Sequential use of double-balloon catheter and oral misoprostol versus oral misoprostol alone for induction of labour at term (CRBplus trial): a multicentre, open-label randomised controlled trial

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

BACKGROUND

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

RESEARCH AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Interval between balloon removal and oxytocin administration in cervical ripening with double-balloon in singleton pregnancies: An observational study

OBJECTIVE

To analyze the influence of the resting interval after removal of a double-balloon for cervical ripening and oxytocin administration on the time to onset of active labor in singleton pregnancies.

METHODS

A retrospective cohort study of women who required a cervical ripening with double-balloon was conducted between January 2019 and December 2022. We collected data for cervical ripening balloon insertion and removal, oxytocin administration, suspicious or pathological cardiotocographic trace, mode of delivery, maternal and neonatal complications, neonatal outcomes. Proportional hazards model comparing resting interval between double-balloon cervical ripening removal and oxytocin administration.

RESULTS

A total of 403 singleton pregnancies were recruited and 213 pregnant women experienced a rest of 12 h between cervical balloon removal and oxytocin administration (resting group). Oxytocin was administered immediately after balloon removal in 190 women (non-resting group). Median insertion-to-active labor interval and insertion-to-delivery interval were significantly shorter in the non-resting group: 18.5 versus 24.0 h, HR 2.59 (CI 95%: 1.97-3.41) and 24.0 versus 29.0 h, HR 2.38 (CI 95%: 1.85-3.05) respectively. Bishop score change and mode of delivery between were similar in both groups. No differences in maternal nor neonatal complications between both groups were found.

CONCLUSIONS

Oxytocin administration immediately after removal of a double-balloon for cervical ripening compared with 12 h delayed interval resulted in a shortened time from insertion to active labor onset and to delivery interval without increasing maternal or neonatal adverse outcomes.

The use of adjunctive mechanical dilation at the time of induction termination and adverse health outcomes: a systematic review

OBJECTIVE

This study aimed to assess if the use of mechanical dilation at the time of induction termination is associated with changes in the time from initiation of labor to expulsion of the fetus (induction-to-expulsion interval) and with the frequency of health complications when compared with medication management alone.

DATA SOURCES

PubMed, CINAHAL, Scopus, and the Cochrane Central Register of Controlled Trials were queried from January 2000 to May 2023.

STUDY ELIGIBILITY CRITERIA

We included randomized controlled trials of individuals who were assigned to undergo mechanical dilation (ie, laminaria, Dilapan-S, and intracervical Foley balloon catheter) in combination with the use of medication and compared it with the outcomes of medication use (eg, prostaglandins, antiprogestins, oxytocin) alone.

METHODS

The primary outcome was the induction-to-expulsion interval. The secondary outcomes were the incidence of clinical chorioamnionitis, sepsis, hemorrhage, the need for blood transfusion and uterotonics, cervical laceration, the need for adjunctive procedures (eg, dilation and curettage), failed induction termination, uterine rupture, intensive care unit admission, or death. Assessment of bias was performed using the Cochrane Risk of Bias tool. A subgroup analysis was performed among studies deemed to be at low risk of bias.

RESULTS

Of 864 abstracts identified, 11 met the inclusion criteria. Five studies demonstrated a shorter induction-to-expulsion interval among those randomized to mechanical dilation, whereas 6 studies demonstrated a similar or longer induction-to-expulsion interval. There were no significant differences reported in the frequency of any adverse outcomes between the trial arms. In addition, most studies (8/11) exhibited moderate to high levels of bias. In an analysis of the 3 studies deemed to have a low risk of bias, 1 (n=60) demonstrated a longer induction-to-expulsion interval with adjunctive laminaria, 1 (n=60) demonstrated a shorter induction-to-expulsion interval with adjunctive intracervical Foley balloon catheter use, and 1 demonstrated no difference in the induction-to-expulsion interval with adjunctive Dilapan-S use (n=180).

CONCLUSION

Only a small number of studies, most of which were of low quality, assessed mechanical dilation for induction termination. The results of these studies were inconsistent in terms of the induction-to-expulsion interval of adjunctive mechanical methods in comparison with medication management alone. Studies did not reveal significant differences between the groups in adverse outcomes. Further research should investigate the use of mechanical dilation at the time of induction termination using high-quality methods.

