Single and repeat cervical-length measurement in twin gestation with threatened preterm labor

Addition of cervical elastosonography to cervical length to predict preterm birth in pregnancy women with prior preterm birth: A preliminary prospective study

OBJECTIVES

To investigate the characteristics of cervical elastosonography in pregnancies and establish an ultrasound-based combing predictor for improving the prediction in pregnant women with prior-preterm birth who might ultimately undergo preterm birth (PTB).

MATERIALS AND METHODS

169 singleton pregnancies with prior-preterm birth were examined by cervical elastography from January to November of 2021. According to the ultrasound image and result of the following-up, the patients were separated into preterm groups and full-term groups with or without cerclage. There were five elastographic parameters: Elasticity Contrast Index (ECI), Cervical hard tissue Elasticity Ratio (CHR), External Cervical os Strain rate (ES), Closed Internal Cervical os Strain rate (CIS), CIS/ES ratio and CLmin. Multivariable logistic regression was used to screen out the most significant predictors. The area under the receiver operating characteristic curve (AUC) was calculated to evaluate the ability of prediction.

RESULTS

The PTB group without cerclage showed significantly softer cervix stiffness, while those with cerclage showed significantly harder. CHRmin with P < 0.05 in the univariate logistic regression analysis was screened as a more valuable cervical elastosonography parameter than other ones. The combination of CLmin and CHRmin in un-cerclage and integrating CHRmin, maternal age and pre-pregnancy BMI in cerclage presented good predictive value. The results of AUC were higher than CLmin, respectively (0.775 vs 0.734, 0.729 vs 0.548).

CONCLUSIONS

The addition of cervical elastography parameters (such as CHRmin) might improve the ability to predict preterm birth in pregnant women with previous preterm delivery, which was better than using CL alone.

Cervical elastography: finding a novel predictor for improving the prediction of preterm birth in uncomplicated twin pregnancies

OBJECTIVE

This study set out to investigate a novel ultrasound parameter using cervical elastosonography for improving the prediction of spontaneous preterm birth (sPTB) in twin pregnancies.

STUDY DESIGN

The study was comprised of 106 twin pregnancies from October 2020 to January 2022 in Beijing Obstetrics and Gynecology Hospital. They were divided into two groups according to gestational age (GA) at delivery (delivery < 35 weeks and delivery ≥ 35 weeks). There were five elastographic parameters: Elasticity Contrast Index (ECI), Cervical Hardness Ratio (CHR), Closed Internal cervical ostium Strain rate (CIS); External cervical ostium strain rate (ES), CIS/ES ratio and Cervical Length (CL). All of the clinical and ultrasonic indicators with P < 0.1 were considered candidate indicators via univariate logistic regression. Based on the extracted unified combination of clinical indicators, the combinations of permutation with the candidate ultrasound indicators were performed step by step in multivariable logistic regression. The best ultrasound indicator with the lowest Akaike Information Criterion (AIC) and the highest Areas Under the receiver operating characteristic Curve (AUC) was chosen for establishing the prediction score.

RESULTS

Over 30% (36/106) of those who delivered before 35 weeks gestation. There were distinct differences in the clinical characteristics and cervical elastography parameters between the two groups. Seven major clinical variables were identified as a unified clinical indicator. CISmin as the best ultrasound elastography predictor indicated the lowest AIC and the highest AUC and outperformed alternative indicators significantly in the prediction of delivery before 35 weeks of gestation. Unfortunately, CLmin which was commonly used in clinical practice ranked far from all of the cervical elastography parameters and presented the highest AIC and the lowest AUC. A preliminary scoring rule was established and the ability to predict the risk of sPTB in twin pregnancies was improved (Accuracy: 0.896 vs 0.877; AIC: 81.494 vs 91.698; AUC: 0.923 vs 0.906).

CONCLUSIONS

The cervical elastosonography predictor such as CISmin might be a more useful indicator applied for enhancing the ability in predicting twin pregnancies preterm birth than CL. Furthermore, there would be more benefits for advancing clinical decision-making in actual clinical practice by using cervical elastosonography in the near future.

Clinical application of cervical shear wave elastography in predicting the risk of preterm delivery in DCDA twin pregnancy

Background

Limited studies have used cervical shear wave elastography (SWE) as a tool to investigate the predictive effect of cervical changes on preterm delivery (PTD) in twin pregnancy. This study is aimed to predict the risk of PTD by cervical SWE in dichorionic diamniotic (DCDA) twin pregnancy.

Methods

A total of 138 women with dichorionic diamniotic (DCDA) twins were included in this prospective study. The mean SWE value of the cervix was obtained from the inner, middle and outer regions of the anterior and posterior cervical lips using a transvaginal ultrasound transducer and measured consecutively across three different gestations (20–23^+ 6 weeks, 24–27^+ 6 weeks, and 28–32 weeks). Follow-up was performed on all subjects, and we compared the mean SWE value between the PTD and term delivery (TD) groups.

