Cervicovaginal fetal fibronectin as a marker for preterm delivery: a meta-analysis

Management, Utilization, and Outcomes of Preterm Labor in an Integrated Health Care System

OBJECTIVE

 Fetal fibronectin (fFN) testing and transvaginal ultrasound (TVUS) are diagnostic tools used to predict impending spontaneous preterm birth (sPTB) among women presenting with preterm labor (PTL). We evaluated the association between fFN testing or TVUS cervical length (CL) measurement in predicting sPTB, respiratory distress syndrome (RDS), neonatal intensive care unit (NICU) admission, and sPTB-related costs.

STUDY DESIGN

 We conducted a retrospective cohort study using data from the Kaiser Permanente Southern California electronic health system (January 1, 2009-December 31, 2020) using diagnostic and procedure codes, along with a natural language processing algorithm to identify pregnancies with PTL evaluations. PTL evaluation was defined as having fFN and/or TVUS assessment. Outcomes were ascertained using diagnostic, procedural, and diagnosis-related group codes. Multivariable logistic regression assessed the association between fFN and/or TVUS results and perinatal outcomes.

RESULTS

 Compared with those without PTL evaluations, those with positive fFN tests had higher adjusted odds ratio (adj.OR) for sPTB (2.95, 95% confidence interval [CI]: 2.64, 3.29), RDS (2.34, 95% CI: 2.03, 2.69), and NICU admission (2.24, 95% CI: 2.01, 2.50). In contrast, those who tested negative had lower odds for sPTB (adj.OR: 0.75, 95% CI: 0.70, 0.79), RDS (adj.OR: 0.67, 95% CI: 0.61, 0.73), and NICU admission (adj.OR: 0.74, 95% CI: 0.70, 0.79). Among those with positive fFN results, the odds of sPTB was inversely associated with CL. Health care costs for mothers and neonates were lowest for those with fFN testing only.

CONCLUSION

 This study demonstrates that positive fFN results were associated with an increased odds of sPTB, RDS, and NICU admission and the association with sPTB was inversely proportional to CL. Additionally, negative fFN results were associated with decreased odds of sPTB, RDS, and NICU admissions. fFN testing may predict these and other sPTB-related adverse outcomes hence its utility should be explored further. Moreover, fFN testing has some cost savings over TVUS.

KEY POINTS

· Patients with positive fFN tests had higher odds of sPTB, RDS, and NICU admission.. · Inverse relationship between sPTB and CL among those with positive fFN tests was observed.. · Health care costs for mothers and neonates were lowest for those with fFN testing only..

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Preterm Birth: Screening and Prediction

Preterm birth (PTB) affects approximately 10% of births globally each year and is the most significant direct cause of neonatal death and of long-term disability worldwide. Early identification of women at high risk of PTB is important, given the availability of evidence-based, effective screening modalities, which facilitate decision-making on preventative strategies, particularly transvaginal sonographic cervical length (CL) measurement. There is growing evidence that combining CL with quantitative fetal fibronectin (qfFN) and maternal risk factors in the extensively peer-reviewed and validated QUanititative Innovation in Predicting Preterm birth (QUiPP) application can aid both the triage of patients who present as emergencies with symptoms of preterm labor and high-risk asymptomatic women attending PTB surveillance clinics. The QUiPP app risk of delivery thus supports shared decision-making with patients on the need for increased outpatient surveillance, in-patient treatment for preterm labor or simply reassurance for those unlikely to deliver preterm. Effective triage of patients at preterm gestations is an obstetric clinical priority as correctly timed administration of antenatal corticosteroids will maximise their neonatal benefits. This review explores the predictive capacity of existing predictive tests for PTB in both singleton and multiple pregnancies, including the QUiPP app v.2. and discusses promising new research areas, which aim to predict PTB through cervical stiffness and elastography measurements, metabolomics, extracellular vesicles and artificial intelligence.

Predictive value of quantitative fetal fibronectin for spontaneous preterm birth in asymptomatic pregnancies: a systematic literature review and meta-analysis

OBJECTIVE

Tests capable of accurate prediction of spontaneous preterm birth (sPTB) are crucial to inform clinical decisions to prevent neonatal deaths and reduce the risk of morbidity in surviving infants. A systematic literature review and meta-analysis were performed to assess the utility of the quantitative fetal fibronectin (fFN) test to predict sPTB at different test concentration thresholds.

METHODS

Literature searches were conducted in MEDLINE, Embase, and the Cochrane Library in May 2022. Observational studies and clinical trials investigating the clinical utility of the quantitative fFN test in asymptomatic pregnancies prior to 37 weeks of gestation were eligible for inclusion. Meta-analysis quantified the risk of sPTB prior to four gestational age milestones (<28, <30, <34 and <37 weeks) based on quantitative fFN levels. No risk of bias assessment was performed however, clinical and methodological heterogeneity was explored to determine the feasibility of performing analyses.

RESULTS

11 studies showed a quantitative assessment of fFN can differentiate between very high and very low risks of sPTB in asymptomatic pregnancies with <10% of women with very low fFN (<10 ng/mL) versus 37-67% of women with very high fFN (>200 ng/mL) delivering before 34 weeks. A meta-analysis of two studies showed, albeit with a low number of events, the odds of sPTB prior to 28 weeks was nine times higher in women testing positive at ≥50 ng/mL, whereas the odds of sPTB was 25 times higher in women with fFN concentrations >200 ng/mL (versus <50 ng/mL reference). Similarly, pooling three studies showed the odds of sPTB prior to 37 weeks was four times higher in women who tested positive at ≥50 ng/ml whereas the odds of delivery before 37 weeks was seven times higher for women with fFN concentrations ≥200 ng/ml (versus <50 ng/mL reference).

CONCLUSION

Quantitative fFN testing demonstrates increased predictive capabilities and utility of fFN testing in clinical practice, potentially preventing unnecessary intervention for women at very low risk and allowing an opportunity to optimize the management of asymptomatic patients at high risk of preterm delivery.

Using Fetal Fibronectin Test to Reduce Hospital Admissions with Diagnosis of Preterm Labor: An Economic Evaluation Study

Background: Preterm labor and delivery remain a major problem in obstetrics accounting for perinatal morbidity and mortality. The challenge is to identify those with true preterm labor to avoid unnecessary hospital admissions. The fetal fibronectin (FFN) test is a strong predictor of preterm birth and can help identify women with true preterm labor. However, its cost-effectiveness as a strategy for triaging women with threatened preterm labor is still debatable. Objective: To evaluate the effect of FFN test implementation on hospital resources by reducing the admission rate of threatened preterm labor in a tertiary hospital, Latifa Hospital, UAE. Methods: A retrospective cohort study of singleton pregnancies between 24 and 34 weeks of gestation who attended Latifa Hospital in the period of September 2015-December 2016, complaining of threatened preterm labor after the availability of an FFN test, and a historical cohort study for those who attended with threatened preterm labor before the availability of an FFN test. Data analysis was performed using a Kruskal-Wallis test, Kaplan-Meier, Fischer exact chi-square and cost analysis. The significance was set at p-value < 0.05. Results: In total, 840 women met the inclusion criteria and were enrolled. The relative risk of FFN for delivery at term was 4.35 times higher among the negative-tested compared to preterm delivery (p-value < 0.001). A total of 134 (15.9%) women were unnecessarily admitted (FFN tested negative, delivered at term) which yielded $107,000 in extra costs. After the introduction of an FFN test, a 7% reduction of threatened preterm labor admissions was recorded.