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.

Maternal and perinatal outcomes of failed prostaglandin induction of labour: A retrospective cohort study

Background

Induction of labor is performed in up to 25% of pregnant women. When the cervix is unfavorable, cervical ripening may be safely and effectively performed using slow-release vaginal inserts of prostaglandin E2. However, the risk factors, management, and outcome of patients who fail to respond remain unclear.

Objective

To evaluate the outcomes of women who fail to respond to cervical ripening with prostaglandins.

Methods

A retrospective cohort analysis (2013-2019) was conducted. Women with a singleton gestation who underwent induction of labor due to post-date pregnancy using a slow-release prostaglandin E2 vaginal insert for cervical ripening were included. Data on clinical and outcome factors were derived from the medical files, and findings were compared between patients who achieved ripening within 24 h of treatment onset and those who did not. The primary outcome measure was the vaginal delivery rate following the ripening process. Secondary outcome measures were adverse composite maternal and neonatal outcomes. A model combining maternal characteristics and response rates to ripening was constructed.

Results

The final cohort included 1285 women: 1202 responded to cervical ripening (93.54%) and 83 (6.46%) did not. Compared to non-responders, responders had higher rates of vaginal delivery (96.51% vs. 66.27%, P < 0.001); lower rates of adverse maternal composite outcome (12.81% vs. 24.10%, P = 0.031) and adverse neonatal composite respiratory outcome (1.33% vs. 6.02%, P = 0.009). Responders were younger than non-responders (mean 30.03 years vs 31.73 years, P = 0.005) and had a lower nulliparity rate (50.99% vs 76.92%, P < 0.001). On multivariate analysis, failure to achieve cervical ripening was an independent risk factor for intrapartum cesarean delivery due to prolonged labor (aOR 11.90, 95% CI 6.13-23.25).

Conclusion

Women who achieve cervical ripening with prostaglandin E2 vaginal inserts are younger and more often multiparous than women who fail to respond. Good response to the cervical ripening process is associated with lower rates of intrapartum cesarean delivery and of adverse outcomes.

Safety and efficacy of double-balloon catheter for cervical ripening: a Bayesian network meta-analysis of randomized controlled trials

BACKGROUND

Various methods are used for cervical ripening during the induction of labor. Mechanical and pharmacological methods are commonly used for cervical ripening. A double-balloon catheter was specifically developed to ripen the cervix and induce labor; however, the efficacy of the double-balloon catheter in cervical ripening compared to other methods is unknown.

METHODS

We searched five databases and performed a Bayesian network meta-analysis. Six interventions (double-balloon catheter, Foley catheter, oral misoprostol, vaginal misoprostol, dinoprostone, and double-balloon catheter combined with oral misoprostol) were included in the search. The primary outcomes were cesarean delivery rate and time from intervention-to-birth. The secondary outcomes were as follows: Bishop score increment; achieving a vaginal delivery within 24 h; uterine hyperstimulation with fetal heart rate changes; need for oxytocin augmentation; instrumental delivery; meconium staining; chorioamnionitis; postpartum hemorrhage; low Apgar score; neonatal intensive care unit admission; and arterial pH.

RESULTS

Forty-eight randomized controlled trials involving 11,482 pregnant women were identified. The cesarean delivery rates of the cervical ripening with a double-balloon catheter and oral misoprostol, oral misoprostol, and vaginal misoprostol were significantly lower than cervical ripening with a Foley catheter (OR = 0.48, 95% CI: 0.23-0.96; OR = 0.74, 95% CI: 0.58-0.93; and OR = 0.79, 95% CI: 0.64-0.97, respectively; all P < 0.05). The time from intervention-to-birth of vaginal misoprostol was significantly shorter than the other five cervical ripening methods. Vaginal misoprostol and oral misoprostol increased the risk of uterine hyperstimulation with fetal heart rate changes compared to a Foley catheter. A double-balloon catheter with or without oral misoprostol had similar outcomes, including uterine hyperstimulation with fetal heart rate changes compared to a Foley catheter.

