Cervicovaginal Fetal Fibronectin Research Articles

Cervicovaginal fetal fibronectin levels in women with preeclampsia

OBJECTIVE:To estimate the mean levels of fetal fibronectin in cervicovaginal secretions of women with preeclampsia and compare them with levels in normotensive controls.METHODS:Cervicovaginal swabs were obtained before digital examination from women who presented to labor and delivery for evaluation of preeclampsia and compared with fetal fibronectin levels from a group of control subjects with a similar gestational age. Fetal fibronectin was assayed by a specific enzyme-linked immunoassay. A concentration greater than 50 ng/mL was considered a positive result.RESULTS:Forty women with preeclampsia (17 mild and 23 severe) and 31 normotensive women were analyzed. The control group had 9.7% positive fetal fibronectins, whereas the preeclampsia group had 15% positive, P = .72, with 80% power to detect a 22% difference. The majority of the quantitative values in both groups were less than 20 ng/mL. There was not a significant difference between the two groups in quantitative cervicovaginal fetal fibronectin, P = .72, nor was there a difference between the women with severe preeclampsia and the controls, P = 1.0, or between the nulliparous women with preeclampsia versus the nulliparous controls, P = .3.CONCLUSION:Fetal fibronectin is not elevated in cervicovaginal secretions of women with preeclampsia.

Cervicovaginal Fetal Fibronectin Levels in Women With Preeclampsia

Cervicovaginal Fetal Fibronectin Levels in Women With Preeclampsia

Interleukins & Fetal Fibronectin Levels In Preterm Delivery

Although the prevention of preterm birth remains the most important challenge in obstetrics, the mechanism for the onset of preterm labor has not been fully explained. The purpose of the present study is to investigate the usefulness of cervicovaginal fetal fibronectin and certain cytokines (interleukin-1B and interleukin-8) levels during pregnancy as markers of preterm and term delivery. This study was performed on 130 pregnant women at 24 to 29 years old age. The women were classified into group I (women not in labor, n=65) and group II (women with spontaneous labor, n=65). Each group was classified into two subgroups [preterm delivery ( 37 weeks gestation, n=25)]. We obtained cervicovaginal swabs for fetal fibronectin and cervicovaginal fluids for cytokines determination. The present study revealed that fetal fibronectin, IL- lB and IL-8 levels were significantly higher in patients in preterm labor than in patients at preterm not in labor. They were significantly higher in women at full term in labor than in women at full term not in labor. Interleukin- lB and IL-8 obtained from women not in labor increased exponentially as gestational age increased, and the cytokines levels were significantly correlated. This study revealed that cervicovaginal measurement of fetal fibronectin, IL-lB and IL-8 in combination with clinical findings may be useful for the evaluation of patients with threatened premature delivery.

The Preterm Prediction Study: Association between cervical interleukin 6 concentration and spontaneous preterm birth

Objective: The aim of this study was to determine the interrelationship between cervical concentration of interleukin 6 and detection of fetal fibronectin and other risk factors for spontaneous preterm birth. Study Design: All patients with spontaneous preterm birth at <35 weeks’ gestation (case patients; n = 125) and subjects matched for race, parity, and center delivered at ≥37 weeks’ gestation (n = 125; control subjects) were selected from women enrolled in the National Institute of Child Health and Human Development’s Preterm Prediction Study. Interleukin 6 concentrations were determined by enzyme-linked immunosorbent assay in cervical swabs obtained at 22 weeks’ to 24 weeks 6 days’ gestation. Cutoffs to define an elevated interleukin 6 concentration included the 90th and 95th percentiles for control subjects (>305 and >538 pg/mL, respectively). Results: The mean (±SD) interleukin 6 concentration was significantly higher in case patients than in control subjects (212 ± 339 vs 111 ± 186 pg/mL; P =.008). With either cutoff value elevated interleukin 6 concentration was significantly associated with spontaneous preterm birth (90th percentile, 20% vs 9.6%; P =.02; 95th percentile, 12% vs 4.8%; P =.04). Cervical interleukin 6 levels were highest within 4 weeks of delivery, and the trend continued until term. Elevated interleukin 6 concentration was not significantly associated with bacterial vaginosis, maternal body mass index <19.8 kg/m2, or a short cervix (≤25 mm), but it was significantly associated with a positive cervicovaginal fetal fibronectin test result (90th percentile, odds ratio, 5.5; 95% confidence interval, 2.6-11.9; 95th percentile, odds ratio, 5.3, 95% confidence interval, 2.1-12.9). The mean interleukin 6 concentration among women with a positive fibronectin test result was 373 ± 406 pg/mL; that among women with a negative fetal fibronectin test result was 130 ± 239 pg/mL (P =.001). In a regression analysis that adjusted for risk factors significantly associated with spontaneous preterm birth in this population (positive fetal fibronectin test result, body mass index <19.8 kg/m2, vaginal bleeding in the first or second trimester, previous spontaneous preterm birth, and short cervix) elevated cervical interleukin 6 concentration was not independently associated with spontaneous preterm birth (odds ratio, 1.8; 95% confidence interval, 0.8-4.3). Conclusions: At 24 weeks’ gestation cervical interleukin 6 concentration in women who subsequently had a spontaneous preterm birth at <35 weeks’ gestation was significantly elevated relative to those who were delivered at term. The association was particularly strong within 4 weeks of testing. A positive fetal fibronectin test result was strongly associated with elevated cervical interleukin 6 concentration, but bacterial vaginosis was not. (Am J Obstet Gynecol 2001;184:483-8.)