The amniotic fluid proteome predicts imminent preterm delivery in asymptomatic women with a short cervix

Preterm birth, the leading cause of perinatal morbidity and mortality, is associated with increased risk of short- and long-term adverse outcomes. For women identified as at risk for preterm birth attributable to a sonographic short cervix, the determination of imminent delivery is crucial for patient management. The current study aimed to identify amniotic fluid (AF) proteins that could predict imminent delivery in asymptomatic patients with a short cervix. This retrospective cohort study included women enrolled between May 2002 and September 2015 who were diagnosed with a sonographic short cervix (< 25 mm) at 16–32 weeks of gestation. Amniocenteses were performed to exclude intra-amniotic infection; none of the women included had clinical signs of infection or labor at the time of amniocentesis. An aptamer-based multiplex platform was used to profile 1310 AF proteins, and the differential protein abundance between women who delivered within two weeks from amniocentesis, and those who did not, was determined. The analysis included adjustment for quantitative cervical length and control of the false-positive rate at 10%. The area under the receiver operating characteristic curve was calculated to determine whether protein abundance in combination with cervical length improved the prediction of imminent preterm delivery as compared to cervical length alone. Of the 1,310 proteins profiled in AF, 17 were differentially abundant in women destined to deliver within two weeks of amniocentesis independently of the cervical length (adjusted p-value < 0.10). The decreased abundance of SNAP25 and the increased abundance of GPI, PTPN11, OLR1, ENO1, GAPDH, CHI3L1, RETN, CSF3, LCN2, CXCL1, CXCL8, PGLYRP1, LDHB, IL6, MMP8, and PRTN3 were associated with an increased risk of imminent delivery (odds ratio > 1.5 for each). The sensitivity at a 10% false-positive rate for the prediction of imminent delivery by a quantitative cervical length alone was 38%, yet it increased to 79% when combined with the abundance of four AF proteins (CXCL8, SNAP25, PTPN11, and MMP8). Neutrophil-mediated immunity, neutrophil activation, granulocyte activation, myeloid leukocyte activation, and myeloid leukocyte-mediated immunity were biological processes impacted by protein dysregulation in women destined to deliver within two weeks of diagnosis. The combination of AF protein abundance and quantitative cervical length improves prediction of the timing of delivery compared to cervical length alone, among women with a sonographic short cervix.

Prediction of preterm birth based on machine learning using bacterial risk score in cervicovaginal fluid

PROBLEM

Preterm birth (PTB) is a major cause of increased morbidity and mortality in newborns. The main cause of spontaneous PTB (sPTB) is the activation of an inflammatory response as a result of ascending genital tract infection. Despite various studies on the effects of the vaginal microbiome on PTB, a practical method for its clinical application has yet to be developed.

METHOD OF STUDY

In this case-control study, 94 Korean pregnant women with PTB (n = 38) and term birth (TB; n = 56) were enrolled. Their cervicovaginal fluid (CVF) was sampled, and a total of 10 bacteria were analyzed using multiplex quantitative real-time PCR (qPCR). The PTB and TB groups were compared, and a PTB prediction model was created using bacterial risk scores using machine learning techniques (decision tree and support vector machine). The predictive performance of the model was validated using random subsampling.

RESULTS

Bacterial risk scoring model showed significant differences (P < 0.001). The PTB risk was low when the Lactobacillus iners ratio was 0.812 or more. In groups with a ratio under 0.812, moderate and high risk was classified as a U. parvum ratio of 4.6 × 10^-3 . The sensitivity and specificity of the PTB prediction model using bacteria risk score were 71% and 59%, respectively, and 77% and 67%, respectively, when white blood cell (WBC) data were included.

CONCLUSION

Using machine learning, the bacterial risk score in CVF can be used to predict PTB.

Periodontal diseases and adverse pregnancy outcomes: Mechanisms

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

Commentary on a combined approach to the problem of developing biomarkers for the prediction of spontaneous preterm labor that leads to preterm birth

INTRODUCTION

Globally, preterm birth has replaced congenital malformation as the major cause of perinatal mortality and morbidity. The reduced rate of congenital malformation was not achieved through a single biophysical or biochemical marker at a specific gestational age, but rather through a combination of clinical, biophysical and biochemical markers at different gestational ages. Since the aetiology of spontaneous preterm birth is also multifactorial, it is unlikely that a single biomarker test, at a specific gestational age will emerge as the definitive predictive test.

METHODS

The Biomarkers Group of PREBIC, comprising clinicians, basic scientists and other experts in the field, with a particular interest in preterm birth have produced this commentary with short, medium and long-term aims: i) to alert clinicians to the advances that are being made in the prediction of spontaneous preterm birth; ii) to encourage clinicians and scientists to continue their efforts in this field, and not to be disheartened or nihilistic because of a perceived lack of progress and iii) to enable development of novel interventions that can reduce the mortality and morbidity associated with preterm birth.

RESULTS

Using language that we hope is clear to practising clinicians, we have identified 11 Sections in which there exists the potential, feasibility and capability of technologies for candidate biomarkers in the prediction of spontaneous preterm birth and how current limitations to this research might be circumvented.

DISCUSSION

The combination of biophysical, biochemical, immunological, microbiological, fetal cell, exosomal, or cell free RNA at different gestational ages, integrated as part of a multivariable predictor model may be necessary to advance our attempts to predict sPTL and PTB. This will require systems biological data using "omics" data and artificial intelligence/machine learning to manage the data appropriately. The ultimate goal is to reduce the mortality and morbidity associated with preterm birth.

Comparison of Fetal Fibronectin and Phosphorylated Insulin-Like Growth Factor Binding Protein-1 Testing to Predict Preterm Delivery in Symptomatic Women: A 10-Year Retrospective Study

OBJECTIVE

To assess the diagnostic accuracy and cost-effectiveness of fetal fibronectin (fFN) and cervical phosphorylated insulin-like growth factor binding protein-1 (phIGFBP-1) tests, individually and in combination, to predict preterm delivery within 48 hours, 7 days and 14 days in symptomatic women.

METHOD

We selected women in Victoria, British Columbia, who presented between January 2008 and December 2017 at <34 weeks gestation at intermediate risk for labour (intact membrane, cervical dilatation <3 cm, and >6 contractions per hour). We calculated sensitivity, specificity, and positive and negative predictive values (PPV, NPV) for independent and concurrent testing and conducted a cost-effectiveness analysis to ensure appropriate test utilization.

RESULTS

We identified 2911 cases. Both fFN and phIGFBP-1 tests showed high and comparable NPV in predicting risk of delivery within 48 hours, 7 days and 14 days (fFN: 99.3%, 98.5% and 97.3%; phIGFBP-1: 98.8%, 97.9% and 96.1%). In 1976 cases, samples for fFN and phIGFBP-1 tests were collected and analyzed concurrently. Concurrent analysis increased specificity (90.8%, 91.4%, and 91.8%) and PPV (11.8%, 19.8% and 24.2%). Independently, both tests had comparable sensitivity, while the fFN test had higher specificity. Concurrent testing offered the highest PPV. The net gain in PPV comes with a clinically insignificant net loss (<1%) in NPV when compared with either of the tests individually.

CONCLUSION

Clinical usefulness of PPV for either test is limited. Routine concurrent testing comes with additional costs, and fFN has additional collection requirements. Point-of-care phIGFBP-1 testing has proven to be cheaper, simpler, and equally effective. Ordering physicians should be provided with education on how to interpret test results and should have protocols to guide clinical decision making.

