Methods for assessing pre-induction cervical ripening

Standardized protocol for labor induction: a type I hybrid effectiveness-implementation trial

Background

Cesarean delivery remains the most common obstetrical procedure with more than 250,000 patients in the US undergoing cesarean following labor induction annually. Here, we evaluated the impact of prospectively implementing a standardized labor induction protocol on cesarean delivery rates.

Methods

This multi-site type I hybrid effectiveness-implementation study compared 2 years before (PRE) and 2 years after (POST) implementation of a standardized labor induction protocol at two hospitals within the University of Pennsylvania Health System (2018-2022). The protocol included multiple components and recommended active management of labor induction, including frequent cervical examinations, amniotomy if cervical exam ≥4 cm, and interventions for labor dystocia. The primary effectiveness outcome was cesarean delivery. Secondary effectiveness outcomes included labor length, chorioamnionitis, and maternal and neonatal morbidity. The primary implementation outcome was fidelity, defined as adherence to ≥75% of the protocol components among 8 individual components that could be evaluated discretely. All data was collected via individual chart review.

Findings

8509 patients were included (PRE: n = 4214, POST: n = 4295). Our population was of median age of 31 years interquartile range (IQR) [26-35], and 44.6% identified as Black, 40.1% as white, 6.9% as Asian, and 8.4% as other or unknown; 7.4% of the population identified as Latinx. There was no significant difference in cesarean delivery rate between the two time periods overall (PRE: 21.6% vs. POST: 21.8%, p = 0.85; adjusted relative risk (aRR) 0.99 95% confidence interval (CI) [0.90-1.09]). There were no significant differences in labor length, chorioamnionitis, or composite neonatal morbidity. Maternal morbidity decreased PRE to POST (PRE: 9.3% vs. POST: 6.5%, p < 0.001; aRR 0.67 95% CI [0.58-0.79]). POST-implementation, inductions with fidelity to ≥75% of protocol components increased (PRE: 52.4% vs. POST: 59.6%, p < 0.001), evidenced by more frequent cervical examinations, earlier dilation at amniotomy, and increased labor dystocia management.

Interpretation

Despite increasing standardized induction management, no significant difference in cesarean delivery was found.

Funding

NICHD K23HD102523.

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.

The Use of Evening Primrose Oil for Cervical Ripening in Low-Risk Women with Term Pregnancy: A Randomized Double-Blinded Controlled Trial

BACKGROUND

Several methods have been developed for cervical ripening. The data regarding the efficiency of evening primrose oil (EPO) are inconsistent. The purpose of this study was to investigate the outcomes of EPO use on cervical ripening in low-risk women with term pregnancy.

PATIENTS AND METHODS

Low-risk term pregnant women referred to the obstetrics clinic of Imam Hossein Hospital in Tehran who were eligible according to the inclusion were randomized either to the case or control group. The case group received 1,000 mg vaginal EPO capsule, and the other group received a vaginal placebo capsule daily, similar to the original drug. The primary outcome was Bishop score, while the duration of labor phases and the inducing procedures were the secondary outcomes.

RESULTS

Forty-eight participants were randomized to each group and were considered for data analysis. Although Bishop score was not statistically different before the intervention, it was significantly higher in case group compared to the placebo group after the intervention (EPO = 5.83 ± 1.68, placebo = 5.19 ± 1.52, p value = 0.002). Four participants in the case group and two in the control group underwent cesarean section (p value = 0.677). The need for labor induction was significantly higher in the placebo group than EPO group (oxytocin injection: 10.4% vs. 31.3%, p value = 0.012, amniotomy: 75% vs. 41.7, p value = 0.001).

CONCLUSION

The vaginal use of EPO could be considered as a safe and efficient approach for cervical ripening in low-risk term pregnant women.

Hintergrund

Es wurden verschiedene Methoden zur Zervixreifung entwickelt. Die Daten zur Wirksamkeit von Nachtkerzenöl (evening primrose oil, EPO) sind uneinheitlich. Mit dieser Studie sollen die Ergebnisse der Anwendung von EPO zur Zervixreifung bei Frauen mit niedrigem Risiko und termingerechter Schwangerschaft untersucht werden.

Patientinnen und Methoden

Schwangere Frauen mit niedrigem Risiko und termingerechter Schwangerschaft, die in die Geburtsklinik des Imam-Hossein-Krankenhauses in Teheran eingewiesen wurden und gemäss den Einschlusskriterien für die Teilnahme infrage kamen, wurden randomisiert der Fall- oder der Kontrollgruppe zugewiesen. Die Fallgruppe erhielt 1.000 mg EPO als Vaginalkapseln, während die andere Gruppe täglich eine vaginale Placebokapsel erhielt, die dem Originalpräparat ähnelte. Primäres Zielkriterium war der Bishop-Score und sekundäre Zielkriterien waren die Dauer der Wehenphasen sowie die Verfahren zur Geburtseinleitung.

