Tension compared to no tension on a Foley transcervical catheter for cervical ripening: a randomized controlled trial

Women's Experiences of Mechanical Balloon Catheter Induction With Self-Traction

OBJECTIVE

To explore women's experiences of mechanical labor induction using a balloon catheter with self-traction.

DESIGN

Descriptive qualitative.

SETTING

Birth unit of an urban hospital in Quebec, Canada.

PARTICIPANTS

Fourteen women who experienced labor induction with a balloon catheter using self-traction.

METHODS

We conducted individual structured interviews between May 2022 and January 2023 to collect data that we subsequently analyzed using the manifest content analysis approach of Graneheim et al. We adhered to the Consolidated Criteria for Reporting Qualitative Research (COREQ).

RESULTS

We identified five categories: Expectations, Pain or Comfort Experienced, Emotions Felt, Support From Nursing Staff, and Appreciation of the Procedure. The participants anticipated rapid, effective induction, expressed concerns about potential discomfort, and appreciated control of their experiences. We found a generally positive trend in terms of appreciation for all categories.

CONCLUSION

The positive experiences of participants underline the promising potential of the balloon catheter method of labor induction with self-traction. Given the continuing growth in labor induction rates, it becomes necessary to continue efforts to offer services specifically geared to women's needs. Offering an additional option such as self-traction is a step in this direction.

Applying Tension to the Transcervical Foley Balloon and Delivery Times in Term Nulliparous Women Undergoing Induction of Labor: A Randomized Controlled Trial

OBJECTIVE

To investigate the effects of applying tension to a transcervical Foley balloon on delivery time in term nulliparous patients undergoing labor induction.

METHODS

This cluster randomized clinical trial included 279 term nulliparous women presenting for labor induction with a plan for cervical ripening through transcervical Foley balloon placement. Participants were assigned to either the tension group (n=138) or the no-tension group (n=141) on the basis of randomized, weekly clusters (26 total clusters). The primary outcome measured was the time from initial Foley balloon insertion to delivery. Secondary outcomes included cesarean delivery rates, peripartum infection, and neonatal intensive care unit (NICU) admission. Our prior data suggested that delivery time in the tension group would be about 1,053 minutes. We estimated a sample size of 260 (130 per group, 26 clusters) on the basis of a 25% difference, power of 80%, and two-sided α of 0.05.

RESULTS

A total of 279 term nulliparous patients were included in the analysis. The median time from Foley placement to delivery was 1,596 minutes (range 430-3,438 minutes) for the tension group and 1,621 minutes (range 488-3,323 minutes) for the no-tension group ( P =.8); similar results were noted for time to vaginal delivery. No significant differences were observed in the secondary outcomes, including the rates of cesarean delivery (34.1% vs 29.8%, P =.7), peripartum infection, and NICU admission, between the two groups.

CONCLUSION

Applying tension to a transcervical Foley balloon in term nulliparous women undergoing labor induction did not significantly reduce delivery time or improve secondary outcomes.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov , NCT05404776.

Self-Traction During Mechanical Cervical Dilatation, Acceptability, Feasibility and Satisfaction of its Application: A Pilot Study

This study aims to measure acceptability, feasibility, and satisfaction with self-traction during mechanical cervical dilatation to induce labour and to explore its effects on pain and the process of labour and delivery. 60 parturients were randomly assigned to self-traction or regular traction. Participants completed questionnaires about sociodemographic characteristics, acceptability, and satisfaction. Self-traction participants reported significantly higher acceptability (P = 0.026), and adequacy (P = 0.018). They also reported satisfaction with the procedure. A group comparison regarding feasibility, pain, and the process of labour and delivery showed no significant difference. Self-traction is an acceptable and feasible intervention for full-term parturients.

A comparison of 30-, 50-, and 60-mL foley catheter balloon volume and time to achieve cervical ripening for labor induction: A triple-blind randomized controlled trial

Background

Cervical ripening is one of the most important determinants of the outcome of induction of labor. The findings of studies on the most efficacious inflatable catheter balloon volume for pre-induction cervical ripening have been inconclusive.

Aim

To compare the efficacy of the use of different intracervical Foley catheter balloon volumes (30-, 50-, and 60-mL) on cervical ripening.