Development and validation of predictive models for QUiPP App v.2: tool for predicting preterm birth in women with symptoms of threatened preterm labor

OBJECTIVE

To develop enhanced prediction models to update the QUiPP App prototype, a tool providing individualized risk of spontaneous preterm birth (sPTB), for use in women with symptoms of threatened preterm labor (TPTL), incorporating risk factors, transvaginal ultrasound assessment of cervical length (CL) and cervicovaginal fluid quantitative fetal fibronectin (qfFN) test results.

METHODS

Participants were pregnant women between 23 + 0 and 34 + 6 weeks' gestation with symptoms of TPTL, recruited as part of four prospective cohort studies carried out at 16 UK hospitals between October 2010 and October 2017. The training set comprised all women whose outcomes were known in May 2017 (n = 1032). The validation set comprised women whose outcomes were gathered between June 2017 and March 2018 (n = 506). Parametric survival models were developed for three combinations of predictors: risk factors plus qfFN test results alone, risk factors plus CL alone, and risk factors plus both qfFN and CL. The best models were selected using the Akaike and Bayesian information criteria. The estimated probability of sPTB < 30, < 34 or < 37 weeks' gestation and within 1 or 2 weeks of testing was calculated and receiver-operating-characteristics (ROC) curves were created to demonstrate the diagnostic ability of the prediction models.

RESULTS

Predictive statistics were similar between the training and the validation sets at most outcome time points and for each combination of predictors. Areas under the ROC curves (AUC) demonstrated that all three algorithms had good accuracy for the prediction of sPTB at < 30, < 34 and < 37 weeks' gestation and within 1 and 2 weeks' post-testing in the validation set, particularly the model combining risk factors plus qfFN alone (AUC: 0.96 at < 30 weeks; 0.85 at < 34 weeks; 0.77 at < 37 weeks; 0.91 at < 1 week from testing; and 0.92 at < 2 weeks from testing).

CONCLUSIONS

Validation of the new prediction models suggests that the QUiPP App v.2 can reliably calculate risk of sPTB in women with TPTL. Use of the QUiPP App in practice could lead to better targeting of intervention, while providing reassurance and avoiding unnecessary intervention in women at low risk. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

The diagnostic value of fetal fibronectin testing in clinical practice

AIM

To evaluate the clinical management to withhold treatment for preterm labor in symptomatic women with an intermediate cervical length and negative fetal fibronectin (fFN) testing.

METHODS

A retrospective cohort study was performed in a tertiary care teaching hospital in the Netherlands. Pregnant women with a gestational age between 23⁺⁵ to 34⁺⁰ weeks, with the presence of regular uterine contractions accompanied by a cervical length between 15 and 30 mm and intact membranes, who underwent fFN testing were included to obtain the diagnostic value of fFN testing for preterm delivery within 7 days.

RESULTS

Fetal fibronectin testing has an extremely high negative predictive value (100%) and sensitivity (100%) for delivery within 7 days, in singleton and multiple pregnancies. However, specificity (64%) and positive predictive value (10%) of fFN testing in singleton pregnancies are low. Blood present on the fFN sample does not affect the reliability of the fFN test; the negative predictive value remains 100%.

CONCLUSION

Women with symptoms of early preterm labor, intact membranes, a cervical length between 15 and 30 mm and negative fFN testing do not deliver within 7 days. Administration of corticosteroids and tocolytics can safely be withhold. Furthermore, blood on the fFN sample does not change the reliability of the fFN test.

Preterm birth prediction in asymptomatic women at mid-gestation using a panel of novel protein biomarkers: the Prediction of PreTerm Labor (PPeTaL) study

BACKGROUND

Accurate prediction of spontaneous preterm labor/preterm birth in asymptomatic women remains an elusive clinical challenge because of the multi-etiological nature of preterm birth.

OBJECTIVE

The aim of this study was to develop and validate an immunoassay-based, multi-biomarker test to predict spontaneous preterm birth.

MATERIALS AND METHODS

This was an observational cohort study of women delivering from December 2017 to February 2019 at 2 maternity hospitals in Melbourne, Australia. Cervicovaginal fluid samples were collected from asymptomatic women at gestational week 16⁺⁰-24⁺⁰, and biomarker concentrations were quantified by enzyme-linked immunosorbent assay. Women were assigned to a training cohort (n = 136) and a validation cohort (n = 150) based on chronological delivery dates.

RESULTS

Seven candidate biomarkers representing key pathways in utero-cervical remodeling were discovered by high-throughput bioinformatic search, and their significance in both in vivo and in vitro studies was assessed. Using a combination of the biomarkers for the first 136 women allocated to the training cohort, we developed an algorithm to stratify term birth (n = 124) and spontaneous preterm birth (n = 12) samples with a sensitivity of 100% (95% confidence interval, 76-100%) and a specificity of 74% (95% confidence interval, 66-81%). The algorithm was further validated in a subsequent cohort of 150 women (n = 139 term birth and n = 11 preterm birth), achieving a sensitivity of 91% (95% confidence interval, 62-100%) and a specificity of 78% (95% confidence interval, 70-84%).

CONCLUSION

We have identified a panel of biomarkers that yield clinically useful diagnostic values when combined in a multiplex algorithm. The early identification of asymptomatic women at risk for preterm birth would allow women to be triaged to specialist clinics for further assessment and appropriate preventive treatment.

Fetal fibronectin testing for reducing the risk of preterm birth

BACKGROUND

Fetal fibronectin (FFN) is an extracellular matrix glycoprotein localized at the maternal-fetal interface of the amniotic membranes, between chorion and decidua, where it is concentrated in this area between decidua and trophoblast. In normal conditions, FFN is found at very low levels in cervicovaginal secretions. Levels greater than or equal to 50 ng/mL at or after 22 weeks have been associated with an increased risk of spontaneous preterm birth. In fact, FFN is one of the best predictors of preterm birth in all populations studied so far, and can help in selecting which women are at significant risk for preterm birth. This is an update of a review first published in 2008.

OBJECTIVES

To assess the effectiveness of management based on knowledge of FFN testing results for preventing preterm birth.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register (7 September 2018), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (7 September 2018), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomized controlled trials of pregnant women screened with FFN for risk of preterm birth. Studies included are based exclusively on knowledge of FFN results versus no such knowledge, and we have excluded studies including women with only positive or only negative FFN results.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data, and checked them for accuracy. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

We identified 16 trials, of which six were eligible for inclusion. The six included studies randomized 546 women with singleton gestations and threatened preterm labor (PTL) at 23 0/7 to 34 6/7 weeks. A total of 277 women were randomized to knowledge and 269 to no knowledge of FFN. No trials were identified on asymptomatic women or multiple gestations.The risk of bias of included studies was mixed. For selected important outcomes, preterm birth before 37, 34, and 32 weeks, and maternal hospitalization, we graded the quality of the evidence and created a 'Summary of findings' table. For these outcomes, the evidence was graded as mainly low quality due to the imprecision of effect estimates.Management based on knowledge of FFN results may reduce preterm birth before 37 weeks (21.6%) versus controls without such knowledge (29.2%) (risk ratio (RR) 0.72, 95% confidence interval (CI) 0.52 to 1.01; 4 trials; 357 women; low-quality evidence). However, management based on knowledge of FFN results may make little or no difference to preterm birth before 34 (RR 1.09, 95% CI 0.54 to 2.18; 4 trials; 357 women; low-quality evidence) or maternal hospitalization (RR 1.06, 95% CI 0.79 to 1.43; 5 trials; 441 women; low-quality evidence). The evidence for preterm birth before 32 weeks is uncertain because the quality was found to be very low (average RR 0.79, 95% CI 0.16 to 3.96; 4 trials; 357 women; very low-quality evidence).For all other outcomes, for which there were available data (preterm birth less than 28 weeks; gestational age at delivery (weeks); birthweight less than 2500 g; perinatal death; tocolysis; steroids for fetal lung maturity; time to evaluate; respiratory distress syndrome; neonatal intensive care unit (NICU) admission; and NICU days), knowledge of FFN results may make little or no difference to the outcomes.