Ergebnisse

Jeder Gruppe wurden randomisiert 48 Teilnehmerinnen zugewiesen und bei der Datenanalyse berücksichtigt. Während vor der Intervention kein statistisch signifikanter Unterschied im Bishop-Score bestand, fiel dieser nach der Intervention in der Fallgruppe signifikant höher aus als in der Placebogruppe (EPO = 5,83 ± 1,68, Placebo = 5,19 ± 1,52, p-Wert = 0,002). Bei vier Teilnehmerinnen in der Fallgruppe und zwei in der Kontrollgruppe wurde ein Kaiserschnitt durchgeführt (p-Wert = 0,677). Die Notwendigkeit einer Weheneinleitung war in der Placebogruppe signifikant höher als in der EPO-Gruppe (Oxytocin-Injektion: 10,4% vs. 31,3%, p-Wert = 0,012, Amniotomie: 75% vs. 41,7%, p-Wert = 0,001).

Schlussfolgerung

Die vaginale Anwendung von EPO kann als sicherer und wirksamer Ansatz zur Zervixreifung bei Frauen mit niedrigem Risiko und termingerechter Schwangerschaft angesehen werden.

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.

An evaluation of cervical maturity for Chinese women with labor induction by machine learning and ultrasound images

BACKGROUND

To evaluate the improvement of evaluation accuracy of cervical maturity for Chinese women with labor induction by adding objective ultrasound data and machine learning models to the existing traditional Bishop method.

METHODS

The machine learning model was trained and tested using 101 sets of data from pregnant women who were examined and had their delivery in Peking University Third Hospital in between December 2019 and January 2021. The inputs of the model included cervical length, Bishop score, angle, age, induced labor time, measurement time (MT), measurement time to induced labor time (MTILT), method of induced labor, and primiparity/multiparity. The output of the model is the predicted time from induced labor to labor. Our experiments analyzed the effectiveness of three machine learning models: XGBoost, CatBoost and RF(Random forest). we consider the root-mean-squared error (RMSE) and the mean absolute error (MAE) as the criterion to evaluate the accuracy of the model. Difference was compared using t-test on RMSE between the machine learning model and the traditional Bishop score.

RESULTS

The mean absolute error of the prediction result of Bishop scoring method was 19.45 h, and the RMSE was 24.56 h. The prediction error of machine learning model was lower than the Bishop score method. Among the three machine learning models, the MAE of the model with the best prediction effect was 13.49 h and the RMSE was 16.98 h. After selection of feature the prediction accuracy of the XGBoost and RF was slightly improved. After feature selection and artificially removing the Bishop score, the prediction accuracy of the three models decreased slightly. The best model was XGBoost (p = 0.0017). The p-value of the other two models was < 0.01.

CONCLUSION

In the evaluation of cervical maturity, the results of machine learning method are more objective and significantly accurate compared with the traditional Bishop scoring method. The machine learning method is a better predictor of cervical maturity than the traditional Bishop method.

A Retrospective Comparative Study of the Effect of Controlled-Release Dinoprostone Vaginal Delivery System (Propess®) and Mechanical Methods for Cervical Ripening in Nulliparous Women in Late-Term Pregnancy

OBJECTIVE

The effects of the controlled-release dinoprostone vaginal delivery system (Propess®) and mechanical methods for cervical ripening in nulliparous women in late-term pregnancy were compared retrospectively.

METHODS

This retrospective comparative study included 46 nulliparous pregnant women (24 in the Propess® group and 22 in the mechanical methods groups) with a low Bishop score (≤1) who needed labor induction at 41 weeks of gestation. The primary outcome was the success rate of cervical ripening (= Bishop score >6 or vaginal delivery) by the next day following the insertion of Propess® only or mechanical cervical dilation only. In the cases in which cervical ripening was unsuccessful, other methods were performed, and the success rate of cervical ripening the day after was compared as the secondary outcome.

RESULTS

As the primary outcome, there was not a significant difference in the success rate of cervical ripening between the Propess® and mechanical methods groups (21 vs. 22%, p = 0.88). As for the secondary outcomes, there was not a significant difference in the total success rate of cervical ripening between the two groups (75 (5+13/24) vs. 73 (5+11/22)%, p = 0.86)). Of the unsuccessful cervical ripening cases as secondary outcomes, the Bishop score of all was ≤2 on the second day of hospitalization.

CONCLUSION

The combined use of Propess® and mechanical methods was effective for cervical ripening in nulliparous women with a low Bishop score in late-term pregnancy, regardless of order.

Comparison of Obstetric Outcomes Between Controlled-Release Dinoprostone Vaginal Delivery System (PROPESS) and Administration of Oral Dinoprostone for Labor Induction in Multiparous Women at Term

OBJECTIVE

The aim of this study was to compare the rate of vaginal delivery and adverse outcomes of a controlled-release dinoprostone vaginal delivery system (PROPESS) and the administration of oral dinoprostone for labor induction in multiparous women at term.

METHODS

This retrospective case-controlled study included 92 multiparous pregnant women (46 and 46 in the PROPESS and oral dinoprostone groups, respectively) who required labor induction at ≥37 weeks of gestation. The primary outcome was the success rate of vaginal delivery following the insertion of PROPESS only or the administration of oral dinoprostone (up to six tablets) only. The secondary outcomes were uterine tachysystole with non-reassuring fetal status, the proportion of cases requiring pre-delivery oxytocin, and the rate of cesarean delivery.

