Can ultrasound measurements replace digitally assessed elements of the Bishop score?

Association between placental site and successful induction of labor among postdate primiparous women

PURPOSE

This study aimed to determine the association between placental site and successful labor induction.

METHODS

This cross-sectional study recruited all postdate primiparous women undergoing induction of labor. Eligible women were subjected to proper history taking and clinical examination. Vaginal examination to determine the bishop score was done. Routine antenatal scan was done for fetal biometry and the placental site. Transvaginal ultrasound was done for cervical length assessment. Induction of labor was commenced and women were subdivided into those with successful induction (delivered vaginally) and those with failed induction (needed cesarean delivery).

RESULTS

Successful induction was achieved in 73/91 (80.2%) participants. The bishop score was significantly increased among women with successful induction (4.6 ± 0.9 vs 3.9 ± 1.1, p value 0.014). In addition, the cervical length was significantly shorter among those who delivered vaginally (2.6 ± 0.5 vs 4.2 ± 0.5, p value 0.0001). There was no significant difference in the placental site among women with failed or successful induction. The cervical length was the only significant predictor for successful induction of labor (p value 0.0001). The placental site showed a non-significant role in the prediction of successful vaginal delivery (p value 0.280).

CONCLUSION

The placental site is not associated with the outcome of labor induction. The cervical length was the significant predictor for successful induction of labor.

2D-transperineal ultrasound in delivery room: Contribution in assessing labor progress, predicting outcome of labor and recognizing obstetric anal sphincter injuries (OASIS). A systematic review

AIMS

Ultrasound is used in the delivery room to assess fetal head position, engagement during labor, and anal sphincter injuries in the immediate postpartum period. The transperineal approach allows for direct visualization of the structures of interest without altering anatomical landmarks. Various ultrasound measurements during labor have been described in the literature, and their use varies widely across maternity units. Our objective was to conduct a systematic review of the literature on relevant ultrasound parameters for the management of labor and delivery.

MATERIAL AND METHODS

We reviewed articles indexed in MEDLINE from 1990 to 2022, selecting those that evaluated transperineal ultrasound during labor for term singleton fetuses in cephalic presentation.

RESULTS

We identified 124 articles out of 394 references, including 4 randomized controlled trials, 108 prospective studies, 6 cross-sectional studies, and 6 retrospective studies. The Angle of Progression (AOP) is better documented and appears more reliable than the Head-Perineum Distance (HPD) for diagnosing engagement, monitoring labor, and predicting its outcome. The HPD is easier to perform but shows inconsistencies in the literature. The Head Progression Distance (HPrD) shows good performance but requires further studies before routine use, as does Head-Symphysis Distance (HSD). Recent studies show a growing interest in ultrasound biofeedback of fetal head progression to improve pushing efforts as well as screening for Obstetrical Anal Sphincter Injuries (OASIS).

CONCLUSIONS

Transperineal ultrasound is a minimally invasive technique that can be used routinely in the delivery room. It can aid in monitoring labor, predicting the mode of delivery, and may serve as valuable biofeedback to optimize pushing during expulsion.

Reliability of the sonographic evaluation for cervical length and elastography with pelvic parameters in term pregnancy by experienced operators with varying levels of experience

OBJECTIVE

To assess the reliability of sonographic measurements of six cervical and pelvic parameters by three sonographers with varying levels of experience.

METHODS

A cross-sectional study was conducted in pregnant women with a gestational age of ≥39 weeks. Each pregnant woman was examined by two sonographers with different levels of experience. Six parameters were measured: cervical length (CL), cervical strain elastography (extrinsic type), posterior cervical angle (PCA), fetal head-to-perineum distance (FHPD), fetal head-to-pubic symphysis distance (FHSD), and angle of progression (AOP). Intra- and interobserver reliabilities were assessed using the intraclass correlation coefficient with a 95% confidence interval. Pearson pairwise correlation coefficients were used to analyze the correlation between the parameter values.

RESULTS

In all, 66 pregnant women were enrolled in this study. We found excellent intraobserver reliability for measurements of CL, PCA, FHPD, FHSD, and AOP and good-to-excellent intraobserver reliability for cervical strain values in the cross-sectional view of the endocervix in the internal os area and cross-sectional view of the entire cervix in the internal os area. Interobserver reliability was excellent for all pelvic parameters, except for the FHPD. Strain values were moderate to excellent in the area of the internal os. A significant negative correlation between CL and strain values at the internal os was observed.

CONCLUSIONS

Pelvic parameters, except for FHPD, have excellent intra- and interobserver reliabilities. The high reproducibility of CL and cervical strain elastography at the internal os level, with a negative correlation between these two parameters, may play an important role in predicting successful induction of labor.

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.

Digital Examination vs. 4D Transperineal Ultrasound-Do They Compare in Labour Management? A Pilot Study

The aim was to compare transperineal ultrasound (TPU) with parameters of the Bishop Score during the first stage of labour and evaluate how TPU can contribute towards improving labour management. Digital examination (DE) and TPU were performed on 42 women presenting at the labour ward with regular contractions. TPU measurements included the head-symphysis distance, angle of progression, diameter of the cervical wall, cervical dilation (CD) and cervical length (CL). To examine if TPU can monitor labour progress, correlations of TPU parameters were calculated. Agreement of DE and TPU was examined for CL and CD measurements and for two groups divided into latent (CD < 5 cm) and active stages of labour (CD ≥ 5 cm). TPU parameters indicated a moderate negative correlation of CD and CL (Pearson: r = -0.667; Spearman = -0.611). The other parameters showed a weak to moderate correlation. DE and TPU measurements for CD showed better agreement during the latent stage than during the active stage. The results of the present study add to the growing evidence that TPU may contribute towards an improved labour management, suggesting a combined approach of TPU and DE to monitor the latent first stage of labour and using only DE during the active stage of labour.

Reliability and Reproducibility of Analyzing 3D Transperineal Ultrasound Volumes Obtained in the First Phase of Labor - A Pilot Study

PURPOSE

The aim of this study was to investigate the reliability and reproducibility of transperineal ultrasound (TPUS) in the initial phase of labor. As TPUS is a common method, it could supplement vaginal palpation and even replace it in certain situations. In addition, we used a 4-dimensional method for the assessment of cervical effacement.

