Ultrasound cervical length measurement in prediction of labor induction outcome

The Uterocervical Angle Combined with Bishop Score as a Predictor for Successful Induction of Labor in Term Vaginal Delivery

The objective of this study was to determine the value of uterocervical angle (UCA) in predicting successful induction of labor (IOL) in singleton pregnant women compared to the Bishop score and cervical length (CL). A total of 205 normal term, singleton labor-induction cases were analyzed. Successful IOL was defined as the onset of active labor of induction. A comparative analysis was performed to evaluate the effectiveness of UCA, Bishop score, and CL in predicting IOL. Compared to the non-successful IOL group, the women in the successful IOL group had significantly wider UCA (p = 0.012) and higher Bishop score (p = 0.001); however, the CL was not significantly different (p = 0.130). UCA alone did not perform better than the Bishop score when predicting successful IOL. However, UCA combined with the Bishop score showed higher performance in predicting IOL (combined UCA > 108.4° and favorable Bishop score as sensitivity of 44.6%, specificity of 96.0%, PPV of 96.2%, and NPV of 43.6; combined UCA > 108.4° or favorable Bishop score as sensitivity of 85.7%, specificity of 50.0%, PPV of 78.7%, and NPV of 61.9). In conclusion, UCA combined with Bishop score may be an effective sonographic method for predicting successful IOL.

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.

Recent advances in the induction of labor

The rate of labor induction is steadily increasing and, in industrialized countries, approximately one out of four pregnant women has their labor induced. Induction of labor should be considered when the benefits of prompt vaginal delivery outweigh the maternal and/or fetal risks of waiting for the spontaneous onset of labor. However, this procedure is not free of risks, which include an increase in operative vaginal or caesarean delivery and excessive uterine activity with risk of fetal heart rate abnormalities. A search for “Induction of Labor” retrieves more than 18,000 citations from 1844 to the present day. The aim of this review is to summarize the controversies concerning the indications, the methods, and the tools for evaluating the success of the procedure, with an emphasis on the scientific evidence behind each.

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.

[The opening of the internal cervical os predicts cervical ripening better than Bishop's score in nulliparous women at 41 weeks gestation]

Introduction

L'objectif était d'évaluer la mesure échographique de l’ouverture de l’orifice interne du col dans la prédiction de l’issue de la maturation cervicale et la comparer au Score de Bishop.

Méthodes

Nous avons mené une étude prospective sur 10 mois, entre Juillet 2012 et avril 2013 colligeant 77 femmes nullipares admises pour déclenchement du travail à un terme de 41 SA avec un Score de Bishop < 6. La mesure de l’ouverture de l’orifice interne du col a été réalisée par échographie transvaginale et le score de Bishop a été déterminé par l'examen clinique. Toutes les patientes ont eu une maturation cervicale par des prostaglandines.

Résultats

La maturation cervicale était réussie chez 63 patients (81%). Le Score de Bishop et l’ouverture de l’orifice interne du col se sont révélés statistiquement associés au succès ou l’échec de la maturation cervicale. Le taux de succès de la maturation était de 100% lorsque l’ouverture de l’orifice interne du col était égale ou supérieure à 5 mm (sensibilité: 54%; spécificité: 86%). Les courbes ROC ont montré que la mesure de l’orifice interne du col était plus prédictive de l’issue de la maturation cervicale que le Score de Bishop (Aire sous la courbe respectivement 0.733 et 0.704).

Conclusion

Comparée au score de Bishop, la mesure échographique de l’ouverture de l’orifice interne du col est plus prédictive du succès de la maturation cervicale chez les femmes nullipares à 41 semaines d’aménorrhée avec un col défavorable.

Simplified Bishop score including parity predicts successful induction of labor

OBJECTIVE

Our objectives were to confirm the predictiveness of parity for successful labor induction and propose an improvement in the Bishop's score to take parity into account and simultaneously simplify the original Bishop score.

STUDY DESIGN

Retrospective study of 326 deliveries induced by oxytocin and amniotomy before prostaglandins between January 1, 1987, and June 30, 1988. We conducted a univariate and then a multivariate analysis of the relation between successful labor induction - defined by vaginal delivery- and the components of Bishop's score and parity.

RESULTS

Nulliparous accounted for 38% of the studied population. The mean Bishop at induction was 5.75±1.4. Fetal station, cervical effacement, and parity were the only factors associated with the success of induction in this study. Removing the cervical position and consistency from the score as well as adding parity significantly improved the prediction of success (ROC curves, AUC 0.88 vs 0.68, p<0.001). By taking 5% as the maximum risk of induction failure, a cutoff point of 4 for the new score makes it possible to induce labor in 90% of the women that were considered in the study (vs 26% or 60%, according to whether the cutoff point of the original Bishop's score is set, respectively, at 7 or 6, p<0.001).

CONCLUSION

Cervical position and consistency are not necessary for predicting successful labor induction by oxytocin and amniotomy. We confirmed the usefulness of a simplified Bishop score that considers parity.