Fetal fibronectin, cervical length, and the risk of preterm birth in patients with an ultrasound or physical exam indicated cervical cerclage

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Association between maternal family history of hypertension and preterm birth: modification by noise exposure and multivitamin intake

OBJECTIVE

To measure the effect of maternal family history of hypertension on preterm birth (PTB) and to identify factors that modified this association.

METHODS

A case-control study was nested in a prospective cohort of the entire pregnant population in Wuhan, China, from 2011 to 2013. Home-visit interviews were scheduled for all PTBs and their controls, to collect extensive information on maternal exposures to behavioral, environmental, and intergenerational risk factors of PTB. The effects of maternal family history of hypertension on PTB were measured by logistic regression analyses, controlling for potential confounders. Potential effect modifiers were examined using stratified analyses.

RESULTS

There were 2393 PTBs and 4263 full-term births out of all eligible births. A positive association was observed between maternal family history of hypertension and PTB, after adjusted for potential confounders (adjusted odds ratio: 1.17 [1.03, 1.33]). A higher effect was observed when mothers were exposed to certain noise during pregnancy (adjusted odds ratio: 1.37 [1.14, 1.65]) and/or when they did not take multivitamins during pregnancy (adjusted odds ratio: 1.46 [1.20, 1.78]), whereas, this association was weaker and no longer significant when mothers took multivitamins during pregnancy (adjusted odds ratio: 1.00 [0.84, 1.19]) and/or when they were not exposed to certain noise during pregnancy (adjusted odds ratio: 1.01 [0.85, 1.12]). The modification effect from maternal multivitamin intake was significant on both spontaneous and medically indicated PTBs, and the modification effect from maternal exposure to certain noise was only significant on spontaneous PTB.

CONCLUSIONS

Increased PTB risk was observed for pregnant women with a family history of hypertension in Wuhan, China. This effect was stronger when pregnant women did not take multivitamin and/or exposed to certain noise during pregnancy, than those who took multivitamin and/or unexposed to certain noise.

Successful term pregnancy following cervical cerclage for uterine atrophy secondary to childhood radiotherapy

Pelvic radiotherapy can lead to scarring and atrophy of reproductive organs including the uterus. This may lead to complications, such as preterm birth, during pregnancy. The mechanism by which preterm birth is associated with pelvic radiation is believed to be due to inefficient uterine stretch or a deficient cervix. We report a case of cervical shortening during the second trimester in a pregnant woman with a history of pelvic radiotherapy in childhood. Ultrasound surveillance and cervical cerclage inserted in the shortening cervix successfully prevented preterm labour in this case. Cerclage insertion led to a longer cervix and lower fibronectin. Although cervical cerclage does not influence uterine stretch, it may be able to prevent cervical dilatation and therefore prevent ascending infections and subsequent inflammatory sequelae which results in preterm labour. We recommend cervical surveillance and targeted cerclage interventions to prevent preterm labour in women with prior childhood pelvic radiotherapy.

Maternal H-antigen secretor status is an early biomarker for potential preterm delivery

OBJECTIVE

Pre-pregnancy or first trimester biomarkers predicting preterm delivery are lacking. The purpose of this study was to determine whether maternal H-antigen (secretor status) is a potential biomarker for preterm delivery.

METHODS

This cohort study examined maternal saliva samples and birth data gathered by the National Children's Study Vanguard pilot phase (2009-2014) and included 300 women who were ≥18 years old and provided birth data and saliva samples. The maternal secretor status phenotype was determined by quantifying H-antigen in saliva using enzyme-linked immunoassay. Mothers were stratified by secretor status and multivariable analysis estimated adjusted associations with preterm delivery.

RESULTS

Maternal lack of H-antigen production was an independent risk factor for preterm delivery after adjusting for known confounders (aOR 4.53; 95% CI: 1.74, 11.81; P = 0.002).

CONCLUSIONS

Maternal H-antigen may be a biomarker identifying women at-risk for preterm delivery. Prospective cohort studies validating these findings are needed.

The association between sonographic cervical length components and preterm birth in women with ultrasound- or exam-indicated cerclage

OBJECTIVE

To evaluate which parameters of a sonographic cervical length measurement are associated with preterm birth in women with ultrasound- or exam-indicated cerclage.