The Preterm Prediction Study: Quantitative fetal fibronectin values and the prediction of spontaneous preterm birth

Objective: A cervicovaginal fetal fibronectin value of ≥50 ng/mL has been used to define women at risk of having a preterm birth. We evaluated the relationship between quantitative fetal fibronectin values and spontaneous preterm birth. Study Design: Cervical and vaginal specimens for fetal fibronectin were obtained at 24, 26, 28, and 30 weeks’ gestation from 2926 women. Quantitative fetal fibronectin values were calculated by using absorbances determined by enzyme-linked immunosorbent assay. The highest fetal fibronectin value (cervical or vaginal) for each woman at each visit was evaluated in relation to spontaneous preterm birth at <35 weeks’ gestation. Receiver operating characteristic curves were constructed to determine the optimal cutoff point for fetal fibronectin values to predict spontaneous preterm birth at <35 weeks’ gestation and within 4 weeks of testing. Results: The risk of spontaneous preterm birth increased as a function of increasing fetal fibronectin values from approximately 20 to 300 ng/mL. Fetal fibronectin values ≥300 ng/mL were not associated with a further increase in spontaneous preterm birth. Examination of the receiver operating characteristic curve indicates that the optimal cutoff point for a positive fetal fibronectin test result at 24 to 30 weeks’ gestation to predict spontaneous preterm birth at <35 weeks is between 45 and 60 ng/mL. Conclusion: Increasing levels of cervicovaginal fetal fibronectin up to 300 ng/mL are associated with an increasing risk of spontaneous preterm birth. Nevertheless, at 24 to 30 weeks, the value currently used, 50 ng of fetal fibronectin per milliliter, appears to be a reasonable cutoff point for predicting spontaneous preterm birth at <35 weeks’ gestation. (Am J Obstet Gynecol 2000;183:1480-3.)

The Preterm Prediction Study: Prediction of preterm premature rupture of membranes through clinical findings and ancillary testing

Objective: Our objective was to determine the relative importance of demographic characteristics, clinical risk factors, and ancillary screening tests in the prediction of preterm birth as a result of premature rupture of membranes. Study Design: A total of 2929 women were evaluated in 10 centers at 23 to 24 weeks’ gestation. Demographic and clinical characteristics were ascertained. Cervicovaginal fetal fibronectin and bacterial vaginosis were evaluated. Cervical length was measured by vaginal ultrasonography. Patients were evaluated for spontaneous preterm birth caused by preterm premature rupture of membranes at <37 and <35 weeks’ gestation. Multivariate analyses were performed separately for nulliparous women and multiparous women. Results: Premature rupture of membranes at <37 weeks’ gestation complicated 4.5% of pregnancies, accounting for 32.6% of preterm births. Univariate analysis revealed low body mass index, pulmonary disease, contractions within 2 weeks, short cervix (≤25 mm), positive results of fetal fibronectin screening, bacterial vaginosis, and a previous preterm birth caused by premature rupture of membranes (in multiparous women) to be significantly associated with preterm birth caused by premature rupture of membranes in the current gestation. Short cervix, previous preterm birth caused by premature rupture of membranes in multiparous women, and presence of fetal fibronectin were the strongest predictors for both preterm birth caused by premature rupture of membranes at <37 and <35 weeks’ gestation. Women with positive fetal fibronectin screening results and a short cervix had greater risks both of preterm birth caused by premature rupture of membranes at <37 weeks’ gestation (relative risk, 4.9) and of preterm birth caused by premature rupture of membranes at <35 weeks’ gestation (relative risk, 13.5) than did those without these risk factors. Multiparous women with all three risk factors had a 31.3-fold increased risk of preterm birth caused by premature rupture of membranes at <35 weeks’ gestation. Conclusion: The combination of short cervical length, previous preterm birth caused by preterm premature rupture of membranes, and positive fetal fibronectin screening results was highly associated with preterm delivery caused by preterm premature rupture of membranes in the current gestation. (Am J Obstet Gynecol 2000;183:738-45.)