RESULTS

The proportion of pregnant women who delivered vaginally as the primary outcome was significantly higher in the PROPESS group (33/46 [72%]) than in the oral dinoprostone group (16/46 [35%], p < 0.01). In the secondary outcomes, the proportion of cases requiring pre-delivery oxytocin in the PROPESS group was significantly lower than that in the oral dinoprostone group (24% vs. 57%, p < 0.01).

CONCLUSIONS

In multiparous women at term, PROPESS may be able to induce labor and lead to a higher vaginal delivery rate without adverse outcomes compared to oral dinoprostone.

Prediction of an effective cervical ripenning in the induction of labour using vaginal dinoprostone

To develop a predictive model for successful cervical ripening in women that undergo induction of labour by means of a vaginal prostaglandin slow-release delivery system (Propess®).  Prospective observational study on 204 women that required induction of labour between February 2019 and May 2020 at "La Mancha Centro" hospital in Alcázar de San Juan, Spain. The main variable studied was effective cervical ripening (Bishop score > 6). Using multivariate analysis and binary logistic regression, we created three initial predictive models (model A: Bishop Score + Ultrasound cervical length + clinical variables (estimated fetal weight, premature rupture of membranes and body mass index)); model B: Ultrasound cervical lenght + clinical variables; and model C: Bishop score + clinical variables) to predict effective cervical ripening. All three predictive models obtained (A, B and C) presented good predictive capabilities, with an area under the ROC curve ≥ 0.76. Predictive model C, composed of the variables: gestational age (OR 1.55, 95% CI 1.18-2.03, p = 0.002), premature rupture of membranes (OR 3.21 95% CI 1.34-7.70, p = 0.09) body mass index (OR 0.93, 95% CI 0.87-0.98, p = 0.012), estimated fetal weight (OR 0.99, 95% CI 0.99-1.00, p = 0.068) and Bishop score (OR 1.49 95% CI 1.18-1.81, p = 0.001), is presented as the model of choice with an area under the ROC curve of 0.76 (95% CI 0.70-0.83, p < 0.001). A predictive model composed of the variables: gestational age, premature rupture of membranes, body mass index, estimated fetal weight and Bishop score upon admission presents good capabilities in predicting successful cervical ripening following administration of prostaglandins. This tool could be useful in making clinical decisions with regard to induction of labour.

Gestational diabetes mellitus: The optimal time of delivery

Gestational diabetes mellitus (GDM) is a common pregnancy complication strongly associated with poor maternal-fetal outcomes. Its incidence and prevalence have been increasing in recent years. Women with GDM typically give birth through either vaginal delivery or cesarean section, and the maternal-fetal outcomes are related to several factors such as cervical level, fetal lung maturity, the level of glycemic control still present, and the mode of treatment for the condition. We categorized women with GDM based on the latter two factors. GDM that is managed without medication when it is responsive to nutrition- and exercise-based therapy is considered diet- and exercise-controlled GDM, or class A1 GDM, and GDM managed with medication to achieve adequate glycemic control is considered class A2 GDM. The remaining cases in which neither medical nor nutritional treatment can control glucose levels or patients who do not control their blood sugar are categorized as class A3 GDM. We investigated the optimal time of delivery for women with GDM according to the classification of the condition. This review aimed to address the benefits and harms of giving birth at different weeks of gestation for women with different classes of GDM and attempted to provide an analytical framework and clearer advice on the optimal time for labor.

Association between the cervical sliding sign and successful induction of labor in women with an unfavorable cervix: A prospective observational study

OBJECTIVES

To evaluate the role of the cervical sliding sign (CSS) in the prediction of the outcome of induction of labor (IOL).

STUDY DESIGN

Two-center prospective observational cohort study involving a non-consecutive series of uncomplicated singleton term pregnancies, planned for IOL, with a fetus in cephalic presentation and unfavorable cervix as defined by a Bishop score ≤ 6. The Bishop score was evaluated by transvaginal digital examination and the cervical length and CSS by transvaginal ultrasound. The presence of CSS was defined as the sliding of the anterior cervical lip on the posterior one under gentle pressure of the transvaginal probe. The primary outcome of the study was successful vaginal delivery within 24 h. The secondary outcome was the induction-to-active-labor time. The interobserver agreement for the CSS was also evaluated.

RESULTS

Over a period of 12 months, 179 women were included. The CSS was found in 86 (48.0 %) patients and was associated with an increased likelihood of vaginal delivery within 24 h (60/86 or 69.8 % vs 27/93 or 29.0 %, P < 0.001) and a shorter induction-to-active-labor time (954 ± 618 min vs 1416 ± 660 min, P < 0.001). Multivariable regression analysis showed that the CSS was an independent predictor of vaginal delivery within 24 h (aOR 5.37, 95 % CI 2.26-12.75) and shorter induction-to-active-labor time interval (HR 1.81, 95 % CI 1.19-2.74). The interobserver variability based on intraclass correlation coefficient for the CSS was excellent (ICC = 0.90).

