Pre-induction cervical assessment using transvaginal ultrasound versus Bishops cervical scoring as predictors of successful induction of labour in term pregnancies: A hospital-based comparative clinical trial

Comparing Pre-Induction Ultrasound Parameters and the Bishop Score to Determine Whether Labor Induction Is Successful

Background and Objectives: The incidence of labor induction is steadily increasing worldwide. The main aim of this study was to evaluate the ultrasound parameters and their mutual correlation and to analyze the parameters' predictive capability in assessing the success of labor induction. The secondary goal was to assess patients' tolerability and acceptance of transvaginal ultrasound and digital gynecological examination. Materials and Methods: This prospective observational follow-up study included 252 women selected for labor induction. The transvaginal ultrasound examination measured the posterior cervical angle, cervical length, the length and width funneling of the cervix, the distance between the head of the fetus and the external uterine os, and the position of the fetal occiput. After the ultrasound, a digital vaginal examination was performed (according to the Bishop score), and the women were asked to rate their perception of pain for each procedure. Results: The most common indication for labor induction was post-term pregnancy (57.59%), and the most common method of labor induction was oxytocin with amniotomy (70%). The results showed that a significant independent prediction of vaginal delivery could be provided based on the Bishop score and cervical length. Other investigated ultrasound parameters, the length and width of the funneling of the cervix (p < 0.001), the fetal head stage (p < 0.001), and the size of the posterior cervical angle (p < 0.05), showed statistical significance in relation to the success of labor induction. Patients reported lower discomfort and pain during transvaginal ultrasound examination (mean score 2, IQR 3) compared to digital examination (mean score 5, IQR 4), with p < 0.001. Conclusions: The results imply that the assessment of ultrasound parameters before induction of labor is necessary to predict the outcome and reduce the possibility of complications. In terms of tolerability and choice by the patients, the transvaginal ultrasound examination was better rated than the vaginal gynecological examination.

Effect of cervical Bishop score on induction of labor at term in primiparas using Foley catheter balloon: a retrospective study

BACKGROUND

Previous studies had found that the mechanical methods were as effective as pharmacological methods in achieving vaginal delivery. However, whether balloon catheter induction is suitable for women with severe cervical immaturity and whether it will increase the related risks still need to be further explored.

RESEARCH AIM

To evaluate the efficacy and safety of Foley catheter balloon for labor induction at term in primiparas with different cervical scores.

METHODS

A total of 688 primiparas who received cervical ripening with a Foley catheter balloon were recruited in this study. They were divided into 2 groups: Group 1 (Bishop score ≤ 3) and Group 2 (3 < Bishop score < 7). Detailed medical data before and after using of balloon were faithfully recorded.

RESULTS

The cervical Bishop scores of the two groups after catheter placement were all significantly higher than those before (Group 1: 5.49 ± 1.31 VS 2.83 ± 0.39, P<0.05; Group 2: 6.09 ± 1.00 VS 4.45 ± 0.59, P<0.05). The success rate of labor induction in group 2 was higher than that in group 1 (P<0.05). The incidence of intrauterine infection in Group 1 was higher than that in Group 2 (18.3% VS 11.3%, P<0.05).

CONCLUSION

The success rates of induction of labor by Foley catheter balloon were different in primiparas with different cervical conditions, the failure rate of induction of labor and the incidence of intrauterine infection were higher in primiparas with severe cervical immaturity.

Transvaginal Ultrasound Versus Bishop Score in Predicting Labour Dystocia at Full-Term Nullipara Undergoing Labour Induction

Objective

Precise assessment of cervical conditions before labor induction is crucial for predicting the success of normal vaginal delivery. The cervix primary condition has a significant value in determining the succession of induction of labour. Traditionally, assessment of cervix before induction has been based on a cervix digital examination using Bishop's scoring method.This study compares transvaginal ultrasonographic (TVS) cervical assessment with the traditional Bishop score in nulliparous women undergoing labor induction, aiming to evaluate their predictive abilities for labor dystocia.

Materials and methods

In a prospective observational study of 200 pregnant women at Al Hussein University Hospital between October 2022 and July 2023, cervical length, funneling, and posterior cervical angle were measured using transvaginal ultrasound. The Bishop score was recorded before induction. Statistical analyses, including Student's "t"-test and ROC curve, were conducted using SPSS.