CONCLUSION

Double-balloon catheter did not show superiority when compared with other single method in primary and secondary outcomes of labor induction. The combination of double-balloon catheter with oral misoprostol was significantly reduced the rate of cesarean section compared to Foley catheter without increased risk of uterine hyperstimulation with fetal heart rate changes, which was shown in oral or vaginal misoprostol.

Achieving an appropriate cesarean birth (CB) rate and analyzing the changes using the Robson Ten-Group Classification System (TGCS): Lessons from a Tertiary Care Hospital in Italy

BACKGROUND

To describe the interventions that were implemented at a Tertiary University Hospital and how they affected the rate of cesarean birth (CB) and main obstetrics and neonatal outcomes.

STUDY DESIGN

An analysis of the contemporaneously collected data from all deliveries that occurred from 2014 to 2018. Major obstetric and neonatal outcomes were analyzed and grouped according to the Ten-Group Classification System (TGCS).

RESULTS

A significant decrease in CB rates, from 28.4% to 23.0% (P < 0.001), was found over the study period. Although the relative sizes of both nulliparous (groups 1 + 2) and multiparous (groups 3 + 4) women remained stable over the study period, a significantly higher incidence of CB was reported in 2014 for both groups, compared with 2018 (2.6% vs. 13.0%, P < 0.001 for nulliparous women and 7.5% vs. 3.3%, P < 0.001 for multiparous women). In contrast, the relative size of Group 5 was significantly lower in 2014 than in 2018 (9.9% vs. 11.5%, P = 0.003), but a 13.3% reduction in CB was also reported for this group. No significant differences were noted in the occurrence of major obstetrics and neonatal outcomes that were reported.

CONCLUSIONS

A reduction in CB rate may be safely achieved through implementing a multifaceted strategy.

Sequential use of drugs (prostaglandin e1 after failed trial of PGE2 gel) for induction of labour: Retrospective observational study

With advancements in medicine, the scope of pregnancies have increased. This has subsequently increased the number of inductions and therefore more caesarean sections. We looked at the efficacy and safety of sequential induction with PGE2 gel followed by PGE1 tablets after a period of rest in a retrospective observational study. Women with failed induction of labour with 3 PGE2 gel were re-induced with 25ug vaginal PGE1 tablets, with a maximum of five doses (sequential regimen). Fetomaternal outcome and vaginal delivery rates were compared between the only-PGE2 gel group and the sequential group.There were 296 inductions of labour, of which 41 were included in the sequential group, amongst whom the vaginal delivery rate was 56%. Caesarean delivery rate with only PGE2 gel would have been 32%, but with the addition of PGE1 vaginal tablet (sequential induction), it reduced by >8% (p  =  0.02). Fetomaternal outcomes were comparable in the two groups. We thus conclude that sequential induction with PGE1 tablets is an effective option.

Multicentre randomised controlled trial comparing the safety in the first 12 h, efficacy and maternal satisfaction of a double balloon catheter and prostaglandin pessary for induction of labour

OBJECTIVE

To evaluate the safety in the first 12 h, efficacy and maternal satisfaction of a double balloon catheter (DBC) with vaginal prostaglandin (PGE) for induction of labour (IOL).

METHODS

We conducted a multicentre randomised controlled study of 420 patients from 1st January 2016 to 31st December 2017 to evaluate the use of DBC in IOL in an Asian population looking at the adverse effects in the first 12 h after insertion. Women were assigned randomly to cervical ripening with either a DBC or a prostaglandin pessary. The adverse events in the 12 h after DBC or first prostaglandin inserted, the efficacy of a DBC to a prostaglandin in labour induction and maternal satisfaction were evaluated.

RESULTS

There were significantly less women with uterine hyperstimulation in the DBC (2 vs 24, p ≤ 0.0001) compared to the prostaglandin group. There were no women with uterine hyperstimulation and non-reassuring foetal status in the DBC while there were 5 women with uterine hyperstimulation and foetal distress in the prostaglandin group. Use of entonox was significantly less in the DBC group (p = 0.009). There were no significant differences in both groups in caesarean section, vaginal deliveries and time to delivery, although significant less time was needed to achieve cervical os dilation more than 4 cm in the DBC group (p ≤ 0.0001). Neonatal birth outcomes were similar. Women's pain scores were similar for both methods. 80.1% of women allocated the DBC and 76.8% of women allocated the PGE were keen to recommend their method of induction.