AUTHORS' CONCLUSIONS

The evidence from this review suggests that management based on knowledge of FFN results may reduce preterm birth before 37 weeks. However, our confidence in this result is limited as the evidence was found to be of low quality. Effects on other substantive outcomes are uncertain due to serious concerns in study design, inconsistency, and imprecision of effect estimates. No trials were identified on asymptomatic women, or multiple gestations.Future studies are needed that include specific populations (e.g. singleton gestations with symptoms of preterm labor), a study group managed with a protocol based on the FFN results, and that report not only maternal but also important perinatal outcomes. Cost-effectiveness analyses are also needed.

Re-evaluation of Urinary Trypsin Inhibitor on Pregnancy Course in Patients with Threatened Preterm Delivery: A Single-Center Retrospective Study

Background

We evaluated the necessity of urinary trypsin inhibitor for patients with threatened premature labor.

Methods

We enrolled 146 women with singleton pregnancies who were treated for threatened premature labor as inpatients. The uterine cervical length of each patient was ≤ 25 mm at 22-35 weeks of gestation on transvaginal ultrasonography. The patients were divided into two groups: the urinary trypsin inhibitor group (91 patients treated with urinary trypsin inhibitor daily) or non-urinary trypsin inhibitor group (55 patients not treated with urinary trypsin inhibitor). The childbirth outcomes were retrospectively assessed.

Results

The median cervical length measured on the day of admission was almost similar between the urinary trypsin inhibitor and non-urinary trypsin inhibitor groups. Depending on the symptoms of uterine contractions, we determined whether ritodrine hydrochloride and/or magnesium sulfate would be appropriate for treatment. The median gestational week at birth was 38 weeks in the urinary trypsin inhibitor group, and no obvious differences were observed when compared with the non-urinary trypsin inhibitor group. With regard to birth weight, no significant difference was found between the two groups (urinary trypsin inhibitor group, 2776 g; non-urinary trypsin inhibitor group, 2800 g).

Conclusion

Our data showed no significant beneficial effects of urinary trypsin inhibitor in the maternal course and delivery outcomes.

Fetal fibronectin test for threatened preterm delivery 48h after admission: Cost-effectiveness study

OBJECTIVE

The aim of this work was to assess the cost-effectiveness of the fetal fibronectin (fFN) test at 48 h after admission for threatened preterm delivery to promote early discharge.

STUDY DESIGN

Before-and-after study to calculate the incremental cost-effectiveness ratio (ICER). Patients were enrolled 48 h after admission in a tertiary care centre for threatened preterm delivery between 24⁺⁰ and 34⁺⁶ weeks. fFN testing was performed. During the first period, physician was blinded to fFN test and discharge occurred after apparent reduced symptomatology at physician's discretion. During the second period, fFN test was revealed to physician and discharge was immediately proposed to negative test patients. The costs considered in this analysis were the direct medical costs from the hospital perspective: costs of hospitalisation, treatment, and imaging procedures. The efficacy criterion selected was the number of deliveries at 7 and at 14 days after admission for threatened preterm delivery.

RESULTS

The study included 178 pregnant patient, 99 during the first period (July 2008-October 2009) and 79 during the second (March 2010-February 2012). The lengths of hospital stays were shorter during the second period, with more than 50% of women discharged home between 48 and 72 h (p < 0.0001) resulting in a cost-saving of 76 051 euros. The number of deliveries at 7 and at 14 days was similar between the two periods.

CONCLUSION

The fFN test at 48 h after admission supported early discharge and was safe and cost-effective.

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.

Accuracy of a combined insulin-like growth factor-binding protein-1/interleukin-6 test (Premaquick) in predicting delivery in women with threatened preterm labor

PURPOSE

To determine values of combinations of interleukin-6 (IL-6)/cervical native insulin-like growth factor-binding protein-1 (IGFBP-1)/total IGFBP-1 (Premaquick©) in predicting spontaneous deliveries and spontaneous exclusive preterm deliveries in women with threatened preterm labor.

METHODS

Women with singleton pregnancies between gestation age (GA) of 24 weeks and 36 weeks and 6 days with preterm labor were recruited during a prospective multicenter study. Premaquick© was positive when at least two of three biomarkers were positive. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were estimated for both prediction of spontaneous deliveries and spontaneous exclusive preterm deliveries.

RESULTS

Ninety-seven (99.0%) out of 98 women enrolled were analyzed. Based on delivery status 7/14 days post-enrollment of general study population, Premaquick© had a sensitivity of 87.1/85.7%, a specificity of 92.4/96.8%, a PPV of 84.4/93.8% and a NPV of 93.9/92.3% for prediction of spontaneous delivery. Predictive accuracy of Premaquick© test in relation to days of enrollment were: 90.7% (≤7 days) and 92.8% (≤14 days). For women enrolled at GA <35 weeks, Premaquick© had a sensitivity of 100.0/87.5%, a specificity of 94.1/96.9%, a PPV of 70.5/87.5%, a NPV of 100.0/96.9% and an accuracy of 95.0/95.0% for prediction of preterm delivery within 7/14 days of enrollment, respectively. PPV was most significantly different in both groups when outcomes were compared between 2 days and 14 days post-enrollment (P<0.001).

CONCLUSION

This novel triple biomarker model of native and total IGFBP-1 and IL-6 appears to be an accurate test in predicting spontaneous deliveries and spontaneous exclusive preterm deliveries in threatened preterm labor in singleton pregnancies.

Prediction of Delivery in Women with Threatening Preterm Labour using Phosphorylated Insulin-Like Growth Factor Binding Protein-1 and Cervical Length using Transvaginal Ultrasound

INTRODUCTION

Preterm delivery remains a challenge in Obstetrics as it is responsible for significant cause of perinatal morbidity and mortality. At present there is no standard test for prediction of preterm labour for timely referral to a center with NICU facilities.

AIM

To evaluate the effectiveness of the cervical phosphorylated insulin like growth factor binding protein-1(phIGFBP-1), cervical length measurement and combination of phIGFBP-1 with cervical length for Predicting Preterm Labour (PTL).

MATERIALS AND METHODS

It was a observational prospective study done from January 2014 to April 2015 in Department of Obstetrics and Gynaecology, NDMC Medical College and Hindu Rao Hospital, Delhi, India. A total of 100 women with singleton pregnancy, between 24 and 36 weeks of gestation with complaint of uterine contractions were randomly selected. These women were subjected to detect phIGFBP-1 in cervical secretions and cervical length measurement by Transvaginal Sonography (TVS). Result of the test, cervical length and time lapse between test and delivery was noted and the results were analysed. The cervical length less than 25 mm was used as a cut off point for predicting pre-term delivery. Data was analysed using SPSS software version 20.0.

RESULTS

The Negative Predictive Value (NPV) of phIGFBP-1 and cervical length was similar (95.2% vs 94.05%) respectively for prediction of preterm labour within one week of admission and 93.92% vs 94.80% at 37 weeks of gestational age. Combined test had higher NPV of 96.38% at 34 weeks of gestation and 94% within two days of admission. Positive Predictive Value (PPV) was low for both the test and combining the two-test did not have any advantage as far as PPV was concerned. Receiver Operating Characteristic (ROC) curve showed that the combined test had a superior result in predicting PTL compared to either phIGFBP-1 or cervical length. The combined test had steepest ROC curve at < 34 weeks of gestation (AUC-0.83 with 95% CI).