Subjects and Methods

This study was a triple-blind randomized controlled trial. Two hundred and sixteen women with a Bishop score ≤5 at term were randomly assigned into three groups (1:1:1) to receive an intracervical single size eighteen Foley balloon catheter inflated either with 30-mL (control arm) or 50-mL and 60-mL (intervention arm) of sterile saline which was retained for a duration of 12 h. The primary outcome measures were the mean change in Bishop score and achieving a Bishop score of ≥6 at the twelfth-hour post-Foley catheter balloon insertion.

Results

In the total study population and among nulliparous women, the 50-mL and 60-mL balloons compared with the 30-mL Foley catheter balloon achieved a statistically significantly greater mean change in Bishop scores at the twelfth hour\post-insertion (P = 0.005 and P = 0.001), while the 60-mL balloon compared with the 30-mL and 50-mL balloons achieved statistically significant higher mean change in Bishop scores among multiparous women (P = 0.047 and P = 0.003) and cervical dilatation irrespective of parity (P = 0.003 and P = 0.002), at the twelfth-hour post-insertion. The larger catheter balloons were also associated with a statistically significant greater chance of having an induction to delivery interval of <12 h in nulliparous women P = 0.003.

Conclusion

The findings of this study showed that the larger single Foley catheter balloon volumes (50-mL and 60-mL) aside from being well tolerated and acceptable have the ability to induce faster changes in Bishop score, produce higher cervical dilation, and thus likely reduce significantly the total labor induction process compared to the 30-mL single catheter balloon volume irrespective of parity.

Mechanical methods for induction of labour

BACKGROUND

Mechanical methods were the first methods developed to ripen the cervix and induce labour. During recent decades they have been substituted by pharmacological methods. Potential advantages of mechanical methods, compared with pharmacological methods may include reduction in side effects that could improve neonatal outcomes. This is an update of a review first published in 2001, last updated in 2012.

OBJECTIVES

To determine the effectiveness and safety of mechanical methods for third trimester (> 24 weeks' gestation) induction of labour in comparison with prostaglandin E2 (PGE2) (vaginal and intracervical), low-dose misoprostol (oral and vaginal), amniotomy or oxytocin.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP), and reference lists of retrieved studies (9 January 2018). We updated the search in March 2019 and added the search results to the awaiting classification section of the review.

SELECTION CRITERIA

Clinical trials comparing mechanical methods used for third trimester cervical ripening or labour induction with pharmacological methods. Mechanical methods include: (1) the introduction of a catheter through the cervix into the extra-amniotic space with balloon insufflation; (2) introduction of laminaria tents, or their synthetic equivalent (Dilapan), into the cervical canal; (3) use of a catheter to inject fluid into the extra-amniotic space (EASI). This review includes the following comparisons: (1) specific mechanical methods (balloon catheter, laminaria tents or EASI) compared with prostaglandins (different types, different routes) or with oxytocin; (2) single balloon compared to a double balloon; (3) addition of prostaglandins or oxytocin to mechanical methods compared with prostaglandins or oxytocin alone.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and assessed risk of bias. Two review authors independently extracted data and assessed the quality of the evidence using the GRADE approach.

