A systematic review and quality assessment of systematic reviews of fetal fibronectin and transvaginal length for predicting preterm birth

Guideline No. 401: Sonographic Cervical Length in Singleton Pregnancies: Techniques and Clinical Applications

OBJECTIVES

• To assess the association between sonography-derived cervical length measurement and preterm birth. • To describe the various techniques to measure cervical length using sonography. • To review the natural history of the short cervix. • To review the clinical uses, predictive ability, and utility of sonography-measured short cervix.

OUTCOMES

Reduction in rates of prematurity and/or better identification of those at risk, as well as possible prevention of unnecessary interventions.

INTENDED USERS

Clinicians involved in the obstetrical management or cervical imaging of patients at increased risk of a short cervix.

TARGET POPULATION

Women at increased risk of a short cervix or at risk of preterm birth.

EVIDENCE

Literature published up to June 2019 was retrieved through searches of PubMed and the Cochrane Library using appropriate controlled vocabulary and key words (preterm labour, ultrasound, cervix, cervical insufficiency, transvaginal, transperineal, cervical length, fibronectin). Results were restricted to general and systematic reviews, randomized controlled trials, controlled clinical trials, and observational studies. There were no date or language restrictions. Grey (unpublished) literature was identified through searching the websites of health technology assessment agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The evidence and this guideline were reviewed by the Diagnostic Imaging Committee of the Society of Obstetricians and Gynaecologists of Canada, and the recommendations were made and graded according to the rankings of the Canadian Task Force on Preventive Health Care (Online Appendix Table A1).

BENEFITS, HARMS, COSTS

Preterm birth is a leading cause of perinatal morbidity and mortality. Use of the sonographic technique reviewed in this guideline may help identify women at risk of preterm birth and, in some circumstances, lead to interventions that may reduce the rate of preterm birth. SUMMARY STATEMENTS (CANADIAN TASK FORCE ON PREVENTIVE HEALTH CARE GRADING IN PARENTHESES): RECOMMENDATIONS (CANADIAN TASK FORCE ON PREVENTIVE HEALTH CARE GRADING IN PARENTHESES).

Evaluation of the effectiveness of foetal fibronectin as a predictor of preterm birth in symptomatic preterm labour women

BACKGROUND

The prediction of preterm birth (PTB) is important in the management of symptomatic preterm labour women. We evaluated the effectiveness of the foetal fibronectin (fFN) test for predicting PTB in symptomatic preterm labour women with consideration of physiologic changes in cervical length (CL) during pregnancy.

METHODS

This prospective study included 85 women with symptomatic preterm labour of a singleton pregnancy. Positive fFN was defined as a fFN level of > 50 ng/mL in cervicovaginal secretion, while a short CL was defined as that below 25th percentile at the corresponding gestational age. We evaluated effectiveness of the fFN test, CL, and the combination of these two tests, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), positive likelihood ratio (LR⁺), negative likelihood ratio (LR^-) to predict the PTB within 7 and 14 days of testing and PTB at < 34 and 37 weeks of gestation. We also present the odds ratios (ORs) of the test results, defining the women with both negative results as the reference group.

RESULTS

Of the 85 women, 31 (36.5%) showed a positive fFN and 44 (51.8%) had a short CL. PTB occurred within 7 and 14 days of testing and before 34 and 37 weeks of gestation in 17.6, 20.0, 23.5 and 49.4% of the women, respectively. The fFN and CL results showed low predictive effectiveness for the studied outcomes with LR⁺ (fFN, 1.5-1.9; CL, 1.0-1.5) and LR^- (fFN, 0.7; CL, 0.7-0.9). The combined use of fFN and CL could not improve these results (LR⁺, 1.4-2.3; LR^-, 0.7-0.9). However, the risk of PTB before 37 weeks was increased in women with positive fFN but not CL shortening compared to the reference group (odds ratio [OR], 3.8; 95% confidence interval [CI], 1.1-1.3). The risk of PTB before 34 weeks was increased in both positive fFN and CL compared to the reference group (OR, 8.1; 95% CI, 1.9-34.5).

