Mid-trimester sonographic cervical consistency index to predict spontaneous preterm birth in a low-risk population.

To investigate the effectiveness of mid-trimester sonographic cervical consistency index (CCI) for the prediction of spontaneous preterm birth (sPTB) in low-risk pregnancies and to compare its performance with that of mid-trimester sonographic cervical-length (CL) measurement. This was a prospective cohort study of women with a singleton pregnancy examined by ultrasound at 19 + 0 to 24 + 6 weeks' gestation. All women underwent transvaginal ultrasound examination of the cervix, but CCI and CL were measured, offline, only in women without a risk factor for sPTB. Staff and participants were blinded to CL and CCI results. CCI was obtained by calculating the ratio between the anteroposterior diameter of the uterine cervix at maximum compression and at rest. The primary outcome was prediction of sPTB before 37 + 0 weeks. Receiver-operating characteristics (ROC) curves were produced and sensitivity and specificity were calculated for the optimal cut-off based on the ROC curve and for the 1st , 5th and 10th centiles of CCI and CL. Intraclass correlation coefficients (ICC) and Bland-Altman plots were used to estimate intra- and interobserver agreement and reliability for measurement of CCI and CL. Of the 749 women who underwent ultrasound examination of the cervix, 532 were included for analysis. The rates of sPTB before 37 + 0 and before 34 + 0 weeks were 4.1% (22/532) and 1.3% (7/532), respectively. The rates of short cervix < 25 mm and ≤ 20 mm were 0.9% (5/532) and 0.4% (2/532), respectively. The area under the ROC curve (AUC) with regard to predicting sPTB before 37 + 0 weeks was 0.84 (95% CI, 0.75-0.93) for CCI compared with 0.68 (95% CI, 0.56-0.81) for CL (P = 0.03). The optimal cut-off based on the ROC curve was 64.6% for CCI (sensitivity, 77.3%; specificity, 82.7%) and that for CL was 37.9 mm (sensitivity, 72.7%; specificity, 61.2%). The AUC with regard to predicting sPTB before 34 + 0 weeks was 0.87 (95% CI, 0.71-1.0) for CCI compared with 0.71 (95% CI, 0.47-0.94) for CL (P = 0.25). The optimal cut-off based on the ROC curve was 63.6% for CCI (sensitivity, 85.7%; specificity, 84.0%) and that for CL was 37.9 mm (sensitivity, 85.7%; specificity, 61.3%). Intraobserver ICC was > 0.90 both for CCI and CL, while interobserver ICC was 0.89 for CCI and 0.90 for CL. Second-trimester CCI is a better predictor of sPTB < 37 weeks in low-risk pregnancies than is CL. External validation is needed as well as studies assessing the value of CCI as a screening tool in unselected and high-risk populations. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Baños N ，Murillo-Bravo C ，Julià C ，Migliorelli F ，Perez-Moreno A ，Ríos J ，Gratacós E ，Valentin L ，Palacio M ... -  《-》

Quantitative analysis of cervical texture by ultrasound in mid-pregnancy and association with spontaneous preterm birth.

New tools are required to improve the identification of women who are at increased risk for spontaneous preterm birth (sPTB). Quantitative analysis of tissue texture on ultrasound has been used to extract robust features from the ultrasound image to detect subtle changes in its microstructure. This may be applied to the cervix. The aim of this study was to determine if there is an association between quantitative analysis of cervical texture (CTx) on mid-trimester ultrasound and sPTB < 37 + 0 weeks' gestation. This was a single-center nested case-control study of a prospective cohort of 677 consecutive women with singleton pregnancy assessed between 19 + 0 and 24 + 6 weeks' gestation. Women at increased risk for sPTB were included unless they received treatment to prevent sPTB. Women who delivered < 37 + 0 weeks (sPTB) were considered as cases and were matched in a 1: 10 ratio with randomly selected contemporary controls who delivered at term. For each woman, one ultrasound image of the cervix was obtained for which quality was assessed, cervical length (CL) measured offline and a region of interest in the midportion of the anterior cervical lip delineated for use in local binary patterns analysis of CTx. A learning algorithm was developed to obtain the combination of CTx features best associated with sPTB based on feature transformation and discriminant analysis regression. The ability of the learning algorithm to predict sPTB was evaluated using a leave-one-out cross-validation technique, which produced a CTx-based score for each participant. Receiver-operating characteristics (ROC) curves were produced and sensitivity, specificity, and positive and negative likelihood ratios were calculated for the optimal cut-off based on the ROC curve. The results were compared with those obtained for CL. Investigators studying the images were blinded to pregnancy outcome at all times. Images from 310 women (27 cases and 283 controls) were of sufficient quality and included in the study. Median CTx-based score was significantly lower in cases compared with controls (-1.01 vs -0.07, P ≤ 0.0001). CTx-based score maintained its significant association with sPTB after adjusting for possible confounders (history of sPTB, conization or Müllerian malformation, and CL < 25 mm). CTx-based score was a better predictor of sPTB (AUC, 0.77; 95% CI, 0.66-0.87) than was CL (AUC, 0.60; 95% CI, 0.47-0.72) (P = 0.03). Median CL was similar for cases and controls (37.7 vs 38.6 mm, P = 0.26), although cases were more likely to have CL < 25 mm (18.5% vs 0.4%, P < 0.001). Quantitative analysis of CTx enables the extraction of information relevant to sPTB from ultrasound images to generate a CTx-based score that is associated independently with sPTB. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Baños N ，Perez-Moreno A ，Julià C ，Murillo-Bravo C ，Coronado D ，Gratacós E ，Deprest J ，Palacio M ... -  《-》

Cervical length at mid-gestation in screening for preterm birth in twin pregnancy.