MATERIALS AND METHODS

54 women in labor were included and underwent TPUS. The resulting images from the acquired 4D volumes were evaluated after the examination for the first time and a second time after 21 days. The measured values were cervical length, dilatation and effacement, the angle of progression (AoP), and head-perineum distance.

RESULTS

54 patients were examined. TPUS images were unable to be evaluated in 12 patients because of cervical dilatation of more than 5 cm or poor image quality. Thus, 42 measurements were included. The concordance correlation coefficients according to Lin are satisfactory overall, with one exception for cervical effacement. The accuracy component of cervical length (CCCLin: 0.93; accuracy: 1.00), dilatation (CCCLin: 0.93; accuracy: 1.00), and AoP (CCCLin: 0.87; accuracy: 1.00) is excellent and still high for the head-perineum distance (CCCLin: 0.89; accuracy: 0.96) and cervical effacement (CCCLin: 0.77; accuracy: 0.97).

CONCLUSION

TPUS is a valuable noninvasive tool with good diagnostic accuracy for the AoP, cervical length, and dilatation. Our study provides support for the use of TPUS to complement a vaginal examination. It should not replace a digital examination but should serve as a suitable alternative method for monitoring labor progression in the future.

Prediction of mode of delivery by an ultrasound score similar to Bishop score and performance of independent predictors

INTRODUCTION

There is evolving literature on the superiority of transperineal ultrasound (TPU) in predicting the mode of delivery either before induction or during the course of labour. An ultrasound score (USG score) similar to a Bishop score or an ultrasound scoring method based on independent predictors before the onset of labour at term gestation would serve as a baseline objective record over which further progress of labour could be evaluated.

OBJECTIVE

1. To sonographically examine the clinical parameters evaluated during a digital examination. 2. To derive an USG score using TPU parameters, similar to a Bishop score, and determine its performance in predicting pregnancy outcomes. 3. To identify which are the independent predictors of caesarean section among all the studied ultrasound (USG) parameters.

MATERIALS AND METHODS

In this prospective study, all the eligible women who came for routine antenatal care at term gestation and who were due for pelvic assessment were recruited. They underwent transabdominal ultrasound (TAS) for evaluating head position and head circumference, and TPU for evaluating head station with and without applying fundal pressure, various cervical parameters, sub pubic angle. Equivalent five USG parameters were scored along similar lines as the Bishop score. These women underwent vaginal examination for Bishop score and pelvic adequacy by an obstetrician who was blinded about USG parameters. While spontaneous onset of labour (SOL) was awaited in some of these women, some were induced as and when indicated. After delivery, the Bishop scores, pregnancy outcome in terms of SOL or induction of labour (IOL), mode of delivery and duration of labour were noted retrospectively from case records. Independent predictors of caesarean were obtained by univariate and multivariate analysis.

RESULTS

All the parameters were assessed for predictive ability of caesarean section by univariate analysis. The cervical length, angle of progression (AOP) at rest, head perineal distance (HPD) at rest and with pressure, Bishop score and USG score were found significant. On multivariate analysis, cervix length and USG score were found to be statistically significant. At a USG score of ≤ 5, the sensitivity and specificity to predict caesarean section were 84% and 68%, respectively. The relative risk (RR) was 4.9 (95% CI 2.3-12). The USG score could predict SOL. The p value was 0.001. The area under the curve (AUC) for the ultrasound score was 0.74.

CONCLUSIONS

USG examination by USG score at term gestation before the onset of labour can predict mode of delivery by caesarean section. It can predict spontaneous onset of labour. However, among all the individual parameters, cervix length has best predictive ability for caesarean section.

Predictive factors for vaginal delivery by induction of labor in uncomplicated pregnancies at 40-41 gestational weeks: A Japanese prospective single-center cohort study

AIM

We investigated cervical parameters predictive of vaginal delivery in elective labor induction among women at 40-41 gestational weeks.

METHODS

This Japanese prospective single-center cohort study was conducted between July 2019 and June 2020. We enrolled women with an uncomplicated singleton pregnancy who underwent labor induction at 40-41 gestational weeks. We analyzed background characteristics and cervical parameters, including Bishop score, cervical length, posterior cervical angle, and changes in cervical parameters before and after cervical dilatation. The endpoint was the rate of vaginal delivery.

RESULTS

Of 142 eligible participants, all 24 multiparous women underwent vaginal delivery. Among the nulliparous women (n = 118), the following categories showed significantly higher rates of vaginal delivery: Bishop scores of ≥6 before and after dilatation, compared with Bishop score <6 (adjusted prevalence ratio (aPR) [95% confidence interval (CI)]; 1.58 [1.17-2.13] and 1.56 [1.13-2.14], respectively) and cervical length of <10 and 10-20 mm before dilation, compared with cervical length of >30 mm (aPR [95% CI]; 1.47 [1.00-2.15] and 2.13 [1.42-3.18], respectively). The posterior cervical angle and other background characteristics showed no significant associations. Furthermore, women with cervical lengths of ≥20 mm before and <20 mm after dilatation showed a higher rate of vaginal delivery, compared to cervical length of ≥20 mm even after dilatation (aPR [95% CI]; 1.95 [1.19-3.20]).

CONCLUSIONS

High Bishop score, short cervical length, and changes in cervical length with dilatation are potential independent predictors of vaginal delivery following elective labor induction in nulliparous women at 40-41 gestational weeks.

Lower uterine segment thickness assessed by transvaginal ultrasound before labor induction: reproducibility analysis and relationship with delivery outcome

OBJECTIVES

To evaluate the reproducibility of lower uterine segment (LUS) thickness measurement before induction of labor (IOL), and to assess the relationship between LUS thickness and IOL outcomes.