CONCLUSION

In women undergoing IOL with an unfavorable cervix, the CSS is associated with a higher frequency of vaginal delivery within 24 h and a shorter induction-to-active-labor time.

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

Objective

To evaluate the association between transvaginal ultrasound scan of cervix and Bishop’s score in predicting successful induction of labour, cut-off points and patients’ tolerability and acceptance for both procedures.

Design

A comparative clinical trial.

Setting

A tertiary hospital in Selangor, Malaysia.

Participants

294 women planned for elective induction of labour for various indications were included. All women had transvaginal ultrasound to assess the cervical length and digital vaginal examination to assess the Bishop cervical scoring by separate investigators before induction of labour.

Primary outcome measure

To evaluate the association of the cervical length by transvaginal ultrasound scan and Bishop score in predicting successful induction of labour.

Secondary outcome measure

Variables associated with successful induction of labour and patients’ tolerability and acceptance for transvaginal ultrasound scan of cervix.

Results

There was no statistically significant difference among the vaginal and Caesarean delivery groups in terms of mean maternal age, height, weight, body mass index, ethnicity and gestational age at induction. Vaginal delivery occurred in 207 women (70.4%) and 87 women (29.6%) delivered via Caesarean section. There was a high degree of correlation between the cervical length and Bishop score (r-value 0.745; p <0.001). Sonographic assessment of cervical length demonstrated a comparable accuracy in comparison to Bishop score. Analysis using ROC curves noted an optimal cut-off value of ≤27mm for cervical length and Bishop score of ≥ 4, with a sensitivity of 69.1% vs 67%, specificity 60.9% vs 55%, and area under the curves (AUCs) of 0.672 and 0.643 respectively (p <0.001). Multivariate logistic regression analysis demonstrated that parity (OR 2.70), cervical length (OR 0.925), Bishop score (OR 1.272) and presence of funnelling (OR 3.292) were highly significant as independent predictors of success labour induction. Women also expressed significantly less discomfort with transvaginal ultrasound compared with digital vaginal examination.

Conclusion

Sonographic assessment of cervical measurement predicts the success of induction of labour with similar diagnostic accuracy with conventional Bishop score.

A Peripheral Immune Signature of Labor Induction

Approximately 1 in 4 pregnant women in the United States undergo labor induction. The onset and establishment of labor, particularly induced labor, is a complex and dynamic process influenced by multiple endocrine, inflammatory, and mechanical factors as well as obstetric and pharmacological interventions. The duration from labor induction to the onset of active labor remains unpredictable. Moreover, prolonged labor is associated with severe complications for the mother and her offspring, most importantly chorioamnionitis, uterine atony, and postpartum hemorrhage. While maternal immune system adaptations that are critical for the maintenance of a healthy pregnancy have been previously characterized, the role of the immune system during the establishment of labor is poorly understood. Understanding maternal immune adaptations during labor initiation can have important ramifications for predicting successful labor induction and labor complications in both induced and spontaneous types of labor. The aim of this study was to characterize labor-associated maternal immune system dynamics from labor induction to the start of active labor. Serial blood samples from fifteen participants were collected immediately prior to labor induction (baseline) and during the latent phase until the start of active labor. Using high-dimensional mass cytometry, a total of 1,059 single-cell immune features were extracted from each sample. A multivariate machine-learning method was employed to characterize the dynamic changes of the maternal immune system after labor induction until the establishment of active labor. A cross-validated linear sparse regression model (least absolute shrinkage and selection operator, LASSO) predicted the minutes since induction of labor with high accuracy (R = 0.86, p = 6.7e-15, RMSE = 277 min). Immune features most informative for the model included STAT5 signaling in central memory CD8⁺ T cells and pro-inflammatory STAT3 signaling responses across multiple adaptive and innate immune cell subsets. Our study reports a peripheral immune signature of labor induction, and provides important insights into biological mechanisms that may ultimately predict labor induction success as well as complications, thereby facilitating clinical decision-making to improve maternal and fetal well-being.

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.

Transvaginal two-dimensional ultrasound measurement of cervical volume to predict the outcome of the induction of labour: a prospective observational study

Background

Assessing the likelihood of success of induction of labour using ultrasonically measured cervical volume is an important research question.

Method

A prospective observational study was carried out at North Colombo Teaching Hospital, Ragama, Sri Lanka. Pre-induction digital cervical assessment, transvaginal cervical length, and cervical volume measurements were performed. Inductions with singleton pregnancies at term were included. Basic demographic and clinical details, independent variables (Bishop score, cervical length and cervical volume), and dependent variables (frequency of delivery within 24 h and induction to delivery interval) were recorded. Vaginal delivery within 24 h was the primary outcome.