CONCLUSION

Double balloon catheter remains a good alternative method for inducing women in view of a good safety profile with low risk of hyperstimulation and high maternal satisfaction.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02620215.

Foley Bulb Added to an Oral Misoprostol Induction Protocol: A Cluster Randomized Trial

OBJECTIVE

To evaluate whether the induction of labor in term gravid women with cervical dilation 2 cm or less and intact membranes by using oral misoprostol preceded by transcervical Foley bulb placement results in a significantly increased vaginal delivery rate compared with the use of oral misoprostol alone.

METHODS

We randomized the induction method by week of admission to labor and delivery, with each week group described as a cluster in a block randomized design. Women with gestational age of 37 weeks or greater, cervical dilation 2 cm or less, intact membranes, and indication for labor induction were included. Study arms were either 100 micrograms of oral misoprostol after transcervical Foley bulb placement or 100 micrograms of oral misoprostol alone. The primary outcome was vaginal delivery with the first induction attempt. Secondary outcomes included time to delivery, clinical chorioamnionitis (maternal temperature of 38°C or greater during labor with or without fundal tenderness, without other identified cause), cesarean delivery indication, and adverse outcomes. We estimated that a sample size of 1,077 per arm was needed to detect a 5% increase in vaginal delivery rate with a type I error of 5% and power of 80%, accounting for interim analysis and cluster size of 30 inductions per week. This was a pragmatic trial, and analysis was by intention-to-treat.

RESULTS

From January 1, 2018, to May 13, 2019, 1,117 women (34 clusters) were assigned to oral misoprostol plus Foley and 1,110 women (34 clusters) to oral misoprostol alone. Demographic characteristics were similar. Vaginal delivery at the first induction occurred in 78% of the misoprostol plus Foley arm and in 77% of the misoprostol arm (relative risk [RR] 1.00; 95% CI 0.96-1.05; adjusted relative risk [aRR], 1.00; 95% CI 0.95-1.05). Clinical chorioamnionitis occurred in 18% of the misoprostol plus Foley arm and in 14% of the misoprostol arm (RR 1.30; 95% CI 1.07-1.58; aRR 1.30; 95% CI 1.08-1.56). There were no differences in neonatal outcomes.

CONCLUSION

Induction of labor in gravid women at term with intact membranes by using oral misoprostol plus Foley bulb did not result in a higher vaginal delivery rate, but it did result in more clinical chorioamnionitis compared with the use of oral misoprostol alone.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT03407625.

Implementation of Evidence-Based Cervical Ripening Protocol: Outcomes and Next Steps

Objective  A prominent randomized controlled trial demonstrated that low-dose misoprostol with the concurrent cervical Foley shortened the median time to delivery when compared with either method alone. Our study aims to address implementation of this protocol and evaluate its impact on time to delivery. Study Design  This was a retrospective before-and-after study of nulliparous women who delivered nonanomalous, term, singletons at the University of California San Francisco (UCSF) in two separate 2-year periods before and after changes in UCSF's cervical ripening protocol. The primary outcome was time from first misoprostol dose to delivery. Results  A total of 1,496 women met inclusion criteria, with 698 in the preimplementation group and 798 in the postimplementation group. There were no statistically significant differences in time to delivery (29 vs. 30 hours, p  = 0.69), rate of cesarean delivery (30 vs. 26%, p  = 0.09), or cesarean delivery for fetal indications (11 vs. 8%, p  = 0.15) between the groups. Conclusion  Implementing evidence-based low-dose misoprostol with the concurrent cervical Foley did not change the time to delivery, time to vaginal-delivery, or likelihood of vaginal delivery in our population. This may be due to differences in labor management practices and incomplete fidelity to the protocol. Real-world effectiveness of these interventions will vary and should be considered when choosing an induction method.

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.

Induction of labour with sequential double-balloon catheter and oral misoprostol versus oral misoprostol alone in obese women

Objective

To evaluate the efficacy of induction of labour in obese women using sequential double-balloon catheter and oral misoprostol in comparison with oral misoprostol alone.