METHODS

This was a retrospective cohort study of women with singleton pregnancies who underwent ultrasound- or exam-indicated Shirodkar cerclage by a single maternal-fetal medicine practice between 2011 and 2019. All patients underwent sonographic cervical length measurement 2-3 weeks after cerclage placement, and then every 2-4 weeks up to 32 weeks. The images from the first and second post-cerclage cervical lengths were reviewed. Total cervical length, upper cervical length (from the internal cervical os to the cerclage), and lower cervical length (from the cerclage to the external os) were measured. The primary outcome for this study was gestational age at delivery.

RESULTS

A total of 114 women with cerclage were included (85 (74.6%) ultrasound-indicated and 29 (25.4%) exam-indicated). The first and second total cervical lengths correlated with gestational age at delivery (r = 0.26, p=.005; r = 0.33, p<.001, respectively), and the change from first to second was inversely correlated with gestational age at delivery (r = -0.20, p=.032). The first and second upper cervical lengths also correlated with gestational age at delivery (r = 0.22, p = .019; r = 0.33, p<.001, respectively), and the change from first to second upper cervical length was inversely correlated with gestational age at delivery (r= -0.20, r = 0.029). Neither the first nor the second lower cervical lengths were significantly associated with gestational age at delivery. On regression analysis, total cervical length and upper cervical length were not independently associated with gestational age at delivery (p = .108 and p=.806, respectively, for the first scan; p = .153 and p=.166, respectively, for the second scan).

CONCLUSIONS

Postcerclage total cervical length and upper cervical length are both associated with gestational age at delivery and risk of preterm birth, but not independently. After ultrasound- or exam-indicated cerclage, sonographic monitoring of either the total cervical length or the upper cervical length might be predictive of gestational age at delivery and the risk of preterm birth.

Torquetenovirus Titer in Vaginal Secretions from Pregnant and Postpartum Women: Association with Absence of Lactobacillus crispatus and Levels of Lactic Acid and Matrix Metalloproteinase-8

Vaginal samples from women with term deliveries were tested for torquetenovirus (TTV) by gene amplification, matrix metalloproteinase (MMP)-8 and D- and L-lactic acid by ELISA, and microbiome composition by analysis of the bacterial 16S ribosomal RNA gene. TTV was detected in 43.2%, 31.5%, and 41.4% of first trimester, third trimester, and postpartum samples, respectively. The viral titer was higher in postpartum than in the first (p = 0.0018) or third (p = 0.0013) trimester. The mean gestational age at delivery was lower in women positive for TTV in their first trimester (p = 0.0358). In the first and third trimester, the MMP-8 level was higher if TTV was also present (p < 0.0091). The D-lactic acid level was lower in first trimester samples if TTV was present (p = 0.0334). Lactobacillus crispatus dominance in first and third trimester samples was higher when TTV was absent (p < 0.0033). We conclude that TTV is present in the vagina in many women with normal pregnancy outcomes and that its occurrence is associated with a lack of L. crispatus dominance, an increase in vaginal MMP-8 and a decrease in D-lactic acid.

Factors associated with preterm birth in women undergoing cervical cerclage

OBJECTIVES

Cervical cerclage is used to manage women at high risk of late miscarriage (LM) and spontaneous preterm birth (PTB) due to factors such as history of cervical insufficiency (CI), uterine anomaly, cervical surgery and ultrasound (US) diagnosed cervical shortening. Urinary tract infection (UTI) and subsequent pyelonephritis, and bacterial infection are associated with PTB, but their role in PTB after cervical cerclage is unknown. We examined the relationship between UTI and bacterial vaginosis (BV), fetal fibronectin (fFN) test and PTB in women undergoing elective- or US-indicated cervical cerclage. We also investigated whether fetal fibronectin (fFN) test were useful to predict PTB.

STUDY DESIGN

This is a single center, retrospective study of singleton pregnant women at PTB clinic, University College London Hospital (UCLH, 2005-2015) who underwent elective or US-indicated cervical cerclage. Women were tested for UTI and BV before cerclage placement and received mid-gestation fFN testing. Patient data were extracted from the PTB clinic database and electronic records. Statistical analyses used Pearson's chi-square and Mann-Whitney U tests. P values were corrected by Bonferroni method as required.

RESULTS

267 singleton pregnant women attended our clinic with completed birth outcome. Of those, 32.2% (86/267) delivered prematurely. All women with UTI or BV received antibiotic treatment. Women with a UTI before cerclage placement were more likely to deliver preterm when compared to those with negative MSU culture (OR 3.39, 95%CI 1.24-9.27, p = 0.04). Their gestational age at delivery were also lower than those with negative MSU result (36⁺⁶, IQR 31⁺⁴-38⁺²week vs 38⁺¹, IQR 36⁺¹-39⁺⁵-week, p = 0.05). However, UTI after cerclage placement or BV either before or after cerclage placement were not associated with PTB. Women who had a positive fFN result were more likely to deliver preterm (OR 3.85, 95% CI 1.81-8.41, p = 0.0007).