Results

We studied 100 pregnant women who had induction of labour. Median (IQR) Bishop score was 5 (3–6), mean (SD) cervical length was 3.6 (0.7) cm, and mean (SD) cervical volume was 27.5 (10.4) cm³. Cervical length was the best predictor for predicting the likelihood of vaginal delivery within 24 h [aOR – 12.12 (3.44, 42.71); < 0.001], and cervical volume also appeared to be a significant potential predictor [aOR-1.10 (1.01, 1.17); 0.01]. Cervical length was found to have the highest AUC (0.83) followed by the cervical volume (0.74). The best cut-off value for cervical volume in predicting the likelihood of vaginal delivery within 24 h was less than 28.5 cm³ with a sensitivity of 72% and specificity of 74%.

Conclusions

Transvaginal sonographic measurement of cervical volume appears to be a potential novel predictor for the likelihood of vaginal delivery within 24 h of induction of labour. Cervical length is still more superior to cervical volume in predicting the likelihood of vaginal delivery. Bishop score was not a significant predictor in this context.

Is Unfavourable Cervix prior to Labor Induction Risk for Adverse Obstetrical Outcome in Time of Universal Ripening Agents Usage? Single Center Retrospective Observational Study

Cervical assessment on the Bishop scale prior to induction of labor (IOL) is one of the strongest prognostic criteria in relation to the success of the procedure. The commonly used preinduction methods are mainly aimed at reducing the percentage of cesarean sections. Our study has analyzed obstetric results of patients who had unripe cervix (Bishop score <7) before IOL and used preinduction (Foley catheter or misoprostol vaginal insert releasing 7 mcg of misoprostol per hour for 24 hours) with obstetric results of patients in whom, due to favourable cervix, only a low-dose infusion of oxytocin was used. We reviewed the medical records of 1010 single pregnancies in whom IOL was performed. We divided the patients into two groups: group A (where preinduction was used) and group B (Bishop score ≥7 points) where preinduction was not used. Patients in group A were more likely to complete the delivery by caesarean section (OR = 4.58, 95% CI 3.22-6.51), and more likely to have events that were indications for operative delivery: unreassuring fetal heart rate trace (OR = 3.29, 95% CI 2.07-5.23) and arrested labor or failed induction (OR = 3.4, 95% CI 2.06-5.62). The groups did not differ in the percentage of vacuum extraction, postpartum haemorrhage, and meconium stained amniotic fluid. In group B, more infants were born with umbilical cord blood pH <7.1 (1.38% vs. 0%), both groups included no deliveries of newborns with Apgar score ≤3 points, the groups did not differ in terms of the percentage of newborns with Apgar score between 4 and 7 at birth (OR = 0.66, 95% CI 0.29-1.49). The immature cervix and the need to use labor preinduction is a risk factor for caesarean section. The necessity of preinduction does not impair neonatological results.

The Effect of Ultrasound-Measured Preinduction Cervical Length on Delivery Outcome in a Low-Resource Setting

Background

Induction of labour is not without risk, and it calls for a method that will be sensitive enough to predict successful labour induction.

Aim

This study aims to evaluate the role of transvaginal ultrasonographic cervical length measurement at term in the prediction of successful induction of labour (IOL).

Materials and Methods

This prospective study was carried out in the Department of Obstetrics and Gynaecology of Federal Teaching Hospital Abakaliki between 1st of July and 30^th of November 2015. Preinduction Bishop score and cervical length were assessed before induction of labour. Intracervical, cervical, extraamniotic Foley catheter was used to improve the Bishop score. The data were analyzed using the IBM SPSS Statistics 20.

Results

The mean maternal age of the study group was 30.68 ± 6.38 years with a range of 19–43 years. The mean gestational age and parity were 39.57 ± 1.49 and 1.85 ± 0.63, respectively. All the women studied had successful induction of labour with mean induction delivery time of 8.1 ± 3.0 hours and mean duration of labour of 7.4 ± 2.9 hours. Preinduction cervical length is a good predictor of a short duration of labour (P = 0.001). Parturient with a preinduction cervical length of less than 3 cm was likely to have labour lasting less than 6 hours (RR = 4.20 (95% CI 1.85–9.529).

Conclusion

Transvaginal sonographic measurement of cervical length provides a useful prediction of the likelihood of duration of labour following the induction of labour. It is recommended that IOL should be considered and success anticipated in a parturient with a cervical length less than 3 cm.

Antenatal cervical length measurement as a predictor of successful vaginal birth

Background

Antenatal cervical length measurement has paramount importance in the prediction of labor. It was compared to the Bishop Score and incorporated in the modified Bishop score due to its relevance and convenience. It is a more accurate tool that imposes no harm or distress to the patients. The study aimed to evaluate the role of antenatal cervical length measurement in the prediction of a successful vaginal birth and its relation to the duration of labor.

Methods

This was a prospective cohort study, conducted at the emergency ward of obstetrics and gynecology department. We recruited 162 women over 1 year from January 2018 to January 2019. Women eligible for the study had a transvaginal ultrasound for the examination of the cervical length before the onset of labor. The success of vaginal delivery was evaluated.

