Ultrasonographic Measurement Of Cervical Length Research Articles

Screening to prevent spontaneous preterm birth: systematic reviews of accuracy and effectiveness literature with economic modelling

Screening to prevent spontaneous preterm birth: systematic reviews of accuracy and effectiveness literature with economic modelling

Cervical length measurement and cervical phosphorylated insulin‐like growth factor binding protein‐1 testing in prediction of preterm birth in patients reporting uterine contractions

To evaluate the performance of cervical phosphorylated insulin-like growth factor binding protein-1 (phIGFBP-1) testing and cervical length measurement separately and in combination with physician's clinical judgment in prediction of preterm birth among patients with self-reported uterine contractions and intact membranes. We enrolled a total of 246 women between 22 and 34 weeks of gestation. The initial evaluation included cervical length measurement using transvaginal ultrasonography. Short cervix was defined as <25 mm. A swab sample was obtained from the cervix for phIGFBP-1. Admission was used as a clinical marker of an increased risk of preterm delivery <or=34 weeks. The diagnostic performances of the tests and clinician's judgment, as well as likelihood ratios (LRs) were calculated. Delivery <or=34 weeks and within 14 days. The overall rate of spontaneous preterm delivery <or=34 weeks was 4.1% (10/246). Short cervix, positive phIGFBP-1 test, combination of both, and clinician's judgment were all associated with preterm delivery <or=34 weeks or within 14 days (p<0.01). The negative predictive values for delivery <or=34 weeks were 97.4, 97.6, 97.1, and 98.7%, respectively, and within 14 days 98.7, 99.0, 98.3, and 99.6%, respectively. The corresponding positive LRs for delivery <or=34 weeks were 6.8, 3.8, 75.0, 14.9, and within 14 days 9.7, 5.5, 107.3, 17.1. The negative LRs were 0.6, 0.6, 0.7, 0.3 and 0.5, 0.3, 0.6, 0.2. The rapid phIGFBP-1-test has a high negative predictive value for preterm delivery, comparable to that of ultrasonographic cervical length measurement.

The secret cervix

Recently receiving much interest in the field of obstetric ultrasound are the assessment of its accuracy to predict spontaneous onset of labor at term, the success rate of induction of labor and the risk of Cesarean section after onset of spontaneous or induced labor. Two main factors drive current research. (i) Although the Bishop score1 remains the standard method for predicting the duration and safety of induced labor, digital cervical examination is subjective2 and the Bishop score may be of limited value in women with a low score3, 4. Ultrasound assessment of the cervix is more objective and reproducible5. (ii) The ultrasonographic measurement of cervical length is predictive of delivery before 37 weeks of gestation, the risk of spontaneous preterm delivery increasing as the ultrasonographic length of the cervix decreases6-8. Numerous studies, therefore, have compared ultrasonographic measurement of cervical length with digital cervical examination in the prediction of the time interval to delivery and the incidence of vaginal delivery in patients undergoing induction of labor9-20. Their results, however, are contradictory, probably because of the numerous weaknesses and/or differences in their methodologies (e.g. heterogeneous populations, including variable proportions of patients with an unripe cervix, absence of standardization of the method of induction (amniotomy and/or oxytocin and/or different prostaglandins), lack of power, secondary exclusion of patients) and the multiple and different endpoints used to evaluate success or failure of induction (e.g. total Cesarean section rate or vaginal delivery rate, duration of latent phase or total duration of labor, vaginal delivery within 24 h of induction, rate of active labor within 12 h, Cesarean section rate before dilatation reaches 8 cm). The different parameters used to assess the cervix both clinically (Bishop score or one of its components) and ultrasonographically (cervical length, dilatation, presence of wedging or funneling, cervical angle) also contribute to the differing results. Recently, Hatfield et al.21 reviewed the literature and performed a meta-analysis, evaluating sonographic cervical assessment to predict successful induction of labor; they concluded that it is not an effective predictor of successful labor induction and that it cannot predict any specific outcome (such as mode of delivery). However, studies investigating the usefulness of sonographic assessment of cervical length in the prediction of spontaneous onset of labor in low-risk women enrolled at 37 or more weeks of gestation consistently report more encouraging results. Seven studies22-28, including a total of 2308 patients, found cervical length measurement to be a significant predictor of the likelihood of the onset of spontaneous labor and/or of delivery within 7 days and/or delivery by 41 weeks. Overall, therefore, the published data show that ultrasonographic measurement of cervical length is a useful tool to predict imminent spontaneous delivery in preterm and term births, but that it is ineffective in predicting the success or failure of induction of labor. These apparently discordant results are in fact convergent: while cervical length is not a marker of cervical ripening, it may well be a marker of myometrial ripeness. The processes of cervical ripening and of uterine activity are independent29. Cervical and myometrial ripeness are often correlated, but this is not necessarily always the case; thus, it is possible that myometrial ripeness may sometimes precede cervical ripening and, conversely, that uterine activity is not coordinated with physiological preparedness for labor. We have shown previously22 that ultrasound measurement of cervical length between 39 + 4 weeks and 40 + 3 weeks of gestation is predictive of the onset of spontaneous labor within 7 days, while fetal fibronectin (fFN) assay is useful in predicting the risk of Cesarean section. We hypothesized that ultrasound examination of the cervix and fFN assay addressed two different physiological processes involved in parturition. In predicting the time to the onset of spontaneous labor, cervical length may be a marker of myometrial ripeness, whereas fFN is a confirmed marker of cervical ripening. Furthermore, the absence of preliminary myometrial ripeness among patients requiring prostaglandins for induction of labor may explain the absence of correlation between cervical length and induced labor duration18. Clearly, other sonographic approaches are necessary to predict the success rate of induction of labor and the risk of Cesarean section after induction. Eggebo et al.30 in this issue of the Journal contribute to this area of research, by evaluating fetal head–perineum distance as a predictive factor for vaginal delivery after induction of labor. Although its predictive value was similar to that of ultrasonographically measured cervical length and Bishop score, the main strength of this study is to open our minds towards the investigation of new approaches to better predict the outcome of induction of labor when the cervix is unripe. As unsatisfying as it may be, we must concede that the cervix has secrets as yet undiscovered by ultrasound.