CONCLUSIONS

The presence of a UTI before cervical cerclage is associated with a higher rate of PTB in women who receive a cervical cerclage, even when treated. We did not find an association between pre or post-cerclage BV or post-cerclage UTI and PTB. Further research is needed to elucidate the link between UTI and PTB in women undergoing cervical cerclage.

Beyond Cervical Length: Association between Postcerclage Transvaginal Ultrasound Parameters and Preterm Birth

OBJECTIVE

To assess the value of transvaginal ultrasound parameters after cerclage placement in estimating the risk of spontaneous preterm birth.

STUDY DESIGN

This is a retrospective cohort at a single tertiary care center from 2013 to 2016. Women carrying a singleton, nonanomalous fetus with cerclage in situ and at least one postcerclage transvaginal ultrasound from 16^0/7 to 25^6/7 weeks' gestation were included. In addition to abstracting maternal demographic and obstetric characteristics, two study investigators separately reviewed each of the images from the first transvaginal ultrasound after cerclage placement, masked to pregnancy outcomes. We measured the angle between the anterior uterine wall and cervical canal at the internal os and external os, closed canal length above and below the stitch, width of the anterior and posterior cervix at the level of the cerclage, and stitch distance from the cervical canal. The presence of additional ultrasound findings such as sludge and cervical funneling was also noted. The main outcomes were preterm birth < 34 weeks and preterm birth < 37 weeks. Transvaginal ultrasound parameters were compared between women with preterm birth and those without preterm birth using chi-square, Fisher's exact, and Wilcoxon's rank-sum tests, as appropriate. Log binomial regression was used to estimate the relative risk of preterm birth for all significant obstetric and ultrasound characteristics.

RESULTS

A total of 102 women met inclusion criteria: 58% had history-indicated, 20% ultrasound-indicated, and 23% exam-indicated cerclages. Of these, 28 (27.5%) women delivered at < 34 weeks' gestation, and 48 (47.0%) women delivered at < 37 weeks' gestation. Preterm birth did not vary by race, maternal age, insurance, smoking, or gestational age of the earliest prior preterm birth (for multiparous women), but women who had preterm birth were more likely to have exam-indicated cerclage. There were several transvaginal ultrasound parameters associated with preterm birth < 34 weeks and preterm birth < 37 weeks. Of these, cervical length below the stitch, stitch distance from the cervical canal, straight cervical canal, funneling to or past the stitch, and presence of sludge had the greatest effect sizes.

CONCLUSION

Rates of preterm birth are high postcerclage. In addition to measuring cervical length, utilization of postcerclage transvaginal ultrasound to evaluate the location of the cerclage within the cervix, the curvature of the cervical canal, and the presence of funneling and sludge may help identify women who are at the highest risk for preterm birth.

Sex-specific maternofetal innate immune responses triggered by group B Streptococci

Group B Streptococcus (GBS) is one of the most common bacteria isolated in human chorioamnionitis, which is a major risk factor for premature birth and brain injuries. Males are at greater risk than females for developing lifelong neurobehavioural disorders, although the origins of this sex bias remain poorly understood. We previously showed that end-gestational inflammation triggered by GBS led to early neurodevelopmental impairments mainly in the male rat progeny. Identifying key inflammatory players involved in maternofetal immune activation by specific pathogens is critical to develop appropriate novel therapeutic interventions. We aimed to map out the GBS-induced profile of innate immune biomarkers in the maternal-placental-fetal axis, and to compare this immune profile between male and female tissues. We describe here that the GBS-induced immune signalling involved significantly higher levels of interleukin (IL)-1β, cytokine-induced neutrophil chemoattractant-1 (CINC-1/CXCL1) and polymorphonuclear cells (PMNs) infiltration in male compared to female maternofetal tissues. Although male - but not female - fetuses presented increased levels of IL-1β, fetuses from both sexes in-utero exposed to GBS had increased levels of TNF-α in their circulation. Levels of IL-1β detected in fetal sera correlated positively with the levels found in maternal circulation. Here, we report for the first time that the maternofetal innate immune signalling induced by GBS presents a sexually dichotomous profile, with more prominent inflammation in males than females. These sex-specific placental and fetal pro-inflammatory responses are in keeping with the higher susceptibility of the male population for preterm birth, brain injuries and neurodevelopmental disorders such as cerebral palsy and autism spectrum disorders.