Results

The mean cervical length (mm) was 43.3 ± 8.0. The majority of the patients labored spontaneously [102 (63.0%)] while the remaining ones required induction of labor due to different causes. One hundred and eight patients (66.7%) had a successful vaginal delivery. The cervical length was significantly shorter among patients who delivered vaginally than those delivered by CS (P-value < 0.001). Multiple factors had a significant role in the prediction of the mode of delivery (cervical length, BMI, the onset of labor, parity). Maternal body mass index and labor induction were associated with a prolonged duration of the active phase of labor.

Conclusion

Antenatal cervical length measurement predicted the mode of delivery as well as the gestational age at which delivery ensued. It can be used in patients’ counseling regarding the mode of delivery.

CERVICAL RIPENING BALLOON AS A METHOD OF PREINDUCTION - ONE CENTER STUDY

- Cervical ripening can be promoted in many ways, but mechanical methods are among the oldest. Like all other methods, this one also has its pros and cons. Disadvantages compared to pharmacological methods include some maternal discomfort upon manipulation of the cervix, a theoretical increase in the risk of maternal and neonatal infection from the introduction of a foreign body, potential disruption of a low-lying placenta, and increase in the need of oxytocin induction of labor. The aim of the study was to evaluate the effect of using cervical ripening balloon in preinduction on the mode of delivery. This was a longitudinal, cohort, intervention, non-randomized one center study. Inclusion criteria were term pregnancies with gestational diabetes, oligohydramnios, intrauterine growth restriction, gestational hypertension/preeclampsia and pregnancies after 41 weeks of pregnancy. Preinduction of labor was performed in term pregnancies at Sestre milosrdnice University Hospital Center. Results in the first 150 women having undergone labor preinduction with cervical ripening balloon were included. Two-sided p values <0.05 were considered significant. Statistical analysis was done using SPSS Version 20.0. The study included 150 women; one woman was excluded from further analyses due to conversion of fetal presentation (head to breech). Indications for labor preinduction were as follows: gestational diabetes, oligohydramnios, intrauterine growth restriction, gestational hypertension/preeclampsia and pregnancies after 41 weeks of pregnancy. Women with normal vaginal delivery (96/149) had lower rates of gestational diabetes and oligohydramnios and used epidural analgesia more frequently. Women with dystocia (32/53) had a significantly longer labor duration and higher neonatal birth weight. In multivariate analysis, multiparity, greater cervical dilatation after balloon removal and use of epidural analgesia were associated with a decreased risk of cesarean section, while the presence of gestational diabetes and oligohydramnios was associated with an increased risk of cesarean section. We found this preinduction method safe and efficient, with a potential to increase the rate of vaginal deliveries.

Cervical length measurement in nulliparous women at term by ultrasound & its relationship to spontaneous onset of labour

Background & objectives:

Data on serial cervical length (CL) measurements in pregnancy at term to predict spontaneous labour onset are scarce and conflicting. This study was conducted to observe CL changes preceding spontaneous onset of labour, by serial transvaginal sonography (TVS) and transabdominal sonography (TAS), in nulliparous Indian women near term.

Methods:

Only nulliparous women with a singleton foetus in cephalic presentation and who confirmed their gestational age were recruited. Sonographic CL measurements were taken at weekly intervals from 36 wk gestation onwards by a single ultrasonologist. Transabdominal and transvaginal measurements were undertaken using the suitable transducer probes with the women in the supine position.

Results:

A total of 104 women with spontaneous onset of labour were evaluated. There was substantial variation in CL measurements, both by TVS and by TAS, from 36 to 40 wk gestation, although the two sets of measurements correlated closely. Mean CL changed significantly over the last three weeks before delivery. However, only one-third of the women showed CL change of >5 mm per week in the last three weeks. There was poor correlation between gestational age at delivery and the last measured CL, either by TVS or TAS. Length >3.1 mm, measured by TVS at 38 wk gestation, predicted post-dated pregnancy to a limited extent.

Interpretation & conclusions:

Inter-individual variations in CL and in CL changes were large. Thus, it was not practical to predict spontaneous onset of labour by sonographic CL measurement near term. Post-dated pregnancy may be predicted with limited success. Further studies should explore other parameters, in addition to CL.

Labor Induction Techniques: Which Is the Best?

Induction of labor is a common procedure undertaken whenever the benefits of prompt delivery outweigh the risks of expectant management. Cervical assessment is essential to determine the optimal approach. Indication for induction, clinical presentation and history, safety, cost, and patient preference may factor into the selection of methods. For the unfavorable cervix, several pharmacologic and mechanical methods are available, each with associated advantages and disadvantages. In women with a favorable cervix, combined use of amniotomy and intravenous oxytocin is generally the most effective approach. The goal of labor induction is to ensure the best possible outcome for mother and newborn.

Comparison of vaginal misoprostol, laminaria, and isosorbide dinitrate on cervical preparation and labor duration of term parturient: a randomized double-blind clinical trial

Background

Cervical ripening plays an important role in successful labor induction.

Objective

This study aimed to compare the effects of misoprostol, laminaria tent, and isosorbide dinitrate (ISDN) on cervical ripening.

