristic (ROC) were used to validate the performance of the nomogram.

Results

Upon finalizing the univariate analysis, we progressed to a multivariable analysis, integrating 8 variables with P < 0.05 from the univariate analysis. The multivariable analysis identified 7 independent risk factors: maternal age (OR = 1.072; P < 0.001), cervical length (OR = 0.854; P < 0.001), uterine curettage (OR = 7.208; P < 0.001), GDM (OR = 3.570; P = 0.006), HDP (OR = 4.661; P = 0.003), C-reactive protein (OR = 1.138; P < 0.001), and strain of AI (OR = 7.985; P < 0.001). The nomogram, tailored for sPTB prediction, was grounded on these 7 independent predictors. In predicting sPTB, the C-indices manifested as 0.873 (95% CI, 0.827-0.918) for the training cohort and 0.916 (95%CI, 0.870-0.962) for the validation cohorts, underscoring a good discrimination of the model. Additionally, the ROC curves served to evaluate the discrimination of nomogram model across both cohorts. Calibration curves were delineated, revealing no statistically significant differences in both the training (χ2 = 5.355; P = 0.719) and validation (χ2 = 2.708; P = 0.951) cohorts as evidenced by the HL tests. Furthermore, the DCA underscored the model's excellence as a predictive tool for sPTB.

Conclusions

By amalgamating patient characteristics and cervical elastography data from the second trimester, the nomogram emerged as a visually intuitive and dependable tool for predicting sPTB. Its relevance was particularly pronounced for singleton pregnancies characterized by a short CL, an absence of prior sPTB incidents, and those receiving vaginal progesterone therapy.

Immune regulation by activation markers at feto-maternal interface in infection-associated spontaneous preterm birth

BACKGROUND

Spontaneous preterm birth (sPTB) is a global health concern. Studies reveal infections are majorly responsible for sPTB and immune activation markers play a role in regulation of maternal immune responses against pathogens during sPTB.

AIM

To study the mRNA expression and correlation of activation markers (CD66a, ICAM1, ITGB1, TIM3, CD25, CD95) and associated cytokines (IL-1β and IL-17)/prostaglandin receptors (EP2 and IP) in the placenta of Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum-infected sPTB women.

METHODS

Placental samples were collected from 160 sPTB and 160 term birth women. PCR was used for the detection of C. trachomatis, M. hominis, U. urealyticum. The mRNA expression of activation markers, cytokines and prostaglandin receptors was evaluated by real-time qPCR.

RESULTS

The fold-change expression of CD66a, ICAM1, TIM3, CD25 and CD95 was 2.89, 5.5, 4.95, 6.44 and 6.95-fold (p < 0.001), respectively; while for cytokines- IL-1β and IL-17 was 5.41 and 4.71-fold (p < 0.001), respectively and for prostaglandin receptors- EP2 and IP was 5.5 and 5-fold (p < 0.001) upregulated, respectively in infected sPTB women. Significant positive correlation was obtained among ICAM-1 and IL-1β/EP2/IL-17, TIM3 and IP/IL-17. Significant negative correlation was obtained between CD66a and EP2/IL-17, CD25 and IL-1β/EP2, CD95 and IL-1β/EP2 in infected sPTB women.

CONCLUSIONS

CD66a, ICAM1 and TIM3 may play role in inflammation and have potential for the clinical beginning of preterm labour during infection while CD25 and CD95 are possibly involved in immunotolerance at feto-maternal interface during C. trachomatis, M. hominis and U. urealyticum infection.

Impact of exposure to air pollution on cervicovaginal microbial communities

PURPOSE

Vaginal microbial communities can be dominated by anaerobic (community state type IV, CST IV) or Lactobacillus (other CSTs) species. CST IV is a risk factor for spontaneous preterm birth (sPTB) and is more common among Black than White populations. In the US, average air pollution exposures are higher among Black compared to White people and exert systemic health effects. We sought to (1) quantify associations of air pollution, specifically particulate matter <2.5 μm in diameter (PM2.5), with CST IV and (2) explore the extent to which racial disparities in PM2.5 exposure might explain racial differences in the prevalence of CST IV.

DESIGN

Methods: We performed a secondary analysis of 566 participants of the Motherhood & Microbiome study. PM2.5 exposures were derived from a machine learning model integrating NASA satellite and EPA ground monitor data. Previously, cervicovaginal swabs from 15 to 20 weeks' gestation were analyzed using 16 S rRNA sequencing and hierarchical clustering assigned CSTs. Multivariable logistic regression models calculated adjusted odds ratios of CST IV (vs. other CSTs) per interquartile range (IQR) increment of PM2.5. Race-stratified and mediation analyses were performed.

RESULTS

Higher PM2.5 exposure was associated with CST IV (aOR 1.39, 95% CI 1.02-1.91). Further adjustment for race/ethnicity attenuated the association (aOR 1.34, 95% CI: 0.97-1.83). Black participants (vs. White) had higher median PM2.5 exposure (10.6 vs. 9.6 μg/m3, P < 0.001) and higher prevalence of CST IV (47% vs. 11%, P < 0.001). Mediation analysis revealed that higher PM2.5 exposure may explain 3.9% (P = 0.038) and 3.3% (P = 0.15) of the Black-White disparity in CST IV in unadjusted and adjusted models, respectively.

CONCLUSION

PM2.5 was associated with CST IV, a risk factor for sPTB. Additionally, PM2.5 exposure may partially explain racial differences in the prevalence of CST IV. Further research is warranted to discover how environmental exposures affect microbial composition and perpetuate racial health disparities.

A systematic review of prediction models for spontaneous preterm birth in singleton asymptomatic pregnant women with risk factors

Backgrounds

Spontaneous preterm birth (SPB) is a global problem. Early screening, identification, and prevention in asymptomatic pregnant women with risk factors for preterm birth can help reduce the incidence and mortality of preterm births. Therefore, this study systematically reviewed prediction models for spontaneous preterm birth, summarised the model characteristics, and appraised their quality to identify the best-performing prediction model for clinical decision-making.

Methods

PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, China Biology Medicine disc, VIP Database, and Wanfang Data were searched up to September 27, 2021. Prediction models for spontaneous preterm births in singleton asymptomatic pregnant women with risk factors were eligible for inclusion. Six independent reviewers selected the eligible studies and extracted data from the prediction models. The findings were summarised using descriptive statistics and visual plots.

Results

Twelve studies with twelve developmental models were included. Discriminative performance was reported in 11 studies, with an Area Under the Curve (AUC) ranging from 0.75 to 0.95. The AUCs of the seven models were greater than 0.85. Cervical length (CL) is the most commonly used predictor of spontaneous preterm birth. A total of 91.7% of the studies had a high risk of bias in the analysis domain, mainly because of the small sample size and lack of adjustment for overfitting.

Conclusion

The accuracy of the models for spontaneous preterm births in singleton asymptomatic women with risk factors was good. However, these models are not widely used in clinical practice because they lack replicability and transparency. Future studies should transparently report methodological details and consider more meaningful predictors with new progress in research on preterm birth.

Spontaneous preterm birth with placental maternal vascular malperfusion is associated with cardiovascular risk in the fifth decade of life

Women with a history of spontaneous preterm birth (SPTB) have a mildly elevated cardiovascular risk (CVR) later in life and women with a history of preeclampsia have a highly elevated CVR. In placentas of women with preeclampsia pathological signs of maternal vascular malperfusion (MVM) are often seen. These signs of MVM are also seen in a substantial part of the placentas of women with SPTB. We therefore hypothesize that in women with a history of SPTB, the subgroup with placental MVM has an elevated CVR. This study is a secondary analysis of a cohort study including women 9-16 years after a SPTB. Women with pregnancy complications known to be associated with CVR were excluded. The primary outcome was hypertension defined as blood pressure ≥ 130/80 mmHg and/or treatment with antihypertensive medication. Secondary outcomes were mean blood pressure, anthropometrics, blood measurements including cholesterol and HbA1c, and creatinine in urine. Placental histology was available in 210 (60.0%) women. MVM was found in 91 (43.3%) of the placentas, most often diagnosed by the presence of accelerated villous maturation. Hypertension was diagnosed in 44 (48.4%) women with MVM and in 42 (35.3%) women without MVM (aOR 1.76, 95% CI 0.98 - 3.16). Women with a SPTB and placental MVM showed significantly higher mean diastolic blood pressure, mean arterial pressure and HbA1c approximately 13 years after delivery, compared to women with a SPTB without placental MVM. We therefore conclude that placental malperfusion in women with a SPTB might differentiate in CVR later in life.