CONCLUSION

Although, our approach could not improve the ability to predict PTB, it could identify women at risk for delivery before 34 or 37 weeks of gestation. Therefore, it could be used to manage women with symptomatic preterm labour.

Use of metabolomics for predicting spontaneous preterm birth in asymptomatic pregnant women: protocol for a systematic review and meta-analysis

INTRODUCTION

Preterm birth (PTB) is the leading cause of neonatal mortality and short- and long-term morbidity. The aetiology and pathophysiology of spontaneous PTB (sPTB) are still unclear, which makes the identification of reliable and accurate predictor markers more difficult, particularly for unscreened or asymptomatic women. Metabolomics biomarkers have been demonstrated to be potentially accurate biomarkers for many disorders with complex mechanisms such as PTB. Therefore, we aim to perform a systematic review of metabolomics markers associated with sPTB. Our research question is 'What is the performance of metabolomics for predicting spontaneous preterm birth in asymptomatic pregnant women?'

METHODS AND ANALYSIS

We will focus on studies assessing metabolomics techniques for predicting sPTB in asymptomatic pregnant women. We will conduct a comprehensive systematic review of the literature from the last 10 years. Only observational cohort and case-control studies will be included. Our search strategy will be carried out by two independent reviewers, who will scan title and abstract before carrying out a full review of the article. The scientific databases to be explored include PubMed, MedLine, ScieLo, EMBASE, LILACS, Web of Science, Scopus and others.

ETHICS AND DISSEMINATION

This systematic review protocol does not require ethical approval. We intend to disseminate our findings in scientific peer-reviewed journal, the Preterm SAMBA study open access website, specialists' conferences and to our funding agencies.

PROSPERO REGISTRATION NUMBER

CRD42018100172.

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.

Clinical trials registries are underused in the pregnancy and childbirth literature: a systematic review of the top 20 journals

Background

Systematic reviews and meta-analyses that do not include unpublished data in their analyses may be prone to publication bias, which in some cases has been shown to have deleterious consequences on determining the efficacy of interventions.

Methods

We retrieved systematic reviews and meta-analyses published in the past 8 years (January 1, 2007–December 31, 2015) from the top 20 journals in the Pregnancy and Childbirth literature, as rated by Google Scholar’s h5-index. A meta-epidemiologic analysis was performed to determine the frequency with which authors searched clinical trials registries for unpublished data.

Results

A PubMed search retrieved 372 citations, 297 of which were deemed to be either a systematic review or a meta-analysis and were included for analysis. Twelve (4 %) of these searched at least one WHO-approved clinical trials registry or clinicaltrials.gov.

Conclusion

Systematic reviews and meta-analyses published in pregnancy and childbirth journals do not routinely report searches of clinical trials registries. Including these registries in systematic reviews may be a promising avenue to limit publication bias if registry searches locate unpublished trial data that could be used in the systematic review.

Fetal fibronectin (Quick Check fFN test) versus placental alpha microglobulin-1 (AmniSure test) for detection of premature rupture of fetal membranes

OBJECTIVES

To compare accuracy of fetal fibronectin (fFN) versus placental alpha microglobulin-1 for detection of premature rupture of fetal membranes (PROM).

METHODS

Two hundred and twenty pregnant women >34 and <37 weeks were included in this comparative prospective study and divided into two groups according to presence or absence of PROM. The diagnosis of PROM was based on patient's history of sudden gush of water, pooling of amniotic fluid, positive ferning, positive nitrazine test, confirmed by visualization of fluid passing from the cervical canal and amniotic fluid index ≤5 cm measured by trans-abdominal ultrasound. Patients included in this study were examined by sterile speculum for visualization of membranes and for collection of samples (swabs) from posterior vaginal fornix.