Results

A total of 1656 cervical mean SWE data were collected for analysis. Among the 138 twin pregnant women, only 92 women completed the three elastography examinations; PTD occurred in 58.7% (54/92), and TD in 41.3% (38/92). The mean (SD) maternal age was 33.1 ± 4.1 years, and the mean (SD) body mass index was 21.1 ± 2.6 kg/m². As gestational age increased, the mean SWE value of each part of the cervix decreased. The cervical mean SWE value was lower in the preterm group than in the term group in all three gestations, except for the anterior cervical lip at 28–32 weeks. Receiver operating characteristics (ROC) curves showed the sensitivity of mean SWE value of the anterior cervical lip was 83.3% (95% CI, 70.7–92.1) with a specificity of 57.9% (95% CI, 40.8–73.7) for predicting PTD at a cutoff value of 7.94 kPa. The positive likelihood ratio (LR+) was 1.67 (95% CI, 1.19–2.34), and the negative likelihood ratio (LR–) was 0.33 (95% CI, 0.17–0.64).

Conclusions

There is a significant negative correlation between cervical stiffness and gestational age in DCDA twin pregnancy. SWE is a potential tool for assessing cervical stiffness and predicting PTD in DCDA twin pregnancy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04526-0.

Development and external validation of a nomogram for predicting preterm birth at < 32 weeks in twin pregnancy

The purpose of this study was to develop a dynamic model to predict the risk of spontaneous preterm birth at < 32 weeks in twin pregnancy. A retrospective clinical study of consecutively asymptomatic women with twin pregnancies from January 2017 to December 2019 in two tertiary medical centres was performed. Data from one centre were used to construct the model, and data from the other were used to evaluate the model. Data on maternal demographic characteristics, transvaginal cervical length and funnelling during 20-24 weeks were extracted. The prediction model was constructed with independent variables determined by multivariate logistic regression analyses. After applying specified exclusion criteria, an algorithm with maternal and biophysical factors was developed based on 88 twin pregnancies with a preterm birth < 32 weeks and 639 twin pregnancies with a delivery ≥ 32 weeks. It was then evaluated among 34 pregnancies with a preterm birth < 32 weeks and 252 pregnancies with a delivery ≥ 32 weeks in a second tertiary centre without specific training. The model reached a sensitivity of 80.00%, specificity of 88.17%, positive predictive value of 50.33% and negative predictive value of 96.71%; ROC characteristics proved that the model was superior to any single parameter with an AUC of 0.848 (all P < 0.005). We developed and validated a dynamic nomogram model to predict the individual probability of early preterm birth to better represent the complex aetiology of twin pregnancies and hopefully improve the prediction and indication of interventions.

Measurement of the uterocervical angle for the prediction of preterm birth in symptomatic women

Purpose

To examine if the uterocervical angle (UCA) can be used to predict preterm delivery in women with painful and regular uterine contractions and a cervical length of 25 mm or less.

Methods

Retrospective study at the perinatal unit of the University Hospital of Tuebingen, Germany. Women with singleton gestation and preterm contractions between 24 + 0 and 33 + 6 weeks’ gestation were included. For the UCA measurement, a line is placed from the internal os to the external os irrespective of whether the cervix is straight or curved. A second line is drawn to delineate the lower uterine segment. The angle between the two lines is the UCA measurement. The measurements were taken on stored images from our database.

Results

The study consisted of 213 singleton pregnancies. At the time of UCA measurement, median maternal and gestational age was 31.4 years and 29.7 weeks’ gestation. Median gestational age at delivery was 35.3 weeks and the corresponding birth weight 2480 g, respectively. The UCA measurement in women who delivered within 2 days, between 3–7 days and after 7 days was not helpful to distinguish between these three groups [median UCA measurements: 108.5°, 108.0° and 107.3° (Kruskal–Wallis test p = 0.576)]. Uni- and multivariate logistic multiple regression analysis demonstrated that the delivery within 2 days was only dependent on the gestational age and the cervical length at the time of presentation.

Conclusion

The measurement of UCA is not useful in predicting preterm birth in the subsequent 7 days after an episode of preterm contractions.

Transvaginal ultrasound cervical length for prediction of spontaneous labor at term: A protocol for systematic review and meta-analysis

PURPOSE

To evaluate the predictive accuracy of transvaginal ultrasound (TVU) cervical length (CL) for spontaneous onset of labor in singleton gestation enrolled at term by a meta-analysis.

MATERIALS AND METHODS

This protocol established in this study has been reported following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. Web of Science, PubMed, EMBASE, and the Cochrane Library were searched for all clinical trials assessing the accuracy of TVU CL in prediction of spontaneous onset of labor in singleton gestations with vertex presentation who were enrolled at term until August 15, 2020. We will use a combination of Medical Subject Heading and free-text terms with various synonyms to search based on the eligibility criteria. Two investigators independently reviewed the included studies and extracted relevant data. The 95% confidence intervals (CIs) of was used as effect estimate. I-square (I2) test, substantial heterogeneity, sensitivity analysis, and publication bias assessment will be performed accordingly. Stata 15.0 and Review Manger 5.3 are used for meta-analysis and systematic review.

RESULTS

The results will be published in a peer-reviewed journal.

CONCLUSION

The results of this review will be widely disseminated through peer-reviewed publications and conference presentations. This evidence may also assess the accuracy of TVU CL in prediction of spontaneous onset of labor in singleton gestations with vertex presentation.

REGISTRATION NUMBER

INPLASY202080065.