METHODS

This was a prospective cohort study of pregnant women undergoing IOL at term, conducted in a single tertiary hospital between July 2014 and February 2017. Women with a singleton pregnancy at ≥ 37 weeks' gestation, with a live fetus in cephalic presentation and a Bishop score of ≤ 6, were eligible for inclusion. Both nulliparous and parous women, and those with a previous Cesarean section (CS), were eligible. All women underwent transvaginal ultrasound assessment before IOL admission, and cervical length and LUS thickness were measured offline after delivery. Maternal and obstetric characteristics and Bishop score were recorded. The main outcome was the overall rate of CS after IOL, and secondary outcomes were CS for either failure to progress in the active phase of labor or failed IOL, and CS for failed IOL only. Interobserver agreement for measurement of LUS thickness between two operators was assessed using the intraclass correlation coefficient (ICC) and Bland-Altman analysis with the ANOVA test to evaluate systematic bias. Univariable and multivariable analysis were employed to evaluate the relationship between clinical and sonographic characteristics and IOL outcomes.

RESULTS

Of 265 women included in the analysis, 195 (73.6%) had a vaginal delivery and 70 (26.4%) required a CS after IOL. Reproducibility analysis showed excellent interobserver agreement for the measurement of LUS thickness (ICC, 0.96 (95% CI, 0.93-0.98)). On Bland-Altman analysis, the mean difference in LUS thickness between the two operators was 0.15 mm (95% limits of agreement, -1.84 to 2.14 mm), and there was no evidence of systematic bias (ANOVA test, P = 0.46). Univariable analysis showed that LUS thickness was associated significantly with overall CS (P = 0.002), CS for failure to progress in the active phase of labor or failed IOL (P = 0.03) and CS for failed IOL (P = 0.037). On multivariable logistic regression analysis, LUS thickness was an independent predictive factor for overall CS (odds ratio (OR), 1.149 (95% CI, 1.031-1.281)) and CS for failure to progress in the active phase of labor or failed IOL (OR, 1.226 (95% CI, 1.039-1.445)).

CONCLUSIONS

In women undergoing IOL at term, measurement of LUS thickness is feasible and reproducible, and is associated significantly with IOL outcome. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Assessment of labor progress by ultrasound vs manual examination: a randomized controlled trial

BACKGROUND

Assessment of labor progress via digital examination is considered the standard of care in most delivery rooms. However, this method can be stressful, painful, and imprecise, and multiple examinations increase the risk for chorioamnionitis. Intrapartum ultrasound was found to be an objective, noninvasive tool to monitor labor progression.

OBJECTIVE

This study aimed to investigate whether, among nulliparous women, the use of intrapartum ultrasound can reduce the rate of intrapartum fever by reducing the number of digital examinations.

STUDY DESIGN

This was a prospective, randomized controlled trial in term nulliparas admitted with prelabor rupture of membranes, induction of labor, or in latent phase of labor with a cervical dilation of <4 cm. Women were randomized into 1 of the following 2 arms: (1) labor progress assessed by ultrasound, avoiding digital examinations as much as possible; and (2) control group in which labor progression was assessed according to the regular protocol. Before the study, all labor ward physicians underwent training in intrapartum ultrasound.

RESULTS

A total of 90 women were randomized to the ultrasound group and 92 were randomized to the control group. When compared with the control group, the ultrasound group had significantly lower rates of intrapartum fever (11.1% vs 26.1%; P=.01), clinical chorioamnionitis (3.3% vs 16.5%; P>.01), and histologic chorioamnionitis (2.2% vs 9.8%; P=.03). The median number of digital examinations was significantly lower in the ultrasound group (5; interquartile range, 4-6) than in the control group (8; interquartile range, 6-10; P<.01). The median number of digital examinations per hour in the ultrasound group was significantly lower than in the control group (0.2 vs 0.4; P<.01). The induction rates, time from admission to delivery, mode of delivery, Apgar score at 5 minutes, and neonatal intensive care unit admission rates did not differ significantly between the groups.

CONCLUSION

The use of intrapartum ultrasound lessens the total number of digital examinations needed to be performed during labor and, consequently, the incidence of intrapartum fever and chorioamnionitis are reduced. No adverse effects on labor progression and short-term maternal or neonatal outcomes were noted.

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.

Agreement between digital vaginal examination and intrapartum ultrasound for labour monitoring

Sonographic approach for labour monitoring was introduced in order to improve the shortcomings of digital vaginal examination (DVE). This was a prospective study. We aimed to investigate the agreement between transperineal ultrasound (TPUS) measurements and DVE during first and second stages of labour. Patients in the first stage of labour were included. Cervical length (CL), cervical dilation (CD), cervical position (CP), foetal head descent (FHD) and foetal head rotation (FHR) were assessed by both DVE and TPUS. Agreement between two methods was examined. Eighty-five patients were included. One hundred and eighty-three paired TPUS and DVE assessments were performed. Satisfactory agreement between both methods was obtained regarding CL: systematic bias= -0.05 cm (95%CI, -0.13; 0.03), R = 0.7, p<.0001; CD: systematic bias = 0.07 cm (95%CI, -0.08 to 0.22), R = 0.93, p<.0001 and FHD: systematic bias = 0.83 cm (95%CI, 0.685-0.977), R = 0.55, p<.0001. There was a low correlation for the assessment of CP (kappa = 0.24) and FHR (kappa = 0.06). DVE was inefficient in determining FHR especially during latent phase with failure and error rates of 86% and 36%, respectively. A conceptual sonopartogram covering the hole childbirth process is presented based on reliable ultrasound measurements.Impact StatementWhat is already known on this subject? Digital vaginal examination (DVE) is used worldwide for labour monitoring. However, it is far from perfect. Some investigators have raised concerns about the value of the Bishop score because it is a subjective measure with great intra- and inter-observer variability, affected by a physician's clinical experience. Moreover, this method is intrusive, uncomfortable and may increase the risk of infection. The sonographic approach for labour monitoring was introduced in order to improve the shortcomings of DVE. Multiple studies focussed on the reliability of the sonographic method in assessing each parameter during labour. Hassan et al. were the first to determine whether it is feasible to perform assessment in the first stage of labour based only on US, and to describe a method of recording these observations: the 'sonopartogram'.What do the results of this study add? The outcomes concluded that sonographic approach was at least as accurate as the clinical examination. Moreover, a conceptual sonopartogram covering the hole childbirth process is presented based on reliable ultrasound measurements.What are the implications of these findings for clinical practice and/or further research? Clinical relevance of this sonopartogram should be evaluated in further studies.