RESULTS

Sensitivity and specificity of AmniSure test to diagnose PROM were 97.3 and 98.2 %, respectively, compared with 94.5 and 89.1 %, respectively, for fFN test. Positive predictive value, negative predictive value, and accuracy of AmniSure test to diagnose PROM were 98.2, 97.3, and 97.7 %, respectively, compared with 89.7, 94.2, and 91.8 %, respectively, for fFN test. Predictive values and accuracy of fFN test to diagnose PROM were statistically insignificant compared with predictive values and accuracy of ferning, nitrazine and AmniSure tests.

CONCLUSION

fFN bedside test is better than nitrazine and ferning tests in detection of PROM, but is not suited for identification of clinically difficult cases with suspected PROM, because, it is influenceable and can give false-positive results in preterm labor, women >34 gestational weeks and after any vaginal manipulation without PROM.

A systematic review and meta-analysis of diagnostic and prognostic serum biomarkers of colorectal cancer

BACKGROUND

Our systematic review summarizes the evidence concerning the accuracy of serum diagnostic and prognostic tests for colorectal cancer (CRC).

METHODS

The databases MEDLINE and EMBASE were searched iteratively to identify the relevant literature for serum markers of CRC published from 1950 to August 2012. The articles that provided adequate information to meet the requirements of the meta-analysis of diagnostic and prognostic markers were included. A 2-by-2 table of each diagnostic marker and its hazard ratio (HR) and the confidence interval (CI) of each prognostic marker was directly or indirectly extracted from the included papers, and the pooled sensitivity and specificity of the diagnostic marker and the pooled HR and the CI of the prognostic marker were subsequently calculated using the extracted data.

RESULTS

In total, 104 papers related to the diagnostic markers and 49 papers related to the prognostic serum markers of CRC were collected, and only 19 of 92 diagnostic markers were investigated in more than two studies, whereas 21 out of 44 prognostic markers were included in two or more studies. All of the pooled sensitivities of the diagnostic markers with > = 3 repetitions were less than 50%, and the meta-analyses of the prognostic markers with more than 3 studies were performed, VEGF with highest (2.245, CI: 1.347-3.744) and MMP-7 with lowest (1.099, CI: 1.018-1.187)) pooled HRs are presented.

CONCLUSIONS

The quality of studies addressing the diagnostic and prognostic accuracy of the tests was poor, and the results were highly heterogeneous. The poor characteristics indicate that these tests are of little value for clinical practice.

A futuristic vision of pocket ultrasound machines: watch this space

Introduction: Australian medical ultrasound started in 1959 with the establishment of the Ultrasonics Institute. Since then the technology has advanced tremendously. We are now not only able to obtain clearer images on high specification ultrasound machines but also on pocket-sized ultrasound machines that are compact, lightweight and affordable. Method: The following descriptive review will examine the indication for use of pocket ultrasound machines in different clinical settings as well as provide evidence of its image clarity and accuracy. Potentially eligible studies were sought primarily through searches of the electronic databases PubMed, Medline (1996-Present), Embase (1996-Present) and Cochrane Library. Conclusion: Pocket ultrasound machines, with appropriate ultrasound knowledge and training, can be incorporated successfully in patient management. The addition of point-of-care ultrasound has been shown to improve management recommendations and outcomes.

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.

Prenatal administration of progesterone for preventing preterm birth in women considered to be at risk of preterm birth

BACKGROUND

Preterm birth is a major complication of pregnancy associated with perinatal mortality and morbidity. Progesterone for the prevention of preterm labour has been advocated.

OBJECTIVES

To assess the benefits and harms of progesterone for the prevention of preterm birth for women considered to be at increased risk of preterm birth and their infants.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (14 January 2013) and reviewed the reference list of all articles.

SELECTION CRITERIA

Randomised controlled trials, in which progesterone was given for preventing preterm birth.

DATA COLLECTION AND ANALYSIS

Two review authors independently evaluated trials for methodological quality and extracted data.