Left ventricular diastolic function in the fifth decade of life in women with a history of spontaneous preterm birth

OBJECTIVE

Cardiovascular disease (CVD) is the number one cause of death in women and defining its risk factors is necessary to reduce its prevalence. A history of preeclampsia is shown to be associated with hypertension and alterations in left ventricular (LV) diastolic function parameters. Because of overlapping mechanisms between preeclampsia and spontaneous preterm birth (SPTB), our most recent study investigated the association between SPTB and hypertension, and found an almost 2 times higher prevalence of hypertension after SPTB. No previous studies have focused on the association between SPTB and LV diastolic function. The aim of this study is to investigate LV diastolic function as potential early parameter of CVD in women with a history of SPTB.

STUDY DESIGN

We included cases with a history of SPTB between 22 and 37 weeks and controls who had a term birth. Women with hypertensive disorders or gestational diabetes in any of their pregnancies, were excluded. Both groups underwent cardiovascular risk assessment and transthoracic echocardiography 9 to 16 years after pregnancy. Echocardiographic measures were adjusted using a linear regression analysis accounting for hypertension and other risk factors known to be associated with CVD. A subgroup analysis was performed based on hypertension at follow-up.

RESULTS

A total of 94 cases and 94 controls were included, on average 13 years after pregnancy. There were no significant differences in LV diastolic function parameters. Women with a history of SPTB and diagnosed hypertension at follow-up, showed significant higher late diastolic mitral flow velocity, lower e'septal velocity and higher E/e'ratio, compared to women with a history of SPTB without hypertension, although within normal ranges.

CONCLUSIONS

When a history of SPTB is accompanied by hypertension at follow-up, significant changes in LV diastolic function were seen. Therefore, hypertension is the central factor in preventive screening methods, and transthoracic echocardiography has no additional value at this follow-up duration.

Genetic variants associated with spontaneous preterm birth in women from India: a prospective cohort study

Background

Despite having the highest number of preterm births globally, no genomic study on preterm birth was previously published from India or other South-Asian countries.

Methods

We conducted a genome-wide association (GWA) study of spontaneous preterm birth (sPTB) on 6211 women from India. We used a novel resampling procedure to identify the associated single nucleotide polymorphisms (SNPs) followed by haplotype association analysis and imputation.

Findings

We found that 512 maternal SNPs were associated with sPTB (p < 2.51e-3), of which minor allele at 19 SNPs (after Bonferroni correction) had increased genotype relative risk. Haplotypes containing six of the 19 SNPs (rs13011430, rs8179838, rs2327290, rs4798499, rs7629800, and rs13180906) were associated with sPTB (p < 9.9e-4; Bonferroni adjusted p-value <0.05). After imputation in regions around the 19 SNPs, 15 imputed SNPs were found to be associated with sPTB (Bonferroni adjusted p-value <0.05). One of these imputed SNPs, rs35760881, and three other SNPs (rs17307697, rs4308815, and rs10983507) were also reported to be associated with sPTB in women belonging to European ancestry. Moreover, we found that GG genotype at rs1152954, one of the associated SNPs, enhanced risk of sPTB and reduced telomere length.

Interpretation

This is the first study from South Asia on the genome-wide identification of maternal SNPs associated with sPTB. These SNPs are known to alter the expression of genes associated with major pathways in sPTB viz. inflammation, apoptosis, cervical ripening, telomere maintenance, selenocysteine biosynthesis, myometrial contraction, and innate immunity. From a public health perspective, the trans-ethnic association of four SNPs identified in our study may help to stratify women with risk of sPTB in most populations.

Funding

Department of Biotechnology (India), Grand Challenges India - All Children Thriving Program and Biotechnology Industry Research Assistance Council (BIRAC).

Early pregnancy biomarker discovery study for spontaneous preterm birth

(1) OBJECTIVE: discover new candidate biomarkers for spontaneous preterm birth in early pregnancy samples. When fully clinically validated, early pregnancy biomarkers for sPTB give the possibility to intervene or monitor high-risk pregnancies more intensively through, as example, pelvic exams, ultrasound or sonographic cervical length surveillance. (2) STUDY DESIGN: Early pregnancy serum samples of eight spontaneous extreme and very preterm birth cases (<32 weeks of gestational age) without any symptoms of preeclampsia and fetal growth restriction and eight uncomplicated pregnancies were analyzed by liquid chromatography mass spectrometry (LC-MS). Thirteen proteins, which were differentially expressed according to the LC-MS data, were subsequently selected for confirmation by enzyme-linked immunosorbent assay (ELISA). (3) RESULTS: Differential expression of four candidate biomarkers was confirmed by ELISA with decreased early pregnancy levels of gelsolin and fibulin-1 and increased levels of c-reactive protein and complement C5 in the preterm birth group. (4) CONCLUSIONS: The confirmed candidate biomarkers are all to some extent related to inflammatory pathways and/or the complement system. This supports the hypothesis that both play a role in extreme and very preterm birth without any symptoms of preeclampsia and fetal growth restriction. The predictive value of complement C5, c-reactive protein, fibulin-1 and gelsolin should, therefore, be validated in another cohort with early pregnancy samples.

Sexual intercourse during pregnancy and its association with spontaneous preterm birth

This study investigated whether sexual intercourse during pregnancy is associated with spontaneous preterm birth (SPTB). We included 77 women with SPTB and 145 women with a term birth. A total of 195 (87.8%) women had sexual intercourse during pregnancy, which was comparable between the groups. Primiparas with SPTB tended to report more often having sexual intercourse 3 - 4 times a week compared to primiparas with a term birth (8.8% vs. 0%, p =.082). We advise not to completely discourage sexual intercourse among pregnant women. Yet, high sexual intercourse frequency could be associated with SPTB.

Anti-β2-glycoprotein I antibody maybe a novel biomarker of spontaneous preterm birth

BACKGROUND

Spontaneous preterm birth is challenging to prevent. Only few predictors of spontaneous preterm birth risk have been reported, and further studies on spontaneous preterm birth should be conducted to reduce the number of cases.

PURPOSE

The aim of the present study was to explore if anti-β₂-glycoprotein I antibody can be used to predict the risk of spontaneous preterm birth, and its clinical value in assessing the risk of spontaneous preterm birth.

METHODS

A total of 302 pregnant women who had delivered between January 2019 and December 2021 were enrolled into the study. The subjects were assigned to the case group (28-33⁺⁶ weeks, n = 41; 34-36⁺⁶ weeks, n = 96) and control group (37-42 weeks, n = 165) according to the gestational period. The age, body mass index, and gestational days of the two groups were recorded. Blood samples were collected and the levels of anti-β₂-glycoprotein I antibody, white blood cell, red blood cell, hemoglobin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, urea, creatinine, glucose, triglyceride, and total cholesterol were evaluated. Pregnant women diagnosed with sPTB that met the standards after evaluation by the clinician were included in the study.

RESULTS

The level of anti-β₂-glycoprotein I antibody was higher in case group than in the control group [(23.93 ± 8.11)Ru/mL vs (11.50 ± 5.33)Ru/mL]. The results showed that anti-β₂-glycoprotein I antibody was an independent risk factor for spontaneous preterm birth. The area under ROC curve of anti-β₂-glycoprotein I antibody to predict spontaneous preterm birth was 0.8875 (95%CI 0.8443-0.9307). The highest predicted value of anti-β₂-glycoprotein I antibody was 16.49Ru/ml.

CONCLUSION

Anti-β₂-glycoprotein I antibody has a high clinical significance and can be used by clinicians to evaluate the probability of spontaneous 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.

