You are here
Balloon catheters for induction of labor at term after previous cesarean section: a systematic review
European Journal of Obstetrics & Gynecology and Reproductive Biology, September 2016, Pages 44 - 50
To systematically review the application of balloon catheters for cervical ripening and labor induction at term after previous cesarean section.
All pregnancies at term with previous cesarean section were included when cervical ripening or labor induction was conducted with balloon catheters. MEDLINE, Cochrane database and bibliography of identified articles were searched for English language studies. Reviews and meta-analysis, randomized and non-randomized controlled trials, prospective and retrospective cohort studies as well as case-control studies were considered.
A total of 48 potentially relevant studies were identified. The title and abstract were screened for eligibility and 32 articles were excluded. The remaining 16 publications included 1447 women (single-balloon catheter: n = 1329, double-balloon catheter: n = 118). There were no randomized controlled trials. Most of the trials were retrospective studies (n = 10). The rate of uterine rupture after labor induction was low (n = 18, 1.2%). Meta-analysis of studies comparing the risk of uterine rupture between labor induction and spontaneous onset of labor found a higher risk after induction (OR 2.45, 95%CI 1.34–4.47, NNH 186). The average rate of oxytocin application was 68.4%, and vaginal birth was achieved in 56.4%. The risk for cesarean delivery was higher when labor was induced (OR 2.63, 95%CI 2.24–3.10).
Data on balloon catheters for labor induction after previous cesarean section are limited by small sample size and retrospective analyses. The present data show a moderately increased risk for uterine rupture (OR = 2.45) compared to spontaneous onset of labor. However, for evidence based recommendations much more well-conducted trials are needed.
Keywords: Balloon catheter, Foley, Double-balloon catheter, Labor induction, Previous cesarean section.
With the increasing number of cesarean sections worldwide, the number of women with a scarred uterus who will need induction of labor in a subsequent pregnancy will also rise . It has been estimated that nearly one-quarter of women who were candidates for a trial of labor after cesarean section (TOLAC) requires induction of labor . For all patients, attempting vaginal birth after cesarean section (VBAC), the success rates range from 60 to 85% , however, dramatic reduction of TOLAC has been observed after reports of worrying increase in rupture-associated severe perinatal outcome (e.g., hypoxic-ischemic encephalopathy) and also in severe maternal complications (e.g., severe postpartum hemorrhage, hysterectomy) , , and . This increase in short-term morbidity must be balanced by the increase in maternal and neonatal risk associated with multiple repeat cesarean sections , , , , and . It is not clear whether all induction agents have been associated with the same magnitude of increased risk of uterine rupture in the setting of TOLAC  and . Evaluation of the evidence on specific methods of induction reveals that the lowest rate of uterine rupture occurs with oxytocin at 1.1% (95% CI 0.9–1.52%), then dinoprostone at 2% (95% CI 1.1–3.5%) and the highest rate is with misoprostol, 6% (95% CI 0.74–51.4) , , , , and .
The use of a transcervical Foley catheter for cervical ripening is reported to have similar success rates for induction of labor with intravaginal prostaglandins in women without a history of cesarean section , , and . In addition, the use of balloon catheters is a relatively inexpensive method and is associated with fewer abnormalities of contraction pattern, and fewer maternal side-effects when compared to prostaglandins , , and . Balloon catheters (single- or double-balloon) have become an attractive alternative to prostaglandins for patients with an unfavorable cervix without previous cesarean section. The ‘renaissance‘ of balloon catheters is reflected by a yearly rising number of publications since 2010. However, the use of balloon catheters for cervical ripening and labor induction varies from country to country. It is rarely used in Switzerland , and in only 2% of all labor inductions in Germany , while the corresponding rate for the Netherlands is 10%  and for France nearly 50% . Neither balloon catheters nor dinoprostone are licensed for inducing labor in patients with a scarred uterus, but there is a growing body of evidence, that the use of balloon catheters is an effective and safe method for cervical ripening and labor induction also after previous cesarean section . In the Netherlands, for instance, the use of the Foley catheter for labor induction after prior cesarean section has increased from 49% in 2006 to 72.2% in 2010 . The aim of this article was to review the evidence about efficacy and safety of balloon catheters for cervical ripening and induction of labor in women with a previous cesarean section.
Patients and methods
A criteria list based on the PICOS (population, intervention, comparison, outcomes and study designs) was created to identify all the pertinent manuscripts. All pregnancies at term with previous cesarean section were included (population) when cervical ripening or labor induction was conducted with balloon catheters (e.g., single-balloon, double-balloon, Foley) (intervention). Cervical ripening/labor induction with these mechanical devices was compared with any other methods or spontaneous onset of labor (comparison). There were no restrictions to outcome measures (outcomes). Reviews and meta-analysis, randomized and non-randomized controlled trials, prospective and retrospective cohort studies as well as case-control studies were included (study designs). The relevant articles were identified by using an extensive search string from the MEDLINE and Cochrane databases (“balloon”[Title/Abstract] OR “catheter”[Title/Abstract] OR “Foley”[Title/Abstract]) AND (“induction”[Title/Abstract] OR “ripening”[Title/Abstract]) AND (“previous cesarean”[Title/Abstract] OR “previous cesarean”[Title/Abstract] OR “scarred uterus”[Title/Abstract] OR “prior cesarean”[Title/Abstract] OR “prior cesarean”[Title/Abstract]). Titles and abstracts between January 1990 and June 2015 identified as a result of the literature search were screened by the authors to select potentially suitable papers for full-text assessment. Manuscripts were excluded in case of intrauterine fetal death, fetal malformation and abnormality. If they were not published in English but an abstract in English was provided, they were considered for abstract assessment. The bibliography of the articles was searched for further relevant studies. After all, the remaining articles were reviewed to give an update for the use after previous cesarean section.