Prostaglandin endoperoxide H synthase mRNA expression in the fetal membranes correlates with fetal fibronectin concentration in the cervico-vaginal fluids at term: evidence of enzyme induction before the onset of labour.

To determine the relationship of prostaglandin endoperoxide H synthase (PGHS) expression in the gestational tissues and fetal fibronectin in cervico-vaginal fluids before the onset of labour at term. Cross-sectional, observational study. Amnion, chorion laeve and decidua were collected from 24 term pregnant women following elective caesarean section. Samples of cervico-vaginal secretions were obtained from the same women immediately before caesarean section. PGHS-1 and PGHS-2 mRNA levels in tissues were determined by specific ribonuclease protection assays. Fetal fibronectin concentrations in the cervico-vaginal fluids were measured by enzyme-linked immunosorbent assay. The abundance of PGHS mRNA was compared between groups of patients with the same mean gestational age but different cervico-vaginal fetal fibronectin levels. Linear regression analysis was used to determine the association between PGHS levels and fetal fibronectin. Two groups of women were identified who had significantly different fetal fibronectin values but the same gestational ages. The group with the higher fetal fibronectin concentrations had significantly higher PGHS- 1 and PGHS-2 mRNA levels in the chorion laeve and higher PGHS-2 mRNA levels in the amnion, than the group with lower fetal fibronectin concentrations. PGHS- 1 and PGHS-2 mRNA levels in the chorion laeve and PGHS-2 mRNA in the amnion showed an overall significant association with fetal fibronectin levels. High concentrations of fetal fibronectin in cervico-vaginal secretions before the onset of spontaneous labour at term are associated with high levels of PGHS-2 mRNA in the chorion laeve and the amnion and of PGHS- 1 mRNA in the chorion laeve. Increased expression of PGHS in these tissues may therefore be involved in the events leading to term birth.

Fetal fibronectin as a predictor of term labor: A literature review

Accurately predicting the onset of delivery continues to be problematic notwithstanding the clinical relevance of this capability, especially with regard to the elective induction of labor. While the assessment of the cervix according to Bishop, to date, constitutes the single generally recognized method, the determination of fetal fibronectin (FFN) cervicovaginal secretions promises greater precision in this context.English-language medical literature was analyzed using the search parameter 'fetal fibronectin', 'term delivery', 'induction of labor', 'labor', and 'birth', respectively. All those original reports examining cervicovaginal FFN that were originally published in English and followed a prospective design were subsequently included in the study at hand. These reports were evaluated in regard to their findings on the predictive value of FFN for spontaneous delivery and induction of labor.A total of eight reports were included in the present study: five of these, covering a total of 480 patients, discussed the relationship between FFN and the spontaneous onset of labor; the other three addressed the subject of FFN and the induction of labor (300 patients). All reports clearly related the presence of FFN in cervicovaginal secretions to the imminent onset of delivery; three studies, furthermore, demonstrated a correlation with the spontaneous onset of labor, with a sensitivity greater than 90%. In case of the studies concerning induction of labor, a positive FFN result was accompanied by a significantly shorter interval until delivery than a negative FFN result.Determining the presence of FFN in cervicovaginal secretions promises to provide an indicator relating to the prediction of term labor, as well as to the prediction of successful labor induction.