Associations between short-term and long-term exposure to particulate matter and preterm birth

Despite the longstanding evidence on the effect of air pollutants on preterm birth (PTB), few studies have focused on its subtypes, including spontaneous preterm birth (sPTB) and medically indicated preterm birth (miPTB). Most studies evaluated only the short-term or long-term effects of particulate matter (PM) on PTB. Thus, we designed this study, based on a cohort of 179,385 women, to evaluate both short- and long-term effects of PM with diameters ≤2.5 μm and ≤10 μm (PM_2.5 and PM₁₀) on PTB, sPTB and miPTB in Shanghai. Generalized additive models (GAMs) were applied to evaluate short-term effects. Lagged effects were identified using different lag structures. Exposure-response correlation curves were plotted using GAMs after adjustment for confounders. ORs and 95% CIs were calculated using logistic regression to estimate the long-term effect after adjustment for confounders. There was 5.67%, 3.70% and 1.98% daily incidence of PTB, sPTB, and miPTB on average. Every 10 μg/m³ increase in PM_2.5 and PM₁₀ was positively associated with PTB and sPTB at lag 2 day. The exposure-response curves (lag 2 day) indicated a rapid increase in sPTB for PM_2.5 and a linear increase for PM₁₀, in PTB for PM_2.5 and PM₁₀ at concentrations over 100 μg/m³. Regarding long-term exposure, positive associations were found between 10 μg/m³ increases in PM_2.5 and PM₁₀ in 3rd trimester and greater odds of sPTB (aOR: 1.042, 95% CI: 1.018-1.065, and 1.018, 95% CI:1.002-1.034), and during the 3 months before conception and miPTB (aOR: 1.023, 95% CI: 1.003-1.042, and 1.017, 95% CI: 1.000-1.036). Acute exposure to PM_2.5 and PM₁₀ at lag 2 day and chronic exposure in 3rd trimester was significantly associated with sPTB, while miPTB was related to chronic exposure during the 3 months before pregnancy. These findings indicate that susceptibility windows of PM exposure can be influenced by different underlying etiologies of PTB.

Natural copper isotopic abnormity in maternal serum at early pregnancy associated to risk of spontaneous preterm birth

Spontaneous preterm birth (SPB) has drawn public attention due to its increasing incidence and adverse effects on fetal growth. Effect of copper (Cu) imbalance in maternal bodies on the risk of SPB remains a subject of debate, and the related mechanisms are still unraveled. Here we applied natural stable copper isotopes to explore the underlying association and mechanism of copper imbalance with SPB using a nested case-control study. We collected maternal sera at the early pregnancy stage and then measured their copper isotopic ratio (⁶⁵Cu/⁶³Cu, expressed as δ⁶⁵Cu) as well as physiological and biochemical indexes from women with and without delivering SPB. We found that SPB cases had no significant difference in serum copper level from their controls, but their serum copper was significantly isotopically heavier than the controls (δ⁶⁵Cu value = 0.15 ± 0.34 ‰ versus -0.15 ± 0.17 ‰, P = 0.0149). Compared with the controls with lower δ⁶⁵Cu values, the crude odds ratio (OR) associated with SPB risk increased to 4.00 (95 % confidence interval (CI): 1.37-11.70) and the adjusted OR reached up to 11.35 (95 % CI: 1.35-95.60). Furthermore, via the copper isotopic fractionation, we revealed that dietary intake and blood ceruloplasmin may play more important roles than blood lipids and mother-to-child transmission in the copper imbalance associated with SPB. Further studies will be needed to understand the mechanisms of isotope fractionation related to reproductive health.

Association between preterm births and socioeconomic development: analysis of national data

Background

The increasing prevalence of preterm birth, which is a global phenomenon, is attributable to the increased medical indications, artificial gestations, and some socioeconomic factors. This study was conducted to identify whether development and equality indices are associated with the incidence of preterm birth, specifically, spontaneous and elective preterm births.

Methods

This retrospective observational study comprised an analysis of data on live births from 2019 in Brazil and on socioeconomic indices that were derived from census information in 2017. Data were summarised using absolute and relative frequencies. Spearman’s correlation was used to determine the correlation between socioeconomic factors and the preterm birth rate. Multiple beta regression analysis was performed to determine the best model of socioeconomic covariates and preterm birth rate. The significance level was set at 5%.

Results

In 2019 in Brazil, the preterm birth rate was 11.03%, of which 58% and 42% were spontaneous and elective deliveries, respectively. For all preterm births, Spearman’s correlation varied from ρ = 0.4 for the Gini Index and ρ =  − 0.24 for illiteracy. The best fit modelled the spontaneous preterm birth fraction as a negative function of the Human Development Index (HDI). The best-fit model considered the expected elective preterm birth fraction as a positive function of the HDI and as a negative function of the Gini Index, which was used as a precision parameter.

Conclusions

We observed a reduction in the fraction of spontaneous preterm births; however, the distribution was not uniform in the territory: higher rates of spontaneous preterm birth were noticed in the north, northeast, and mid-west regions. Thus, areas with lower education levels and inequal income distribution have a higher proportion of spontaneous preterm birth. The fraction of elective preterm birth was positively associated with more advantaged indices of socioeconomic status.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14376-2.

Placental pathology in spontaneous and iatrogenic preterm birth: Different entities with unique pathologic features

INTRODUCTION

Placental pathology is an important contributor to the understanding of preterm birth and reveals major differences between spontaneous preterm birth (SPTB) and iatrogenic preterm birth (IPTB). The aim of this study was to investigate these relationships.

METHODS

Research midwives collected placentas from 1101 women with singleton pregnancies who were enrolled in the Safe Passage Study. Trained pathology technologists prepared and processed placenta specimens for macroscopic and microscopic examination by designated pathologists. Statistical analyses were done with STATISTICA version 13.

RESULTS

In SPTB we found more cases of accelerated villous maturation; however, the other features of maternal vascular malperfusion (MVM) were not present. The prevalence rate of funisitis was also increased. In IPTB, multiple features of MVM - accelerated villous maturation, distal villous hypoplasia, decidual arteriopathy, increased syncytial knots, increased perivillous fibrin, and prominent extravillous trophoblast were increased, as were features of fetal vascular malperfusion (FVM) - umbilical cord vessel thrombosis, avascular villi, and fetal vascular thrombosis. Increased syncytial knots were found in 26% of preterm stillbirths and in 29% of preterm infant demises as compared to 81% of IPTB infants alive at one year.

DISCUSSION

SPTB and IPTB differ. The detected "abnormal" accelerated villous maturation pattern in SPTB and preterm demises, suggests an inability of the placenta to adapt and may be a trigger for SPTB. Funisitis was the only inflammatory response significant for SPTB. MVM and FVM are implicated in IPTB, but not an inflammatory process.

Diagnostic value of Serum Amyloid A, Interleukin-6 in gravidas with spontaneous preterm birth

PURPOSE

Spontaneous preterm birth (SPB) can't be predicted accurately nowadays. We aim to investigate the value of serum amyloid A(SAA) and interleukin-6(IL-6) for forecasting the risk of SPB.

METHODS

A total of 302 pregnant women who completed delivery in our hospital from January 2019 to December 2021 were included. According to gestational days, they were divided into the case group (28-33⁺⁶ weeks, 41 cases; 34-36⁺⁶ weeks, 96 cases) and the control group (37-42 weeks, 165 cases). The general data of the two groups were analyzed and the values of SAA and IL-6 in speculating the risk of SPB were studied in this study.

RESULTS

The levels of SAA and IL-6 in the case group were higher than those in the control group(P < 0.05), and the most practical value of SAA and IL-6 access SPB risk were 17.35 mg/L, 112.41 pg/mL respectively. The area under the ROC curve of diagnosis to predict SPB were 0.8849, 0.8664.

CONCLUSIONS

The assessment of SPB risk by SAA and IL-6 bearscertain clinical value, which could assist clinicians in recognizing and evaluating the potential dangers of SPB.

Deprived neighborhoods and spontaneous preterm birth: A national cohort study

OBJECTIVE

Spontaneous preterm birth is the leading cause of infant morbidity and mortality in the developed world. Environmental socio-economic factors, such as neighborhood deprivation, are known to negatively affect birth outcomes, including overall preterm birth. However, the role of neighborhood deprivation in spontaneous preterm birth (SPTB) is unclear. The aim of the study is to 1) to determine the effect of neighborhood deprivation on SPTB birth and 2) to investigate the trend in rates of SPTB between 2010 and 2019 for each quintile of neighborhood deprivation.

