Contribution of ultrasonography to the prediction of the induction-delivery interval: The ECOLDIA prospective multicenter cohort study.

INTRODUCTION: To evaluate the ability of preinduction ultrasonographic cervical length to predict the interval between induction and delivery in women at term with a Bishop score of 4 to 6 at induction. STUDY DESIGN: This multicenter prospective observational cohort recruited 334 women from April 2010 to March 2014. Inclusion criteria were women with singleton pregnancies at a gestational age ≥37 weeks, with no previous caesarean, a medical indication for induction of labor, and a Bishop score of 4, 5, or 6. All women underwent cervical assessment by both transvaginal ultrasound and digital examination (Bishop score). The induction protocol was standardized. The primary outcome measure was the induction-delivery interval. Hazard ratios (HR) and their 95% confidence intervals (95% CI) were used to assess potential predictors. RESULTS: Mean gestational age at induction was 40.1 weeks, 60.8% of the women were nulliparous, and the cesarean rate was 13.4%. The mean induction-delivery interval was 20.8 h (± 10.6). Delivery occurred within 24 h for 56.9% (n=190) of the women. An ultrasonographic cervical length measurement less than 25 mm (HR=1.50, 95% CI 1.18-1.91, P<0.01) and parity (HR=1.41, 95% CI 1.21-1.65, P<0.01) appeared to predict induction-delivery interval. The cervical length cutoff to reduce the induction-delivery interval was 25 mm. CONCLUSION: A cervical length cutoff of 25 mm was associated with shorter induction-delivery interval in women at term with a Bishop score of 4 to 6.

Implementation of universal screening for preterm delivery by mid-trimester cervical-length measurement.

OBJECTIVE: To assess the feasibility and results of introducing a policy of universal screening for preterm delivery (PTD) by mid-trimester cervical-length (CL) measurement. METHODS: In this retrospective cross-sectional study of singleton pregnancies, transvaginal sonography for CL measurement was performed at 20-24 weeks of gestation. Vaginal progesterone therapy was offered to women with CL ≤ 15 mm. The incidence of spontaneous PTD (sPTD) according to CL and the distribution of CL measurements were assessed. Rate of PTD before implementation of screening was compared with that after. RESULTS: A total of 10 506 singleton pregnancies were assessed. The decline rate was 1.32%. sPTD < 32 weeks, < 34 weeks and < 37 weeks occurred in 0.51%, 0.82% and 3.90% of pregnancies, respectively. CL measurement was best described by a mixture model distribution comprising a 'short' and a 'long' component. The percentage of the two components varied between subgroups of PTD, with the short component being greater the earlier the birth. CL, history of miscarriage, smoking status and prior PTD were independent predictors in the construction of a model predictive of PTD < 34 weeks (area under the curve = 0.74, P < 0.001). The rate of sPTD < 34 weeks in women with CL ≤ 15 mm receiving progesterone treatment was 20.4%. In the progesterone-treated group, a plateau was observed in the increase in risk for PTD for CL 9-13 mm, whereas below 9 mm the risk increased exponentially. Following the introduction of mid-trimester CL measurement, there was a trend for reduction in the rate of any PTD < 34 weeks of about 20% in comparison with the prescreening period (odds ratio = 0.81; 95% CI, 0.59-1.13). CONCLUSIONS: Universal screening for PTD by transvaginal sonographic measurement of CL at 20-24 weeks is feasible and well accepted by pregnant women. This policy identifies a very high-risk group that may benefit from intervention. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Assessment of a cervicometer compared to transvaginal ultrasound in identifying women with a short cervical length: a multicenter study.