MAIN RESULTS

Thirty-six randomised controlled trials (8523 women and 12,515 infants) were included. Progesterone versus placebo for women with a past history of spontaneous preterm birth Progesterone was associated with a statistically significant reduction in the risk of perinatal mortality (six studies; 1453 women; risk ratio (RR) 0.50, 95% confidence interval (CI) 0.33 to 0.75), preterm birth less than 34 weeks (five studies; 602 women; average RR 0.31, 95% CI 0.14 to 0.69), infant birthweight less than 2500 g (four studies; 692 infants; RR 0.58, 95% CI 0.42 to 0.79), use of assisted ventilation (three studies; 633 women; RR 0.40, 95% CI 0.18 to 0.90), necrotising enterocolitis (three studies; 1170 women; RR 0.30, 95% CI 0.10 to 0.89), neonatal death (six studies; 1453 women; RR 0.45, 95% CI 0.27 to 0.76), admission to neonatal intensive care unit (three studies; 389 women; RR 0.24, 95% CI 0.14 to 0.40), preterm birth less than 37 weeks (10 studies; 1750 women; average RR 0.55, 95% CI 0.42 to 0.74) and a statistically significant increase in pregnancy prolongation in weeks (one study; 148 women; mean difference (MD) 4.47, 95% CI 2.15 to 6.79). No differential effects in terms of route of administration, time of commencing therapy and dose of progesterone were observed for the majority of outcomes examined. Progesterone versus placebo for women with a short cervix identified on ultrasound Progesterone was associated with a statistically significant reduction in the risk of preterm birth less than 34 weeks (two studies; 438 women; RR 0.64, 95% CI 0.45 to 0.90), preterm birth at less than 28 weeks' gestation (two studies; 1115 women; RR 0.59, 95% CI 0.37 to 0.93) and increased risk of urticaria in women when compared with placebo (one study; 654 women; RR 5.03, 95% CI 1.11 to 22.78). It was not possible to assess the effect of route of progesterone administration, gestational age at commencing therapy, or total cumulative dose of medication. Progesterone versus placebo for women with a multiple pregnancy Progesterone was associated with no statistically significant differences for the reported outcomes. Progesterone versus no treatment/placebo for women following presentation with threatened preterm labour Progesterone, was associated with a statistically significant reduction in the risk of infant birthweight less than 2500 g (one study; 70 infants; RR 0.52, 95% CI 0.28 to 0.98). Progesterone versus placebo for women with 'other' risk factors for preterm birth Progesterone, was associated with a statistically significant reduction in the risk of infant birthweight less than 2500 g (three studies; 482 infants; RR 0.48, 95% CI 0.25 to 0.91).

AUTHORS' CONCLUSIONS

The use of progesterone is associated with benefits in infant health following administration in women considered to be at increased risk of preterm birth due either to a prior preterm birth or where a short cervix has been identified on ultrasound examination. However, there is limited information available relating to longer-term infant and childhood outcomes, the assessment of which remains a priority.Further trials are required to assess the optimal timing, mode of administration and dose of administration of progesterone therapy when given to women considered to be at increased risk of early birth.

Dysregulation of diurnal salivary cortisol production is associated with spontaneous preterm delivery: a pilot study

OBJECTIVES

The purpose of this study was to evaluate whether the diurnal fluctuation of salivary cortisol and its overall diurnal secretion are associated with the length of gestation in patients who were admitted to the hospital with an assigned diagnosis of possible preterm labor (PL) at a gestational age of 28-33 weeks.

METHODS

In 22 patients, maternal saliva samples were collected for a cortisol assay 4 times per day (8 AM, 12 AM, 4 PM and 8 PM) on day 4 and day 6 after antenatal corticosteroid prophylaxis to prevent neonatal respiratory distress syndrome.