STUDY DESIGN

Based on the national perinatal registry, we included 1,584,225 singleton pregnancies resulting in a birth from 22 to 42 completed weeks of gestation between 2010 and 2019 in the Netherlands. Deprivation scores per neighborhood were derived from the Netherlands Institute of Social Research and were linked to the perinatal registry data, using the woman's home address. The scores were divided into quintiles (Q). Rates of SPTB were calculated, categorized into <37 weeks, <32 weeks and <28 weeks of gestation. We used logistic regression analysis to adjust for maternal age, parity and ethnicity.

RESULTS

Compared to the most affluent neighborhoods (Q1), women in all other quintiles had a statistically significant increased risk for SPTB. The largest effect was observed in the most deprived neighborhoods (Q5); adjusted odds ratio 1.16 (95% confidence interval 1.13 - 1.19). From 2010 to 2019, we observed an overall decrease of 0.21% in SPTB < 37 weeks (p < 0.0001). All quintiles showed a decrease in SPTBs < 37 weeks, but only in Q1, Q2 & Q5 this decline in SPTB was statistically significant.

CONCLUSIONS

Pregnant women in deprived neighborhoods in the Netherlands are more at risk for spontaneous preterm birth. From 2010 to 2019, the rate of spontaneous preterm birth decreased. Efforts should be made by both governmental and medical professionals to develop intervention programs to reduce spontaneous preterm birth in more deprived neighborhoods.

Spontaneous preterm birth as a function of normal cervical length in low-risk women

OBJECTIVES

To identify if there is an increased risk for spontaneous preterm birth (sPTB) across the continuum of measured, normal cervical lengths (CL) in low-risk women.

METHODS

Retrospective cohort study of women with singleton pregnancies and no history of prior sPTB. Women were included if they underwent mid-trimester transvaginal CL measurement between February 2016 and August 2018 and had a measured, normal CL ≥25mm. Women were excluded for progesterone exposure, fetal anomalies, or an unmeasurable CL due to a poorly developed lower uterine segment. The primary study outcome was sPTB <37 weeks. Secondary outcomes included: sPTB <35 weeks, birth gestational age (GA), and the number of hospital evaluations for suspected preterm labor (PTL). Cervical length was considered in interval groups 25-29mm, 30-34mm, 35-39mm, 40-44mm, and ≥45mm. Outcomes were analyzed with χ² test of trend and as a continuum (linear models, logistic regression and ROC curve), where appropriate.

RESULTS

985 women were included. The incidence of sPTB <37 weeks was 3.7%, with a mean birth GA of 38.7 ± 2.4 weeks. The odds of sPTB <37 weeks decreased with increasing cervical length, considered in 5 mm intervals (odds ratio = 0.67; 95% confidence interval 0.49-0.90) and an increasing birth GA of 1 additional day for each CL increase of 3mm (p = .0002). Conversely, sPTB <35 weeks (p = .49) and mean hospital evaluations for PTL (p = .26) were similar across groups. The ROC curve area-under-the-curve for sPTB <37 weeks of 0.64 showed poor predictive value.

CONCLUSIONS

Among women without a history of sPTB, there was an association of decreased risk of sPTB <37 weeks and advanced delivery GA with increasing, but normal-range CL measurements. However, the association was poor and was not associated with spontaneous preterm birth <35 weeks, or the number of hospital evaluations for PTL.

Previous term emergency caesarean section is a risk factor for recurrent spontaneous preterm birth; a retrospective cohort study

OBJECTIVES

Emergency caesarean sections (EmCS), particularly those performed in the second stage of labour, have been associated with a risk of subsequent preterm birth. More worrying is that the risk of sPTB recurrence appears to be high in women who have had a second stage EmCS and a subsequent sPTB. However, there is a paucity of evidence regarding the risk of recurrence in women who have had a prior term EmCS at any stage of labour followed by a sPTB. This study aims to investigate the relationship between all term in labour EmCS and the risk of recurrent spontaneous preterm birth (sPTB).

STUDY DESIGN

This is an observational, retrospective cohort study conducted at St Thomas' Hospital, a tertiary-level maternity hospital in London, United Kingdom. 259 women were included; 59 women with a term in labour EmCS preceding a sPTB (EmCS group) and 200 women with a prior sPTB only (control group). The initial EmCS was further categorised into first stage (FS)-EmCS or second stage (SS)-EmCS. Primary outcome was sPTB in Pregnancy C < 37 weeks' gestation. Secondary outcomes included sPTB < 34 weeks' and < 24 weeks' gestation.

RESULTS

54% (32/59) of the EmCS group had a recurrent sPTB < 37 weeks compared to 20% (40/200) of the control women (p < 0.0001) with a relative risk of 2.71 [95%CI 1.87-3.87]). Of women who had a SS-EmCS and a subsequent PTB, 61.9% (13/21) had a further sPTB (RR 3.0 [95%CI, 1.8-4.5] compared to control women). In addition, there is nearly a 6-fold increased risk of a recurrent sPTB or midtrimester loss < 24 weeks' gestation in these women (RR 5.65 [95%CI2.6-12.0]).

CONCLUSIONS

In women who have had a previous sPTB in which a term in labour EmCS is a risk factor, the risk of a further sPTB is much higher than in those women where a prior sPTB is the sole risk factor. Furthermore, EmCS at both the first and second stage of labour are associated with a increased risk of recurrent sPTB. Further work should ascertain which women who have had a prior term EmCS are at risk of sPTB and recurrence, and how best to identify and treat them.

Associations of maternal exposure to 41 metals/metalloids during early pregnancy with the risk of spontaneous preterm birth: Does oxidative stress or DNA methylation play a crucial role?

BACKGROUND

Few studies have explored the effects of multiple types of metals/metalloids on spontaneous preterm birth (SPB). A nested case-control study was conducted in Shanxi Province to investigate the associations between maternal exposure to 41 metals/metalloids during early pregnancy and the risk of SPB, and to clarify the underlying mechanisms of oxidative stress and DNA methylation.

METHODS

A total of 74 controls with full-term delivery and 74 cases with SPB were included in the nested case-control study. The metals/metalloids in serum and the DNA adducts in peripheral blood cell DNA were determined using ICP-MS and UPLC-QqQ-MS/MS, respectively. Unconditional logistic regression models were employed to estimate the associations of the risk of SPB with the metal concentrations, as well as with the levels of oxidative stress/DNA methylation. In addition, linear regression models were used to investigate the associations between the metal/metalloid concentrations and the levels of oxidative stress/DNA methylation.

RESULTS

After adjusting for potential confounders, the concentrations of Mn, Fe, Cu, Nd, Hg, and Pb in maternal serum during early pregnancy were positively associated with the risk of SPB. Compared with the lowest levels (Quartile 1) of Mn, Fe, Cu, Nd, Hg, and Pb, the odds ratios of SPB increased to 5.21 (95% CI: 1.63, 16.68), 3.47 (95% CI: 1.07, 11.21), 16.23 (95% CI: 3.86, 68.18), 10.54 (95% CI: 2.79, 39.86), 5.88 (95% CI: 1.72, 20.11), and 4.09 (95% CI: 1.31, 12.77) in the highest levels (Quartile 4), respectively. A significant increase in 8-OHdG was associated with the increased exposure to Fe, Pr, Eu, Er, and Lu. The levels of 5-MdC, 5-HmdC, and N6-MdA-the indicators of DNA methylation-were associated with exposure to multiple metals/metalloids. However, no significant associations were observed between the levels of oxidative stress or DNA methylation and the risk of SPB.

CONCLUSIONS

Exposure to multiple types of metals/metalloids during early pregnancy is positively associated with the risk of SPB. Oxidative stress and DNA methylation are significantly associated with exposure to multiple metals/metalloids. Systemic oxidative stress and DNA methylation have not been proven to be the mediating mechanisms of metals increasing the risk of SPB.