Study design

In this cohort study, 400 pregnant women with BMI higher than 35 kg/m2 undergoing labour induction at term were included. Induction of labour with a double-balloon catheter and, if necessary, sequential oral misoprostol (n = 216) was compared to oral misoprostol alone (n = 184). The primary outcome measure was the caesarean section rate. Secondary outcome parameters were, among others, the induction-to-delivery-interval, the rate of vaginal delivery within 24 and 48 h as well as fetal outcome parameters.

Results

The caesarean section rate was significantly lower in the group with sequential use of double-balloon catheter and oral misoprostol (27.6% versus 37.5%, p = 0.0345). After stratification for parity this reduction was seen especially in nulliparous (38.6% versus 56.9%, p = 0.0039). The rate of abnormal CTG was significantly lower as well (19.9% versus 30.4%, p = 0.0150), particularly in nulliparous (25.9% versus 40.4%, p = 0.0138). Uni- and multivariable analyzes showed that the caesarean section rate was significantly influenced by the method of induction of labour (p = 0.0026), parity (p < 0.0001) and Bishop score (p = 0.0425).

Conclusion

In obese women, induction of labour with sequential use of double-balloon catheter and oral misoprostol is associated with significantly more normal vaginal deliveries and less caesarean sections.

Double-balloon catheter versus dinoprostone insert for labour induction: a meta-analysis

OBJECTIVE

To assess the efficacy and safety of a double-balloon catheter versus dinoprostone insert for labour induction.

STUDY DESIGN

PubMed, MEDLINE, Embase, ClinicalTrials.gov, and the Cochrane Central Register of Clinical Trials databases were searched from 1985 to April 2018. Randomized controlled trials that compared a double-balloon catheter and dinoprostone insert for cervical ripening were identified. Eligible study populations consisted of women with singleton pregnancies that had any indication for labour induction and were randomly assigned to undergo induction with a double-balloon catheter or dinoprostone insert. The main outcomes were incidence of vaginal delivery within 24 h and caesarean section, and neonatal outcomes.

RESULTS

Five randomized trials (603 women; 305 with a double-balloon catheter and 298 with a dinoprostone insert) were eligible for inclusion. No differences were observed between the two groups in terms of vaginal delivery within 24 h [relative risk (RR) 1.21, 95% confidence interval (CI) 0.93-1.59] and incidence of caesarean section (RR 0.99, 95% CI 0.77-1.27). Compared with the double-balloon catheter, the dinoprostone insert was associated with a reduced need for oxytocin administration in the process of labour induction (RR 1.95, 95% CI 1.45-2.62). However, there was a higher incidence of excessive uterine activity (RR 0.17, 95% CI 0.06-0.54) and neonatal umbilical cord arterial blood pH < 7.1 (RR 0.36, 95% CI 0.15-0.84) in the dinoprostone insert group.

CONCLUSION

This review showed that the efficacy of labour induction using both the double-balloon catheter and dinoprostone insert was similar. However, the double-balloon catheter seemed to be a safer method.

Challenges and Limitations of Clinical Trials on Labor Induction: A Review of the Literature

Induction of labor is a common obstetric procedure performed in nearly a quarter of all deliveries in the United States. Pharmacological (prostaglandins, oxytocin) and/or mechanical methods (balloon catheters) are commonly used for labor induction; however, there is ongoing debate as to which method is the safest and most effective. This narrative review discusses key limitations of published trials on labor induction, including the lack of well-designed randomized controlled trials directly comparing specific methods of induction, heterogeneous trial populations, and wide variation in the protocols used and outcomes reported. Furthermore, the majority of published trials were underpowered to detect significant differences in the most clinically relevant efficacy and safety outcomes (e.g., cesarean delivery, neonatal mortality). By identifying the limitations of labor induction trials, we hope to highlight the importance of quality published data to better inform guidelines and drive evidence-based treatment decisions.

Sequential Versus Concurrent Use of Vaginal Misoprostol Plus Foley Catheter for Induction of Labor: A Randomized Clinical Trial

Background

To compare between the sequential and concurrent use of vaginal misoprostol plus Foley catheter for labor induction.