Transvaginal ultrasonographic measurement of cervical length in predicting intra-amniotic infection and impending preterm delivery in preterm labor: a comparison with amniotic fluid white blood cell count

To determine whether sonographic measurement of cervical length predicts intra-amniotic infection and impending preterm delivery (within 7 days of amniocentesis) in women with preterm labor and intact membranes, and to compare the predictability with that of amniotic fluid (AF) white blood cell (WBC) count. Transvaginal ultrasonographic assessment of cervical length was performed immediately after amniocentesis in 67 consecutive women with preterm labor. AF obtained by amniocentesis was cultured for aerobic and anaerobic bacteria and for Mycoplasmas, and WBC count was determined. Patients with a positive AF culture had a significantly shorter median cervical length, higher median AF WBC count, and lower median gestational age at delivery than did those with a negative AF culture. Multivariate analysis indicated that only the AF WBC count bears a significant relationship with the presence of intra-amniotic infection, whereas only cervical length correlates with impending preterm delivery. Transvaginal sonographic measurements of cervical length are a valuable method for predicting intra-amniotic infection as well as impending preterm delivery in women with preterm labor. However, in comparison with AF WBC, cervical length is less predictive for intra-amniotic infection, whereas cervical length demonstrates better predictability of impending preterm delivery.

P49.11: Prediction of preterm delivery in threatened preterm labor: comparison between ultrasonographic cervical length measurement and digital examination

P49.11: Prediction of preterm delivery in threatened preterm labor: comparison between ultrasonographic cervical length measurement and digital examination

Ultrasonographic measurement of cervical length in predicting mode of delivery after oxytocin induction

This study was conducted to explore the value of transvaginal ultrasonographic cervical length measurement, in addition to gestational age, maternal age, parity, Bishop score, and weight of the newborn, in predicting the mode of delivery in pregnancies in which labor is induced with oxytocin at or beyond the 40th gestational week. A total of 73 pregnancies at 40 to 42 weeks of gestation were included. After labor was induced, 29 women delivered vaginally and 44 underwent cesarean section. These groups were compared with respect to possible predictive parameters of delivery outcomes. Student t test, Pearson's correlation analysis, and logistic regression analysis were used for statistical evaluation. Mean preinduction cervical length was 26.8+/-9.9 mm in the vaginal delivery group and 34.2+/-8.1 mm in the cesarean section group (P<.05). Mean maternal age, parity, and Bishop score were significantly higher and mean weight of the newborn was significantly lower in the vaginal delivery group. Cervical length measurements showed a significant negative correlation with Bishop scores (r=-.584; P<.05). Logistic regression analysis revealed that Bishop score (likelihood ratio=.472; 95% confidence interval=.338-.658; P<.05) and weight of the newborn (likelihood ratio=1.002; 95% confidence interval=1.00007-1.003; P<.05) were significant independent predictors of the route of delivery. According to the results of this study, maternal age, parity, Bishop score, cervical length, and weight of the newborn all might affect the mode of delivery after labor induction. Bishop score, although a subjective measure, must be considered an important component of preinduction evaluation.