RESULTS

Eight patients who ultimately delivered before term (32.6 ± 1.7 gestation weeks) showed an inverted fluctuation of salivary cortisol on both days 4 and 6, morning cortisol levels being significantly lower than evening levels. In contrast, in 14 patients who delivered at term (39.5 ± 0.6 gestation weeks), the physiological diurnal fluctuation of salivary cortisol was maintained. In addition, a distinctive feature of women delivering before term was a significantly hampered salivary cortisol diurnal production measured on day 6.

CONCLUSIONS

Corticoadrenal activity is dysregulated and anticipates very preterm delivery in women with an assigned diagnosis of possible PL.

Fetal fibronectin (Quick Check fFN test(®)) for detection of premature rupture of fetal membranes

OBJECTIVES

This study was designed to detect the accuracy of the fetal fibronectin (Quick Check fFN test(®)) in diagnosing premature rupture of fetal membranes.

STUDY DESIGN

This comparative prospective study was carried out over 1 year in Ahmadi Kuwait Oil Company (KOC) Hospital, Kuwait from March 2011 till March 2012.

PATIENTS AND METHODS

Two hundred and twenty (220) pregnant women >34 and <37 weeks gestation were included in this study and divided into two groups according to presence or absence of PROM; 110 patients with PROM were included in group I, and 110 patients without PROM were included in group II as controls. Patients with multiple pregnancies or >37 weeks gestation or not sure of dates or fetal distress or vaginal bleeding or preterm labor or chorioamnionitis were excluded from this study. The diagnosis of PROM was based on patient's history of sudden gush of water, pooling of amniotic fluid, positive ferning pattern, positive nitrazine test, confirmed by visualization of fluid passing from the cervical canal during sterile speculum examination and Trans-abdominal ultrasound to measure the amniotic fluid index (AFI ≤ 5 cm in PROM). The gestational age was calculate from the first day of LMP and confirmed by early ultrasound scan (done before 20 weeks gestation). Patients included in this study were subjected to standard examination, trans-abdominal ultrasound and sterile speculum examination to detect amniotic fluid pooling through the cervical canal and for collection of samples on admission. Some laboratory investigations were done to exclude chorioamnionitis (maternal fever, maternal tachycardia, fetal tachycardia, maternal leucocytosis, CRP).

RESULTS

In this study, the sensitivity and the specificity of fetal fibronectin in diagnosing PROM were 94.5 and 89.1 %, respectively, as compared with 84.5 % sensitivity and 78.2 % specificity for Ferning test, respectively, and 87.3 % sensitivity and 80.9 % specificity for Nitrazine test, respectively. The PPV and NPV of fetal fibronectin were 89.7 and 94.2 %, respectively, as compared with 79.5 % PPV and 83.5 % NPV for Ferning test, respectively, and 82.1 % PPV and 86.4 % NPV for Nitrazine test, respectively. Fetal fibronectin was more accurate (91.8 %) for detection of PROM than Ferning (81.4 %) or Nitrazine (84.1 %) tests.

CONCLUSION

The Quick Check fFN test(®) for detection of the fetal fibronectin in the vaginal fluid is a simple bedside test, more sensitive, and specific than Ferning and Nitrazine tests, it can be used as complimentary test to confirm the clinical diagnosis of premature rupture of fetal membranes.

Isoform α of PKC may contribute to the maintenance of pregnancy myometrial quiescence in humans

We postulate that protein kinase C α (PKCα) may contribute to the maintenance of pregnancy myometrial quiescence in humans. We studied the changes in myometrial PKCα gene products (messenger RNA [mRNA] and protein) in 4 groups of women: preterm not in labor (PT-NL), preterm in labor (PT-L), term not in labor (T-NL), and term in labor (T-L). The degree of PKCα activation was studied by comparing the levels of particulate (active) PKCα with the total PKCα protein levels and by measuring PKCα activity in the cytosolic and particulate fractions. Protein kinase Cα abundance (mRNA and protein) did not increase during myometrial quiescence (PT-NL), whereas the level of PKCα activity significantly increased during quiescence. The activity of PKCα significantly decreased in the T-NL, T-L, and PT-L groups. These findings suggest that PKCα plays a significant role in the maintenance of myometrial quiescence and that PKCα activity must decrease at the end of pregnancy allowing myometrial activation. Additionally, our data demonstrate an association between reduced PKCα activity and preterm labor, which merits further investigation.