The Value of Posterior Cervical Angle as a Predictor of Vaginal Delivery: A Preliminary Study

Accurate prediction of failure to progress and rapid decision making regarding the mode of delivery can improve pregnancy outcomes. We examined the value of sonographic cervical markers in the prediction of successful vaginal delivery beyond 34 weeks of gestation. A retrospective chart review was carried out. Medical information of singleton gestations delivered at a single center from 1 July 2019 to 30 August 2020 was collected. Transvaginal sonographic records of cervical length, anterior and posterior cervical angles, and cervical dilatation were obtained and re-measured. The value of these markers and clinical characteristics of mother and baby on vaginal delivery were investigated and compared to women who underwent cesarean section. A total of 90 women met the inclusion criteria. The rate of vaginal delivery was 75.6%. There were no differences found in terms of maternal age, rate of abortion, induction of labor, premature rupture of membranes, preterm labor, hypertension, diabetes, cervical length, and neonatal sex and weight. The prediction of vaginal delivery was provided by parity, maternal body mass index, and posterior cervical angle. The area under the receiver operating characteristic curve for prediction of vaginal delivery was 0.667 (95% CI 0.581–0.864, p = 0.017) for the posterior cervical angle, with a cutoff of 96.5°. Regression analysis revealed a posterior cervical angle ≥96.5° in the prediction of vaginal delivery (adjusted odds ratio: 6.24; 95% confidence interval: 1.925–20.230, p = 0.002). Posterior cervical angle ≥96.5° is associated with successful vaginal delivery. It is simple and easy to measure and can be useful in determining the mode of delivery.

Sonographic Evaluation of the Mechanism of Active Labor (SonoLabor Study): observational study protocol regarding the implementation of the sonopartogram

INTRODUCTION

Over the last decades, a large body of literature has shown that intrapartum clinical digital pelvic estimations of fetal head position, station and progression in the pelvic canal are less accurate, compared with ultrasound (US) scan. Given the increasing evidence regarding the advantages of using US to evaluate the mechanism of labour, our study protocol aims to develop sonopartograms for fetal cephalic presentations. They will allow for a more objective evaluation of labour progression than the traditional labour monitoring, which could enable more rapid decisions regarding the mode of delivery.

METHODS/ANALYSIS

This is a prospective observational study performed in three university hospitals, with an unselected population of women admitted in labour at term. Both clinical and US evaluations will be performed assessing fetal head position, descent and rotation. Specific US parameters regarding fetal head position, progression and rotation will be recorded to develop nomograms in a similar way that partograms were developed. The primary outcome is to develop nomograms for the longitudinal US assessment of labour in unselected nulliparous and multiparous women with fetal cephalic presentation. The secondary aims are to assess the sonopartogram differences in occiput anterior and posterior deliveries, to compare the labour trend from our research with the classic and other recent partogram models and to investigate the capability of the US labour monitoring to predict the outcome of spontaneous vaginal delivery.

ETHICS AND DISSEMINATION

All protocols and the informed consent form comply with the Ministry of Health and the professional society ethics guidelines. University ethics committees approved the study protocol. The trial results will be published in peer-reviewed journals and at the conference presentations. The study will be implemented and reported in line with the Strengthening the Reporting of Observational Studies in Epidemiology statement.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT02326077).

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.

Can We Use the Bishop Score as a Prediction Tool for the Mode of Delivery in Primiparous Women at Term Before the Onset of Labor?

The Bishop score serves as an evaluation system performed by digital vaginal examination (DVE) to determine cervical ripening. The scoring system includes cervical dilatation, position, effacement and consistency of the cervix and fetal head station1. Nowadays, the Bishop score is frequently used as an important parameter for the prediction of successful induction of labor.

OBJECTIVE

Our objective was to demonstrate the role of the Bishop scoring system in prediction of the mode of delivery in primiparous women at term before the onset of labor.

METHOD

We included in this study unselected primiparous women at term, after 37 weeks of gestation, who presented to the Prenatal Diagnostic Unit (PDU) of the University Emergency County Hospital of Craiova. We excluded from the study multiparous patients, pregnancies with a planned Caesarean section delivery (CD), non-cephalic presentations and multiple pregnancies, twin pregnancies and those with detected fetal anomalies. The protocol included weekly DVEs until delivery for all patients, to determine the evolution of the Bishop score at term and in the week before delivery, and potential correlations with delivery outcome. To reduce clinical bias, the DVEs were performed by three experienced obstetricians involved in the research.

RESULTS

Statistical analysis yielded a 4 to 6 Bishop score in all weekly examinations. At 37 weeks of gestation, the majority of primiparous women had a Bishop score of 4, with no significant differences between the primiparous who delivered vaginally and the ones where Caesarean section was necessary. During the following weekly evaluations, we noted a slight turn to a Bishop score of 6 for most of them, without any significant differences between the two groups. However, at 41 weeks of gestation, there was a significant higher Bishop score in the group of primiparous women who delivered vaginally.

CONCLUSION

In our study, the use of the Bishop score failed as a prediction tool for the mode of delivery in primiparous women at term before the onset of labor, at a gestational age less than 40 weeks. Therefore, Bishop score should not be used to counsel regarding the probability of an uncomplicated vaginal delivery (VD) before the onset of labor.