Transcriptomic analysis of fetal membranes reveals pathways involved in preterm birth

Background

Preterm birth (PTB), defined as infant delivery before 37 weeks of completed gestation, results from the interaction of both genetic and environmental components and constitutes a complex multifactorial syndrome. Transcriptome analysis of PTB has proven challenging because of the multiple causes of PTB and the numerous maternal and fetal gestational tissues that must interact to facilitate parturition. The transcriptome of the chorioamnion membranes at the site of rupture in PTB and term fetuses may reflect the molecular pathways of preterm labor.

Methods

In this work, chorioamnion membranes from severe preterm and term fetuses were analyzed using RNA sequencing. Functional annotations and pathway analysis of differentially expressed genes were performed with the GAGE and GOSeq packages. A subset of differentially expressed genes in PTB was validated in a larger cohort using qRT-PCR and by comparing our results with genes and pathways previously reported in the literature.

Results

A total of 270 genes were differentially expressed (DE): 252 were upregulated and 18 were down-regulated in severe preterm births relative to term births. Inflammatory and immunological pathways were upregulated in PTB. Both types of pathways were previously suggested to lead to PTB. Pathways that were not previously reported in PTB, such as the hemopoietic pathway, appeared upregulated in preterm membranes. A group of 18 downregulated genes discriminated between term and severe preterm cases. These genes potentially characterize a severe preterm transcriptome pattern and therefore are candidate genes for understanding the syndrome. Some of the downregulated genes are involved in the nervous system, morphogenesis (WNT1, DLX5, PAPPA2) and ion channel complexes (KCNJ16, KCNB1), making them good candidates as biomarkers of PTB.

Conclusions

The identification of this DE gene pattern will help with the development of a multi-gene disease classifier. These markers were generated in an admixed South American population in which PTB has a high incidence. Since the genetic background may differentially impact different populations, it is necessary to include populations such as those from South America and Africa, which are usually excluded from high-throughput approaches. These classifiers should be compared to those in other populations to obtain a global landscape of PTB.

Electronic supplementary material

The online version of this article (10.1186/s12920-019-0498-3) contains supplementary material, which is available to authorized users.

The fetal fibronectin test: 25 years after its development, what is the evidence regarding its clinical utility? A systematic review and meta-analysis

Background: The identification of women at risk for preterm birth should allow interventions which could improve neonatal outcome. Fetal fibronectin, a glycoprotein which acts normally as glue between decidua and amniotic membranes could be a good marker of impending labour when its concentration in cervicovaginal secretions between 22 and 36 weeks of gestation is ≥50 ng/mL. Many authors worldwide have tested this marker with many different methodologies and clinical settings, but conclusions about its clinical use are mixed. It is time for a comprehensive update through a systematic review and meta-analysis.Methods: We searched PubMed, Cochrane Library, and Embase, supplemented by manual search of bibliographies of known primary and review articles, international conference papers, and contact with experts from 1-1990 to 2-2018. We have selected all type of studies involving fetal fibronectin test accuracy for preterm delivery. Two authors independently extracted data about study characteristics and quality from identified publications. Contingency tables were constructed. Reference standards were preterm delivery before 37, 36, 35, 34, and 32 weeks, within 28, 21, 14, or 7 d and within 48 h. Data were pooled to produce summary likelihood ratios for positive and negative tests results.Results: One hundred and ninety-three primary studies were identified allowing analysis of 53 subgroups. In all settings, none of the summary likelihood ratios were >10 or <0.1, thus indicating moderate prediction, particularly in asymptomatic women and in multiple gestations.Conclusions: The fetal fibronectin test should not be used as a screening test for asymptomatic women. For high-risk asymptomatic women, and especially for women with multiple pregnancies, the performance of the fetal fibronectin test was also too low to be clinically relevant. Consensual use as a diagnostic tool for women with suspected preterm labor, the best use policy probably still depends on local contingencies, future cost-effectiveness analysis, and comparison with other more recent available biochemical markers.

Gastric fluid used to assess changes during the latency period in preterm prelabor rupture of membranes

OBJECTIVE

To determine changes in the intraamniotic environment during the latency period using paired amniotic and gastric fluid samples in pregnancies complicated by preterm prelabor rupture of membranes (PPROM).