Methods

This single-center, non-blinded randomized study was conducted at the department of Obstetrics and Gynecology, Faculty of medicine, Zagazig University. A total of 160 women with full term singleton pregnancy, cephalic presentation and bishop score ≤ 6 were randomized for labor induction with either concurrent or sequential use of vaginal misoprostol plus Foley catheter (80 cases in each group). The primary outcome measured was induction-to-delivery interval and secondary outcomes mesaured were vaginal delivery within 24 h, number of doses needed to induce labor, need of oxytocin for augmentation of labor, cesarean section rate, maternal or neonatal complications.

Results

The mean induction-to-delivery interval was 22.33 ± 13.28 h versus 18.45 ± 14.34 h (p = 0.041) in sequential and concurrent group, respectively. The percentage of women who completed vaginal delivery within 24 h was 51% versus 61% (p = 0.046) in sequential and concurrent group, respectively. Other maternal and neonatal outcomes were similar in both groups.

Conclusion

Concurrent use of vaginal misoprostol plus Foley catheter for labor induction was associated with shorter induction-to delivery interval compared to sequential use, and it increases the rate of vaginal delivery in the first 24 h.

Transcervical double-balloon catheter as an alternative and salvage method for medical termination of pregnancy in midtrimester

OBJECTIVE

Termination of pregnancy in midtrimester can be performed surgically or medically. The aim of this study was to evaluate the medical methods, and the additional efficacy of using a transcervical double-balloon catheter in midtrimester termination.

MATERIALS AND METHODS

In this retrospective study, we included 167 pregnant women admitted during the period from January 1, 2011, to June 31, 2015, who were between 14 weeks and 28 weeks of gestation, and underwent intended termination of pregnancy at our center. Each of the 167 patients was allocated to either the cervical ripening balloon (CRB) group (with double-balloon catheter) or the non-CRB (without double-balloon catheter) group, by the choice or preference of the patient and her attending physician. Termination of pregnancy in the CRB group (72 patients) was conducted by placing a transcervical double-balloon catheter (COOK CRB), with both the uterine and vaginal balloons inflated with 30-80 mL of normal saline, and held in place for 12 hours, whereas in the non-CRB group (95 patients) vaginal and oral misoprostol alone were administered.

RESULTS

There were no significant differences between the CRB and non-CRB groups with regard to induction-to-delivery time (23.1 hours vs. 21.1 hours) and successful abortion rate within 30 hours (80.0% vs. 83.7%). There were no severe complications in both groups.

CONCLUSION

There was no significant additional benefit of using a double-balloon catheter in midtrimester termination of pregnancy, although the technique was considered simple and generally well-tolerated. Placing a transcervical double-balloon catheter could be the primary method, or one of the alternative medical methods if the patient and/or obstetrician prefers no operation.

Oral misoprostol alone versus oral misoprostol and Foley's catheter for induction of labor: A randomized controlled trial

AIM

The aim of this study was to evaluate the efficacy of oral misoprostol and Foley's catheter versus oral misoprostol alone for induction of labor.

METHODS

This open-label randomized controlled trial included 335 women requiring induction of labor. A total of 166 women were randomly allocated to induction with oral misoprostol alone and 169 women were assigned for induction with Foley's balloon catheter and oral misoprostol using a computer-generated allocation sequence. The primary outcome was rate of failure to achieve vaginal delivery within 24 h of induction.

RESULTS

The proportion of women failing to achieve vaginal delivery within 24 h in the combination group was lower (11.8% vs 28.7%, P = 0.001). When the two groups were stratified according to parity, the difference remained statistically significant only for parous women. The median induction-to-delivery interval (13.0 h vs 19 h, P = 0.000) and the median number of doses of misoprostol used (2 vs 3, P = 0.000) were lower in the combination group. The number of women who delivered vaginally in the combination group was significantly higher (91% vs 79%, P = 0.001). More neonates born to women in the misoprostol group had Apgar scores < 7 and were admitted to the neonatal intensive care unit (P = 0.016 and P = 0.007, respectively).

CONCLUSION

The rate of failure to achieve vaginal delivery within 24 h was lower with Foley's balloon and oral misoprostol as compared to oral misoprostol alone.