Short cervical length (CL) in mid-gestation is considered predictive of spontaneous preterm birth (PTB). The medical literature suggests 20 mm as the cut-off for high risk in twin pregnancies. Our objective was to assess the predictive value of CL for spontaneous PTB < 32 weeks' gestation in twin pregnancies and to calculate the cut-off point with the best sensitivity and specificity. This was a single-center retrospective cohort study of women in whom CL had been measured by transvaginal ultrasound at 18-23 weeks' gestation. Pregnancies complicated by twin-to-twin transfusion syndrome, those requiring intrauterine therapy or those with indicated PTB were excluded. The predictive value of CL for PTB < 32 weeks was assessed. The distribution of CL measurements and the optimal cut-off in patients with PTB were calculated and logistic regression analysis was performed to assess the association between pregnancy characteristics and PTB. A total of 940 twin pregnancies were included. CL showed an area under the receiver-operating characteristics curve of 0.65 (95% CI, 0.58-0.71) for the prediction of PTB < 32 weeks. The optimal cut-off value for predicting PTB was 36 mm (sensitivity, 64.1%; specificity, 62.8%; positive predictive value, 13.5%; negative predictive value, 95.1%; accuracy, 62.9%). The relative risk of PTB with CL ≤ 36 mm was 2.35 (95% CI, 1.53-3.60; P < 0.001). After adjusting for confounders in logistic regression analysis, only CL (adjusted odds ratio (aOR), 0.94 (95% CI, 0.90-0.99); P = 0.03), and not monochorionicity (aOR 4.14 (95% CI, 0.89-19.25); P = 0.07), was independently associated with PTB. More than one-third (36%) of PTB cases delivering < 32 weeks had a normal CL in mid-gestation. This proportion rose to 85% when considering the 20-mm cut-off suggested by the medical literature. This study shows that, despite the weak independent association, CL assessed in mid-gestation is a poor predictor of PTB < 32 weeks' gestation in asymptomatic twin pregnancies. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Pagani G ，Stagnati V ，Fichera A ，Prefumo F ... -  《-》

Cervical elastography in predicting spontaneous preterm birth in singleton pregnancy with a short cervix receiving progesterone treatment at 18 to 24 weeks' gestation.

He B ，Zhou Y ，Cao L ，Yao B ，Gao H ，Zhang H ... -  《-》

Transvaginal sonographic cervical length in first and second trimesters in a low-risk population: a prospective study.

To assess cervical length (CL) longitudinally between the first and second trimesters and to determine the proportion of women with short CL. The study also aimed to assess if women with short CL at 19-24 weeks' gestation could be identified at the time of combined first-trimester screening (cFTS) at 11-14 weeks' gestation, in order to determine the potential value of implementation of CL screening for prediction of preterm delivery in a Danish population. This was a prospective longitudinal study of women with singleton pregnancy attending three University Hospitals in Denmark for combined first-trimester screening from 1 November 2013 to 1 December 2014. Exclusion criteria were multiple pregnancy, uterine anomaly, cerclage or progesterone treatment at inclusion. CL was measured on transvaginal sonography at 11-14 weeks (Cx1), 19-21 weeks (Cx2) and 23-24 weeks (Cx3), by trained operators as a straight line from external to internal os. Women with CL ≤ 25 mm were referred to a maternal-fetal medicine specialist for treatment according to a standardized management protocol. Of the 4904 eligible women, 3477 (71%) participated and had Cx1 recorded. Of those, 3232 (93.0%) had CL measured on all three scans. Median Cx1 was 37 mm, and median Cx2 and Cx3 were 40 mm. The proportion of women with CL ≤ 25 mm increased with gestational age, from 0.41% (95% CI, 0.19-0.62%) at Cx1 to 1.79% (95% CI, 1.34-2.24%) at Cx3. In total, the proportion of women with second-trimester CL (Cx2 or Cx3) ≤ 25 mm was 2.0% (n = 67), of which 38.8% (n = 26) were detected at 19-21 weeks. The probability of short CL between 19 and 24 weeks was greater for those with shorter first-trimester CL. It was nearly nine-fold higher for women with Cx1 ≤ 25 mm compared with Cx1 ≥ 35 mm (17% vs 2%). The performance of Cx1 for prediction of short second-trimester CL was 50% at a 10% false-positive rate. It was found that more than 1500 women would need to be screened for short CL at 19-21 weeks to prevent one case of spontaneous preterm delivery before 34 weeks in a population such as the one in this study. There is an association between first-trimester CL and risk of short cervix in the second trimester. Once short CL was observed, risk of preterm delivery was greatly increased. However, whether universal CL screening should be implemented in this low-risk population depends on cost-benefit analysis taking into account the low proportions of women with short CL and at risk for preterm delivery. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Wulff CB ，Rode L ，Rosthøj S ，Hoseth E ，Petersen OB ，Tabor A ... -  《-》