METHODS

A total of 34 women with singleton pregnancies complicated by PPROM prior to 34 weeks were included in the study. Amniotic fluid was obtained by transabdominal amniocentesis at the time of admission. Immediately after delivery, umbilical cord blood and gastric fluid were obtained.

RESULT

Microorganisms in amniotic and gastric fluid samples were found in 38% and 59% of women, respectively. Bedside IL-6 levels were higher in amniotic than in gastric fluid in pregnancies without fetal inflammatory response syndrome (FIRS) (263 pg/mL vs. 50 pg/mL; p < 0.0001), but not in pregnancies with FIRS (318 pg/mL vs. 444 pg/mL; p = 0.91). Funisitis and FIRS was associated with the highest bedside IL-6 levels in gastric fluid. A gastric fluid bedside IL-6 level of 275 pg/mL was found to be the ideal cutoff value to predict funisitis and FIRS.

CONCLUSIONS

The microbial and inflammatory status of the intraamniotic compartment changes during the latency period in PPROM. Bedside IL-6 assessment of gastric fluid may be useful in the rapid diagnosis of funisitis and FIRS.

Delivery-associated presence of supramolecular fibronectin-fibrin complexes in puerperal and cord plasma

Objective: The variable fibronectin (FN) molecular forms are known to be engaged in coagulation and fibrinolysis pathways as well as tissue remodeling and repair processes. Some of them seem to be indispensable molecules within intensive biological processes associated with delivery. The aim of the study was to evaluate the FN molecular status in maternal and cord plasma after vaginal birth and cesarean section (C-section). Materials and methods: The study included nonpregnant women's plasma samples (n = 31) and puerperal and cord plasma samples collected from 49 mothers who delivered healthy newborns at term by vaginal birth (n = 25) and C-section (n = 24). The maternal and cord plasma FN concentrations and presence and relative ratios of different FN-fibrin complexes were determined by ELISA and sodium dodecyl sulfate (SDS) -agarose immunoblotting, respectively. Results: FN concentration in puerperal plasma after vaginal birth (232.08 ± 71.8 mg/L) and C-section (228.17 ± 71.2 mg/L) was significantly higher than in the plasma of nonpregnant women (190.00 ± 48.75 mg/L). In contrast, FN concentration in cord plasma of the C-section group (101.95 ± 30.3 mg/L) was significantly lower than that of the vaginal birth group (121.80 ± 22.2 mg/L). Immunoblotting of puerperal and cord plasma distinguished the most abundant dimeric plasma FN form, the 220-280-kDa FN degradation products and 750-1900-kDa FN-fibrin complexes, which occurred more frequently and in higher amounts in puerperal and cord plasma groups than the nonpregnant women group, although independently of the mode of delivery. Conclusions: Occurrence and relative amount of delivery-associated FN-fibrin complexes in both puerperal and cord plasmas might be bound with the physiological adaptive mechanisms reducing the risk of hemorrhage and intensive remodeling and repair processes after delivery.

Intra-amniotic inflammation and child neurodevelopment: a systematic review protocol

BACKGROUND

Intra-amniotic inflammation is associated with adverse pregnancy and neonatal outcomes. However, the impact on child neurodevelopment remains unclear. We aim to assess the effect of intra-amniotic inflammation on neurodevelopmental outcomes in children.

METHODS

The databases MEDLINE, Embase, CINAHL, and Cochrane will be searched from their inception until November 2017. Randomized trials and cohort studies in which inflammatory markers were measured in amniotic fluid collected by amniocentesis and in which infant's neurodevelopment was assessed will be eligible. Two reviewers will independently select eligible studies, assess their risk of bias, and extract data. Results will be compared and a third party will be consulted in case of disagreement. Our primary outcome of interest is child neurodevelopment, assessed with either a validated tool or by revision of medical records for specific diagnosis. Secondary outcomes will include abnormal brain imaging. Relative risks will be pooled and sensitivity analyses will be performed for the indication of amniocentesis, gestational age at amniocentesis, gestational age at delivery, and fetal sex. Risk of bias will be assessed using the Cochrane Collaboration's tool for assessing the risk of bias in randomized trials or an adapted version of the ROBINS-1 for the risk of bias in non-randomized studies.

DISCUSSION

This systematic review will report the current evidence regarding the association between amniotic inflammation and child neurodevelopment, and the modifiers of this association. The review will generate new hypotheses on pathological pathways and will guide future research.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO 2017 65065.