Prediction of Preterm Delivery among Women with Threatened Preterm Labor

Background/Aims: To determine predictive values of fetal fibronectin and phosphorylated insulin-like growth factor binding protein-1 (phIGFBP-1) in cervicovaginal secretions and ultrasonographic measurement of cervical length for delivery <35 weeks in patients with uterine contractions. Methods: Our study included 51 women between 24 and 35 weeks’ gestation with uterine contractions and 90 controls. Cervicovaginal samples were analyzed for presence of fetal fibronectin and phIGFBP-1. Cervical length was measured by transvaginal sonography. Results: Preterm birth rate was 19.6% (10/51) in the study group. Negative predictive values of fetal fibronectin, phIGFBP-1 and ultrasonographic cervical length <20 mm, and <25 mm for delivery <35 weeks were 91.9, 92.3, 91.1, and 90.5%, respectively. Positive predictive values were 50, 58.3, 100 and 66.7%, respectively. When results of fetal fibronectin/phIGFBP-1 test and ultrasonographic cervical length <25 mm were combined, specificity and positive predictive values of each test for delivery within 7 days increased. Conclusion: Fetal fibronectin and phIGFBP-1 tests have approximately equivalent ability to predict delivery <35 weeks’ gestation. An ultrasonographic cervical length measurement >20 mm or a negative fetal fibronectin/phIGFBP-1 test obtained from patients with uterine contractions at 24–35 weeks’ gestation may avoid overdiagnosis.

Prediction of Prolonged Pregnancy in Nulliparous Women by Transvaginal Ultrasonographic Measurement of Cervical Length at 20-24 Weeks and 37 Weeks

This study was done to evaluate transvaginal ultrasonographic measurement of cervical length at 20 to 24 weeks and 37 weeks as a predictor of prolonged pregnancy (defined as a pregnancy that extended beyond 41+2 weeks of gestation [289 days]) in nulliparous women. This prospective observational study enrolled 149 consecutive nulliparous women with singleton gestation at 37 weeks. Cervical length was measured by transvaginal ultrasonography at 20 to 24 weeks and 37 weeks. Cervical length at 37 weeks, but not at 20 to 24 weeks, was significantly longer in women delivered at >41+2 weeks than in those delivered at ≤41+2 weeks (p<0.005). There was a significant correlation between cervical length at 37 weeks and gestational age at delivery (Pearson correlation coefficient, r=0.387, p<0.0001). In the receiver operating curve, the best cut-off value of cervical length at 37 weeks for the prediction of prolonged pregnancy was 30 mm, with a sensitivity of 78% and a specificity of 62%. Cervical length assessed by transvaginal ultrasonography at 37 weeks can predict the likelihood of prolonged pregnancy in nulliparous women. However, there is no association between cervical length at 20 to 24 weeks and the occurrence of prolonged pregnancy.

P11.10: Prediction of post‐term pregnancy in nulliparous women by transvaginal ultrasonographic measurement of cervical length at 20 to 24 weeks and 37 weeks

P11.10: Prediction of post‐term pregnancy in nulliparous women by transvaginal ultrasonographic measurement of cervical length at 20 to 24 weeks and 37 weeks

P11.01: Ultrasonographic measurement of cervical length at term in predicting onset of spontaneous labor with intact membranes and premature rupture of membranes

P11.01: Ultrasonographic measurement of cervical length at term in predicting onset of spontaneous labor with intact membranes and premature rupture of membranes

Transvaginal ultrasonographic cervical length measurement as a predictor of successful labor induction

transvaginal ultrasonographic cervical length measurement as a predictor of successful labor induction

Ultrasonographic cervical length measurement at 10–14 and 20–24 weeks gestation and the risk of preterm delivery