Fetal fibronectin as a predictor of term labor:

Accurately predicting the onset of delivery continues to be problematic notwithstanding the clinical relevance of this capability, especially with regard to the elective induction of labor. While the assessment of the cervix according to Bishop, to date, constitutes the single generally recognized method, the determination of fetal fibronectin (FFN) cervicovaginal secretions promises greater precision in this context. English-language medical literature was analyzed using the search parameter 'fetal fibronectin', 'term delivery', 'induction of labor', 'labor', and 'birth', respectively. All those original reports examining cervicovaginal FFN that were originally published in English and followed a prospective design were subsequently included in the study at hand. These reports were evaluated in regard to their findings on the predictive value of FFN for spontaneous delivery and induction of labor. A total of eight reports were included in the present study: five of these, covering a total of 480 patients, discussed the relationship between FFN and the spontaneous onset of labor; the other three addressed the subject of FFN and the induction of labor (300 patients). All reports clearly related the presence of FFN in cervicovaginal secretions to the imminent onset of delivery; three studies, furthermore, demonstrated a correlation with the spontaneous onset of labor, with a sensitivity greater than 90%. In case of the studies concerning induction of labor, a positive FFN result was accompanied by a significantly shorter interval until delivery than a negative FFN result. Determining the presence of FFN in cervicovaginal secretions promises to provide an indicator relating to the prediction of term labor, as well as to the prediction of successful labor induction.

Diagnostic value of cervical fetal fibronectin in detecting extrauterine pregnancy

Objective: To determine whether fetal fibronectin (FFN) might serve as a marker to distinguish intrauterine versus extrauterine pregnancy.Design: Prospective cohort study.Setting: Academic research center.Patient(s): Cervicovaginal FFN samples were obtained from 46 women who were at high risk for or presented with signs and/or symptoms of extrauterine pregnancy.Intervention(s): Samples of blood were analyzed for FFN with use of an enzyme-linked immunoabsorbent assay (ELISA).Main Outcome Measure(s): Fetal fibronectin level.Result(s): The rate of extrauterine pregnancy in our study was 26.1%, with 12 extrauterine and 34 intrauterine pregnancies identified by ultrasonography or at time of surgery. Seventeen samples had FFN levels of >50 ng/mL and were considered positive (range, 0–1,000 ng/mL). Positive FFN levels were observed in 41.7% (5 of 12) of women with extrauterine pregnancies versus 35.3%) (12 of 34) of women with intrauterine pregnancies. The sensitivity, specificity, and positive and negative predictive values for extrauterine pregnancy were 41.7%, 64.7%, 29.4%, and 75.9%, respectively.Conclusion(s): The use of FFN does not appear to alter significantly the likelihood of identifying extrauterine pregnancy over current laboratory or ultrasonographic methods.

Misleading authors’ inferences in obstetric diagnostic test literature

Objective: Our goal was to determine the validity of authors’ inferences about the value of the cervico-vaginal fetal fibronectin test in the prediction of preterm birth and the utility of uterine artery Doppler waveform analysis in the prediction of preeclampsia. Study Design: We evaluated all 35 diagnostic test studies (14 on fetal fibronectin and 21 on uterine artery Doppler) included in 2 meta-analyses. The information on authors’ conclusions regarding the value of a positive or negative test result was independently abstracted from each article by 2 reviewers, and it was classified as definitely useful, moderately useful, slightly useful, or not at all useful. For the “gold” standard, likelihood ratios of >10 and <0.1 were regarded as definitely useful, 5 to 10 and 0.1 to 0.2 were regarded as moderately useful, 2 to 5 and 0.2 to 0.5 were regarded as slightly useful, and 1 to 2 and 0.5 to 1 were regarded as not at all useful. The agreement between the authors and the reference standard was computed by simple percentage agreement and weighted κ statistic. Results: Among articles assessing the diagnostic value of fetal fibronectin the simple agreement between the authors and the “gold” standard was 26% (7/26) with a κ of 0.05 ( P = .83), and authors overestimated the value of the test result in 66% (17/26) of instances. Similarly, among articles assessing uterine artery Doppler the simple agreement between the authors and the “gold” standard was 31% (13/42) with a κ of 0.28 ( P = .31), and authors overestimated the value of the test result in 48% (20/42) of instances. Conclusion: Authors claimed more positive conclusions than could be supported by their data. When studies are reported in a misleading manner, the chance of misinterpretation on the part of the clinical reader is increased. The use of explicit criteria that are based on likelihood ratios may reduce the risk of erroneous inferences. (Am J Obstet Gynecol 1999;181:112-5.)