Magnitude of spontaneous preterm birth and its associated factors among preterm birth in NICU wards in Asella Teaching and Referral Hospital, Asella, Oromia, Ethiopia

Objective

To assess the prevalence of spontaneous preterm births and to identify the associated risk factors.

Methods

This single-centre cross-sectional study enrolled women that experienced a preterm birth as registered on the neonatal log-book between 30 December 2019 and 30 December 2020. A pre-tested structured checklist was used to collect data (sociodemographic characteristics; obstetric-related factors; medical history; and pregnancy-related factors). Bivariate logistic regression analyses were applied to identify factors associated with spontaneous preterm birth. A multivariate model identified significant independent risk factors.

Results

A total of 310 patients participated in the study. The prevalence of spontaneous preterm birth in this population was 67.1% (208 of 310; 95% confidence interval [CI] 61.5, 71.9). Patients without a partner (adjusted odds ratio [AOR] = 1.470, 95% CI 1.23, 4.42), patients residing in a rural area (AOR = 2.51, 95% CI 1.123, 5.513) and those with a history of PIH during their current pregnancy (AOR = 0.104, 95% CI 0.053, 0.014) were significantly more likely to have a spontaneous preterm birth.

Conclusion

The prevalence of spontaneous preterm birth in in this study was high. Healthcare providers and all stakeholders should focus on screening pregnant women at the risk of spontaneous preterm birth.

"Does the use of gestation-specific centiles for cervical length change the management of pregnancies at risk of recurrent spontaneous preterm birth?"

INTRODUCTION

Preterm birth is the leading cause of neonatal morbidity and mortality. Spontaneous Preterm Birth (sPTB) has many and varied causes but is known to be strongly associated with a short or shortening cervix in the midtrimester of pregnancy. The strongest risk factor for sPTB is a previous sPTB. In women with a history of sPTB, we can offer surveillance and treatments which have been proven to reduce the risk of sPTB, such as cervical cerclage and vaginal progesterone supplementation. Alongside other indications, we currently use 25 mm or shorter as a "trigger threshold" for offering cervical cerclage treatment in the Preterm Birth Prevention Clinic at The National Maternity Hospital.

AIM

To determine if using gestation-specific centiles instead of a 25 mm cut-off for cervical length changes the antenatal management of women at high risk of sPTB.

METHOD

This was a retrospective chart review of all women attending the preterm birth clinic over the 2-year period 2018-2020 in a large tertiary referral unit in Dublin, Ireland. Demographic details, obstetric history, preterm birth risk factors and preventative treatments offered were collected and analysed. Cervical lengths were measured with ultrasound using a standardised protocol and all performed or supervised by 2 experienced sonographers.

RESULTS

A total of 200 patients with known risk factors for sPTB attended the Preterm Birth Surveillance Clinic at the National Maternity Hospital during the study period. Of these, 36/200 (18%) went on to deliver again prior to 37 weeks despite attending the clinic +/- receiving interventions & this group are the focus of this paper. The indications for surveillance in this group that had a recurrent sPTB included recurrent second-trimester pregnancy losses/preterm delivery < 34 weeks (26/36 (72%)), cervical trauma (including treatment of CIN) (12/36 (33%)), congenital abnormalities (1/36 (2.8%)), uterine anomaly (1/36 (2.8%)) and placental bleeding (1/36 (2.8%)). There was one smoker in this series. Funnelling was observed in 3/36 cases (8.3%). Of the 36 patients, an additional 15 would have received a cerclage had gestation-specific centiles, i.e., <5th centile, been used and an additional 10/36 (28%) would have been offered progesterone therapy.

CONCLUSION

In those at high risk of preterm birth, the use of gestation-specific centiles for cervical length increases the proportion of patients that would be eligible for cervical cerclage. It is unclear whether this would change clinical outcome.

Distribution of mercury in serum and blood cells and risk of spontaneous preterm birth: A nested case-control study in China

The relationship between maternal mercury (Hg) intake and the risk of spontaneous preterm birth (SPB) remains unclear. We conducted a nested case-control study from a prospective cohort in Shanxi Province, China, to explore their associations. In total, 126 pregnant women with SPB (cases) and 348 controls with term delivery were included. We measured the Hg concentrations in their serum (Hg^s) and blood cell (Hg^c) fractions and calculated the concentration ratio of Hg in serum to Hg in blood cells (Hg^s/c). We found that only the Hg^s/c in the case group was slightly higher than that in control group. The OR of Hg^s/c associated with SPB risk was 1.57 [95%CI: 0.99-2.46] with adjusting confounders. After stratification by sampling time, the association above was only statistically significant in the first trimester. High Hg^s/c may increase the risk of SPB in the first trimester among women with relatively low Hg exposure.

Autism-associated synaptic vesicle transcripts are differentially expressed in maternal plasma exosomes of physiopathologic pregnancies

BACKGROUND

During intrauterine development, the formation and function of synaptic vesicles (SVs) are thought to be fundamental conditions essential for normal development of the brain. Lacking advanced technology during the intrauterine period, such as longitudinal real-time monitoring of the SV-associated transcripts (SVATs), which include six pairs of lncRNA-mRNA, has limited acquisition of the dynamic gene expression profile (GEP) of SVATs. We previously reported the differential expression of SVATs in the peripheral blood of autistic children. The current study was designed to determine the dynamic profiles of differentially-expressed SVATs in circulating exosomes (EXs) derived from autistic children and pregnant women at different gestational ages.

METHODS

Blood samples were collected from autistic children and women with variant physiopathologic pregnancies. EXs were isolated with an ExoQuick Exosome Precipitation Kit and characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and Western blotting. The expression of lncRNAs and lncRNA-targeted mRNAs were quantified using real-time PCR.

RESULTS

SVAT-associated lncRNAs-mRNAs were detected in autistic children and differentially expressed from the first trimester of pregnancy to the term of delivery. Pathologic pregnancies, including spontaneous preterm birth (sPTB), preeclampsia (PE), and gestational diabetes mellitus (GDM), were compared to normal physiologic pregnancies, and shown to exhibit specific correlations between SVAT-lncRNA and SVAT-mRNA of STX8, SLC18A2, and SYP with sPTB; SVAT-lncRNA and SVAT-mRNA of STX8 with PE; and SVAT-lncRNA and SVAT-mRNA of SV2C as well as SVAT-mRNA of SYP with GDM.

CONCLUSION

Variant complications in pathologic pregnancies may alter the GEP of SVATs, which is likely to affect the intrauterine development of neural circuits and consequently influence fetal brain development.

The Intricate Interactions between Maternal Smoking and Drinking During Pregnancy and Birthweight Z-Scores of Preterm Births

BACKGROUND

The extent to which smoking and drinking in a local community is associated with nutrition and Z-scores of infants from spontaneous preterm deliveries, is uncertain.

AIM

To investigate associations of different levels of maternal smoking and drinking in spontaneous preterm birth with infant birthweight Z-scores.

METHODS

Information, including gestational age (determined by earliest ultrasound), maternal arm circumference (measured at enrolment), smoking-drinking data (obtained up to 4 occasions), birthweight data (obtained from medical records) and birthweight Z-scores (calculated from INTERGROWTH- 21st study), collected over a period of nine years was used to compare 407 spontaneous preterm births with 3 493 spontaneous term births Analyses of variance, correlations and multiple regression were performed in STATISTICA.

RESULTS

Women with spontaneous preterm birth, had significantly lower gravidity and smaller arm circumference when compared to women with spontaneous birth at term. Women with spontaneous preterm birth drank more and heavier during pregnancy, and more smoked. Gestational age at birth was significantly longer in heavy-smokers-heavy-drinkers compared to heavy-smokers-no-drinkers (7.1 days) and in no-smokers-heavy-drinkers when compared to no-smokers-no-drinkers (11.2 days). Birthweight was significantly lower in low-smokers-heavy-drinkers when compared to low-smokers-no-drinkers (240g) and in heavy-smokers-low-drinkers when compared to no-smokers-low-drinkers (273g). Birthweight Z-scores were significantly lower in low-smokers-heavy-drinkers when compared to low-smokers-low-drinkers and low-smokers-no-drinkers; and, also significantly lower in heavy-smokers-low-drinkers when compared to low-smokers-low-drinkers and no-smokers-low-drinkers.