Objective To compare cervical length measurements at 10–14 and 20–24 weeks gestation in asymptomatic women with singleton pregnancies and to assess the measurements as a predictor of preterm delivery. Study design In this prospective study, cervical length was measured in 152 asymptomatic women with singleton pregnancies using transvaginal ultrasonography at 10–14 and 20–24 weeks gestation. The primary outcome measure was spontaneous preterm delivery before 35 weeks of gestation. The mean cervical length was calculated at both stages, and lengths were compared between the term and preterm groups. Results The rate of spontaneous preterm deliveries was 10.5%. The mean cervical length at 10–14 and 20–24 weeks was 40.5 and 37.1 mm, respectively. The cervical length at 10–14 weeks was not significantly different between those who delivered at term (40.9 mm) and those who delivered preterm (38.6 mm). By contrast, the cervical length at 20–24 weeks was significantly shorter in the group that had preterm deliveries (28.4 mm) than in those who had term deliveries (37.8 mm) ( P < 0.001). The cervical shortening was more apparent in the group that delivered prematurely (from 38.6 to 28.4 mm) than in that which delivered at term (from 40.9 to 37.8 mm). Conclusion Cervical length measurement used to predict preterm delivery was found to be more predictive at 20–24 weeks. Cervical length measurement at 10–14 weeks was not reliable for predicting preterm delivery. The mean cervical length tapered gradually from the first to the second scan, and the more rapid cervical shortening was found to be associated with increased risk for preterm delivery.

The value of cervical length and plasma proMMP-9 levels for the prediction of preterm delivery in pregnant women presenting with threatened preterm labor

Objective To assess the value of plasma proMMP-9 levels in predicting the progress of threatened preterm labor to true preterm labor and delivery within 7 days of presentation, along with the ultrasonographic measurement of cervical length. Study design The study included sixty two pregnant women presented in the 2nd Department of Obstetrics and Gynecology of University of Athens at Aretaieion Hospital with threatened preterm labor. On subjects’ presentation, cervical length was evaluated with transvaginal ultrasonography, plasma proMMP-9 levels were measured with the use of a solid phase enzyme immunoassay, and maternal characteristics (smoking, history of preterm delivery and parity) as well as the use of tocolytics were recorded. Subjects were followed up for premature delivery within 7 days. ROC analysis for plasma proMMP-9 levels was performed and logistic regression analysis was used for the evaluation of the prognostic effect of the parameters. Results The only significant predictors for establishment of true preterm labor and delivery within 7 days of presentation were cervical length (with cutoff value 15 mm: odds ratio = 0.022, 95% CI = 0.002–0.243, p = 0.002) and plasma proMMP-9 (with cutoff value 67.15 ng/ml: odds ratio = 0.035, 95% CI = 0.003–0.388, p = 0.006). The combination of the adopted proMMP-9 and cervical length cutoff values was characterized by a sensitivity of 90.9% and a specificity of 98.3% for predicting the progress to true preterm labor and delivery. Conclusion Plasma proMMP-9 levels could possibly serve as a predictive factor for the progress of threatened preterm labor to true preterm labor and delivery within 7 days of presentation, along with the ultrasonographic evaluation of cervical length.

P11.10: Ultrasonographic cervical length measurement in the assessment of preterm delivery risk

To determine if cervical shortening between 12 and 28 weeks' gestation predicts risk of spontaneous preterm birth or cervical funneling requiring cerclage. We reviewed retrospectively all the patients who had transvaginal cervical ultrasound assessment during one year. 49 patients who had a second and early third trimester delivery or cerclage placement were chosen for the study. The control group consisted of 78 patients without signs of preterm labor and cervical shortening as assessed by transvaginal ultrasound. The results of the last ultrasound cervical length measurement were correlated with the likelihood of preterm delivery or cervical funneling requiring cerclage. 34 of 127 patients studied delivered preterm and 15 required cervical cerclage because of cervical shortening and funneling. The mean cervical length assessed by ultrasound was 20.22 ± 3.07 mm in the group with preterm contractions and delivery and 15.99 ± 7.05 mm in the group with cervical incompetence. In the normal pregnancy group mean cervical length was 35.59 ± 3.07 mm. Cervical length of < 2.5 cm and further shortening of the cervix is predictive of preterm delivery or cervical incompetence requiring cerclage.