MAIN RESULTS

This review includes a total of 112 trials, with 104 studies contributing data (22,055 women; 21 comparisons). Risk of bias of trials varied. Overall, the evidence was graded from very-low to moderate quality. All evidence was downgraded for lack of blinding and, for many comparisons, the effect estimates were too imprecise to make a valid judgement.   Balloon versus vaginal PGE2: there may be little or no difference in vaginal deliveries not achieved within 24 hours (risk ratio (RR) 1.01, 95% confidence interval (CI) 0.82 to 1.26; 7 studies; 1685 women; low-quality evidence) and there probably is little or no difference in caesarean sections (RR 1.00, 95% CI 0.92 to 1.09; 28 studies; 6619 women; moderate-quality evidence) between induction of labour with a balloon catheter and vaginal PGE2. A balloon catheter probably reduces the risk of uterine hyperstimulation with fetal heart rate (FHR) changes (RR 0.35, 95% CI 0.18 to 0.67; 6 studies; 1966 women; moderate-quality evidence), serious neonatal morbidity or perinatal death (RR 0.48, 95% CI 0.25 to 0.93; 8 studies; 2757 women; moderate-quality evidence) and may slightly reduce the risk of aneonatal intensive care unit (NICU) admission (RR 0.82, 95% CI 0.65 to 1.04; 3647 women; 12 studies; low-quality evidence). It is uncertain whether there is a difference in serious maternal morbidity or death (RR 0.20, 95% CI 0.01 to 4.12; 4 studies; 1481 women) or five-minute Apgar score < 7 (RR 0.74, 95% CI 0.49 to 1.14; 4271 women; 14 studies) because the quality of the evidence was found to be very low and low, respectively. Balloon versus low-dose vaginal misoprostol: it is uncertain whether there is a difference in vaginal deliveries not achieved within 24 hours between induction of labour with a balloon catheter and vaginal misoprostol (RR 1.09, 95% CI 0.85 to 1.39; 340 women; 2 studies; low-quality evidence). A balloon catheter probably reduces the risk of uterine hyperstimulation with FHR changes (RR 0.39, 95% CI 0.18 to 0.85; 1322 women; 8 studies; moderate-quality evidence) but may increase the risk of a caesarean section (RR 1.28, 95% CI 1.02 to 1.60; 1756 women; 12 studies; low-quality evidence). It is uncertain whether there is a difference in serious neonatal morbidity or perinatal death (RR 0.58, 95% CI 0.12 to 2.66; 381 women; 3 studies), serious maternal morbidity or death (no events; 4 studies, 464 women), both very low-quality evidence, and five-minute Apgar score < 7 (RR 1.00, 95% CI 0.50 to 1.97; 941 women; 7 studies) and NICU admissions (RR 1.00, 95% CI 0.61 to 1.63; 1302 women; 9 studies) both low-quality evidence. Balloon versus low-dose oral misoprostol: a balloon catheter probably increases the risk of a vaginal delivery not achieved within 24 hours (RR 1.28, 95% CI 1.13 to 1.46; 782 women, 2 studies, and probably slightly increases the risk of a caesarean section (RR 1.17, 95% CI 1.04 to 1.32; 3178 women; 7 studies; both moderate-quality evidence) when compared to oral misoprostol. It is uncertain whether there is a difference in uterine hyperstimulation with FHR changes (RR 0.81, 95% CI 0.48 to 1.38; 2033 women; 2 studies), serious neonatal morbidity or perinatal death (RR 1.11, 95% CI 0.60 to 2.06; 2627 women; 3 studies), both low-quality evidence, serious maternal morbidity or death (RR 0.50, 95% CI 0.05 to 5.52; 2627 women; 3 studies), very low-quality evidence, five-minute Apgar scores < 7 (RR 0.71, 95% CI 0.38 to 1.32; 2693 women; 4 studies) and NICU admissions (RR 0.82, 95% CI 0.58 to 1.17; 2873 women; 5 studies) both low-quality evidence.

AUTHORS' CONCLUSIONS

Low- to moderate-quality evidence shows mechanical induction with a balloon is probably as effective as induction of labour with vaginal PGE2. However, a balloon seems to have a more favourable safety profile. More research on this comparison does not seem warranted. Moderate-quality evidence shows a balloon catheter may be slightly less effective as oral misoprostol, but it remains unclear if there is a difference in safety outcomes for the neonate. When compared to low-dose vaginal misoprostol, low-quality evidence shows a balloon may be less effective, but probably has a better safety profile. Future research could be focused more on safety aspects for the neonate and maternal satisfaction.

Guideline No. 432b: Cervical Ripening

OBJECTIVE

This guideline presents evidence and recommendations for cervical ripening and induction of labour. It aims to provide information to birth attendants and pregnant individuals on optimal perinatal care while avoiding unnecessary obstetrical intervention.

TARGET POPULATION

All pregnant patients.

BENEFITS, HARMS, AND COSTS

Consistent interprofessional use of the guideline, appropriate equipment, and trained professional staff enhance safe intrapartum care. Pregnant individuals and their support person(s) should be informed of the benefits and risks of induction of labour.

EVIDENCE

Literature published to March 2022 was reviewed. PubMed, CINAHL, and the Cochrane Library were used to search for systematic reviews, randomized controlled trials, and observational studies on cervical ripening and induction of labour. Grey (unpublished) literature was identified by searching the websites of health technology assessment and health technology related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and conditional [weak] recommendations).

INTENDED AUDIENCE

All providers of obstetrical care.