[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.

Clinical application of surface plasmon resonance-based biosensors for fetal fibronectin detection

Preterm birth is the leading cause of perinatal morbidity and mortality. Fetal fibronectin (fFN), a glycoprotein in the extracellular matrix of the amniotic membranes, is the most powerful biomarker for predicting the risk of preterm birth. Biosensors using the surface plasmon resonance (SPR) response are potentially useful in quantitatively measuring molecules. We established a standard calibration curve of SPR intensity against fFN concentration and used the SPR-based biosensor to detect fFN concentrations in the cervicovaginal secretions of pregnant women between 22 and 34 weeks of gestation. The calibration curve extends from 0.5 ng/mL to 100 ng/mL with an excellent correlation (R(2) = 0.985) based on standard fFN samples. A cutoff value of 50 ng/mL fFN concentration in commercial ELISA kits corresponds to a relative intensity of 17 arbitrary units (a.u.) in SPR. Thirty-two pregnant women were analyzed in our study. In 11 women, the SPR relative intensity was greater than or equal to 17 a.u., and in 21 women, the SPR relative intensity was less than 17 a.u. There were significant differences between the two groups in regular uterine contractions (p = 0.040), hospitalization for tocolysis (p = 0.049), and delivery weeks (p = 0.043). Our prospective study concluded that SPR-based biosensors can quantitatively measure fFN concentrations. These results reveal the potential utility of SPR-based biosensors in predicting the risk of preterm birth.

SOGC Clinical Practice Guideline. Ultrasonographic cervical length assessment in predicting preterm birth in singleton pregnancies

OBJECTIVES

To review (1) the use of ultrasonographic-derived cervical length measurement in predicting preterm birth and (2) interventions associated with a short cervical length.

OUTCOMES

Reduction in rates of prematurity and/or better identification of those at risk, as well as possible prevention of unnecessary interventions.

EVIDENCE

Published literature was retrieved through searches of PubMed and The Cochrane Library up to December 2009, using appropriate controlled vocabulary and key words (preterm labour, ultrasound, cervix, incompetent cervix, transvaginal, transperineal, cervical length, fibronectin). Results were restricted to general and systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The evidence and this guideline were reviewed by the Diagnostic Imaging Committee and the Maternal Fetal Medicine Committee of the Society of Obstetricians and Gynaecologists of Canada, and the recommendations were made according to the guidelines developed by The Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

Preterm birth is a leading cause of perinatal morbidity and mortality. Use of the ultrasonographic technique reviewed in this guideline may help identify women at risk of preterm birth and, in some circumstances, lead to interventions that may reduce the rate of preterm birth.

SPONSORS

The Society of Obstetricians and Gynaecologists of Canada.

Methodology in conducting a systematic review of systematic reviews of healthcare interventions

BACKGROUND

Hundreds of studies of maternity care interventions have been published, too many for most people involved in providing maternity care to identify and consider when making decisions. It became apparent that systematic reviews of individual studies were required to appraise, summarise and bring together existing studies in a single place. However, decision makers are increasingly faced by a plethora of such reviews and these are likely to be of variable quality and scope, with more than one review of important topics. Systematic reviews (or overviews) of reviews are a logical and appropriate next step, allowing the findings of separate reviews to be compared and contrasted, providing clinical decision makers with the evidence they need.

METHODS

The methods used to identify and appraise published and unpublished reviews systematically, drawing on our experiences and good practice in the conduct and reporting of systematic reviews are described. The process of identifying and appraising all published reviews allows researchers to describe the quality of this evidence base, summarise and compare the review's conclusions and discuss the strength of these conclusions.