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

Objective: We performed a meta-analysis to determine the value of cervicovaginal fetal fibronectin as a marker for preterm delivery. Study Design: Selection criteria confined the analysis to original, English-language reports of prospective studies including women at <37 weeks’ gestation with intact amniotic membranes. For the outcomes of delivery at <37 or <34 weeks’ gestation or delivery within 7, 14, 21, or 28 days after fibronectin sampling, we calculated sensitivity and specificity rates for each study, for subgroups of studies, and for all studies combined. Results: A total of 27 studies met our inclusion criteria. For the outcomes of delivery at <37 and <34 weeks’ gestation, overall sensitivity rates were 56% and 61% and overall specificity rates were 84% and 83%, respectively. For the outcomes of delivery within 7, 14, 21, and 28 days, we calculated sensitivity rates of 76%, 68%, 61%, and 43% and specificity rates of 88%, 89%, 91%, and 93%, respectively. For the subgroup of patients with symptoms of preterm labor, sensitivity rates for delivery within 7, 14, 21, and 28 days of 89%, 78%, 76%, and 71% and specificity rates of 86%, 86%, 88%, and 83%, respectively, were calculated. Conclusion: Among patients with symptoms of preterm labor, cervicovaginal fetal fibronectin appears to be among the most effective predictors of preterm delivery. (Am J Obstet Gynecol 1999;180:1169-76.)

Cervicovaginal fetal fibronectin testing in threatened preterm labour--translating research findings into clinical practice.

A retrospective audit was undertaken involving 70 women with a singleton pregnancy who attended hospital with symptoms of threatened preterm labour prior to 34 weeks' gestation and who had a bedside fetal fibronectin (FFN) Membrane Immunoassay Kit Test (Adeza Biomedical) performed. The aim of the study was to determine if the results of the FFN test when used in routine clinical practice would be similar to those of a previous research study (1) that was performed at the same centre, and whether or not knowledge of the result of the FFN test might influence clinical management. The audit revealed that the sensitivity of the FFN test in the prediction of delivery prior to 34 weeks' gestation was 90%, the specificity was 82%, whilst the positive and negative predictive values were 45% and 98% respectively. These results were very similar to those of the previous, blinded research study. Compared to women with a negative FFN test, more women with a positive FFN test received corticosteroids (100% versus 71%, p=0.02) and tocolysis (35% versus 12%, p=0.04) and more remained in hospital longer than 24 hours (85% versus 56%, p=0.1).

Cervicovaginal fetal fibronectin concentrations: predictive value of impending birth in postterm pregnancies

Objective: To determine the predictive value of cervicovaginal fetal fibronectin (fFN) concentrations ≥50 ng/ml for spontaneous onset of labour within 3 days in pregnancies of 41 weeks gestation or more. Study design: In the Department of Obstetrics, Leiden University Medical Centre, and of the Diaconessen Hospital, Voorburg (The Netherlands), 126 cervicovaginal secretions of fFN, from 80 consenting women between 287 and 304 days gestation were collected. Pregnant women underwent sterile speculum examinations for cervicovaginal sampling from the 41st week onwards. The fFN concentration in these samples was determined with a quantitative solid-phase enzyme-linked immunosorbent assay. Concentrations of <50 ng fFN per ml were characterised as negative test results, meaning that spontaneous delivery would not take place within 3 days, and those of ≥50 fFN ng/ml were taken as positive test results. Sensitivity and specificity of the fFN test were calculated for predicting spontaneous birth. Parametric and nonparametric tests were used for evaluating differences and correlations. Results: Spontaneous delivery took place after 2.5±2.5(SD) days with fFN values ≥50 ng/ml and after 4.7±3.6 days with fFN concentrations <50 ng/ml ( P<0.001). Sensitivity and specificity of the fFN test predicting spontaneous onset of labour within 3 days, were 0.71 [95% confidence interval (CI) 0.58–0.86] and 0.64 (95% CI 0.48–0.78). If fFN ≥50 ng/ml then a spontaneous onset of labour is more likely to occur within 3 days (odds ratio 4.5 (95% CI 1.8–11.3). Conclusions: The fFN test does not predict accurately enough whether or not birth will take place within 3 days of sampling. Nevertheless, the higher odds for spontaneous delivery within a few days when the test is positive may be of use in planning adjusted induction of labour.