RECOMMANDATIONS

Directive clinique no 432b : Maturation cervicale

OBJECTIF

Présenter des données probantes et des recommandations sur la maturation cervicale et le déclenchement artificiel du travail. Fournir de l'information aux professionnels accoucheurs et aux personnes enceintes sur les soins périnataux optimaux et la prévention des interventions obstétricales inutiles.

POPULATION CIBLE

Toutes les patientes enceintes. BéNéFICES, RISQUES ET COûTS: La mise en application interprofessionnelle et cohérente de la présente directive, l'équipement adéquat et le personnel compétent améliorent la sécurité des soins per partum. Les personnes enceintes et leurs personnes de soutien doivent être informées des risques et bénéfices du déclenchement artificiel du travail. DONNéES PROBANTES: La littérature publiée jusqu'en mars 2022 a été passée en revue. Une recherche a été effectuée dans les bases de données PubMed, CINAHL et Cochrane Library pour répertorier des revues systématiques, des essais cliniques randomisés et des études observationnelles sur la maturation cervicale et le déclenchement artificiel du travail. La littérature grise (non publiée) a été obtenue à l'aide de recherches menées dans des sites Web d'organismes s'intéressant à l'évaluation des technologies dans le domaine de la santé et d'organismes connexes, dans des collections de directives cliniques, des registres d'essais cliniques et des sites Web de sociétés de spécialité médicale nationales et internationales. MéTHODES DE VALIDATION: Les auteurs ont évalué la qualité des données probantes et la force des recommandations en utilisant le cadre méthodologique GRADE (Grading of Recommendations Assessment, Development and Evaluation). Voir l'annexe A en ligne (tableau A1 pour les définitions et tableau A2 pour l'interprétation des recommandations fortes et conditionnelles [faibles]). PROFESSIONNELS CONCERNéS: Tous les fournisseurs de soins obstétricaux.

RECOMMANDATIONS

Traction vs no traction in Foley catheter use for induction of labor: a systematic review and meta-analysis of randomized trials

OBJECTIVE

Intracervical Foley catheter is a safe and effective method for cervical ripening. There are a variety of ways to modify this ripening method, including adding traction or tension to the catheter. The utility of this practice is uncertain. The aim of this systematic review and meta-analysis of randomized controlled trials was to investigate whether the placement of traction vs no traction on a Foley catheter during cervical ripening decreases total time from induction to delivery.

DATA SOURCES

Electronic sources include MEDLINE, Scopus, ClinicalTrials.gov, the International Prospective Register of Systematic Reviews, SciELO, the Cochrane Central Register of Controlled Trials, and Google Scholar from inception through June 2020.

STUDY ELIGIBILITY CRITERIA

Randomized trials comparing Foley catheter with traction (ie, intervention) vs Foley catheter without traction (ie, control) for cervical ripening were included in the meta-analysis. All types of traction were analyzed (weighted, taped to thigh) and whether the traction was placed only initially at Foley catheter placement or repeated throughout the ripening process.

METHODS

The primary outcome was the mean time from induction to delivery in hours. Meta-analysis was performed using the random-effects model of DerSimonian and Laird to produce summary treatment effects in terms of mean difference with 95% confidence interval. Heterogeneity was measured using I-squared (Higgins I²).

RESULTS

Three trials including 790 singleton gestations were identified as relevant and included in the systematic review. Women randomized to traction on the Foley balloon had a similar time from induction to delivery compared with no traction (mean difference, 0.25; confidence interval, -0.78 to 1.27). No significant differences were found in the secondary outcomes. There was no difference in cesarean delivery between groups (relative risk, 0.94; 95% confidence interval, 0.74-1.19). Foley catheter expulsion was faster in the tension group (mean difference, -3.74; 95% confidence interval, -6.29 to -1.19) CONCLUSION: Adding traction to an intracervical Foley catheter during cervical ripening does not decrease time to delivery.

Review of Evidence-Based Methods for Successful Labor Induction

Induction of labor is increasingly a common component of the intrapartum care. Knowledge of the current evidence on methods of labor induction is an essential component of shared decision-making to determine which induction method meets an individual's health needs and personal preferences. This article provides a review of the current research evidence on labor induction methods, including cervical ripening techniques, and contraction stimulation techniques. Current evidence about expected duration of labor following induction, use of the Bishop score to guide induction, and guidance on the use of combination methods for labor induction are reviewed.