Clinical and ultrasonographic parameters in assessment of labor induction success in nulliparous women

Purpose: Evaluation of simplified Bishop score and ultrasound cervicometry in the assessment of labor induction success in nulliparous women.Methods: Prospective cohort study included 146 nulliparous women with singleton pregnancy and indications for labor induction. Prior to labor induction, cervicometry and Bishop score were determined. Upon delivery, patients were classified as those delivered vaginally and by cesarean section (CS) after unsuccessful labor induction.Results: Bishop score >5 was found in 47.95% of vaginally delivered women and 12.33% of patients delivered by CS (p < .01). Cervicometry had appropriate findings in 34.2% of vaginally delivered women and 75.3% of those delivered by CS (p < .01). Bishop score (>5 versus ≤5) had lower sensitivity (52.05%) and specificity (12.33%) than cervicometry (good versus unfavorable findings) (sensitivity 65.75%, specificity 75.34%) for prediction of labor induction success. If Bishop score was ≤5, cervicometry had 50.0% sensitivity and 78.13% specificity, while if Bishop score was >5, 82.86% sensitivity and 55.56% specificity. Obtained model for predicting labor induction outcome in nulliparous women based on their clinical and ultrasonographical characteristics identified the Bishop score as the most important predictor.Conclusions: Study confirmed the usefulness of simplified Bishop score and ultrasound cervicometry in the assessment of labor induction success in nulliparous women.

Relationship between cervical elastography and spontaneous onset of labor

Cervical elastography might be an objective method for evaluating cervical ripening during pregnancy, but its usefulness has not been fully investigated. We examined the significance of cervical elastography in the last trimester of pregnancy. Cervical elastography was performed at weekly checkups after 36 weeks of gestation in 238 cases delivered at our hospital from 2017 to 2018. The correlation with the onset time of natural labor, which is an index for judging maternal delivery preparation status, was examined. A total of 765 examinations were conducted, and cervical stiffness determined by cervical elastography was positively correlated with the Bishop score (r = 0.46, p < 0.0001). When examined separately for each week, only the examinations performed at 39 weeks were associated with the onset of spontaneous labor up to 7 days later (p = 0.0004). Furthermore, when stratified and analyzed by the Bishop score at 39 weeks of gestation, cervical elastography was associated with the occurrence of spontaneous labor pain for up to seven days in the groups with Bishop scores of 3–5 and 6–8 (p = 0.0007 and p = 0.03, respectively). In conclusion, cervical elastography at 39 weeks of pregnancy is useful for judging the delivery time.

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.

Ultrasound examination of the cervix for predicting labor induction success: failed validation in a routine clinical setting of a successful previous pilot study

BACKGROUND

Induction of labor (IL) involves an overload of work in hospitals, as well as increased intervention. Traditionally, the Bishop score (BS) has been used to predict the outcome of a IL, but there is a growing interest in studying the predictive capacity of ultrasound variables.

OBJECTIVE

Validate a pilot predictive model performed by a single observer (Alvarez-Colomo C), based on clinical parameters and ultrasound parameters, that showed a significant association with the IL result, obtaining a correct prediction of vaginal delivery in 82.8%, with 15% false positive (FP). This validation was carried out under the usual conditions of clinical practice by four observers without distinction.

METHODS

A prospective, observational study was conducted between September 2010-July 2012, recruiting 231 single pregnancies (Group 2), who were to initiate the IL process, according to the methodology and inclusion criteria of the Alvarez-Colomo study (Group 1151 patients). The outcome variable was the method of delivery.

RESULTS

Only fetal head-perineal distance (FHPD), cervical length (CL) and BS showed significant association with the result of IL. After applying the logistic regression equation of the pilot study, the model developed by these four observers reached a predictive capacity of 70.74% (FP = 20%). Clinical characteristics were similar in both groups. Statistically significant differences were found between the two groups for: FHPD, posterior cervical angle (PCA) and funnel existence.

CONCLUSION

It has not been possible to validate the mathematical model of Alvarez's study in the daily conditions of clinical practice, probably due to differences in the ultrasound measurement of FHPD.

Accuracy of the Manipal Cervical Scoring System for predicting successful induction of labour

The Manipal Cervical Scoring System is an accurate and objective sonographic score that predicts the outcome of induced labour. The aim of the current study was to compare the performance of the Manipal Cervical Scoring System against the Bishop Score. A prospective study was conducted on 105 women underwent labour induction in Ain Shams University Hospital, Cairo, Egypt. Both scores were assessed pre-induction. Successful induction occurred in 78.09% of the cases. The area under the ROC curve (AUC) was of 0.940 (95% CI = 0.876 to 0.977; p value <.0001) for the Manipal Score and 0.863 (95% CI = 0.783-0.923; p value <.0001) for the Bishop Score. The Manipal Score >5 had a sensitivity of 91.5% and a specificity of 91.3%. While the Bishop score >4 had a sensitivity of 98.8% and specificity of 69.6% to predict the outcome of induced labour. The Manipal Cervical Scoring system is a better objective tool to predict the outcome of labour induction compared to the Bishop Score. However, other female and fetal characteristics, including body mass index (BMI) at gestation, gestational weight gain, occiput position and parity should be taken into consideration when performing labour induction. Impact statement What is already known on this subject? The ultimate fate of 20% of women having an induction of labour (IOL) is a Caesarean delivery. Thus, predicting the possible response to IOL before starting induction could guide clinicians to determine the efficacy of starting and/or continuing the induction process and in counselling women regarding the possible response to IOL. The main predictor for IOL outcome is based on the pre-induction cervical status which has been traditionally assessed by the Bishop Score. However, the Bishop Score remains subjective, thereby, associated with high rates of bias and several studies have demonstrated its poor predictive value for the outcome of induction. What do the results of this study add? Proposed use of ultrasound parameters that are equivalent to Bishop Score will be objective, reliable and reproducible method. It allows for patient re-evaluation by other obstetricians without the need for re-examination (thus decreasing exposing the patient to pain and anxiety). What are the implications of these findings for clinical practice and/or further research? According to WHO and FIGO, oral misoprostol (25 μg, 2-hourly) is recommended for induction of labour. This helps to decrease the discomfort of repeated vaginal examination and increases the women satisfaction with labour process, especially in women at higher risk of infection. Thus evaluating cervical status using an ultrasound cervical scoring system can similarly increase women's satisfaction with labour process. Our goal in the upcoming trial is to perform RCT comparing ultrasound versus Bishop in women undergoing IOL using oral misopristol regarding measures of satisfaction during labour in the parturient women.