CONCLUSION

The phIGFBP-1 test and cervical length have an almost equivalent ability to predict preterm delivery independently. The combined use of phIGFBP-1 and TVS for cervical length shows an increase in efficacy in predicting preterm labour.

Estimation of preterm labor immediacy by nonlinear methods

Preterm delivery affects about one tenth of human births and is associated with an increased perinatal morbimortality as well as with remarkable costs. Even if there are a number of predictors and markers of preterm delivery, none of them has a high accuracy. In order to find quantitative indicators of the immediacy of labor, 142 cardiotocographies (CTG) recorded from women consulting because of suspected threatened premature delivery with gestational ages comprehended between 24 and 35 weeks were collected and analyzed. These 142 samples were divided into two groups: the delayed labor group (n = 75), formed by the women who delivered more than seven days after the tocography was performed, and the anticipated labor group (n = 67), which corresponded to the women whose labor took place during the seven days following the recording. As a means of finding significant differences between the two groups, some key informational properties were analyzed by applying nonlinear techniques on the tocography recordings. Both the regularity and the persistence levels of the delayed labor group, which were measured by Approximate Entropy (ApEn) and Generalized Hurst Exponent (GHE) respectively, were found to be significantly different from the anticipated labor group. As delivery approached, the values of ApEn tended to increase while the values of GHE tended to decrease, suggesting that these two methods are sensitive to labor immediacy. On this paper, for the first time, we have been able to estimate childbirth immediacy by applying nonlinear methods on tocographies. We propose the use of the techniques herein described as new quantitative diagnosis tools for premature birth that significantly improve the current protocols for preterm labor prediction worldwide.

Fetal fibronectin testing for prevention of preterm birth in singleton pregnancies with threatened preterm labor: a systematic review and metaanalysis of randomized controlled trials

OBJECTIVE DATA

Fetal fibronectin is an extracellular matrix glycoprotein that is produced by amniocytes and cytotrophoblasts and has been shown to predict spontaneous preterm birth.

STUDY

The aim of this systematic review and metaanalysis of randomized clinical trials was to evaluate the effect of the use of fetal fibronectin in the prevention of preterm birth in singleton pregnancies with threatened preterm labor.

STUDY APPRAISAL AND SYNTHESIS METHODS

The research was conducted with the use of MEDLINE, EMBASE, Web of Sciences, Scopus, ClinicalTrial.gov, OVID, and Cochrane Library as electronic databases from the inception of each database to February 2016. Selection criteria included randomized clinical trials of singleton gestations with threatened preterm labor that were assigned randomly to management based on fetal fibronectin results (ie, intervention group) or not (ie, comparison group). Types of participants included women with singleton gestations at 23 0/7 to 34 6/7 weeks with threatened preterm labor. Studies that included management that was also based on the use of sonographic cervical length were excluded. The primary outcome was preterm birth at <37 weeks of gestation. The summary measures were reported as relative risk or as mean differences with 95% confidence interval.

RESULTS

Six trials that included 546 singleton gestations with symptoms of preterm labor were included in the metaanalysis. The overall risk of bias of the included trials was low. Women were eligible for the random assignment in case of symptoms that suggested preterm labor at 23-34 weeks of gestation. During admission, before digital examination, a Dacron swab was rotated in the posterior fornix for 10 seconds to absorb cervicovaginal secretions that were then analyzed for the fetal fibronectin qualitative method, with results reported as either positive or negative. Women who were assigned randomly to the fetal fibronectin group had a similar incidence of preterm birth at <37 weeks of gestation (20.7% vs 29.2%; relative risk, 0.72; 95% confidence interval, 0.52-1.01), at <34 weeks of gestation (8.3% vs 7.9%; relative risk, 1.09; 95% confidence interval, 0.54-2.18), at <32 weeks of gestation (3.3% vs 5.6%; relative risk, 0.64; 95% confidence interval, 0.24-1.74), and at <28 weeks of gestation (1.1% vs 1.7%; relative risk, 0.74; 95% confidence interval, 0.15-3.67) compared with the control group. No differences were found in the number of women who delivered within 7 days (12.8% vs 14.5%; relative risk, 0.76; 95% confidence interval, 0.47-1.21), in the mean of gestational age at delivery (mean difference, 0.20 week; 95% confidence interval, -0.26 to 0.67), in the rate of maternal hospitalization (27.4% vs 26.9%; relative risk, 1.07; 95% confidence interval, 0.80-1.44), in the use of tocolysis (25.3% vs 28.2%; relative risk, 0.97; 95% confidence interval, 0.75-1.24), antenatal steroids (29.2% vs 29.2%; relative risk, 1.05; 95% confidence interval, 0.79-1.39), in the mean time in the triage unit (mean difference, 0.60 hour; 95% confidence interval, -0.03 to 1.23) and in neonatal outcomes that included respiratory distress syndrome (1.3% vs 1.5%; relative risk, 0.91; 95% confidence interval, 0.06-14.06), and admission to the neonatal intensive care unit (19.4% vs 8.1%; relative risk, 2.48; 95% confidence interval, 0.96-6.46). Management based on the fetal fibronectin test required higher hospitalization charges (mean difference, $153; 95% confidence interval, 24.01-281.99).

CONCLUSION

Fetal fibronectin testing in singleton gestations with threatened preterm labor is not associated with the prevention of preterm birth or improvement in perinatal outcome but is associated with higher costs.

Risk assessment and management to prevent preterm birth

Preterm birth is the most important cause of neonatal mortality and morbidity worldwide. In this review, we review potential risk factors associated with preterm birth and the subsequent management to prevent preterm birth in low and high risk women with a singleton or multiple pregnancy. A history of preterm birth is considered the most important risk factor for preterm birth in subsequent pregnancy. General risk factors with a much lower impact include ethnicity, low socio-economic status, maternal weight, smoking, and periodontal status. Pregnancy-related characteristics, including bacterial vaginosis and asymptomatic bacteriuria, appear to be of limited value in the prediction of preterm birth. By contrast, a mid-pregnancy cervical length measurement is independently associated with preterm birth and could be used to identify women at risk of a premature delivery. A fetal fibronectin test may be of additional value in the prediction of preterm birth. The most effective methods to prevent preterm birth depend on the obstetric history, which makes the identification of women at risk of preterm birth an important task for clinical care providers.

Predicting Preterm Labour: Current Status and Future Prospects

Preterm labour and birth are a major cause of perinatal morbidity and mortality. Despite modern advances in obstetric and neonatal management, the rate of preterm birth in the developed world is increasing. Yet even though numerous risk factors associated with preterm birth have been identified, the ability to accurately predict when labour will occur remains elusive, whether it is at a term or preterm gestation. In the latter case, this is likely due to the multifactorial aetiology of preterm labour wherein women may display different clinical presentations that lead to preterm birth. The discovery of novel biomarkers that could reliably identify women who will subsequently deliver preterm may allow for timely medical intervention and targeted therapeutic treatments aimed at improving maternal and fetal outcomes. Various body fluids including amniotic fluid, urine, saliva, blood (serum/plasma), and cervicovaginal fluid all provide a rich protein source of putative biochemical markers that may be causative or reflective of the various pathophysiological disorders of pregnancy, including preterm labour. This short review will highlight recent advances in the field of biomarker discovery and the utility of single and multiple biomarkers for the prediction of preterm birth in the absence of intra-amniotic infection.