Induction of labor with Foley catheter and risk of subsequent preterm birth: follow-up study of two randomized controlled trials (PROBAAT-1 and -2)

OBJECTIVE

To evaluate the rate of preterm birth (PTB) in a subsequent pregnancy in women who had undergone term induction using a Foley catheter compared with prostaglandins.

METHODS

This was a follow-up study of two large randomized controlled trials (PROBAAT-1 and PROBAAT-2). In the original trials, women with a term singleton pregnancy with the fetus in cephalic presentation and with an indication for labor induction were randomized to receive either a 30-mL Foley catheter or prostaglandins (vaginal prostaglandin E2 in PROBAAT-1 and oral misoprostol in PROBAAT-2). Data on subsequent ongoing pregnancies > 16 weeks' gestation were collected from hospital charts from clinics participating in this follow-up study. The main outcome measure was preterm birth < 37 weeks' gestation in a subsequent pregnancy.

RESULTS

Fourteen hospitals agreed to participate in this follow-up study. Of the 1142 eligible women, 572 had been allocated to induction of labor using a Foley catheter and 570 to induction of labor using prostaglandins. Of these, 162 (14%) were lost to follow-up. In total, 251 and 258 women had a known subsequent pregnancy > 16 weeks' gestation in the Foley catheter and prostaglandin groups, respectively. There were no differences in baseline characteristics between the groups. The overall rate of PTB in a subsequent pregnancy was 9/251 (3.6%) in the Foley catheter group vs 10/258 (3.9%) in the prostaglandin group (relative risk (RR), 0.93; 95% CI, 0.38-2.24), and the rate of spontaneous PTB was 5/251 (2.0%) vs 5/258 (1.9%) (RR, 1.03; 95% CI, 0.30-3.51).

CONCLUSION

In women with term singleton pregnancy, induction of labor using a 30-mL Foley catheter is not associated with an increased risk of PTB in a subsequent pregnancy, as compared to induction of labor using prostaglandins. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Evidence-based labor management: induction of labor (part 2)

Induction of labor is indicated for many obstetrical, maternal, and fetal indications. Induction can be offered for pregnancy at 39 weeks' gestation. No prediction method is considered sensitive or specific enough to determine the incidence of cesarean delivery after induction. A combination of 60- to 80-mL single-balloon Foley catheter for 12 hours and either 25-μg oral misoprostol initially, followed by 25 μg every 2-4 hours, or 50 μg every 4-6 hours (if no more than 3 contractions per 10 minutes or previous uterine surgery), or oxytocin infusion should be recommended for induction of labor. Adding membrane stripping at the beginning of induction should be considered. Once 5-6 cm of cervical dilation is achieved during the induction of labor, consideration can be given to discontinue oxytocin infusion if in use at that time and adequate contractions are present. Induction with oxytocin immediately (as soon as feasible) or up to 12 hours of term prelabor rupture of membranes if labor is not evident is recommended. Outpatient Foley ripening can be considered for low-risk women. Cesarean delivery should not be performed before 15 hours of oxytocin infusion and amniotomy if feasible and ideally after 18-24 hours of oxytocin infusion.

Speculum versus digital insertion of Foley catheter for induction of labor in Nulliparas with unripe cervix: a randomized controlled trial

Background

Induction of labor (IoL) is an increasingly common obstetric procedure. Foley catheter IoL is recommended by WHO. It is associated with the lowest rate of uterine hyperstimulation syndrome and similar duration to delivery and vaginal delivery rate compared to other methods. Insertion is typically via speculum but digital insertion has been reported to be faster, better tolerated and with similar universal insertion success compared to speculum insertion in a mixed population of nulliparas and multiparas. Transcervical procedure is more challenging in nulliparas and when the cervix is unripe. We evaluated the ease and tolerability of digital compared to speculum insertion of Foley catheter for induction of labor in nulliparas with unripe cervixes.

Methods

A randomized trial was performed in a university hospital in Malaysia. Participants were nulliparas at term with unripe cervixes (Bishop Score ≤ 5) admitted for IoL who were randomized to digital or speculum-aided transcervical Foley catheter insertion in lithotomy position. Primary outcomes were insertion duration, pain score [11-point Visual Numerical Rating Scale (VNRS)], and failure. All primary outcomes were recorded after the first insertion.