Timing of sequential use of double-balloon catheter and oral misoprostol for induction of labor

AIM

The best time to commence cervical ripening with a balloon catheter is unknown. The aim of this study was to evaluate whether application of a balloon catheter in the morning or in the evening is better when sequential prostaglandin application is planned.

METHODS

This multicenter historical cohort study included 415 women with an unfavorable cervix undergoing labor induction at term. Labor was induced with a double-balloon catheter and the sequential use of oral misoprostol if necessary. The balloon catheter was placed in the morning group between 02:00-15:00 and in the evening group between 15:00-02:00. The primary outcome measure was the cesarean section rate. Secondary outcome measures included failed labor induction (no vaginal delivery within 72 h).

RESULTS

The cesarean section rate did not differ between the groups (morning 26.9%, evening 24.3%; P = 0.5553); however, more women in the morning group did not deliver within 72 h (8.8% vs 3.1%; P = 0.0138). In nulliparous women, labor induction failed more often in the morning group (12% vs. 4%, P = 0.043). In parous women, the induction-to-delivery interval was longer in the morning group (1756 vs. 1349 min; P = 0.046), and there were fewer deliveries within 24 h (35% vs. 56%, P = 0.016).

CONCLUSIONS

When sequential use of a double-balloon catheter and oral misoprostol for labor induction is planned, the preferable time for catheter placement is in the evening. This resulted in fewer failed inductions in nulliparous women and a shorter induction-to-delivery interval and more deliveries within 24 h in parous women.

Double-balloon catheter and sequential oral misoprostol versus oral misoprostol alone for induction of labour at term: a retrospective cohort study

OBJECTIVE

To evaluate the efficacy of induction of labour using a double-balloon catheter and, if necessary, sequential oral misoprostol without delay after removal of the catheter, in comparison with oral misoprostol alone.

STUDY DESIGN

This retrospective cohort study included women undergoing induction of labour with oral misoprostol or double-balloon catheter with sequential oral misoprostol in singleton pregnancies at term. The catheter was placed in the evening and removed when there was no onset of labour within 12h. Then oral misoprostol was started within 3h. Primary outcome measure was the caesarean section rate.

RESULTS

There were 13,082 deliveries during the study period with 3466 labour inductions out of which 1032 were eligible and analysed. The caesarean section rate was significantly lower in the double-balloon catheter group (26.1% vs. 17.3, p=0.021). Furthermore, in the combination group, the induction-to-delivery interval was shorter (median values 1144 vs. 1365min, p=0.001) and there were more deliveries within 24h (51.9 vs. 64.7%, p=0.003) and 48h (87.4 vs. 95.8%, p=0.002). When stratifying for parity, there were less caesarean sections in the combination group (37.2% vs. 24.2%, p=0.015) in nulliparous women, too. In both, nulliparous and parous women, the induction-to-delivery interval was shorter (1742 vs. 1400min, 0.005; 1020 vs. 912min, p=0.018). Especially in parous women, the rates of delivery within 24h (62.6% vs. 79.0%, p=0.007) and 48h (88.6% vs. 99.0%, p=0.007) were higher in the combination group.

CONCLUSION

Double-balloon catheter and sequential oral misoprostol without long delay in absent onset of labour after removal of the catheter resulted in less caesarean section and shorter induction-to-delivery interval in comparison with oral misoprostol alone.

The Renaissance of Transcervical Balloon Catheters for Cervical Ripening and Labour Induction