CONCLUSION

Alcohol aggravates the detrimental effect of smoking on birthweight and birthweight Z-scores but seems to counteract the negative association of smoking with gestational age.

Impact of history of myomectomy on preterm birth risk in women with a leiomyomatous uterus: a propensity score analysis

BACKGROUND

To evaluate if women with a history of myomectomy have a modified preterm birth risk compared to women with myomas during pregnancy.

METHODS

Retrospective cohort study including all women with a history of myomectomy (operated group) or uterine myomas during pregnancy (unoperated group) who delivered in a tertiary center between January, 2011 and December, 2017. The operated group included women who had a myomectomy history with or without myomas during the ongoing pregnancy. The unoperated group included women with uterine myoma(s) seen on at least one ultrasound during pregnancy without history of myomectomy. The primary outcome was preterm birth < 37 weeks, and the secondary outcome spontaneous preterm birth < 37 weeks. To control for confounding factors, a propensity score approach was used. Two sensitivity analysis were performed, one repeating the analysis using the propensity score after excluding operated women with persistent myomas and one using a classical multivariable logistic regression model.

RESULTS

The cohort included 576 women: 283 operated women and 293 unoperated women. The rate of preterm birth was similar in the two groups: 12.6% in the unoperated group and 12.0% in the operated group (p = 0.82). No difference in preterm birth risk was shown between unoperated and operated women in the cohort matched on the propensity score: OR 0.86; 95%CI [0.47-1.59]. These results were consistent for spontaneous preterm birth (OR 1.61; 95%CI [0.61-4.23]) and for the sensitivity analyses.

CONCLUSION

In women with a leiomyomatous uterus, a history of myomectomy is not associated with a reduced preterm birth risk.

Biomarker discovery for predicting spontaneous preterm birth from gene expression data by regularized logistic regression

In this work, we provide a computational method of regularized logistic regression for discovering biomarkers of spontaneous preterm birth (SPTB) from gene expression data. The successful identification of SPTB biomarkers will greatly benefit the interference of infant gestational age for reducing the risks of pregnant women and preemies. In recent years, various approaches have been proposed for the feature selection of identifying the subset of meaningful genes that can achieve accurate classification for disease samples from controls. Here, we comprehensively summarize the regularized logistic regression with seven effective penalties developed for the selection of strongly indicative genes of SPTB from microarray data. We compare their properties and assess their classification performances in multiple datasets. It shows that elastic net, lasso,L 1 / 2 and SCAD penalties get the better performance than others and can be successfully used to identify biomarkers of SPTB. Particularly, we make a functional enrichment analysis on these biomarkers and construct a logistic regression classifier based on them. The classifier generates an indicator of preterm risk score (PRS) for predicting SPTB. Based on the trained predictor, we verify the identified biomarkers on an independent dataset. The biomarkers achieve the AUC value of 0.933 in the SPTB classification. The results demonstrate the effectiveness and efficiency of the built-up strategy of biomarker discovery with regularized logistic regression. Obviously, the proposed method of discovering biomarkers for SPTB can be easily extended for other complex diseases.

Long non-coding RNA SNHG29 regulates cell senescence via p53/p21 signaling in spontaneous preterm birth

INTRODUCTION

Spontaneous preterm birth affects>5-18% of pregnancies and causes infant morbidity and mortality. Long non-coding RNAs can regulate gene expression and have been associated with preterm birth. In this study, we investigated whether the long non-coding RNA SNHG29 was associated with spontaneous preterm birth.

METHODS

We collected the placentas from women who underwent preterm/full-term birth with/without labor. We determined the levels of expression of SNHG29 in the placental tissues using quantitative real-time polymerase chain reaction. We generated a senescence model by treating HTR8/SVneo cells with 200 μM H2O2 for 2 h. The degree of senescence induced in cells depleted of or overexpressing SNHG29 was determined by measuring senescence-associated gene expression and β-galactosidase activity.

RESULTS

SNHG29 was overexpressed in the placentas of women who delivered preterm with labor and in HTR8/SVneo cells treated with H2O2 (p < 0.05). The levels of mRNA of p53 and p21, protein levels of p53, phospho-p53, p21and phospho-p21, and β-galactosidase activity was decreased in HTR8/SVneo cells depleted of SNHG29, while the opposite trend was observed in HTR8/SVneo cells overexpressing SNHG29 (p < 0.05). We observed an increase in the expression of IL-8 and TNF-α in senescent HTR8/SVneo cells (p < 0.05).

DISCUSSION

SNHG29 was overexpressed in placentas from women who delivered preterm with labor compared to those in women who underwent preterm birth without labor and full-term birth with/without labor. High levels of SNHG29 enhanced senescence in vivo. The increase in pro-inflammatory cytokine expression and release by senescent cells may be pivotal to the pathophysiology of spontaneous preterm birth.

EBF1-Correlated Long Non-coding RNA Transcript Levels in 3rd Trimester Maternal Blood and Risk of Spontaneous Preterm Birth

Biomarkers associated with spontaneous preterm birth (sPTB) before labor onset could aid in prediction, triage, and stratification for testing interventions. In this study we examined maternal blood EBF1-correlated long non-coding RNAs (lncRNAs) in relation to sPTB. We retrieved all lncRNA transcripts from a public gene expression dataset (GSE59491) derived from maternal blood in trimesters 2 and 3 from a Canadian cohort with a matched set of sPTB (n = 51) and term births (n = 106). LncRNA transcripts differentially expressed (limma moderated t-tests) in sPTB vs. term were tested for correlations (Pearson) with EBF1 mRNA levels in the same blood samples. Using logistic regression, EBF1-correlated lncRNAs were divided into tertiles and assessed in relation to odds of sPTB. Two lncRNA transcripts in the 3rd trimester maternal blood were differentially expressed between sPTB and term births (all p < 0.001 and FDR < 0.250) and positively and negatively correlated with EBF1 mRNA levels. They were as follows: (1) LINC00094 r = 0.196 (95% CI: 0.039 to 0.344), p = 0.015, and BH adjusted p = 0.022 and (2) LINC00870 r = - 0.303 (95% CI: - 0.441 to - 0.152), p < 0.001, and BH adjusted p < 0.001. As compared with term births, sPTBs were more likely to be in the highest tertile of LINC00870 (odds ratio (OR) = 4.08 (95% CI 1.60, 10.40), p = 0.003) and the lowest tertile of LINC00094 (OR = 5.16 (95% CI 1.96, 13.61), p < 0.001). Two sPTB-associated EBF1-correlated lncRNAs (LINC00870 and LINC00094) had multiple potential enhancers containing EBF1 binding site(s). Our current findings, along with previous reports linking EBF1 and sPTB, motivate additional research on the EBF1 gene-related gene expression and regulation in relation to sPTB within other cohorts and within laboratory-based models.

Maternal serum level of manganese, single nucleotide polymorphisms, and risk of spontaneous preterm birth: A nested case-control study in China

Manganese (Mn) is an essential trace element, but an excess or accumulation can be toxic. Until now, few studies have examined the effects of maternal Mn level on the risk of spontaneous preterm birth (SPB). The aims of this study were to examine the association between maternal Mn level and the risk of SPB at the early stage of pregnancy, and investigate whether this association was modified by single nucleotide polymorphisms (SNPs) in genes of superoxide dismutase (SOD) and catalase (CAT). We conducted a nested case-control study in three maternal and child health care hospitals in Shanxi province, China, from December 2009 to December 2013. From an overall cohort of 4229 women, 528 were included in our study, including 147 cases of SPB and 381 controls. Maternal blood samples were collected during 4-22 gestational weeks. The maternal serum concentrations of Mn was measured using inductively coupled plasma-mass spectrometry. We found the maternal Mn concentration in the case group (median: 1.55 ng/mL) was significantly higher than that in the control group (median: 1.27 ng/mL). Compared to the lowest level, the SPB risk was significantly increased to 1.44 (95%CI: 0.60-3.43), 2.42 (95%CI: 1.06-5.55) and 2.46 (95%CI: 1.08-5.62) respectively for the second, third and fourth quartiles in first trimester, but not significant in second trimester or overall. When exposure to a high Mn level, women who with AA (6.36, 95%CI: 1.57-25.71) and AG (3.04, 95%CI: 1.59-5.80) of rs2758352, with CC (2.34, 95%CI: 1.31-4.18) of rs699473, and with GG (2.26, 95%CI: 1.22-4.16) of rs769214 were more likely to develop a SPB, but not among women with other genotypes. In conclusion, high maternal serum Mn level is associated with the increased SPB risk in first trimester, and the association is modified by maternal SNPs of SOD2, SOD3 and CAT.