RESULTS

Methodological challenges and possible solutions are described within the context of (i) sources, (ii) study selection, (iii) quality assessment (i.e. the extent of searching undertaken for the reviews, description of study selection and inclusion criteria, comparability of included studies, assessment of publication bias and assessment of heterogeneity), (iv) presentation of results, and (v) implications for practice and research.

CONCLUSION

Conducting a systematic review of reviews highlights the usefulness of bringing together a summary of reviews in one place, where there is more than one review on an important topic. The methods described here should help clinicians to review and appraise published reviews systematically, and aid evidence-based clinical decision-making.

The combination of short cervical length and phIGFBP-1 in the prediction of preterm delivery in symptomatic women

OBJECTIVE

To assess the combined use of cervical length and cervical phosphorylated insulin-like growth factor binding protein-1 (phIGFBP-1) in the prediction of preterm delivery in symptomatic women.

METHODS

Cervical length was prospectively measured in 102 consecutive singleton pregnancies with intact membranes and regular contractions at 24-32 weeks, and phIGFBP-1 was assessed in those with a cervix ≤30 mm.

RESULTS

Among women with a cervix >30 mm (n = 42), none delivered <34 weeks or within 7 days. Among women with a cervical length ≤30 mm (n = 60), eight delivered <34 weeks, four of which within 7 days. A positive phIGFBP-1 conferred a significantly increased risk of delivery before 34 weeks in women with a cervix ≤30 mm (likelihood ratio 2.32, 95% confidence interval 1.15-4.67), and a significantly increased risk of delivering within 7 days in the subgroup of women with a cervical length of 20-30 mm (likelihood ratio 3.64, 95% confidence interval 2.20-6.01).

CONCLUSIONS

In symptomatic women with a cervical length >30 mm the risk of preterm delivery is very low. In women with a cervix ≤30 mm, adding phIGFBP-1 assessment may improve the risk assessment for preterm delivery, and help to plan subsequent pregnancy management.

Evidence for activation of Toll-like receptor and receptor for advanced glycation end products in preterm birth

OBJECTIVE

Individuals with inflammation have a myriad of pregnancy aberrations including increasing their preterm birth risk. Toll-like receptors (TLRs) and receptor for advanced glycation end products (RAGE) and their ligands were all found to play a key role in inflammation. In the present study, we reviewed TLR and RAGE expression, their ligands, and signaling in preterm birth.

RESEARCH DESIGN AND METHODS

A systematic search was performed in the electronic databases PubMed and ScienceDirect up to July 2010, combining the keywords "preterm birth," "TLR", "RAGE", "danger signal", "alarmin", "genomewide," "microarray," and "proteomics" with specific expression profiles of genes and proteins.

RESULTS

This paper provides data on TLR and RAGE levels and critical downstream signaling events including NF-kappaB-dependent proinflammatory cytokine expression in preterm birth. About half of the genes and proteins specifically present in preterm birth have the properties of endogenous ligands "alarmin" for receptor activation. The interactions between the TLR-mediated acute inflammation and RAGE-mediated chronic inflammation have clear implications for preterm birth via the TLR and RAGE system, which may be acting collectively.

CONCLUSIONS

TLR and RAGE expression and their ligands, signaling, and functional activation are increased in preterm birth and may contribute to the proinflammatory state.

Practices for predicting and preventing preterm birth in Ireland: a national survey

BACKGROUND

Preterm birth can result in adverse outcomes for the neonate and/or his/her family. The accurate prediction and prevention of preterm birth is paramount. This study describes and critically analyses practices for predicting and preventing preterm birth in Ireland.

METHODS

A questionnaire seeking information on practices for predicting and preventing preterm birth was mailed to all consultant obstetricians practising in Ireland in February 2006.