Human cervicovaginal fluid biomarkers to predict term and preterm labor

Preterm birth (PTB; birth before 37 completed weeks of gestation) remains the major cause of neonatal morbidity and mortality. The current generation of biomarkers predictive of PTB have limited utility. In pregnancy, the human cervicovaginal fluid (CVF) proteome is a reflection of the local biochemical milieu and is influenced by the physical changes occurring in the vagina, cervix and adjacent overlying fetal membranes. Term and preterm labor (PTL) share common pathways of cervical ripening, myometrial activation and fetal membranes rupture leading to birth. We therefore hypothesize that CVF biomarkers predictive of labor may be similar in both the term and preterm labor setting. In this review, we summarize some of the existing published literature as well as our team's breadth of work utilizing the CVF for the discovery and validation of putative CVF biomarkers predictive of human labor. Our team established an efficient method for collecting serial CVF samples for optimal 2-dimensional gel electrophoresis resolution and analysis. We first embarked on CVF biomarker discovery for the prediction of spontaneous onset of term labor using 2D-electrophoresis and solution array multiple analyte profiling. 2D-electrophoretic analyses were subsequently performed on CVF samples associated with PTB. Several proteins have been successfully validated and demonstrate that these biomarkers are associated with term and PTL and may be predictive of both term and PTL. In addition, the measurement of these putative biomarkers was found to be robust to the influences of vaginal microflora and/or semen. The future development of a multiple biomarker bed-side test would help improve the prediction of PTB and the clinical management of patients.

Interleukin 6 and fetal fibronectin as a predictors of preterm delivery in symptomatic patients

Preterm delivery is the leading cause of neonatal mortality and morbidity. The rate of preterm births has been estimated to be about 15 million, which accounts for 11.1% of all live births worldwide. The purpose of this study was to evaluate the cervico-vaginal (CVF) cytokine IL-6 and fetal fibronectin (fFN) status as predictors of preterm delivery in patients with symptoms of preterm labor. Patients with symptoms suggestive of preterm labor were recruited from September 2013 to March 2014. Vaginal swabs were taken for fetal fibronectin test (fFN) and CVF IL-6. Antibiotics, steroids and tocolytics were administered, where appropriate. The outcome was measured by the occurrence of preterm delivery within 14 days from the day of hospital admission. Cut-off value of 1305 pg/mL for the concentration of IL-6 in the CVF was the best predictor of preterm delivery, with the sensitivity of 69.4% and specificity of 68.2%. Patients with positive fFN test had the OR of 6.429 (95%CI 1.991-20.758) to deliver prematurely. The multivariate analysis of combined fFN and CVF IL-6 tests resulted in risk of 86.7% to deliver prematurely, if both tests were positive. The combination of both tests performed better than the individual tests and decreased the false positive rate, which in turn reduced the chances for inappropriate patient treatment, bringing down the costs.

Whole blood gene expression profile associated with spontaneous preterm birth in women with threatened preterm labor

Threatened preterm labor (TPTL) is defined as persistent premature uterine contractions between 20 and 37 weeks of gestation and is the most common condition that requires hospitalization during pregnancy. Most of these TPTL women continue their pregnancies to term while only an estimated 5% will deliver a premature baby within ten days. The aim of this work was to study differential whole blood gene expression associated with spontaneous preterm birth (sPTB) within 48 hours of hospital admission. Peripheral blood was collected at point of hospital admission from 154 women with TPTL before any medical treatment. Microarrays were utilized to investigate differential whole blood gene expression between TPTL women who did (n = 48) or did not have a sPTB (n = 106) within 48 hours of admission. Total leukocyte and neutrophil counts were significantly higher (35% and 41% respectively) in women who had sPTB than women who did not deliver within 48 hours (p<0.001). Fetal fibronectin (fFN) test was performed on 62 women. There was no difference in the urine, vaginal and placental microbiology and histopathology reports between the two groups of women. There were 469 significant differentially expressed genes (FDR<0.05); 28 differentially expressed genes were chosen for microarray validation using qRT-PCR and 20 out of 28 genes were successfully validated (p<0.05). An optimal random forest classifier model to predict sPTB was achieved using the top nine differentially expressed genes coupled with peripheral clinical blood data (sensitivity 70.8%, specificity 75.5%). These differentially expressed genes may further elucidate the underlying mechanisms of sPTB and pave the way for future systems biology studies to predict sPTB.

Fetal fibronectin as a biomarker of preterm labor: a review of the literature and advances in its clinical use

Spontaneous preterm birth (sPTB) is a challenge in obstetrics today, and is the leading cause of neonatal morbidity and mortality. The ability to predict preterm birth had, until recently, been poor. The biomarker fetal fibronectin (fFN), found at the maternal–fetal interface, when present in high concentrations in cervicovaginal fluid, has been shown to increase the risk of sPTB in symptomatic and asymptomatic women. Recently, further research has been performed into the applicability of such a test to clinical practice, and its effects on management decisions and patient outcomes. Owing to its high negative predictive value, a negative fFN result has been shown to reduce unnecessary interventions, change patient management and reduce healthcare costs, by allowing early reassurance and return to normal care pathways, while care can be concentrated on those at risk. The development of a bedside quantitative fFN test has shown promise to further improve the positive predictive abilities of fFN, as have combined predictive models with cervical length and fFN.

The interplay of the interleukin 1 system in pregnancy and labor

This work assessed the temporal coexpression of interleukin 1 (IL-1) and its inhibitor, IL-1 receptor antagonist (IL-1ra), in the cervicovaginal fluid (CVF) beyond 24 weeks gestation including women in spontaneous term labor. Two cohorts of women were recruited at 24 to 35 weeks' gestation (n = 65) and in late pregnancy (>36 weeks' gestation; n = 88). The CVF was serially collected either every 4 weeks between 24 and 35 weeks' gestation (n = 123 samples) or weekly during late pregnancy (n = 240 samples). The IL-1 and IL-1ra were quantitated by enzyme-linked immunosorbent assay, and the effect of vaginal microflora and unprotected sexual intercourse were also investigated. The IL-1β and IL-1ra remain unaltered between 24 and 35 weeks' gestation. At late pregnancy, IL-1α and β concentrations peak at 4 to 14 days prior to labor onset, while IL-1ra decreases with approaching spontaneous term labor (P < .05, 2-way analysis of variance). The IL-1 and IL-1ra were significantly correlated (P < .001, Pearson r). A combined biomarker model of IL-1α, IL-1β, and IL-1ra can predict term labor with 86% sensitivity and 92% specificity. This study indicates a shifting inflammatory balance in the gestational tissues prior to labor onset.

Costs of unnecessary admissions and treatments for "threatened preterm labor"

OBJECTIVE

Cervical length (CL) of 3 cm or greater has been shown to have a 97-99% negative predictive value for preterm delivery in women with threatened preterm labor. Consequently, hospitalization and treatment are not indicated in these patients. We analyzed how often patients with a CL of 3 cm or greater are still being admitted and treated for preterm labor and how much this contributes to the economic burden of preterm labor hospitalizations.

STUDY DESIGN

Twelve month hospitalizations for preterm labor at less than 34 weeks at a single institution were reviewed and patients with a CL of 3 cm or greater were identified. We chose to use patients' hospital charges as a surrogate for health care costs, recognizing that charges are not synonymous with the final patient bill and also do not reflect additional costs such as the cost of treatment at the referring facility, transportation, physician fees, and other such costs as lost wages, need for additional child care, etc.