BACKGROUND: Preterm birth remains a major cause of neonatal morbidity and mortality worldwide. Short cervical length (CL) as measured by transvaginal ultrasound (TVU) in the second trimester represents the single most predictive risk factor for spontaneous preterm birth. Previous studies have addressed, in part, the limitations of TVU availability by utilizing a cervicometer to screen patients for short cervix, identifying those patients who may not benefit from TVU CL screening. In view of the prior studies indicating that a cervicometer measurement may have a high negative predictive value (NPV) for a sonographically short cervix, we sought to identify the ideal cervicometer threshold value in a prospective, multicenter study. OBJECTIVE: The primary objective was to determine the cervicometer CL measurement threshold that provides a high NPV for the identification of patients who are highly unlikely to have a TVU CL measurement ≤20 and ≤25 mm and, therefore, may forego TVU. STUDY DESIGN: This prospective study, executed in 5 US centers, included 401 women ≥18 years of age who provided written informed consent to undergo CL measurement in the mid trimester. All women underwent both cervicometer- and TVU-measured CLs by individuals blinded to results of the other measurement. Both measurements were performed at 17-23 weeks' gestation (visit 1) and repeated at 24-29 weeks' gestation (visit 2). All TVU measurement images were reviewed by a central reader. Test characteristics and receiver operating characteristic curves were created to determine and confirm the optimal cervicometer CL threshold, maximizing the NPV. RESULTS: In all, 358 subjects were evaluable at visit 1 and 267 at visit 2. At visit 1, the average TVU CL was 38.7 ± 7.6 mm and the average cervicometer CL was 30.3 ± 8.8 mm. Similar measurements were seen at visit 2. Receiver operating characteristic curves were utilized to graphically identify a cervicometer CL threshold of 30 mm that maximized sensitivity while minimizing the false-positive rate. The 30-mm cervicometer CL threshold provided a 98-100% NPV and 0.0 negative likelihood ratio for identification of women who have a low likelihood to have a sonographic short cervix (ie, transvaginal CL ≤20 mm or ≤25 mm). The 17-23 weeks' gestation 30-mm cervicometer CL threshold has 100% sensitivity, 45-46% specificity, and 1.8 and 0.0 positive and negative likelihood ratios to predict sonographic CL ≤20 and ≤25 mm. CONCLUSION: Cervicometer CL screening successfully identifies women at low risk for short transvaginal CL. Use of a 30-mm threshold by cervicometer CL measurement confers a 98-100% NPV, with high sensitivity and moderate specificity to predict a TVU short CL. Cervicometer measurement of CL may permit almost 50% of women to avoid TVU.

Transvaginal ultrasound cervical length for prediction of spontaneous labour at term: a systematic review and meta-analysis.

BACKGROUND: The possibility to predict the delivery date is a question frequently raised by pregnant women. However, a clinician has currently little to predict when a woman at term will deliver. OBJECTIVE: To evaluate the predictive accuracy of transvaginal ultrasound (TVU) cervical length (CL) for spontaneous onset of labour in singleton gestation enrolled at term by a meta-analysis. SEARCH STRATEGY: We performed a literature search in electronic databases. SELECTION CRITERIA: We included only studies assessing the accuracy of TVU CL in prediction of spontaneous onset of labour in singleton gestations with vertex presentation who were enrolled at term. DATA COLLECTION AND ANALYSIS: The primary outcome was the accuracy of CL for prediction of spontaneous labour within 7 days. Pooled sensitivities and specificities were calculated. MAIN RESULTS: Five studies including 735 singleton gestations were included. For the prediction of spontaneous labour within 7 days for CL <30 mm the pooled sensitivity was 64% and pooled specificity was 60%. The higher the CL, the better the sensitivity; the lower the CL, the better the specificity. A woman with a singleton gestation at term and a TVU CL of 30 mm has a <50% chance of delivering within 7 days, while one with a TVU CL of 10 mm has an over 85% chance of delivery within 7 days. CONCLUSIONS: TVU CL at term has moderate value in predicting the onset of spontaneous labour. A woman with a TVU CL of 10 mm or less has a high chance of delivering within a week. TWEETABLE ABSTRACT: Cervical length at term has moderate value in predicting the onset of spontaneous labour.

The use of the Cervilenz device to aid in the diagnosis of premature labor.