Results

68% delivered via normal vaginal delivery (NVD) and 32% via cesarean section (CS). The NVD group exhibited significantly higher Bishop scores (6.82±1.36 vs 3.70±0.94), lower cervical length (25.46±3.99 vs 37.34±2.09), and higher cervical angle (121.39±5.70 vs 89.01±6.09), than the CS group. ROC curve analysis revealed that a Bishop score ≥4.5 had 89% sensitivity and 87.5% specificity, a cervical angle ≥ 92.5 had 98.5% sensitivity and 95.3% specificity, and a cervical length ≥31.5 had 96.9% sensitivity and 97.1% specificity for predicting NVD.

Conclusion

The posterior cervical angle, alongside cervical length, proves to be a more sensitive indicator for predicting labor dystocia during induction compared to the traditional Bishop score.

Comparing Transvaginal Ultrasound Measurements of Cervical Length to Bishop Score in Predicting Cesarean Section Following Induction of Labor: A Prospective Observational Study

INTRODUCTION

 Bishop score (BS) has been used to see the favorability of the cervix for induction of labor (IOL), but it has limitations in today's diverse patient population. We aimed to assess the predictive value of transvaginal ultrasound (TVUS) measurements of cervical length (CL) compared to BS in determining the likelihood of cesarean section (CS) following IOL.

METHODOLOGY

A prospective observational study was conducted on 120 women requiring IOL in a tertiary care hospital in central India. The inclusion criteria of the study were antenatal women more than 18 years of age, in need of IOL, having a singleton pregnancy with a gestational age of > 37 weeks as determined from the date of the last menstrual period and confirmed by sonographic measurements in the first trimester, presenting with a cephalic presentation, and having intact fetal membranes. Women with prior uterine scars and those unwilling to IOL were excluded from the study. TVUS was done just before induction. Statistical analyses were done to compare the predictive abilities of CL and BS for CS.

RESULTS

The mean age and gestation period were 25.96 years and 39 weeks 3 days, respectively. The majority of the study population comprised multigravida (69, 57.5%), followed by primigravida (47, 39.2%), and grand multigravida (≥ G5) (4, 3.3%). Post-maturity (34, 28.3%), preeclampsia (21, 17.5%), and intrahepatic cholestasis of pregnancy (17, 14.2%) were common indications for induction. The overall CS rate was 35.8% (43/120). Women with CS had lower BS (3.60 vs. 4.70, P = 0.010) and higher CL (31.5 mm vs. 23.4 mm, P < 0.001). CL exhibited an area under the curve (AUC) of 0.857, outperforming BS (AUC = 0.643) in predicting CS. Using a CL cutoff of 26.5 mm yielded sensitivity (79.1%), specificity (81.8%), and overall accuracy (80.8%).

CONCLUSIONS

TVUS measurement of CL (>26.5 mm) demonstrated superior predictive ability for CS following labor induction compared to BS (≤5). This study highlights the potential of CL measurement as an objective and reliable tool for optimizing decision-making in labor induction.

Assessment of different sonographic cervical measures to predict labor induction outcomes: a systematic review and meta-analysis

Background

Induction of labor (IOL) is a common obstetric approach to start or encourage uterine contractions to achieve a vaginal birth. It is recommended when continuing the pregnancy may be more dangerous for the mother or baby. Different ultrasonographic measures, such as cervical length, have been investigated as possible predictors of the outcomes of IOL. This meta-analysis aimed to assess the accuracy of ultrasound measurements in anticipating successful IOL.

Methods

The study conducted a thorough search on three databases (PubMed, Scopus, and Web of Science) until 04 March 2023, to find clinical studies published in English that reported different sonographic cervical measures and their ability to predict IOL outcomes. The chosen studies were stratified based on the type of indicator reported, and a meta-analysis was conducted to determine the best indicator for both successful and failed induction. The risk of bias and concerns about the applicability of the included studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) method.

Results

This study analyzed 57 studies with 9,338 patients. Cervical length is moderately effective in predicting successful IOL, with pooled sensitivity (SN) and specificity (SP) of 0.67 and 0.70, respectively. However, cervical length had a pooled SN and SP of 0.70 and 0.61 for predicting failed IOL. The posterior cervical angle was found to have a higher pooled SN and SP of 0.79 and 0.73 for predicting successful IOL. Fetal head-perineum distance demonstrated moderate accuracy with a pooled SN, SP, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the curve of 0.58, 0.66, 1.95, 0.36, 5.33, and 0.9992, respectively, for predicting successful IOL.