Prediction of Preterm Delivery by Sonographic Estimation of Cervical Length

Background: Identification of pregnant women presenting with threatened preterm labor who are destined to deliver prematurely would greatly assist planning their management. Objectives: The purpose of the study was to evaluate the ultrasonographic measurement of cervical length as a prognostic factor for predicting preterm birth in cases of threatened preterm labor. Methods: The study included 104 women with singleton pregnancies who presented with threatened preterm labor at 24–36 weeks of gestation. Cervical length at presentation was evaluated by transvaginal ultrasonography. Other potential prognostic factors, such as previous history of preterm labor, smoking, parity and administration of tocolytics were assessed. All women were observed for preterm delivery within 7 days of presentation. Results: The only significant predictor of preterm delivery was cervical length assessed by ultrasound (p < 0.000001, odds ratio 93.3, 95% Cl 10.4–837.1). Conclusions: Cervical length assessed by transvaginal ultrasonography in women presenting with threatened preterm labor is a powerful predictive tool for progression to preterm delivery.

An additional approach of repeat digital examination for preterm labor. Comment on Volumenie et al. [Eur J Obstet Gynecol RB 117 (2004) 33–7

We read with great interest the article by Volumenie et al. [ [1] Volumenie J.L. Luton D. Spirlet M.D. Sibony O. Blot P. Oury J.F. Ultrasonographic cervical length measurement is not a better predictor of preterm delivery than digital examination in a population of patients with idiopathic preterm labor. Eur J Obstet Gynecol RB. 2004; 117: 33-37 Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar ]. Most studies that have compared digital and ultrasonographic examination of the cervix for the prediction of preterm delivery without distinguishing the population based on the likelihood of preterm delivery, supported the dominance of the latter examination. However, Volumenie's study related that ultrasonographic cervical length measurement is not a better predictor of preterm delivery than digital examination especially in the high-risk population. Recently, Rozenberg suggested that repeating ultrasonographic cervical length measurement after successful tocolysis for preterm labor is useless [ [2] Rozenberg P. Rudant J. Chevret S. Boulogne A.I. Femme S. Ville Y. Repeat measurement of cervical length after successful tocolysis. Obstet Gynecol. 2004; 104: 995-999 Crossref PubMed Scopus (18) Google Scholar ]. In Rozenberg's study, subjects were also inferred to be of the high-risk population as in Volumenie's study because of the gestation with a cervical length on admission and the agreement of preterm delivery rates. Accordingly, Volumenie's study would have become better research if an investigation of repeat digital examination of cervical length for preterm labor had been added to their study. Reply to Dr. Shukunami concerning “Ultrasonographic cervical length measurement is not a better predictor of preterm delivery than digital examination in a population of patients with idiopathic preterm labor” [Eur J Obstet Gynecol Reprod Biol 2004;117:33–7]European Journal of Obstetrics and Gynecology and Reproductive BiologyVol. 120Issue 1PreviewWe thank Dr. Shukunami for his interest in our study and greatly appreciate the relevant remarks made. We did not use the results of repeat digital examination, although such an examination was generally performed on discharge. Theoretically, it could have been of interest, in order to analyse the clinical utility of this attitude, as Rozenberg et al. did for ultrasonography [1]. Full-Text PDF

Repeat Measurement of Cervical Length After Successful Tocolysis

To measure the ultrasonographic cervical length in undelivered women after successful tocolysis for preterm labor, and to determine whether this could improve the predictive value of cervical length measured before initiation of tocolysis on the risk of preterm delivery. This was a prospective study of patients admitted and treated for uterine contractions at 24(+0) to 33(+6) weeks of gestation with a cervical length of 26 mm or less by transvaginal ultrasonography on admission. Intravenous tocolysis was stopped when delivery was delayed by 48 hours, and cervical length was remeasured before discharge. The primary outcome was preterm delivery, defined by a delivery before 37 weeks. Predictive analysis was based on logistic models, with estimated odds ratios and 95% confidence interval. One hundred and nine patients were included in the study. The median (first, third quartile) cervical length on admission was 18 (13, 22) mm. The median (first, third quartile) variation in cervical length after tocolysis was stopped was 3 (0, 8) mm, and ranged from -13 to 26 mm. The median (first, third quartile) time interval from tocolysis to delivery was 53.0 (35.0, 70.0) days, with 45 (41.3%) patients delivered before 37 weeks. After adjustment for cervical length before admission and parity and gestational age on admission, the assessment of the variation in cervical length after successful tocolysis did not improve the predictive value of transvaginal sonography for the risk of preterm delivery (odds ratio 0.97; 95% confidence interval 0.90-1.03; P = .27). To repeat ultrasonographic cervical length measurement after successful tocolysis for preterm labor is useless.