RESULTS

Between July 2009 and June 2010, 139 patients were admitted and treated for preterm labor at our level III center. Fifty of these patients (36%) had a CL of 3 cm or greater. None of them delivered preterm. Total hospital charges for the management of these patients were $1,018 589 (mean, $20,372; median, $14,444).

CONCLUSION

Unnecessary admissions and treatments for threatened preterm labor are part of clinical practice and contribute to exploding health care costs. Using currently available diagnostics, these costs could be lowered significantly without jeopardizing outcome.

Vaginal progesterone in risk reduction of preterm birth in women with short cervix in the midtrimester of pregnancy

Preterm birth is a major health problem for the neonate, family, country, and society in general. Despite many risk factors being identified for women destined to deliver preterm, short cervical length detected on transvaginal ultrasound is the most plausible, practical and sensitive risk factor for prediction of spontaneous preterm birth. The definition of short cervix has varied in various studies, but most commonly accepted is ≤2.5 cm in the midtrimester of pregnancy, though risk of spontaneous preterm birth (sPTB) increases as the cervical length decreases. Vaginal progesterone, a naturally occurring steroid hormone, is the most bioavailable form of progesterone for uterine and cervical effects with the fewest side effects. Multiple prospective studies have consistently shown its benefits in decreasing sPTB rate in women with asymptomatic midtrimester short cervix. The safety for mother and fetus, and tolerability of vaginal progesterone, particularly the gel form, is also well established. Vaginal progesterone is a minimally invasive intervention that is not painful and is very safe, with reasonable cost where the benefits (even if argued to be small) clearly outweigh the risks. Thus there should be little hesitation for implementation of universal transvaginal cervical length screening and preventive vaginal progesterone treatment for women with short cervix.

Reducing recurrent preterm births: best evidence for transitioning to predictive and preventative strategies

Women who have delivered an infant between 16 and 36 weeks' gestation have an increased risk of preterm birth (PTB) in a subsequent pregnancy. The high incidence of recurrent PTB remains relatively unchanged despite intensive research efforts and advances in perinatal care. Attempts to decrease the incidence of recurrent PTB have not always been successful, with research efforts being focused on clinical, pharmacotherapy and biochemical, and ultrasound strategies. Fortunately, there is adequate evidence in the literature to justify clinical management guidelines that may impact the PTB rate: smoking cessation, treatment of asymptomatic bacteriuria, transvaginal ultrasonography of the cervix, administration of vaginal progesterone or 17α-hydroxyprogesterone caproate, cerclage, and fetal fibronectin. This article is intended to give brief highlights of these strategies and the current science that supports their conclusions.

[Predictive value of combined fibronectin and ultrasound cervical assessment in twin pregnancies]

OBJECTIVE

To test a sequential test with fetal fibronectin detection after ultrasound measurement of cervical length to predict preterm delivery in twin pregnancies with preterm labor.

PATIENTS AND METHODS

Descriptive retrospective study on 50 women with twin pregnancy hospitalised for preterm labor between 24 and 34 weeks and 6 days of gestation. The primary outcomes were preterm delivery before 34 or 37 weeks of gestation or within 7 or 14 days. Selective use of fibronectin after cervical length measurement has been tested, with a sequential test considered positive if cervical length was less than or equal to 15mm or if cervical length was between 16 and 30mm with fetal fibronectin positive.

RESULTS

The sensitivity/specificity/and positive and negative predictive values of fetal fibronectin positive were 71%, 64%, 26%, et 93% for delivery within 7 days; those of cervical length less than or equal to 20mm were 89%, 51%, 31%, et 95% for delivery before 34 weeks and 6 days. The efficiency of the sequential test seemed better than each test and than for singleton pregnancies keeping an excellent negative predictive value: sensitivity of 75%, specificity of 63%, positive predictive value of 26% and negative predictive value of 93.5% for prediction of preterm delivery within 14 days. The use of this sequential test could have decreased half of fibronectin tests.

DISCUSSION AND CONCLUSION

A sequential test with selective use of fetal fibronectin detection in twin pregnancies selected by ultrasound measurement of cervical length appears to be effective for predicting preterm birth if preterm labor, avoiding half of fibronectin tests.

Expression and potential biological role of α(1,2)fucosylated glycotopes on amniotic and seminal fibronectins

The present paper describes concisely the expression and role of α(1,2)-linked fucose on some glycoconjugates as well as the detection, distribution and potential role of that glycotope on human soluble plasma and cellular fibronectins in addition to the expression on both normal and pathological amniotic fluid and seminal plasma fibronectins. The determination of α(1,2)fucosylated glycans is considered with respect to its usefulness as a potential clinically applicable biomarker in obstetrics to monitor pregnancy and in andrology to evaluate the ejaculate of infertile men and in vitro fertilization.

Cervicovaginal fetal fibronectin for the prediction of spontaneous preterm birth in multiple pregnancies: a systematic review and meta-analysis

OBJECTIVE

To investigate the accuracy of cervicovaginal fetal fibronectin in predicting preterm birth in women with multiple pregnancies.

METHODS

Systematic review and meta-analysis of predictive test accuracy. Cohort or cross-sectional studies were identified through searches in databases, reference lists, proceedings, and reviews. Study selection, quality assessment, and data extraction were performed. We constructed summary receiver operating characteristic curves and calculated pooled sensitivities and specificities using a bivariate, random-effects meta-regression model. We also calculated summary likelihood ratios and post-test probabilities of preterm birth.

RESULTS

Fifteen studies (11 in asymptomatic women and 4 in women with symptoms of preterm labor) involving 1221 women with multiple pregnancies were included. Among asymptomatic women with multiple or twin pregnancies, the pooled sensitivities, specificities, and positive and negative likelihood ratios for predicting preterm birth before 32, 34, and 37 weeks' gestation ranged from 33% to 45%, 80% to 94%, 2.0 to 5.5, and 0.68 to 0.76, respectively. Among women with twin pregnancies and threatened preterm labor, the test was most accurate in predicting spontaneous preterm birth within 7 days of testing (pooled sensitivity, specificity, and positive and negative likelihood ratios of 85%, 78%, 3.9, and 0.20, respectively).

CONCLUSIONS

Cervicovaginal fetal fibronectin provides moderate to minimal prediction of preterm birth in women with multiple pregnancies. The test is most accurate in predicting spontaneous preterm birth within 7 days of testing in women with twin pregnancies and threatened preterm labor.

Contingent use of fetal fibronectin testing and cervical length measurement in women with preterm labour

OBJECTIVE

To evaluate the contingent use of fetal fibronectin (fFN) testing and cervical length (CL) measurement to predict preterm delivery, and to validate the use of phosphorylated IGFBP-1 as a predictor of preterm delivery.

METHODS

We recruited 71 women with a clinical diagnosis of preterm labour between 24 and 34 weeks, and tested for the presence of fFN and IGFBP-1 in the cervicovaginal secretions of all women immediately before CL measurement.

RESULTS

Among the 66 women with complete outcome, four were excluded from the final analysis as two had assessment for fFN but no CL measurement, and another two had CL measured but no screening for fFN. Among 62 women with complete results, the mean gestational age at recruitment was 29.4 +/- 2.5 weeks. Six women (9.6%) delivered within two weeks of assessment, and 14 (22.5%) delivered before 34 weeks. A positive fFN test resulted in a sensitivity of 83%, a specificity of 84%, a positive predictive value of 36%, and a negative predictive value of 98% for delivery within two weeks; for CL < 25 mm, these figures were 50%, 52%, 10%, and 91%, respectively, and for a positive IGFBP-1, they were 17%, 93%, 20%, and 91%, respectively. A policy of contingent use of fFN (in which the test was assumed to be positive if CL < or = 15 mm, and fFN was only measured if the CL was between 16 and 30 mm) gave sensitivity, specificity, positive and negative predictive values of 80%, 61%, 17%, and 97%, respectively for delivery within two weeks. Using this contingent use protocol, only one third of women needed fFN screening after CL measurement.