RESULTS

For predicting preterm birth, 97% of respondents did not use foetal fibronectin testing, 71% carried out routine second and third trimester cervical assessments and 75% routinely screened for genital tract infection. For preventing preterm birth, 62% prescribed bed rest, 24% prescribed antibiotics, 14% routinely inserted a cervical cerclage in women with a history of mid-trimester miscarriage and 61% routinely used tocolytics.

CONCLUSION

The findings of this survey, for the most part, reflect the empirical evidence base, international practices and best practice recommendations.

Factors associated with tocolytic hospitalizations in Taiwan: evidence from a population-based and longitudinal study from 1997 to 2004

BACKGROUND

The use of tocolytic hospitalization in antenatal care is controversial and worthy of more research. We investigated individual, institutional, and area factors that affect the use of tocolytic hospitalizations in Taiwan where fertility has rapidly declined.

METHODS

Longitudinal data from the 1996 to 2004 National Health Insurance Research Database in Taiwan were used to identify tocolytic hospitalizations. The probit model was used to estimate factors associated with tocolytic hospitalizations.

RESULTS

The decline in fertility was significantly associated with the probability of tocolytic hospitalizations. Several physician and institutional factors-including physician's age, hospital ownership, accreditation status, bed size, and teaching status-were also significantly correlated to the dependent variables.

CONCLUSIONS

The provision of inpatient tocolysis is influenced not only by clinical considerations but also by physician, institutional, and area factors unrelated to clinical need. Fertility declines in Taiwan may have led obstetricians/gynecologists to provide more tocolysis to make up for their lost income. If the explanation is further validated, reimbursement policies may need to be reviewed to correct for overuse of inpatient tocolysis. The correlation could also be explained by the increasing use of artificial reproductive technologies and higher social value of newborns. In addition, the physician and institutional variations observed in the study indicate potential misuse of inpatient tocolysis that warrant further investigation.

Systematic review of reviews of risk factors for intracranial aneurysms

Systematic reviews of systematic reviews identify good quality reviews of earlier studies of medical conditions. This article describes a systematic review of systematic reviews performed to investigate factors that might influence the risk of rupture of an intracranial aneurysm. It exemplifies the technique of this type of research and reports the finding of a specific study. The annual incidence of subarachnoid haemorrhage resulting from the rupture of intracranial aneurysms is estimated to be nine per 100,000. A large proportion of people who have this bleed, will die or remain dependent on the care of others for some time. Reliable knowledge about the risks of subarachnoid haemorrhage in different populations will help in planning, screening and prevention strategies and in predicting the prognosis of individual patients. If the necessary data were available in the identified reviews, an estimate for the numerical relationship between a particular characteristic and the risk of subarachnoid haemorrhage was included in this report. The identification of eligible systematic reviews relied mainly on the two major bibliographic databases of the biomedical literature: PubMed and EMBASE. These were searched in 2006, using specially designed search strategies. Approximately 2,000 records were retrieved and each of these was checked carefully against the eligibility criteria for this systematic review. These criteria required that the report be a systematic review of studies assessing the risk of subarachnoid haemorrhage in patients known to have an unruptured intracranial aneurysm or of studies that had investigated the characteristics of people who experienced a subarachnoid haemorrhage without previously being known to have an unruptured aneurysm. Reports which included more than one systematic review were eligible and each of these reviews was potentially eligible. The quality of each systematic review was assessed. In this review, 16 separate reports were identified, including a total of 46 eligible systematic reviews. These brought together research studies for 24 different risk factors. This has shown that the following factors appear to be associated with a higher risk of subarachnoid haemorrhage: being a woman, older age, posterior circulation aneurysms, larger aneurysms, previous symptoms, "non-white" ethnicity, hypertension, low body mass index, smoking and alcohol consumption of more than 150 g per week. The following factors appear to be associated with a lower risk of subarachnoid haemorrhage: high cholesterol, diabetes and use of hormone replacement therapy.