PREDICTION OF PRETERM DELIVERY BY FETAL FIBRONECTIN

Objective To assess the cervicovaginal fetal fibronectin test to predict preterm delivery. Data Sources We searched MEDLINE, Current Contents, Index Medicus, and proceedings of meetings for studies published between 1991 and June 1997. Methods of Study Selection Inclusion criteria were prospective cohort study; test performed between 20 and 36 weeks' gestation; fetal fibronectin measured by a previously described assay, with a cutoff level set at 50 ng/mL; test results not disclosed to women or physicians; and fewer than 20% of study participants excluded from the analysis. Tabulation, Integration, and Results Twenty-nine relevant studies were stratified according to the prevalence of pre-term delivery, the number of tests performed, and delivery before 34, 35, or 37 weeks. Sensitivities, specificities, and likelihood ratios were calculated in each study. The sum-mary estimates of the likelihood ratio for tests yielding positive results or tests yielding negative results along with their 95% confidence intervals (CIs) were computed in each stratum according to a random-effects model. All summary likelihood ratios for a test yielding positive results indicated a significant association with preterm delivery. The strongest association was found between a single test with positive results and delivery before 37 weeks in a low-risk population (likelihood ratio 7.5; 95% CI 4.6, 12.3). This association also was found in high-risk women (likelihood ratio 3.5; 95% CI 2.6, 4.6). In high-risk women, a test yielding negative results was associated with a reduction in risk of preterm delivery (likelihood ratio 0.4; 95% CI 0.3, 0.5). Conclusion Fetal fibronectin in cervicovaginal secretions is associated with preterm delivery in both high-risk and low-risk women.

The Diagnostic Accuracy of Cervico-Vaginal Fetal Fibronectin in Predicting Preterm Delivery

Chien, Patrick F. W.; Khan, Khalid S.; Ogston, Simon; Owen, Philip Author Information

The preterm prediction study: Patterns of cervicovaginal fetal fibronectin as predictors of spontaneous preterm delivery

OBJECTIVE: Our purpose was to determine how various temporal patterns of fetal fibronectin positivity from 24 to 30 weeks predict subsequent fetal fibronectin test results and spontaneous preterm delivery. STUDY DESIGN: A total of 2929 women had vaginal and cervical fetal fibronectin tests obtained at least once at 24, 26, 28, or 30 weeks, and 1870 women had tests performed at all four gestational ages. Fetal fibronectin values ≥50 ng/ml were considered positive. Various patterns of positive and negative tests were evaluated for prediction of (1) whether the next fetal fibronectin test would be positive or negative and (2) the percent of women with a spontaneous preterm delivery ≥4 weeks after the last fetal fibronectin test at <30, <32, <35, and <37 weeks' gestational age. RESULTS: Women with previous negative test results had only a 3% chance of a subsequent positive test result; however, if the last test result was positive, 29% of the next tests were positive. Of the 1870 women with tests at 24, 26, 28, and 30 weeks, 89% had all negative results, 8.4% had one positive result, 1.8% had two positive results, and 0.8% had three or four positive results. The higher the percent of positive tests at 24 to 26 weeks, at 28 to 30 weeks, or at 24 to 30 weeks, the greater the risk of subsequent spontaneous preterm birth. As an example, the risk of spontaneous preterm birth at <30 weeks for women with two negative fetal fibronectin test results at 24 and 26 weeks was 0.3% versus 16% for women with two positive results. CONCLUSION: The presence of a positive cervical or vaginal fetal fibronectin test result predicts subsequent positive fetal fibronectin positivity and subsequent spontaneous preterm birth. The greater the percent of positive results, the higher is the risk of spontaneous preterm birth. After a positive test result, two negative results are required before the risk of spontaneous preterm birth returns to baseline.(Am J Obstet Gynecol 1997;177:8-12.)

Rapid fetal fibronectin swab-test in preterm labor patients treated by betamimetics