Ultrasound Elastography can Detect Placental Tissue Abnormalities

Background

In this prospective cohort study, we examined the utility of elastography to evaluate the fetus and placenta.

Patients and methods

Pregnant women in their third trimester of pregnancy, by which time the placenta has formed, were included in this study. A total of 111 women underwent ultrasound examinations, including elastography. Elastographic evaluation was performed using two protocols. First, the placental index (PI) was measured, which quantitatively assesses the hardness of tissue. Second, regions of interest (ROI) were categorized into 3-step scores according to the frequency of the blue area (hardness of placental tissue score [HT score]), which is a qualitative method. After delivery, 40 of the 111 placentas were pathologically examined.

Results

The average PI was 44.3 (± 29.4) in the in utero SGA group, which was significantly higher than that in the normal group (8.8 (± 10.0); p < 0.01) during pregnancy. There was a significant correlation between the PI and z score for estimated fetal weight (EFW) (r = -0.55; p < 0.01). Moreover, a significant positive correlation was observed between the PI and the z score of birth weight (r = -0.39; p < 0.01). Pathological ischemia findings of the placenta were identified in 67% of the HT score 3 group, representing 6 of the 9 patients, and in 20% of the HT score 1 group, representing only 3 of the 15 patients.

Conclusions

Placental hardness, as determined by elastography, correlates with both lower estimated fetal body weight and birth weight. These results suggest that ultrasound elastography in the placenta may be an additional marker of intrauterine fetal well-being.

[Are ultrasound measurements of the cervical length and fetal head-perineum distance predictive of delivery outcome in post-term pregnancies?]

OBJECTIVE

Post-term pregnancy is frequently associated with higher fetal and maternal morbidity and mortality. Its management essentially depends on clinical cervical characteristics as evaluated by the Bishop score (BS). However, BS is poorly predictive of the delivery outcome. We sought to demonstrate that ultrasound measurement of cervical length and evaluation of fetal height could predict the outcome in post-term pregnancies.

METHODS

A prospective single center study was undertaken between the 21st of January and the 1st of June 2013. Fetal height was measured using a transperineal technique and cervical length was evaluated by a vaginal ultrasound on patients consulting and their term date. C-section rates were considered to be the primary judgment criteria.

RESULTS

A total of 136 patients were included. C-section rates in this population was 19%. Fetal height and cervical length were not different between the C-section group and the vaginal delivery group.

CONCLUSION

Our study demonstrates that ultrasound measurement of cervical length and fetal height do not show better results than BS in predicting the outcome of post-term pregnancy. Combining these ultrasound measurements has already been suggested in other studies and promising results have been shown. More studies are necessary to further these results.

Prediction of spontaneous vaginal delivery by transperineal ultrasound performed just after full cervical dilatation is determined

PURPOSE

To investigate whether transperineal ultrasound examination just after full cervical dilatation is determined can predict the mode of delivery.

METHODS

This was a prospective observational study of pregnant women. After full cervical dilatation was determined by vaginal examination during labor, transperineal ultrasound was immediately performed, and the head direction (HD), progression distance (PD), and angle of progression (AoP) were measured. The cases were divided into two groups: spontaneous vaginal delivery and operative delivery due to failure of progression. Differences between the groups were statistically analyzed using Student's t test and Fisher's exact test.

RESULTS

Of the 50 women, 42 had spontaneous vaginal deliveries and 8 had vacuum extractions. The spontaneous delivery group had significantly higher HD, PD, and AoP values than the vacuum extraction group. The areas under the receiver-operating characteristic curves for the prediction of spontaneous vaginal delivery were 0.850 for HD, 0.827 for PD, and 0.783 for AoP. The optimum cut-off points and positive predictive values were 83° and 92.9 % for HD, 56 mm and 94.9 % for PD, and 146° and 94.3 % for AoP, respectively.

CONCLUSION

Transperineal ultrasound examination just after full cervical dilatation was determined was useful in predicting spontaneous vaginal delivery.

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.

Manipal Cervical Scoring System by Transvaginal Ultrasound in Predicting Successful Labour Induction

INTRODUCTION

Induction of labour (IOL) nowadays is a common procedure in obstetric practice. The success of IOL largely depends upon "favourability" or "readiness" cervix which is traditionally assessed by manual examination and Scored as Bishop Score. However, this method is limited by subjectivity and reproducibility and though done in all the patients prior to IOL, several studies have demonstrated poor correlation between Bishop Score and outcome of labour.

OBJECTIVE

To evaluate the role of preinduction transvaginal ultrasonographic (TVS) cervical assessment in predicting labour outcome and to compare its performance against Bishop Score in patients undergoing induction of labour (IOL).

SETTING

A tertiary medical college hospital in Southern India.

DESIGN

Prospective observational and investigational study.

MATERIALS AND METHODS

Transvaginal ultrasound was performed in 131 patients who underwent labour induction at term with intact membranes and live fetus. Bishop Score was assessed by pervaginal examination and was compared with preinduction TVS cervical Score (parameters being cervical length, funneling, position of cervix and distance of presenting part from external os). Labour was induced within one hour of cervical assessment. The labour induction was considered successful if patient could get into active labour i.e., onset of regular uterine contractions (at interval of 2-3 minutes) and cervical dilatation of 4 cm or greater within 24 hours of induction.

RESULTS

Labour induction was successful in 86.9% of patients. At cut off Scores of ≥ 4, TVS cervical Score performed better than Bishop Score (Sensitivity 77% vs. 65%, Specificity 93% vs. 86%). ROC analysis indicated that Area Under Curve (AUC) was more for TVS Score (0.90, 95% CI 0.84 - 0.95), compared to Bishop Score. It was found that an increase in cervical length and distance from the os by 1 mm from their means were associated with an increase in odds for failure of induction and there by caesarean delivery by 6.5% and 11% respectively.

CONCLUSION

In women experiencing labour induction, transvaginal ultrasound score comprising of five different parameters indicated success of induction better than Bishop Score. Further, two of its components (longer cervical length and increased distance of presenting part from external os) demonstrated significant and independent prediction of the likelihood of failure of induction and risk of operative delivery.