Increased incidence of hypertensive disorders of pregnancy in women with a history of spontaneous preterm birth: A longitudinal linked national cohort study

OBJECTIVE

Determine the risk of hypertensive disorders of pregnancy (HD) in women with a history of spontaneous preterm birth (SPTB).

STUDY DESIGN

Longitudinal linked national cohort study within the Dutch Perinatal Registry (1999-2009) on linked data among 349,291 women with a first and second singleton pregnancy in the Netherlands.

MAIN OUTCOME MEASURES

The incidence of HD, small for gestational age (SGA) and placental abruption in the second pregnancy.

RESULTS

Out of 349,291 women with a singleton first pregnancy, 19,991 (5.7%) had a SPTB. The incidence of HD in the second pregnancy was 8.1% in women with a previous SPTB, as compared to 5.6% in women with a previous term birth (aOR 1.49 (CI 1.41-1.57)). Also after excluding HD, SGA and/or placental abruption in the first pregnancy, women with a history of SPTB had a higher risk of HD in their second pregnancy compared to women with a previous term birth (4.6% versus 2.7%, aOR 1.77 (CI 1.64-191)). Similarly, the incidence of SGA and placental abruption was higher in the second pregnancy in women with a history of SPTB compared to term birth in the first pregnancy.

CONCLUSIONS

Women with a history of SPTB are at elevated risk of HD in the subsequent pregnancy. These results support shared pathophysiology between SPTB and HD.

The association between parity and spontaneous preterm birth: a population based study

Background

Preterm birth is the leading cause of perinatal mortality and neonatal morbidity worldwide. Many factors have been associated with preterm birth, including parity. The aim of the present study was to investigate associations between parity and risk of spontaneous preterm birth.

Methods

We conducted a retrospective study including live singleton births (≥22 weeks) of women with a first, second, third, fourth or fifth pregnancy in The Netherlands from 2010 through 2014. Our primary outcome was risk of spontaneous preterm birth < 37 weeks. Secondary outcomes were spontaneous preterm birth < 32 and < 28 weeks.

Results

We studied 802,119 pregnancies, including 30,237 pregnancies that ended spontaneously < 37 weeks. We identified an increased risk for spontaneous preterm birth < 37 weeks in nulliparous women (OR 1.95, 95% CI 1.89–2.00) and women in their fifth pregnancy (OR 1.26, 95% CI 1.13–1.41) compared to women in their second pregnancy. Similar results were seen for spontaneous preterm birth < 32 and < 28 weeks.

Conclusion

Our data show an independent association between nulliparity and spontaneous preterm birth < 37, < 32 and < 28 weeks. Furthermore, we observed an increased risk for spontaneous preterm birth in women in their fifth pregnancy, with highest risk for preterm birth at early gestational age.

Association of socioeconomic status and clinical and demographic conditions with the prevalence of preterm birth

OBJECTIVE

To examine the effects of socioeconomic and demographic conditions on the prevalence of preterm birth in a local community.

METHODS

Pregnant women (aged ≥16 years) willing to provide informed consent in one of the two languages of the community were recruited in South Africa between August 2007 and January 2015. Specifically designed case report forms collected information and measurements prospectively.

RESULTS

After reviewing the medical records of 5806 women, it was possible to identify those who had spontaneous preterm birth (SPTB), induced preterm birth (IPTB), or spontaneous term birth (STB). Women with IPTB (vs SPTB) were more obese and had higher education levels and household incomes; more had telephones and running water at home. They enrolled earlier and more developed hypertension and pre-eclampsia. Women with SPTB (vs STB) were less obese, shorter, had smaller arm circumferences and higher gravidities and Edinburgh Depression Scores, lower education, fewer telephones, and less running water at home. More women with SPTB used methamphetamine, cigarettes, and were heavier smokers.

CONCLUSION

SPTB and IPTB should not be conflated. Programs to reduce the high prevalence of SPTB should include improving education, lifestyle, and socioeconomic conditions. Addressing hypertension should help reduce preterm inductions.

The use of specialised preterm birth clinics for women at high risk of spontaneous preterm birth: a systematic review

Background

Specialised preterm birth clinics care for women at high risk of spontaneous preterm birth. This systematic review assesses current practice within preterm birth clinics globally.

Methods

A comprehensive search strategy was used to identify all studies on preterm birth clinics on the MEDLINE, Embase, PsycINFO, CENTRAL and CINAHL databases. There were no restrictions to study design. Studies were limited to the English language and publications from 1998 onwards. Two reviewers assessed studies for inclusion, performed data extraction and reviewed methodological quality. Primary outcomes were referral criteria, investigations and interventions offered in preterm birth clinics. Secondary outcomes were the timing of planned first and last appointments and frequency of review.

Results

Thirty-two records fulfilled eligibility criteria and 20 studies were included in the main analysis following grouping of records describing the same study or clinic. Studies were of mixed study design and methodological quality. A total of 39 clinics were described; outcome data was not available for all clinics. Referral criteria included previous spontaneous preterm birth (38/38, 100%), previous mid-trimester loss (34/38, 89%) and previous cervical surgery (33/38, 87%). All clinics offered transvaginal cervical length scans. Additional investigations varied, including urogenital swabs (16/28, 57%) and fetal fibronectin (8/28, 29%). The primary treatment of choice for a sonographic short cervix was cervical cerclage in 10/33 (30%) clinics and vaginal progesterone in 6/33 (18%), with 10/33 (30%) using multiple first-line options and 6/33 (18%) using a combination of treatments. The majority of clinics planned timing of first review for 12–16 weeks (30/35, 86%) and the frequency of review was usually determined by clinical findings (18/24, 75%). There was a wide variation in gestational age at clinic discharge between 24 and 37 weeks.

Conclusions

There is variation in the referral criteria, investigations and interventions offered in preterm birth clinics and in the timing and frequency of review. Consistency in practice may improve with the introduction of consensus guidelines and national preterm birth prevention programmes.

Trial registration

Systematic review registration number: CRD42019131470.

Association between phospholipid metabolism in plasma and spontaneous preterm birth: a discovery lipidomic analysis in the cork pregnancy cohort

INTRODUCTION

Preterm birth (PTB) is defined as birth occurring before 37 weeks' gestation, affects 5-9% of all pregnancies in developed countries, and is the leading cause of perinatal mortality. Spontaneous preterm birth (sPTB) accounts for 31-50% of all PTB, but the underlying pathophysiology is poorly understood.

OBJECTIVE

This study aimed to decipher the lipidomics pathways involved in pathophysiology of sPTB.

METHODS

Blood samples were taken from SCreening fOr Pregnancy Endpoints (SCOPE), an international study that recruited 5628 nulliparous women, with a singleton low-risk pregnancy. Our analysis focused on plasma from SCOPE in Cork. Discovery profiling of the samples was undertaken using liquid chromatography-mass spectrometry Lipidomics, and features significantly altered between sPTB (n = 16) and Control (n = 32) groups were identified using empirical Bayes testing, adjusting for multiple comparisons.

RESULTS

Twenty-six lipids showed lower levels in plasma of sPTB compared to controls (adjusted p < 0.05), including 20 glycerophospholipids (12 phosphatidylcholines, 7 phosphatidylethanolamines, 1 phosphatidylinositol) and 6 sphingolipids (2 ceramides and 4 sphingomyelines). In addition, a diaglyceride, DG (34:4), was detected in higher levels in sPTB compared to controls.

CONCLUSIONS

We report reduced levels of plasma phospholipids in sPTB. Phospholipid integrity is linked to biological membrane stability and inflammation, while storage and breakdown of lipids have previously been implicated in pregnancy complications. The contribution of phospholipids to sPTB as a cause or effect is still unclear; however, our results of differential plasma phospholipid expression represent another step in advancing our understanding of the aetiology of sPTB. Further work is needed to validate these findings in independent pregnancy cohorts.