Methods

This double-blind three-armed clinical trial was conducted at Shahidan Mombini Teaching Hospital in Sabzevar, Iran, in 2016 on 96 singleton term pregnant women. Participants were randomly allocated to receive either two 20-mg ISDN tablets vaginally every 4 hours for a maximum of three doses or 25 mcg misoprostol vaginally every 6 hours for a maximum of two doses or laminaria tent for a maximum of 12 hours. The method of randomization was covariate adaptive randomization and the primary outcome measures were Bishop Score changes and labor duration. SPSS software version 18 was used for statistical analyses. Kruskal-Wallis, chi-square and ANOVA tests were applied for data analyses.

Results

Bishop Score changes were higher in the misoprostol group than in the two other groups (p=0.014). Time from start of medication to active phase of labor and delivery were 6.22±3.11 and 11.78±5.3 minutes in the misoprostol group, 11.25±3.07 and 17.62±4.07 minutes in the laminaria group, and 10.12±3.48 and 17.37±4.79 minutes in the ISDN group respectively (p<0.001). Cesarean rate was higher in the misoprostol group than the two other groups (p=0.016). No significant differences were observed between the study groups in terms of Apgar score and meconium-stained amniotic fluid.

Conclusions

Use of misoprostol results in more improvement of Bishop Score and reduced length of labor phases in comparison to laminaria tent and ISDN.

Trial registration

The trial was registered at the Iranian Registry of Clinical Trials (http://www.irct.ir) with the Irct ID: IRCT2016050527643N2 in the Iranian Registry of Clinical Trials IRCT2015040921670N1.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Single versus double-balloon catheters for the induction of labor of singleton pregnancies: a meta-analysis of randomized and quasi-randomized controlled trials

OBJECTIVE

To compare the efficacy of single- versus double-balloon catheter (SBC vs. DBC) for cervical ripening and labor induction with an unfavorable cervix.

METHODS

Systematic review and meta-analysis of randomized controlled trials (RCTs) or quasi-RCTs (qRCT) regarding the use of SBC or DBC for labor induction of live singleton cephalic pregnancies (≥ 35 weeks) of any parity with an unripe cervix (Bishop score ≤ 6). Nine research databases were searched for original articles published in all languages up to November 2017 comparing both devices for labor induction. Five RCTs and one qRCT were included. Primary outcome measures were time from intervention (device placement) to birth time, vaginal delivery and cesarean section rates, and maternal satisfaction with the procedure. Risk of bias was evaluated with the Cochrane tool. Random effects models were used to combine data for meta-analyses. Summary measures were reported as mean differences and risk ratios (RR) with 95% confidence intervals.

RESULTS

Regardless of parity, pooled analyses of the six trials (n = 1060 women) found that mean intervention to birth time, vaginal delivery and cesarean section rates, and maternal satisfaction to the procedure were similar for both studied groups (SBC vs. DBC).

CONCLUSION

Measured primary outcome measures were similar regardless of the type of device used for labor induction of singleton pregnancies.

Cervical Evaluation: From Ancient Medicine to Precision Medicine

Since ancient times, cervical assessment for predicting timing of delivery has relied primarily on digital (subjective) assessment of dilatation, softening, and length. To date, transvaginal ultrasound cervical length is the only one of these parameters that meets criteria for a biomarker; no objective, quantitative measure of cervical dilatation or softening has gained clinical acceptance. This review discusses how the cervix has been assessed from ancient times to the present day and how a precision medicine approach could improve understanding of not only the cervix, but also parturition in general.

Comparison of Cervical Length Measured by Transvaginal Ultrasonography and Bishop Score in Predicting Response to Labor Induction

Background

This study aims to compare the value of the Bishop score and cervical length measurement by transvaginal ultrasonography in predicting active labor within 6 h, induction-to-delivery interval, and the duration of active labor and to estimate the most useful cutoff points for the two methods.

Methods

This is a prospective comparative study of Bishop score and cervical length measured by transvaginal sonography on 62 nulliparous subjects who underwent induction of labor.

Results

The Bishop score of the subjects ranged from two to seven (2-7). The mean Bishop in this study population was 4.37 + 1.23. The mean cervical length in this study was 25.59 + 6.07. Bishop score was highly significant (P value < 0.0001) in predicting active phase of labor as compared to cervical length (P = 0.004). The best cutoff value for Bishop score to predict induction of labor within 6 h was more than 4 with sensitivity of 69% and specificity of 79%. Similarly, best cutoff value for cervical length to predict induction of labor within 6 h was less than or equal to 25 mm with sensitivity of 51% and specificity of 70%. Bishop score was more significant (P = 0.001) in predicting induction-to-delivery interval within 12 h as compared to cervical length (P = 0.01).

Conclusion

The Bishop score was superior in predicting the response to induction as compared to the cervical length measured by transvaginal ultrasonography.

Double-balloon catheter for induction of labour in women with a previous cesarean section, could it be the best choice?

Introduction

We analysed the efficacy and safety of double-balloon catheter for cervical ripening in women with a previous cesarean section and which were the most important variables associated with an increased risk of repeated cesarean delivery.