Conclusions

Fetal head-perineum distance was the most effective predictor for successful IOL compared to cervical length, which only had a moderate predictive ability. Shortening of cervical length was not a useful indicator for successful IOL. On the other hand, the posterior cervical angle was the most reliable factor for predicting failed induction. The study's findings can aid in developing more effective management strategies for IOL.

Influence factor analysis and prediction model of successful application of high-volume Foley Catheter for labor induction

BACKGROUND

This study aimed to establish a clinical-based nomogram for predicting the success rate of high-volume Foley catheterization for labor induction.

METHODS

This retrospective study included 1149 full-term pregnant women who received high-volume Foley catheterization for labor induction from January 2019 to December 2021 in Changshu No.1 People's Hospital. Univariate and multivariate logistic regression analyses were performed, in which the labor induction success was set as dependent variables and the characteristics (including age, height, weight, BMI, gravidity, parity, gestational age, uterine height, abdominal circumference, cervical Bishop score, amniotic fluid index, cephalic presentation, neonatal weight, pregnancy complications, etc.) were set as independent variables. A nomogram scoring model was established based on these risk factors, and a calibration curve was plotted to verify the predictive accuracy of the model.

RESULTS

The success rate of labor induction was 83.55% (960/1149). Univariate analysis revealed that the risk factors associated with the success rate of high-volume Foley catheterization for labor induction were height, pregnancy, birth, age, weight, BMI, uterine height, abdominal circumference, and hypertension. Multivariate logistic regression analysis showed that age (OR = 0.950; 95% CI: 0.904 ~ 0.998), height (OR = 1.062; 95% CI: 1.026 ~ 1.100), BMI (OR = 0.871; 95% CI: 0.831 ~ 0.913), and parity (OR = 8.007; 95% CI: 4.483 ~ 14.303) were independent risk factors for labor induction success by high-volume Foley catheterization. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve in the prediction model was 0.752 (95% CI 0.716 ~ 0.788). A nomogram was constructed based on the final multivariate analysis with a corrected C-index of 0.748, which indicated that the model was calibrated reasonably.

CONCLUSION

Four risk factors were used to construct a nomogram to evaluate the success rate of high-volume Foley catheterization for labor induction. The nomogram provides a visual clinical tool to assist in the selection of the most appropriate mode of labor induction for pregnant women of different risk levels.

FIGO good practice recommendations for induced or spontaneous labor at term: Prep-for-Labor triage to minimize risks and maximize favorable outcomes

The goal of induced or spontaneous labor is childbirth by vaginal delivery. Delivery after 37 weeks is desirable and associated with favorable maternal and newborn outcomes. Delivery facilities should have suitable staff and resources on site for antenatal services and delivery care. FIGO's Prep-for-Labor triage method provides rapid diagnostic tools that help define patients as high or low risk to determine whether transfer to a higher-level center is needed. There is often a disconnect between a facility's designation and its ability to achieve safe deliveries. For preplanned labor induction, the designated clinical facility must have the right set-up and prenatal records available to achieve a successful outcome. However, this is often not the case if a patient arrives in labor or needs an induction and the facility has limited patient information and resources, thus requiring rapid management decisions. The practical guidance checklist in this article defines maternal and/or fetal risk factors and delineates approaches and safe practices for labor induction and management, including when antenatal information is limited to maximize safe delivery practices. Guidelines on using the Bishop score (>6 or <6) to manage labor are presented. Evidence supporting successful safe labor induction at 41-42 weeks of gestation in low-risk cases is described. This practice will increase the rate of spontaneous labor and delivery, minimizing intervention and thereby diverting limited clinical resources to those patients in need. In the right setting, this could lead to around 80% of women delivering spontaneously, which remains a desired goal.

The Association between Cervical Length and Successful Labor Induction: A Retrospective Cohort Study