Due to rising rates of labour induction in industrialised countries, safe and effective methods of induction have once again become a focus of interest and research. Prostaglandins are effective for cervical ripening and induction of uterine contractions. They do, however, cause overstimulation of the uterus in up to 20 % of cases, sometimes causing changes in fetal heart rate. Transcervical balloon catheters provide an alternative to prostaglandins for labour induction and have been used for this purpose for almost 50 years. This induction method has experienced a recent renaissance in clinical practice that is reflected in an annually rising number of publications on its use. Balloon catheters allow gentle ripening of the cervix without causing uterine overstimulation. The two catheters available are the Foley catheter (off-label use) and the double balloon catheter, which is licensed for use in induction of labour. Both are as effective as prostaglandins, and do not increase the risk of infection to mother or child. Catheter induction also requires less monitoring compared to prostaglandins resulting in improved patient satisfaction. Balloon catheters provide a useful and promising option to achieve vaginal delivery despite failed prostaglandin induction. Intravenous oxytocin is nevertheless required in up to 85 % of cases for adequate induction/augmentation of contractions. Balloon catheters, vaginal PGE₂ and misoprostol are equally effective in the context of an unripe/unfavourable cervix, the rate of uterine hyperstimulation being significantly lower, and the need for oxytocin significantly higher for catheters. Balloon catheters are increasingly being used in combination or sequentially with oral/vaginal misoprostol, although there is currently inadequate published data on the subject. International guidelines recommend the use of balloon catheters for labour induction with an unripe cervix (also following previous caesarean section) as an alternative to prostaglandins, particularly when these are not available or are contraindicated.

Double-balloon catheter and sequential vaginal prostaglandin E2 versus vaginal prostaglandin E2 alone for induction of labor after previous cesarean section

PURPOSE

To evaluate the efficacy of inducing labor using a double-balloon catheter and vaginal prostaglandin E2 (PGE2) sequentially, in comparison with vaginal PGE2 alone after previous cesarean section.

METHODS

A total of 264 pregnant women with previous cesarean section undergoing labor induction at term were included in this prospective multicentre cohort study. Induction of labor was performed either by vaginal PGE2 gel or double-balloon catheter followed by vaginal PGE2. The primary outcome measure was the cesarean section rate.

RESULTS

The cesarean section rate was 37 % without any statistically significant difference between the two groups (PGE2: n = 41, 37 % vs. balloon catheter/PGE2: n = 41, 42 %; P = 0.438). The median (range) number of applications of PGE2 [2 (1-10) versus 1 (0-8), P < 0.001] and the total amount of PGE2 used in median (range) mg [2 (1-15) vs. 1 (0-14), P = 0.001] was less in the balloon catheter/PGE2 group. Factors significantly increasing risk for cesarean section were "no previous vaginal delivery" (OR 5.391; CI 2.671-10.882) and "no oxytocin augmentation during childbirth" (OR 2.119; CI 1.215-3.695).

CONCLUSIONS

The sequential application of double-balloon catheter and vaginal PGE2 is as effective as the sole use of vaginal PGE2 with less applications and total amount of PGE2.

Induction of Labour: Change of Method and its Effects

Aim: The combination of mechanical and drug procedures for the induction of labour seems to be beneficial. Accordingly, the normal procedure in clinical routine has been changed and induction of labour by means of a balloon catheter has been implemented. The aim of this study was to find out if this procedural change has resulted in a more effective induction of labour. Materials and Method: In this historical cohort study 230 inductions of labour at term in the year 2012 were compared with 291 inductions of labour in the year 2013, all at the University of Erlangen Perinatal Centre. Exclusion criteria were, among others, a multiple pregnancy, a premature rupture of membranes and a prior Caesarean section. In 2012 births were induced solely by use of the drugs dinoprostone and misoprostol, in 2013 not only with misoprostol but also mainly by use of a balloon catheter. The primary target parameter was the rate of failed labour inductions, defined as "no birth within 72 hours". Results: Altogether 521 inductions of labour were analysed. The rate of failed inductions of labour could be reduced by the changes in induction method (first-time mothers: 23 vs. 9 %, p = 0.0059; multiparous women: 10 vs. 1 %, p = 0.0204). Furthermore, the rate of primary Caesarean sections due to failed induction of labour (5.7 vs. 1.4 %, p = 0.0064), that of the observation of green amniotic fluid (first-time mothers: 23 vs. 9 %, p = 0.0059; multiparous women: 10 vs. 1 %, p = 0.0204) and of infantile infections (first-time mothers: 23 vs. 9 %, p = 0.0059; multiparous women: 10 vs. 1 %, p = 0.0204) were all reduced as well. Conclusion: The routine use of a balloon catheter for induction of labour has markedly improved the procedure. There were fewer failed labour inductions and fewer Caesarean sections due to failed induction of labour.