Objective: A preliminary study to examine the value of a rapid fetal fibronectin swab-test used as a bedside test in the prognosis of preterm labor. Study design: Women presenting with preterm labor and intact membranes and less than 3 cm dilated were enrolled in a single referal center. Cervicovaginal swabs were assessed for the presence or absence of fetal fibronectin by means of a rapid monoclonal antibody assay the positivity of which was revealed by a colorimetric reaction. Results were compared with uterine contractions frequency, Bishop cervical score, duration of tocolysis and interval to delivery. The predictive value of fetal fibronectin test for delivery within 7, 14 or 21 days from sampling and before 32 and 37 weeks' of gestation was assessed in the two groups. Results: Among 124 eligible patients, 19 presented with a positive fibronectin test and 105 with a negative one. Gestational age at sampling. Bishop cervical score and duration of tocolysis were identical in the two groups. The number of contractions was significantly lower and gestational age at delivery was significantly higher in the fibronectin negative group. Fetal fibronectin in cervicovaginal secretions has a high sensitivity (89%) for delivery within 7 days. Absence of fetal fibronectin in cervicovaginal secretions of patients presenting with uterine contractions could rule out preterm labor within 7 and 14 days with a predictive value of 99 and 95.2%, respectively. In negative fetal fibronectin patients, preterm delivery before 32 and 37 weeks' is unlikely to occur with a predictive value of 97 and 85%, respectively. Conclusion: Cervicovaginal fetal fibronectin detected by a rapid bedside swab-test in women with symptoms of preterm labor compares favourably with quantitative assays and could prove useful in the management of preterm labor. This should be confirmed in a longer prospective study.

The diagnostic accuracy of cervico-vaginal fetal fibronectin in predicting preterm delivery: an overview.

To determine the accuracy with which cervico-vaginal fetal fibronectin predicts preterm delivery using systematic quantitative overview of the available literature. Online searching of MEDLINE database (1966 to April 1996), scanning of bibliography of known primary and review articles and review of recent journal issues. Study selection, assessment of study quality and data extraction were performed in duplicate under masked conditions. Likelihood ratios were generated in subgroups of symptomatic and asymptomatic pregnant women by pooling data from different studies. An LR of > 10 or < 0.1 indicated conclusive changes in the pretest probability of preterm delivery while an LR of 5-10 or 0.2-0.1 indicated only moderate changes. Seven hundred and twenty-three symptomatic women with threatened preterm labour included in nine studies and 847 asymptomatic women (635 low risk and 212 high risk) included in six studies selected for meta-analyses. Likelihood ratios for positive and negative test results using delivery at < 37 and < 34 weeks of gestation, and within one week of testing as outcome measures. In symptomatic women a positive test predicted delivery < 37 weeks of gestation with a pooled likelihood ratio (LR) of 4.6 (95% CI 3.5-6.1) while a negative test had a pooled LR of 0.5 (95% CI 0.4-0.6). For delivery < 34 weeks of gestation, the pooled LR was 2.6 (95% CI 1.8-3.7) for a positive test and 0.2 (95% CI 0.1-0.5) for a negative test. For delivery within one week of testing, the pooled LR was 5.0 (95% CI 3.8-6.4) for a positive test and 0.2 (95% CI 0.1-0.4) for a negative test. In asymptomatic women at low risk of delivery < 37 weeks of gestation the pooled LR was 3.2 (95% CI 2.2-4.8) for a positive test and 0.8 (95% CI 0.7-0.9) for a negative test. In high risk asymptomatic women using delivery < 37 weeks of gestation as an outcome measure the pooled LR was 2.0 (95% CI 1.5-2.6) for a positive test and 0.4 (95% CI 0.2-0.8) for a negative test. For delivery < 34 weeks of gestation in high risk, asymptomatic women the pooled LR was 2.4 (95% CI 1.8-3.2) for a positive test and 0.6 (95% CI 0.4-0.9) for a negative test. The presence of fetal fibronectin in cervico-vaginal mucus has limited accuracy in predicting preterm delivery as the likelihood ratios for positive and negative test results generated only minimal to moderate changes in the pretest probability of preterm birth.

Review Article: Cervico-vaginal fetal fibronectin: Predictive value during false labor

Objective. The purpose was to determine to what extent fetal fibronectin was a discriminative tesl of preterm delivery in patients hospitalized for uterine contractions without modification of I he cervix. Study design. The prospective double-blind study included patients hospitalized between 24 and 34 weeks for false labor. Cervicovaginal swabs were obtained and assayed for the presence of fetal fibronectin by means of a monoclonal antibody assay. Results. Out of the 61 patients included, 18 showed a positive swab. The correlation of a positive result with preterm delivery revealed a sensitivity of 56%, a specificity of 81%, and positive and negative predictive values of 56% and 81% respectively. Meta-analysis of studies published shows that the presence of fibronectin represents a significant relative risk of 3.3 (IC: 2.5–42) of preterm delivery. Conclusion. The presence of fetal fibronectin in cervicovaginal secretions of patients presenting with false labor indicates a major risk of preterm delivery.