Results

Data from 86 participants were analysed. Insertion duration (with standard deviation) was 2.72 ± 1.85 vs. 2.25 ± 0.55 min p = 0.12, pain score (VNRS) median [interquartile range] 3.5 [2–5] vs. 3 [2–5] p = 0.72 and failure 2/42 (5%) vs. 0/44 (0%) p = 0.24 for digital vs speculum respectively. There was no significant difference found between the two groups for all three primary outcomes. Induction to delivery 30.7 ± 9.4 vs 29.6 ± 11.5 h p = 0.64, Cesarean section 25/60 (64%) vs 28/64 (60%) RR 0.9 95% CI p = 0.7 and maternal satisfaction VNRS score with the birth process 7 [IQR 6–8] vs 7 [7–8] p = 0.97 for digital vs. speculum arms respectively. Other labor, delivery and neonatal secondary outcomes were not significantly different.

Conclusion

Digital and speculum insertion in nulliparas with unripe cervixes had similar insertion performance. As digital insertion required less equipment and consumables, it could be the preferred insertion method for the equally adept and the insertion technique to train towards.

Trial registration

This trial was registered with ISRCTN registration number 13804902 on 15 November 2017.

Induction of labor in continuing pregnancies

This chapter aims to provide an evidence-based approach to cervical-ripening methods and induction of labor in high-, middle-, and low-income countries. We will review the epidemiology of induction and will also review pharmacological and mechanical methods of cervical-ripening as well as oxytocin for induction. Lastly, we will review current guidelines of when to determine an induction to be failed.

Mechanical methods for induction of labour

BACKGROUND

Mechanical methods were the first methods developed to ripen the cervix and induce labour. During recent decades they have been substituted by pharmacological methods. Potential advantages of mechanical methods, compared with pharmacological methods may include reduction in side effects that could improve neonatal outcomes. This is an update of a review first published in 2001, last updated in 2012.

OBJECTIVES

To determine the effectiveness and safety of mechanical methods for third trimester (> 24 weeks' gestation) induction of labour in comparison with prostaglandin E2 (PGE2) (vaginal and intracervical), low-dose misoprostol (oral and vaginal), amniotomy or oxytocin.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP), and reference lists of retrieved studies (9 January 2018). We updated the search in March 2019 and added the search results to the awaiting classification section of the review.

SELECTION CRITERIA

Clinical trials comparing mechanical methods used for third trimester cervical ripening or labour induction with pharmacological methods.Mechanical methods include: (1) the introduction of a catheter through the cervix into the extra-amniotic space with balloon insufflation; (2) introduction of laminaria tents, or their synthetic equivalent (Dilapan), into the cervical canal; (3) use of a catheter to inject fluid into the extra-amniotic space (EASI).This review includes the following comparisons: (1) specific mechanical methods (balloon catheter, laminaria tents or EASI) compared with prostaglandins (different types, different routes) or with oxytocin; (2) single balloon compared to a double balloon; (3) addition of prostaglandins or oxytocin to mechanical methods compared with prostaglandins or oxytocin alone.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and assessed risk of bias. Two review authors independently extracted data and assessed the quality of the evidence using the GRADE approach.