Is it possible to improve diagnostic and prognostic criteria of preterm labour?

Preterm labour is a frequent cause of admission to hospital during pregnancy. However, in most cases, preterm labour is diagnosed with reference to clinical criteria only. Since the clinical assessment of uterine contractions and of cervical changes is highly subjective, few of the patients admitted to the hospital with suspected preterm labour will ultimately deliver preterm. There is a need for sensitive methods of detecting patients who are genuinely at high risk of preterm birth, but on the other hand, specific methods of reducing unnecessary treatments or hospital admissions are also required. Recently, a few techniques such as ultrasonographic measurement of cervical length and fetal fibronectin have been introduced into clinical practice with the aim of improving prediction of the risk of actual preterm delivery. In the future, the assessment of cervical status may be based not only on anatomical changes, but also on functional criteria. New techniques are being developed for evaluation of the mechanical properties of the cervix (cervical distensibility), noninvasive measurement of its collagen content (light-induced fluorescence of cervical collagen), or even direct assessment of the changes in cervical water content (magnetic resonance imaging). Correlations have been found between these measurements and the risk of preterm birth, but clinical studies are still needed to allow better assessment of the predictive value of these new methods in clinical practice.

Ultrasonographic cervical length measurement is not a better predictor of preterm delivery than digital examination in a population of patients with idiopathic preterm labor

Objective: To compare digital and ultrasonographic cervical examination for the prediction of preterm delivery in patients hospitalized for preterm labor. Study design: Fifty-nine patients were included. The Bishop score was evaluated upon admission, weeks gestational age. Ultrasonographic measurement of cervical length was done within 24 h after entry. Delivery before 37 weeks gestational age was the primary endpoint. Attending obstetricians were blinded to the results of echography. Results: Preterm delivery rate was 39% (23/59). The risk of preterm delivery was significantly increased when the Bishop score was greater than or equal to 6 (OR=4.45 [1.41–14.01]) or when ultrasonographic cervical length was less than or equal to 27 mm (OR=4.04 [1.32–12.3]), but digital examination was the only independent risk factor in multivariate analysis. Sensitivity, specificity, positive and negative predictive value for digital examination and ultrasonography were respectively 74, 61, 55 and 79%, 70, 64, 55 and 77%. Combination of digital examination and ultrasonography did not yield better results. Conclusion: In our series, prediction of preterm delivery was not improved by ultrasonography compared to digital examination. The size of the cervical shift observed in most patients hospitalized for preterm labor may render ultrasonography less relevant in identifying patients anticipated to deliver prematurely.

Mesure échographique de la longueur du col de l’utérus dans les grossesses gémellaires avec menace d’accouchement prématuré : comparaison avec les grossesses uniques

Objective. – Our purpose was to assess the utility of ultrasonographic measurement of cervical length for predicting preterm delivery in pregnant women with twin pregnancy and preterm labor. Patients and method. – Prospective study in 192 singleton and 66 twin pregnancies with preterm labor before 34 weeks. Vaginal sonography for measurement of cervical length, and screening for fetal fibronectin in vaginal smears were performed at admission. The incidence of delivery before 34 weeks was compared with cervical length and the presence of fetal fibronectin. Results. – In singleton pregnancies, delivery before 34 weeks was significantly more frequent in women with a cervical length <30 mm (26.6 vs. 2.0%; P = 0.0004), or presence of fetal fibronectin (27.5 vs. 6.0%; P = 0.001). The corresponding negative predictive values (NPV) were 98% and 94%, respectively. In twin pregnancies, receiver characteristic curve analysis showed that a cervical length of 20 mm had the highest diagnostic performance in predicting preterm delivery. The corresponding NPV was 63%. In this group, delivery before 34 weeks showed no significant difference in women with a cervical length < 30 mm (43.7 vs. 38.8%), cervical length < 20 mm (52.0 vs. 36.6%, P = 0.219), or presence of fetal fibronectin (47.6 vs. 21.7%, P = 0.0705). Discussion and conclusion. – Ultrasonographic measurement of cervical length does not predict preterm delivery in twin pregnancies with preterm labor.