The role of sonographic cervical length in labor induction at term

The purpose of this study is to review the literature examining the role of ultrasound in the induction of labor. Databases including Ovid, PubMed, Web of Science, Google Scholar, and UpToDate were searched and current guidelines from the SOGC, the ACOG, the RCOG, and the RANZCOG were reviewed. Although studies have not demonstrated the superiority of cervical sonography to the Bishop score, the evidence indicates that sonography could be useful in planning induction of labor, significantly reducing the need for cervical ripening agents. A more comprehensive method integrating both sonography and digital exam may be more appropriate.

Intrapartum ultrasound assessment of fetal spine position

We investigated the role of foetal spine position in the first and second labour stages to determine the probability of OPP detection at birth and the related obstetrical implications. We conducted an observational-longitudinal cohort study on uncomplicated cephalic single foetus pregnant women at term. We evaluated the accuracy of ultrasound in predicting occiput position at birth, influence of fetal spine in occiput position during labour, labour trend, analgesia request, type of delivery, and indication to CS. The accuracy of the foetal spinal position to predict the occiput position at birth was high at the first labour stage. At the second labour stage, CS (40.3%) and operative vaginal deliveries (23.9%) occurred more frequently in OPP than in occiput anterior position (7% and 15.2%, resp.), especially in cases of the posterior spine. In concordant posterior positions labour length was greater than other ones, and analgesia request rate was 64.1% versus 14.7% for all the others. The assessment of spinal position could be useful in obstetrical management and counselling, both before and during labour. The detection of spinal position, more than OPP, is predictive of successful delivery. In concordant posterior positions, the labour length, analgesia request, operative delivery, and caesarean section rate are higher than in the other combination.

Quantitative elastography for cervical stiffness assessment during pregnancy

AIM

Feasibility and reliability of tissue Doppler imaging-(TDI-) based elastography for cervical quantitative stiffness assessment during all three trimesters of pregnancy were evaluated.

MATERIALS AND METHODS

Prospective case-control study including seventy-four patients collected between the 12th and 42nd weeks of gestation. The tissue strain (TS) was measured by two independent operators as natural strain. Intra- and interoperator intraclass correlation coefficient (ICC) agreements were evaluated.

RESULTS

TS measurement was always feasible and exhibited a high performance in terms of reliability (intraoperator ICC-agreement=0.93; interoperator ICC agreement=0.89 and 0.93 for a single measurement and for the average of two measurements, resp.). Cervical TS showed also a significant correlation with gestational age, cervical length, and parity.

CONCLUSIONS

TS measurement during pregnancy demonstrated high feasibility and reliability. Furthermore, TS significantly correlated with gestational age, cervical length, and parity.

Prediction of successful labor induction using transvaginal sonographic cervical measurements

PURPOSE

To predict the success of labor induction by sonographic cervical measurements, maternal/obstetrical factors, and the Bishop's score.

METHODS

Between February 2008 and February 2010, 190 consecutive pregnant women underwent clinical examination to assess the Bishop's score and transvaginal sonographic cervical measurements (cervical length, fetal head stage, and cervical dilatation) before labor induction. The following outcomes were analyzed: overall vaginal delivery and vaginal delivery up to 24 hours after labor induction.

RESULTS

Overall vaginal delivery occurred in 133 (70.0%) patients and vaginal delivery 24 hours after labor induction happened in 119 (62.6%) patients. The sonographic cervical measurements were significantly associated with all outcomes (p < 0.01). The areas under the ROC curve (AUC) of all ultrasound cervical parameters to predict the two events were 68.9% and 72.0% (cervical length); 71.6% and 73.6% (fetal head stage); and 72.0% and 73.4% (cervical dilatation). Mathematical equations were obtained to calculate the probability for each event considering the sonographic cervical measurements in association with clinical factors after regression analysis, which increased the AUC for both events (80.1% and 79.3%).

CONCLUSIONS

Transvaginal sonographic cervical measurements can predict the successful labor induction, especially when associated to clinical analysis (Bishop's score).

Evaluation of cervical stiffness during pregnancy using semiquantitative ultrasound elastography

OBJECTIVE

To evaluate cervical stiffness during pregnancy using ultrasound-derived elastography, a method used to estimate the average tissue displacement (strain) within a defined region of interest when oscillatory compression is applied.

METHODS

Strain was calculated in two regions of interest, the endocervical canal and the entire cervix, from three anatomical planes of the cervix: mid-sagittal in the plane used for cervical length measurement and in cross-sectional planes located at the internal and external cervical os. Associations between strain values, method of ascertainment and patient characteristics were assessed using linear mixed models to account for within-subject correlation. Inter-rater agreement in defining the degree of cervical stiffness was evaluated in 120 regions of interest acquired by two operators in 20 patients.

RESULTS

A total of 1557 strain estimations were performed in 262 patients at 8-40 weeks of gestation. Adjusting for other sources of variation, (1) cervical tissue strain estimates obtained in the endocervical canal were on average 33% greater than those obtained in the entire cervix; (2) measurements obtained in the cross-sectional plane of the external cervical os and sagittal plane were 45% and 13% greater than those measured in the cross-sectional plane of the internal cervical os, respectively; (3) mean strain rates were 14% and 5% greater among parous women with and without a history of preterm delivery compared with those of nulliparous women, respectively, and were on average 13% greater among women with a cervical length of between 25 and 30 mm compared to those with a cervical length of > 30 mm; and (4) cervical tissue strain was more strongly associated with cervical length than with gestational age.

CONCLUSION

Semiquantitative elastography can be employed to evaluate changes in cervical stiffness during pregnancy.

Can angle of progression in pregnant women before onset of labor predict mode of delivery?

OBJECTIVES

The angle of progression (AOP), measured by transperineal ultrasound, has been used to assess fetal head descent during labor. Our aim was to assess whether, before onset of labor, parous women have a narrower AOP than do nulliparous women and if a narrow AOP is associated with a higher rate of Cesarean delivery.

METHODS

In this prospective, observational study, we performed transperineal ultrasound in pregnant women not yet in labor at ≥ 39 weeks' gestation who delivered within 1 week of sonography. The AOP was compared as follows: in nulliparous women, between those who had a Cesarean section and those who delivered vaginally; and among women who delivered vaginally, between those who were nulliparous and those who were parous.