EBF1 Gene mRNA Levels in Maternal Blood and Spontaneous Preterm Birth

Genetic variants of six genes (EBF1, EEFSEC, AGTR2, WNT4, ADCY5, and RAP2C) have been linked recently to gestational duration and/or spontaneous preterm birth (sPTB). Our goal was to examine sPTB in relation to maternal blood mRNA levels of these genes. We used a public gene expression dataset (GSE59491) derived from maternal blood in trimesters 2 and 3 that included women with sPTB (n = 51) and term births (n = 106) matched for maternal age, race/ethnicity, pre-pregnancy body mass index, smoking during pregnancy, and parity. T tests were used to examine mRNA mean differences (sPTB vs term) within and across trimesters, and logistic regression models with mRNA quartiles were applied to assess associations between candidate gene mRNA levels and sPTB. Based on these analyses, one significant candidate gene was used in a Gene Set Enrichment Analysis (GSEA) to identify related gene sets. These gene sets were then compared with the ones previously linked to sPTB in the same samples. Our results indicated that among women in the lowest quartile of EBF1 mRNA in the 2nd or 3rd trimester, the odds ratio for sPTB was 2.86 (95%CI 1.08, 7.58) (p = 0.0349, false discovery rate (FDR) = 0.18) and 4.43 (95%CI 1.57, 12.50) (p = 0.0049, FDR = 0.06), respectively. No other candidate gene mRNAs were significantly associated with sPTB. In GSEA, 24 downregulated gene sets were correlated with 2nd trimester low EBF1 mRNA and part of previous sPTB-associated gene sets. In conclusion, mRNA levels of EBF1 in maternal blood may be useful in detecting increased risk of sPTB as early as 2nd trimester. The potential underlying mechanism might involve maternal-fetal immune and cell cycle/apoptosis pathways.

The use of quantitative fetal fibronectin for the prediction of preterm birth in women with exposed fetal membranes undergoing emergency cervical cerclage

OBJECTIVE

Emergency cervical cerclage is often considered a controversial salvage measure for those pregnancies at high risk of mid-trimester loss or early preterm birth. To determine the efficacy and benefit of emergency cerclage insertion, we assessed the predictive value of quantitative fetal fibronectin (fFN) concentration in cervicovaginal fluid for spontaneous preterm birth in women with exposed fetal membranes prior to cerclage insertion.

STUDY DESIGN

This was a retrospective observational study from St Thomas' Hospital, London of a cohort of women with singleton pregnancy and exposed fetal membranes presenting between 18 and 23⁺⁶ weeks of gestation (n = 35), in the period 2015-2018. fFN concentrations in cervicovaginal fluid were measured quantitatively at presentation in all women within 24 h prior to cerclage insertion.

RESULTS

35 eligible women with exposed fetal membranes who underwent an emergency cervical cerclage were identified. The median gestational age was 20 + 0 weeks (18 + 6-21 + 2) at presentation and 29 + 3 weeks (23 + 3-38 + 2) at delivery, with a median time from emergency cerclage to delivery of 65.5 days (17-126.5). In total, 12 women (34 %) delivered within 28 days of emergency cerclage insertion. 60 % of women with an fFN level above 500 ng/mL delivered within 28 days of cerclage insertion, and they all delivered before 37 weeks gestation. No women with fFN levels below 10 ng/mL delivered within 28 days and 75 % of these women delivered at term. Concentration of quantitative fFN at presentation correlated negatively with time to delivery (Spearman's rs = -0.52, p = 0.0016). Mann-Whitney U analysis demonstrated a significant difference in the distribution of qfFN concentrations in women who delivered preterm compared to those who did not, both within 28 days from testing (p = 0.0048) and <37 weeks (p = 0.006).

CONCLUSION

Quantitative fFN has a role in predicting spontaneous preterm birth even in women with exposed fetal membranes undergoing emergency cervical cerclage. Given the serious risks associated with cervical cerclage surgery, qfFN could be used to counsel these patients at high risk of preterm delivery, as well as assisting in the decision to insert a cerclage.

Female genital tract microbiota affecting the risk of preterm birth: What do we know so far? A review

Spontaneous Preterm birth (SPTB) is a common obstetric complication affecting 12.9 million births worldwide and is the leading cause of neonatal morbidity and mortality. Disruption in the vaginal microbiota has an impact on the maternal immunological profile leading to SPTBs. Scientists have struggled to link maternal infectious agents with the dysregulation of the maternal immune response in cases of SPTBs. Throughout the last decade, important findings regarding the role of microbiota and its genome, the so-called microbiome, have linked alterations within the population of the microorganisms in our bodies with changes in nutrition, immunity, behaviour and diseases. In this review, evidence regarding the female genital tract microbiota and microbiome has been examined to help further our understanding of its role in disrupting the maternal immune system resulting in spontaneous preterm birth.

Recommended acceptable levels of maternal serum typical toxic metals from the perspective of spontaneous preterm birth in Shanxi Province, China

Preterm birth is an important issue of public reproductive health worldwide. The effects of the toxic metals on the likelihood of spontaneous preterm birth (SPB) are still under discussion. Our study aimed to investigate the association between maternal exposure to the five typical toxic metals or metalloid (i.e. arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb)) and the SPB likelihood. The mothers delivering fetus with SPB (cases) and those with term healthy birth (controls) were chosen from a prospective birth cohort of 3201 women carried out in Shanxi Province, China. A total of 147 SPB cases and 381 controls were included in our nested case-control study. We collected maternal general information by questionnaire and collected their blood sample during recruitment. The serum concentrations of the five toxic metals were measured by inductively coupled-plasma mass spectrometry. We found that the demographic information between the cases and controls were well balanced. The participants in our study had relatively higher serum As concentration. For the other toxic metals (i.e. Cd, Cr, Hg, and Pb), their serum concentrations were overall in the middle range of those from general population. There were no significant associations of the serum concentrations of the five concerned toxic metals with the SPB likelihood. Our study results overall did not support that maternal exposure to As or Cd significantly contribute to the SPB risk in the current exposure level, as well as the other three toxic metals. We further proposed their upper concentration limits in maternal serum from the perspective of SPB likelihood during the early pregnant period, i.e. 18.2 ng/mL of As, 1.05 ng/mL of Cd, 0.96 ng/mL of Cr, 1.07 ng/mL of Hg, and 1.54 ng/mL of Pb.

Serum multiple cytokines for the prediction of spontaneous preterm birth in asymptomatic women: A nested case-control study

BACKGROUND

Current biomarkers such as fetal fibronectin and cervical length are accurate predictors of spontaneous preterm birth (sPTB) in women with clinically suspected preterm risk; however, these are not effective for predicting the risk of sPTB in asymptomatic women. Therefore, we performed this study with the objective of determining whether the combinations of specific serum cytokines could accurately predict the sPTB risk in asymptomatic women.

METHODS

We conducted a nested case-control study with 129 incident sPTB cases and 258 individually matched controls who participated in an ongoing birth cohort study. The maternal serum levels of the selected 35 cytokines were measured. We evaluated the relationship between the multiple cytokines and sPTB risk using conditional logistic regression and elastic net model.

RESULTS

A panel of cytokines was significantly associated with an increased risk of sPTB. The odds ratio (OR) of sPTB per standard deviation (SD) increase of the predictive model score was 1.57 (95% CI 1.25-1.97) for the cytokines model. The combination of the selected serum cytokines was substantially more effective in predicting the risk for sPTB, as the receiver-operator characteristic curve (AUC) values were 0.546 and 0.559 in the single cytokine model and it improved to 0.642 in the multiple cytokines model (P_{AUC difference} = 0.02 for TNF-α vs. multiple cytokines; P_{AUC difference} = 0.05 for TRAIL vs. multiple cytokines). Moreover, the prediction was more accurate in overweight pregnant women, with an AUC = 0.879.

CONCLUSIONS

The current study suggested that the combination of selected serum cytokines can more effectively predict the risk of sPTB in asymptomatic women compared with the use of single cytokine.