This study aimed to determine whether transvaginal sonographic measurement of cervical length before labor induction can predict successful induction. This retrospective study recruited 138 pregnant women who underwent labor induction at 37-41 weeks of gestation. Cervical length was measured using transvaginal ultrasonography before labor induction. Labor was induced according to the hospital protocol. Age, gestational age (GA), parity, body mass index (BMI), Bishop score, hemoglobin level, maternal disease, and epidural anesthesia were also recorded. Labor induction outcomes, including cesarean section for failed induction, time of induction, and the three labor stages, were assessed. From December 2018 to December 2021, 138 women were recruited for our study, including 120 and 18 women with successful and failed labor induction, respectively. Shorter cervical length (≤3.415 cm, OR = 6.22, 95% CI = 1.75-22.15) and multiparity (OR = 17.69, 95% CI = 2.94-106.51) were associated with successful induction. Higher BMI was associated with failed induction (OR = 0.87, 95% CI = 0.75-0.99). Age, GA, Bishop score, and fetal birth weight were not associated with successful labor induction. The ROC curve showed a cervical length cutoff value of 3.415 cm, revealing 76.8% of the area under the curve. In conclusion, a shorter cervical length (≤3.415 cm) was associated with a higher chance of successful labor induction (76.8%). This parameter might be used to predict the chance of successful labor induction. This information could help better inform clinician discussions with pregnant women concerning the chance of successful labor induction and consequent decision-making. Nevertheless, further large-scale clinical trials are warranted.

Nomogram based on the final antepartum ultrasound features before delivery for predicting failed spontaneous vaginal delivery in nulliparous women

Background

Accurate identification of nulliparous women with failed spontaneous vaginal delivery (SVD) is crucial to minimize the hazards associated with obstetrical intervention (OI). While abnormal labor progression can be identified with intrapartum ultrasonography, labor-related complications may be unavoidable due to the limited time window left to the obstetrician. Antepartum ultrasound enables sufficient obstetric planning. However, there is typically a longer gap between ultrasound assessment and delivery that often lowers the prediction accuracy compared to intrapartum ultrasonography.

Objective

In this study, antepartum ultrasound assessment was included to each fetal ultrasound examination after 36 weeks of gestation until the onset of labor. We aim to establish a nomogram to predict the likelihood of failed SVD in nulliparous women using the last antepartum ultrasound findings before labor beginning.

Methods

Of the 2,143 nulliparous women recruited, 1,373 were included in a training cohort and 770 in a validation cohort, based on their delivery date. Maternal and perinatal characteristics, as well as perinatal ultrasound parameters were collected. In the training cohort, the screened correlates of SVD failure were used to develop a nomogram for determining whether a nulliparous woman would experience SVD failure. This model was validated in both training and validation cohorts.

Results

SVD failure affected 217 nulliparous women (10.13%). In the training cohort, SVD failure was independently associated with BMI [odds ratio (OR) = 1.636], FHC (OR = 1.194), CL (OR = 1.398), and PCA (OR = 0.824) (all P < 0.05). They constituted a nomogram to estimate the individual risk of SVD failure. The model obtained clinical net benefits in both the training and validation cohorts and was validated to present strong discrimination and calibration.

Conclusion

The developed nomogram based on the last antepartum ultrasound findings may be helpful in avoiding OI and its related complications by assessing the likelihood of a failed SVD in nulliparous women.

Comparison of transvaginal sonographic cervical length measurement and Bishop score for predicting labour induction outcomes

OBJECTIVES

Induction of labour (IOL) is of increasing prevalence worldwide and reliable prediction of its successful outcome is important. Traditional clinical methods for predicting successful IOL outcomes have been supplemented with newer technologies. The aim of this study was to compare transvaginal sonographic (TVS) cervical length measurement with Bishop score in predicting labour induction outcomes.

METHODS

This study included pregnant women with term pregnancy, indication for IOL and unfavourable cervix (Bishop score >6) who had TVS performed prior to IOL. Exclusion critetia were regular contractions, ruptured membranes, non-cephalic presentation, uterine scar and pregnancy complications potentially influencing study outcomes. Outcomes measured were successful IOL defined as achievement of active phase of labour and vaginal delivery. Receiver operating characteristic (ROC) curves were used to determine diagnostic accuracy and sensitivity, specificity, positive and negative predictive values. Statistical significance was defined as p<0.05.

RESULTS

Among 112 studied participants, IOL was successful in 101 (90.2%) pregnant women. AUC for Bishop score >2 was 0.831 (95% CI, 0.744-0.917, p<0.001) and for cervical length <30 mm 0.679 (95% CI 0.514-0.844, p<0.052). A total of 81 (72.3%) pregnant women delivered vaginally; AUC for Bishop score >2 was 0.754 (95% CI 0.648-0.861, p<0.001) and for cervical length <30 mm 0.602 (95% CI 0.484-0.720, p=0.092) which was the only insignificant predictor.

CONCLUSIONS

Bishop score >2 is a better predictor for both successful IOL and vaginal delivery among induced women with term pregnancy and unfavourable cervix compared to cervical length <30 mm.