RESULTS

Included in the study were 100 nulliparous and 71 parous women. Among those who delivered vaginally (n = 161), the median AOP before onset of labor was narrower in parous than in nulliparous women (98° (interquartile range (IQR)), 90-107° vs 104° (IQR, 97-113°), P < 0.001). Among the 100 nulliparous women, (1) the median AOP before onset of labor was narrower in those who went on to deliver by Cesarean section (n = 9) than in those delivered vaginally (n = 91) (90° (IQR, 85.5-93.5°) vs 104° (IQR, 97-113°), P < 0.001); (2) an AOP ≥ 95° (derived from the receiver-operating characteristics curve) was associated with vaginal delivery in 99% of women; and (3) 89% (8/9) of women who delivered by Cesarean section had an AOP < 95°. Among the 71 parous women, only one delivered by Cesarean section and all of those with an AOP < 95° delivered vaginally.

CONCLUSION

A narrow AOP (< 95°) in non-laboring nulliparous women at term is associated with a high rate of Cesarean delivery. Parous women have a narrower AOP than do nulliparous women before the onset of labor; however, unlike in nulliparous women, a narrow AOP in parous women does not appear to be associated with Cesarean delivery and most parous women with such an angle go on to deliver vaginally.

Transvaginal ultrasonography compared with Bishop score for predicting cesarean section after induction of labor

Background:

Reproductive health researchers are interested in finding better methods for predicting an unwanted type of delivery after induction of labor. The aim of this study was to compare the value of transvaginal ultrasonography findings and the Bishop score in predicting cesarean section after induction of labor.

Methods:

Two hundred women with singleton pregnancies undergoing induction of labor at 37–42 weeks were enrolled in this prospective study. Transvaginal investigation was done for all participants prior to induction. To compare the predictive value of the methods, receiver-operating characteristic (ROC) curves were plotted and equality of the area under curve (AUC) was tested.

Results:

The mean age of the participants was 29.9 years, mean gestational age was 39.6 weeks, and mean gravid was 1.5. The AUC calculated for Bishop score was 0.39 (95% confidence interval [CI] 0.3–0.48). The AUC for cervical length measured by ultrasonography was 0.69 (95% CI 0.6–0.77). The AUC for the posterior cervical angle measured by ultrasonography was 0.38 (95% CI 0.29–0.47). Testing equality of the ROC curves for these three methods showed the ROC for cervical length to be statistically different from both Bishop score and posterior cervical angle (P < 0.001). However, the difference in ROC area compared between Bishop score and posterior cervical angle was not statistically significant.

Conclusion:

Based on our findings and available information in the literature, it seems that cervical length measured by transvaginal ultrasonography has the potential to replace the traditional Bishop score, provided that such a facility is available when needed.

Prediction of delivery mode with transperineal ultrasound in women with prolonged first stage of labor

OBJECTIVE

To investigate if fetal head-perineum distance and angle of progression measured with two-dimensional (2D) and three-dimensional (3D) transperineal ultrasound could predict outcome of labor in primiparous women with prolonged first stage of labor.

METHODS

This was a prospective observational study of 110 primiparous women with singleton cephalic presentation at term diagnosed with prolonged first stage of labor. Digital assessment of fetal station was related to the ischial spine. Fetal head descent was measured with transperineal ultrasound as the shortest distance from the fetal head to the perineum, and the angle between the pubic symphysis and the fetal head. Receiver-operating characteristics (ROC) curves were constructed and 2D and 3D data acquisitions were compared. The stored 3D volumes were assessed by an examiner blinded to all other data. Vaginal delivery vs. Cesarean section was the primary outcome.

RESULTS

Cesarean section was performed in 25% of the women. Areas under the ROC curves for prediction of vaginal delivery were 81% (95% confidence interval (CI), 71-91%) (P < 0.01) and 76% (95% CI, 66-87%) (P < 0.01) for fetal head-perineum distance and angle of progression, respectively, as measured by 2D ultrasound and 66% (95% CI, 54-79%) for digital assessment of fetal station (P = 0.01). In 50% of women fetal head-perineum distance was ≤ 40 mm and 93% (95% CI, 83-97%) of them delivered vaginally vs. 18% (95% CI, 5-48%) with distance > 50 mm. In 48% of women the angle of progression was ≥ 110° and 87% (95% CI, 75-93%) of them delivered vaginally vs. 38% (95% CI, 21-57%) with angle < 100°. Results from 2D and 3D acquisitions were similar.

CONCLUSION

Fetal head-perineum distance and angle of progression measured with 2D or 3D ultrasound can predict labor outcome, with similar predictive values for the two techniques.

Ultrasonographic assessment of cervix size and its correlation with female characteristics, pregnancy, BMI, and other anthropometric features

PURPOSE

Cervical length during the first trimester of pregnancy has not been completely investigated yet. The objective of our study is to compare cervical size in the first ten gestational weeks with that of non-pregnant women, and to determine its correlation with maternal factors, including age, anthropometric features, and reproductive history.

METHODS

We collected retrospective data about women who applied to the Obstetrics and Gynecology Outpatients Facility of Udine between February and June 2009, selecting both pregnant and non-pregnant women possessing a transvaginal ultrasonographic measurement of their cervix, and focusing on their age, parity, BMI, cervical, and uterine size. Data were analyzed by R (version.2.8.0), considering significant P < 0.05.

RESULTS

135 women were recruited. By multivariate linear regression, both cervical length and width result independently influenced by pregnancy status, and among non-pregnant nullipara, cervical length results to be significantly lower in women younger than 20 (P < 0.05).

CONCLUSIONS

During the first ten gestational weeks, cervix results to be longer and wider than in non-pregnant women, suggesting the possible existence of early gestational, morphological, uterine, and cervical modifications. Women under the age of 20 have a significantly shorter cervix, suggesting an incomplete cervix maturity in this group of women, which may justify the higher prevalence of pre-term births in teenage pregnancies.