MAIN RESULTS

This review update includes a total of 113 trials (22,373 women) contributing data to 21 comparisons. Risk of bias of trials varied. Overall, the evidence was graded from very-low to moderate quality. All evidence was downgraded for lack of blinding and, for many comparisons, the effect estimates were too imprecise to make a valid judgement.Balloon versus vaginal PGE2: there may be little or no difference in vaginal deliveries not achieved within 24 hours (average risk ratio (RR) 1.01, 95% confidence interval (CI) 0.82 to 1.26; 7 studies; 1685 women; I² = 79%; low-quality evidence) and there probably is little or no difference in caesarean sections (RR 1.00, 95% CI 0.92 to 1.09; 28 studies; 6619 women; moderate-quality evidence) between induction of labour with a balloon catheter and vaginal PGE2. A balloon catheter probably reduces the risk of uterine hyperstimulation with fetal heart rate (FHR) changes (RR 0.35, 95% CI 0.18 to 0.67; 6 studies; 1966 women; moderate-quality evidence), serious neonatal morbidity or perinatal death (RR 0.48, 95% CI 0.25 to 0.93; 8 studies; 2757 women; moderate-quality evidence) and may slightly reduce the risk of aneonatal intensive care unit (NICU) admission (RR 0.82, 95% CI 0.65 to 1.04; 3647 women; 12 studies; low-quality evidence). It is uncertain whether there is a difference in serious maternal morbidity or death (RR 0.20, 95% CI 0.01 to 4.12; 4 studies; 1481 women) or five-minute Apgar score < 7 (RR 0.74, 95% CI 0.49 to 1.14; 4271 women; 14 studies) because the quality of the evidence was found to be very low and low, respectively.Balloon versus low-dose vaginal misoprostol: it is uncertain whether there is a difference in vaginal deliveries not achieved within 24 hours between induction of labour with a balloon catheter and vaginal misoprostol (RR 1.09, 95% CI 0.85 to 1.39; 340 women; 2 studies; low-quality evidence). A balloon catheter probably reduces the risk of uterine hyperstimulation with FHR changes (RR 0.39, 95% CI 0.18 to 0.85; 1322 women; 8 studies; moderate-quality evidence) but may increase the risk of a caesarean section (average RR 1.28, 95% CI 1.02 to 1.60; 1756 women; 12 studies; I² = 45%; low-quality evidence). It is uncertain whether there is a difference in serious neonatal morbidity or perinatal death (RR 0.58, 95% CI 0.12 to 2.66; 381 women; 3 studies), serious maternal morbidity or death (no events; 4 studies, 464 women), both very low-quality evidence, and five-minute Apgar score < 7 (RR 1.00, 95% CI 0.50 to 1.97; 941 women; 7 studies) and NICU admissions (RR 1.00, 95% CI 0.61 to 1.63; 1302 women; 9 studies) both low-quality evidence.Balloon versus low-dose oral misoprostol: a balloon catheter probably increases the risk of a vaginal delivery not achieved within 24 hours (RR 1.28, 95% CI 1.13 to 1.46; 782 women, 2 studies, and probably slightly increases the risk of a caesarean section (RR 1.17, 95% CI 1.04 to 1.32; 3178 women; 7 studies; both moderate-quality evidence) when compared to oral misoprostol. It is uncertain whether there is a difference in uterine hyperstimulation with FHR changes (RR 0.81, 95% CI 0.48 to 1.38; 2033 women; 2 studies), serious neonatal morbidity or perinatal death (RR 1.11, 95% CI 0.60 to 2.06; 2627 women; 3 studies), both low-quality evidence, serious maternal morbidity or death (RR 0.50, 95% CI 0.05 to 5.52; 2627 women; 3 studies), very low-quality evidence, five-minute Apgar scores < 7 (RR 0.71, 95% CI 0.38 to 1.32; 2693 women; 4 studies) and NICU admissions (RR 0.82, 95% CI 0.58 to 1.17; 2873 women; 5 studies) both low-quality evidence.

AUTHORS' CONCLUSIONS

Low- to moderate-quality evidence shows mechanical induction with a balloon is probably as effective as induction of labour with vaginal PGE2. However, a balloon seems to have a more favourable safety profile. More research on this comparison does not seem warranted.Moderate-quality evidence shows a balloon catheter may be slightly less effective as oral misoprostol, but it remains unclear if there is a difference in safety outcomes for the neonate. When compared to low-dose vaginal misoprostol, low-quality evidence shows a balloon may be less effective, but probably has a better safety profile.Future research could be focused more on safety aspects for the neonate and maternal satisfaction.

Blown out of proportion? Induction Foley balloon ruptures associated with overinflation

BACKGROUND

Larger volume Foley catheters are occasionally used for labor induction. In some instances the balloon is overinflated to obtain this volume. Neither the risk or rate of rupture are known for this practice.

OBJECTIVE

The purpose of this study was to evaluate the use of overinflated Foley catheter balloons and the rate of rupture in prospective trials and to describe rupture events in our institutions.

STUDY DESIGN

Clinical trials and prospective cohorts were identified through a search of MEDLINE from 2000 through May 1, 2017; prospective studies were examined for the use of overinflated Foley catheters. Reports of overinflated balloons were then reviewed in detail to determine if rupture occurred and to record any reported maternal, neonatal, or gynecologic outcomes. Internal reports to the Obstetric Safety Report System were used to describe the local cases at our institutions.