OBJECTIVE: A short cervix measured by transvaginal ultrasound has been correlated with increased risk for preterm delivery (PTD). Many patients presenting with a complaint of possible premature labor (PL); may not have access to cervical length (CL) screening by ultrasound. Cervilenz is an FDA cleared disposable device for obtaining vaginal CL measurements. This study was conducted to correlate Cervilenz measurements of CL with the occurrence of PTD. METHODS: Women presenting with regular uterine contractions at gestational age (GA) ≥22 and <34 weeks with intact membranes and cervical dilation <3 cm were recruited. A speculum examination was performed and Cervilenz measurement of CL was obtained. Patients were treated with tocolytics and/or corticosteroids based upon the attending physician's judgment. The occurrences of PTD as a result of PL or premature rupture of membranes within 7 days, <32 weeks, <34 weeks and <37 weeks, were determined. Patients who were delivered preterm for other maternal or fetal indications were excluded. Negative predictive value (NPV) was calculated. RESULTS: Of the 220 women recruited, 20 were subsequently excluded from analysis because they required PTD for unrelated indications. The mean GA at enrollment was 29.8 ± 2.8 (SD) weeks. One (0.5%), 2 (1.0%), 4 (2.0%) and 29 (14.5%) women delivered at ≤7 days from enrollment, ≤32 weeks, ≤34 weeks, and ≤37 weeks, inclusively. Seventy-seven (38.5%), 39 (19.5%) and 19 (9.5%) women had Cervilenz measurement of ≤30, ≤25 and ≤20 mm, respectively. The NPV for a Cervilenz measurement of >20 mm for delivery at, ≤32, ≤34 and ≤37 weeks were 99.2%, 98.3% and 86.7%, respectively. CONCLUSION: Cervilenz measurement >20 mm appears to have high NPV for PTD prior to 34 weeks.

Cervilenz™ is an effective tool for screening cervical-length in comparison to transvaginal ultrasound.

OBJECTIVE: To assess the accuracy and reliability of cervico-portio (CP) length estimated using the Cervilenz™ compared with transvaginal ultrasound (TVU) cervical-length in women at high and low risk of spontaneous preterm birth (SPTB). METHODS: Cervical-length was assessed longitudinally across gestation utilizing CP-length measured with Cervilenz™ and TVU. Altman-Bland plots were used to compare Cervilenz™ and TVU cervical-length. Regression analysis was used to assess the effect of gestational age, previous SPTB and previous cervical surgery on Cervilenz™ accuracy. Receiver operator curves (ROC) were utilized to determine the CP-length measured by Cervilenz™ with the optimum sensitivity and specificity for predicting TVU cervical-length <25 mm. ROCs were utilised to compare the ability of Cervilenz™ with TVU to predict SPTB. RESULTS: Seventy-five women were recruited (low risk N = 57, high risk N = 18). A total of 259 TVU and 253 Cervilenz™ measurements were taken with up to six measures in each woman. The Cervilenz™ CP-length was on average 9 mm shorter than TVU measured cervical-length. The difference decreased with advancing gestational age (p < 0.001). Cervilenz™ CP-length <24 mm was a good predictor of TVU cervical-length <25 mm (area under the curve (AUC) = 0.867). After accounting for baseline Cervilenz™ measurements, the relationship between Cervilenz™ and TVU measures was not influenced by pregnancy risk status. There were no significant differences between Cervilenz™ (AUC = 0.716) and TVU (AUC = 0.706) in predicting SPTB. CONCLUSION: Cervilenz™ is an effective tool for screening cervical-length in comparison to TVU. Cervilenz™ may facilitate greater access to cervical-length measurement and assessment of risk of preterm birth.

Cervilenz assessment of cervical length compared to fetal fibronectin in the prediction of preterm delivery in women with threatened preterm labor.

OBJECTIVE: To determine whether cervical length (CL) measured by the Cervilenz™ measuring device is an effective screening tool for the prediction of preterm delivery (PTD) compared to fetal fibronectin (fFN). METHODS: We evaluated fFN and CL among women who enrolled into a randomized control trial (RCT) comparing management algorithms for threatened preterm labor between 24 and 34 weeks' gestation. In all subjects, fFN was collected, with CL determined in blinded fashion. The sensitivity, specificity, and positive and negative predictive values (NPV) for fFN or Cervilenz in prediction of PTD within 7 days or prior to 37 weeks were determined. RESULTS: Fifty-two subjects were evaluated. CL <30 mm correlated with PTD <7 days (r = 0.31, p = 0.04) and fFN positivity (r = 0.43, p = 0.006). CL <30 mm and fFN had excellent NPV for PTD <7 days (97.1 vs. 97.3%), and the area under the receiver operator characteristic curves were similar for prediction of PTD <7 days (76.6 vs. 75.2%, p = 0.71) or <37 weeks (56.7 vs. 55.2%, p = 0.71). CONCLUSIONS: Measurement of CL with Cervilenz appears to be equivalent to fFN in screening symptomatic women for PTD within 7 days or prior to 37 weeks. Given cost and turnaround time with fFN testing, Cervilenz represents a promising new tool for real time, clinically useful results in the management of women with threatened preterm labor.