CONCLUSION

In this study, IGFBP-1 screening did not predict preterm delivery and fFN screening provided the best predictive capacity. A policy of contingent use of testing for fFN after CL measurement, or contingent use of CL measurement after fFN screening (depending on available resources) is a promising approach to limit use of resources.

Critical appraisal and clinical utility of atosiban in the management of preterm labor

Preterm birth is the major cause of perinatal morbidity and mortality in the developed world, and spontaneous preterm labor is the commonest cause of preterm birth. Interventions to treat women in spontaneous preterm labor have not reduced the incidence of preterm births but this may be due to increased risk factors, inclusion of births at the limits of viability, and an increase in the use of elective preterm birth. The role of antibiotics remains unproven. In the largest of the randomized controlled trials, evaluating the use of antibiotics for the prevention of preterm births in women in spontaneous preterm labor, antibiotics against anaerobes and bacterial vaginosis-related organisms were not included, and no objective evidence of abnormal genital tract flora was obtained. Atosiban and nifedipine are the main tocolytic agents used to treat women in spontaneous preterm labor, but atosiban is the tocolytic agent with the fewest maternal - fetal side effects. A well conducted randomized controlled trial comparing atosiban with nifedipine for their effectiveness and safety is needed.

Phosphorylated insulin-like growth factor binding protein-1 and cervical measurement in women with threatening preterm birth

OBJECTIVE

To assess the efficacy of the cervical phosphorylated insulin-like growth factor binding protein-1 (pIGFBP-1) in combination with cervical length measurement for the prediction of preterm delivery.

DESIGN

Observational prospective study.

SETTING

University Hospital, Spain.

SAMPLE

A total of 276 women between 24 and 34 weeks gestational age complaining of uterine contractions and intact membranes.

METHODS

Transvaginal scan to assess cervical length and cervical swabs for pIGFBP-1 detection.

MAIN OUTCOME MEASURES

Prevalence of preterm delivery within 48 hours and 7 days, delivery at < 32, < 34 weeks, admission-to-delivery interval by cervical length and the presence of pIGFBP-1. Results. The prevalence of preterm delivery at < 34 weeks was 14.1% (39/276) and 7.6% (21/276) at < 32 weeks. Cervical pIGFBP-1 was positive in 38.7% (107/276), whereas cervical length < 15 mm was present in 7.2% (20/276) and was > 30 mm for 64.8% (179/276) of the women. The presence of a positive pIGFBP-1 appeared useful for prediction of delivery before 32 (likelihood ratio (LR) = 2.21, confidence interval (CI): 1.63-3.00) and 34 weeks (LR = 1.76, CI: 1.25-2.41), respectively. Receiver operating characteristic curves were significant for cervical length and pIGFBP-1 for prediction of delivery at < 34 weeks, < 32 weeks, < 48 hours and < 7 days. Combining pIGFBP-1 and cervical length had a median interval that was shorter when both were positive as compared to only one positive or both negative, but the CIs overlapped.

CONCLUSIONS

Both cervical length measurement and pIGFBP-1 are useful for prediction of spontaneous preterm delivery. A pIGFBP-1 positive result associated with cervical length does not improve preterm delivery prediction rates.

Chorioamnionitis--a complex pathophysiologic syndrome

Chorioamnionitis, inflammation of the amniochorionic membrane (fetal membranes) is a very common disease but a complex syndrome associated with pregnancy. It presents a clinical impasse due to lack of knowledge of specific etiologies associated with this condition making confident clinical interventions difficult. Recent reports provide insight into genetic, epigenetic, behavioral, psychosocial, molecular and pathophysiological factors that are associated with chorioamnionitis. However, a coordinated approach in understanding causality and lack of early indicators (clinical and biomarkers) has hampered gaining knowledge about the disease status preventing proper intervention. Several reviews have provided in-depth analysis of the histologic and clinical evidence associated with chorioamnionitis. In this review, we provide a novel perspective on chorioamnionitis based on recent evidences from scientific literature on inflammation, apoptosis and genetics.

Identification and quantification of preterm birth biomarkers in human cervicovaginal fluid by liquid chromatography/tandem mass spectrometry

Spontaneous preterm birth (PTB) before 37 completed weeks of gestation resulting from preterm labor (PTL) is a leading contributor of perinatal morbidity and mortality. Early identification of at-risk women by reliable screening tests could alleviate this health issue; however, conventional methods such as obstetric history and clinical risk factors, uterine activity monitoring, biochemical markers, and cervical sonography for screening women at risk for PTB have proven unsuccessful in lowering the rate of PTB. Cervicovaginal fluid (CVF) might prove to be a useful, readily available biological fluid for identifying diagnostic PTB biomarkers. Human columnar epithelial endocervical-1 (End1) and vaginal (Vk2) cell secretomes were employed to generate a stable isotope labeled proteome (SILAP) standard to facilitate characterization and relative quantification of proteins present in CVF. The SILAP standard was prepared using stable isotope labeling by amino acids in cell culture (SILAC) of End1 and Vk2 through seven passages. The labeled secreted proteins from both cell lines were combined and characterized by liquid-chromatography-tandem mass spectrometry (LC-MS/MS). In total, 1211 proteins were identified in the End1-Vk2 SILAP standard, with 236 proteins being consistently identified in each of the replicates analyzed. Individual proteins were found to contain <0.5% of the endogenous unlabeled forms. Identified proteins were screened to provide a set of 15 candidates that have either previously been identified as potential PTB biomarkers or could be linked mechanistically to PTB. Stable isotope dilution LC-multiple reaction monitoring (MRM/MS) assays were then developed for conducting relative quantification of the 15 candidate biomarkers in human CVF samples from term and PTB cases. Three proteins were significantly elevated in PTB cases (desmoplakin isoform 1, stratifin, and thrombospondin 1 precursor), providing a foundation for further validation in larger patient cohorts.

Comparison of biochemical markers and cervical length for predicting preterm delivery

AIM

To examine the clinical utility of several prognostic factors for predicting preterm delivery.

METHODS

One hundred and nineteen patients with a singleton pregnancy admitted to our hospital because of symptoms of preterm labor were included in this study. Maternal serum C-reactive protein (CRP), transvaginal sonographic measurement of cervical length (CL), granulocyte elastase (EL) in cervical secretions, fetal fibronectin (fFN), alpha-fetoprotein (AFP), and insulin-like growth factor binding protein-1 (IGFBP-1) in vaginal secretions were examined on admission. EL, fFN, AFP, and IGFBP-1 were measured by bed-side test kits. Correlation between each factor and the duration of pregnancy (from admission to delivery) was investigated.

RESULTS

A significant correlation was found between the duration of pregnancy and CRP (r= -0.37, P<0.001), but not CL. The duration was significantly shorter in the fFN-positive group than in the negative group (P=0.0015). However, no significant difference was observed between the positive group and the negative group for each of CL, EL, AFP and IGFBP-1.

CONCLUSION

Association between the duration of the pregnancy and two biochemical markers (CRP and fFN) was confirmed. As they can be examined quickly and easily, they are quite useful for estimating prognosis of preterm labor.