RESULTS

We reviewed 296 abstracts. Seventeen prospective cohorts or randomized trials used larger balloon volumes (≥50 mL), of which 12 abstracts confirmed routine overinflation of the balloon. Within these studies, 19 patients who underwent cervical ripening with overinflated Foley catheters experienced balloon rupture during use. The incidence of rupture in these studies was 0.9%. No adverse maternal or fetal effects were noted. Internal safety reporting yielded an additional case. One gynecologic case was identified internally. The patient had an overinflated Foley catheter balloon used to tamponade excessive uterine bleeding after uterine evacuation. Balloon rupture was noted, and hysteroscopy was needed to remove fragments of the balloon.

CONCLUSION

Overinflation of Foley catheter balloons in obstetric and gynecologic applications may cause rupture. Because of possible underreporting, the extent of complications that may result from balloon rupture is unknown.

Cervical ripening balloon with and without oxytocin in multiparas: a randomized controlled trial

BACKGROUND

The optimal method for induction of labor for multiparous women with an unfavorable cervix is unknown.

OBJECTIVE

We sought to determine if induction of labor with simultaneous use of oxytocin and a cervical ripening balloon, compared with sequential use, increases the likelihood of delivery within 24 hours in multiparous women.

STUDY DESIGN

We performed a randomized controlled trial from November 2014 through June 2017. Eligible participants were multiparous women with a vertex presenting, nonanomalous singleton gestation ≥34 weeks undergoing induction of labor. Women were excluded for admission cervical examination >2 cm, ruptured membranes, chorioamnionitis or evidence of systemic infection, placental abruption, low-lying placenta, >1 prior cesarean delivery, or contraindication to vaginal delivery. Patients were randomly allocated to the following cervical ripening groups: simultaneous (oxytocin with cervical ripening balloon) or sequential (oxytocin following cervical ripening balloon expulsion). The primary outcome was delivery within 24 hours of cervical ripening balloon placement. Secondary outcomes included induction-to-delivery interval, time to cervical ripening balloon expulsion, mode of delivery, and adverse maternal or neonatal outcomes.

RESULTS

In all, 180 patients were randomized (90 simultaneous, 90 sequential). Baseline demographic and obstetric characteristics were similar between study groups. Women in the simultaneous group were significantly more likely to deliver within 24 hours of cervical ripening balloon placement compared to the sequential group (87.8% vs 73.3%, P = .02). The simultaneous group also had a significantly shorter induction-to-delivery interval and greater cervical dilation at cervical ripening balloon expulsion. There were no differences in mode of delivery, chorioamnionitis, or adverse maternal or neonatal outcomes.

CONCLUSION

In multiparous women with an unfavorable cervix, the simultaneous use of cervical ripening balloon and oxytocin results in an increased frequency of delivery within 24 hours and a shorter induction-to-delivery interval.

Foley's catheter balloon for induction of mid-trimester missed abortion with or without traction applied: a randomized controlled trial

Objective: To determine whether the traction placed on a transcervical Foley catheter balloon inserted for the induction of mid-trimester missed abortion results in faster time of abortion.Study design: It was randomized clinical trial conducted at Assiut Woman's Health Hospital, Egypt, from September 2016 to August 2017 on women with missed abortion in the mid-trimester. Participants were randomly assigned to transcervical Foley catheter balloon insertion with or without traction. The primary outcome of this study was insertion to abortion time. The secondary outcomes included insertion to catheter expulsion time, vaginal bleeding, and pain associated with insertion. The outcome variables were analyzed using Mann-Whitney U and chi-square tests. A logistic regression model was utilized to examine the association between patient's characteristics and the failure of Foley catheter balloon expulsion within 24 hours.Results: Two hundred women were recruited (100 women in each group). The insertion to abortion time was significantly shorter in group I (traction group) than group II (no traction group) (16.49 ± 2.59 versus 18.24 ± 3.30 hours; p = .000). Insertion to balloon expulsion time in group I was also significantly short (7.92 ± 0.86 versus 9.12 ± 1.19 hours; p = .000). However, a significantly higher rate of vaginal bleeding and a higher degree of pain were reported by the women in group I (p = .008, p = .000; respectively). The nulliparity, longer interpregnancy interval (>22 months), smaller gestational age (<14 weeks) and lower Bishop Score before insertion (<2) were significantly associated with a higher likelihood of Foley catheter balloon expulsion failure within 24 hours.Conclusion: The small time advantage of traction does not compensate for the downsides of traction, mainly pain, analgesic use, and vaginal bleeding.