Materials and methods

We designed an observational retrospective study of 418 women with unfavourable cervices (Bishop Score <5), a prior cesarean delivery, and induction of labour with a double-balloon catheter. Baseline maternal data and perinatal outcomes were recorded for a descriptive, bivariate, and multivariate analysis. A p value <0.05 was considered statistically significant.

Results

Most women improved their initial Bishop Score (89.5%) although only a 20.8% of them went into spontaneous active labour. Finally, 51.4% of the women achieved a vaginal delivery. Five cases of intrapartum uterine rupture (1.2%) occurred. After multivariate analysis, main risk factors for repeated cesarean section were dystocia in the previous pregnancy (OR 1.744; CI 95% 1.066–2.846), the absence of previous vaginal delivery (OR 2.590; CI 95% 1.066–6.290), suspected fetal macrosomia (OR 2.410; CI 95% 0.959–6.054), and duration of oxytocin induction period (OR 1.005; CI 95% 1.004–1.006). The area under the curve was 0.789 (p < 0.001).

Conclusions

Double-balloon catheter seems to be safe and effective for cervical ripening in women with a previous cesarean delivery and unfavourable cervix. In our study, most women could have a vaginal delivery in spite of their risk factors for cesarean delivery. A multivariate model based on some clinical variables has moderate predictive value for intrapartum cesarean section.

Methods for assessing pre-induction cervical ripening

BACKGROUND

Induction of labour is the artificial initiation of labour in a pregnant woman after the age of fetal viability but without any objective evidence of active phase labour and with intact fetal membranes. The need for induction of labour may arise due to a problem in the mother, her fetus or both, and the procedure may be carried out at or before term. Obstetricians have long known that for this to be successful, it is important that the uterine cervix (the neck of the womb) has favourable characteristics in terms of readiness to go into the labour state.

OBJECTIVES

To compare Bishop score with any other method for assessing pre-induction cervical ripening in women admitted for induction of labour.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 March 2015) and reference lists of retrieved studies to identify randomised controlled trials (RCTs).

SELECTION CRITERIA

All RCTs comparing Bishop score with any other methods of pre-induction cervical assessment in women admitted for induction of labour. Cluster-RCTs were eligible for inclusion but none were identified. Quasi-RCTs and studies using a cross-over design were not eligible for inclusion. Studies published in abstract form were eligible for inclusion if they provided sufficient information.Comparisons could include the following.1. Bishop score versus transvaginal ultrasound (TVUS).2. Bishop score versus Insulin-like growth factor binding protein-1 (IGFBP-1).3. Bishop score versus vaginal fetal fibronectin (fFN).However, we only identified data for a comparison of Bishop score versus TVUS.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the trials for inclusion, extracted the data and assessed trial quality. Data were checked for accuracy.

MAIN RESULTS

We included two trials that recruited a total of 234 women. The overall risk of bias was low for the two studies. Both studies compared Bishop score withTVUS.The two included studies did not show any clear difference between the Bishop score and TVUS groups for the following main outcomes: vaginal birth (RR 1.07, 95% CI 0.92 to 1.25, moderate quality evidence), caesarean delivery (RR 0.81, 95% CI 0.49 to 1.34, moderate quality evidence), neonatal admission into neonatal intensive care unit (RR 1.67, 95% CI 0.41 to 6.71, moderate quality evidence). Both studies only provided median data in relation to induction-delivery interval and reported no clear difference between the Bishop and TVUS groups. Perinatal mortality was not reported in the included studies.For the review's secondary outcomes, the need for misoprostol for cervical ripening was more frequent in the TVUS group compared to the Bishop score group (RR 0.52, 95% CI 0.41 to 0.66, two studies, 234 women, moderate quality evidence). In contrast, there were no clear differences between the Bishop scope and TVUS groups in terms of meconium staining of the amniotic fluid, fetal heart rate abnormality in labour, and Apgar score less than seven. Only one trial reported median data on the induction-delivery interval and induction to active phase interval, the trialist reported no difference between the Bishop group and the TVUS group for this outcome. Neither of the included studies reported on uterine rupture.

AUTHORS' CONCLUSIONS

Moderate quality evidence from two small RCTs involving 234 women that compared two different methods for assessing pre-induction cervical ripening (Bishop score and TVUS) did not demonstrate superiority of one method over the other in terms of the main outcomes assessed in this review. We did not identify any data relating to perinatal mortality. Whilst use of TVUS was associated with an increased need for misoprostol for cervical ripening, both methods could be complementary.The choice of a particular method of assessing pre-induction cervical ripening may differ depending on the environment and need where one is practicing since some methods (i.e. TVUS) may not be readily available and affordable in resource-poor settings where the sequelae of labour and its management is prevalent.The evidence in this review is based on two studies that enrolled a small number of women and there is insufficient evidence to support the use of TVUS over the standard digital vaginal assessment in pre-induction cervical ripening. Further adequately powered RCTs involving TVUS and the Bishop score and including other methods of pre-induction cervical ripening assessment are warranted. Such studies need to address uterine rupture, perinatal mortality, optimal cut-off value of the cervical length and Bishop score to classify women as having favourable or unfavourable cervices and cost should be included as an outcome.