For the purpose of integrating the findings of individual studies, a statistical meta-analysis has been applied. Study results have been weighted by sample size. In order to compare relative frequencies of two groups, Odds ratio together with 95% confidence interval (95%CI) have been assessed and Chi2 test or Fisher’s exact test have been performed, as appropriate. All statistical calculations have been done with SAS software, release 9.3 (SAS Institute Inc., Cary, NC, USA).
A total of 48 potentially relevant studies were identified (Fig. 1). The title and abstract were screened for eligibility and 32 articles were excluded. Finally, 16 publications were assessed by abstract and full-text screening and assigned to the appropriate question (e.g., single- or double-balloon catheter) (Table 1 and Table 2). There were 7 studies with single-balloon catheter , , , , , , and , 5 trials with double-balloon catheter , , , , and , and 4 manuscripts that were not published in English but provided an English written abstract , , , and .
Rate of uterine rupture with balloon catheters compared to spontaneous onset labor for cervical/labor induction in women with a previous cesarean section.
|Single-balloon catheter (Foley)||Spontaneous onset of labor|
|Author||Year||N||Uterine rupture (n, %)||N||Uterine rupture (n, %)||p-Value|
|1. Ravasia||2000||129||1 (0.78)||1544||7 (0.45)||0.47|
|2. Ben-Aroya||2002||161||1432||2 (0.14)||0.80|
|3. Bujold||2004||255||4 (1.6)||1807||20 (1.1)||0.35|
|4. Hoffmana||2004||138||9 (6.5)a||536||10 (1.87)||0.01|
|6. Jozwiak||2014||208||1 (0.48)||–||–||–|
|7. Sananes||2014||135||1045||6 (0.57)||0.53|
|8. Sarreaub||2014||151||2 (1.2)||–||–||–|
|13. Ferradasc||2013||32||1 (3.1)||–||–||–|
|Total||1447||18 (1.2)||6364||45 (0.7)|
|Meta-analysis of studies , , , , and  comparing risk for uterine rupture between induction of labor with spontaneous onset of labor||OR 2.45, 95%CI 1.34–4.47, p = 0.0027|
|Meta-analysis of studies , , , and  comparing risk for uterine rupture between induction of labor with spontaneous onset of labor [without 4a]||OR 1.23, 95%CI 0.48–3.14, p = 0.6042|
a None of the patients developed uterine rupture during the process of cervical ripening but rather during the active phase of labor.
b Manuscript not in English, considered for abstract assessment.
c Scar dehiscence.
N: number of women included in the study.
There were no randomized controlled trials conducted. One investigation was undertaken prospectively , and 10 were retrospective studies , , , , , , , , , and . In 5 manuscripts, there was no exact information whether the data were collected prospectively or retrospectively , , , , and . These 16 investigations included 1447 women with labor induction using balloon catheters. Most of them had induction of labor with single-balloon catheters (n = 1290), the remaining 157 with double-balloon catheters. There were 9 trials with less than 40 included women and 7 with 129–255 cases.
Rate of uterine rupture
The rate of uterine rupture is depicted in Table 1. Among all women with the balloon catheter (n = 1447) 18 had uterine rupture (1.2%), while the rate of uterine rupture was 0.7% in women with spontaneous onset of labor (45/6364). Meta-analysis of studies comparing the risk of uterine rupture between labor induction and spontaneous onset of labor , , , , and  found a higher risk after induction (OR 2.45, 95%CI 1.34–4.47, p = 0.0027). The number needed to harm (NNH) was 186. Nine of the 18 uterine ruptures were reported in the retrospective cohort study by Hoffman et al. . In this study, the use of a Foley catheter more than tripled the risk of uterine rupture during induction compared with women who entered labor spontaneously (rate of uterine rupture 6.5 vs 1.9%; OR 3.67; 95%CI 1.46–9.23). However, none of the uterine ruptures occurred during preinduction cervical ripening, but rather during the active phase of labor. Since the frequency of uterine ruptures in both groups as well as in patients with amniotomy for labor induction (rate of uterine rupture: 2.4%) was significantly higher than in the majority of case studies, it has been speculated that this may be related to the institutional approach favoring single layer closure of the hysterotomy . If one excludes the results of this study from analysis there were only 9 uterine ruptures in 1270 women corresponding to a rate of uterine rupture of 0.7% in the entire group of patients with balloon catheters and 0.6% (35 uterine ruptures in 5828 women) after spontaneous labor. When excluding this study from meta-analysis, the risk of uterine rupture is not significantly different between induction of labor using balloon catheters and spontaneous onset of labor (OR 1.23, 95%CI 0.48–3.14, p = 0.6042).
Of note, in the study by Ferradas et al.  the uterine rupture was not complete but described as symptomatic uterine scar dehiscence after removing the double balloon device.
The largest retrospective cohort analysis by Bujold et al.  examined the risk of uterine rupture in women with spontaneous labor, induction by amniotomy with or without oxytocin, or preinduction cervical ripening with transcervical Foley catheter. Women undergoing induction with the Foley catheter did not receive oxytocin until the balloon catheter was removed. After adjusting for contributing variables the rate of complete uterine rupture (1.1% vs 1.2% vs 1.6%) was not statistically different between the groups (p = 0.81), the OR for uterine rupture was 0.47 (95%CI 0.06–3.5) for women with labor induction using a Foley catheter when compared to women with spontaneous labor. There were also no significant differences in the rate of asymptomatic scar dehiscence at the time of cesarean section among the three groups (6.3% vs 5.4% vs 2.7%; p = 0.32).
Recently, Jozwiak et al.  evaluated the rate of uterine rupture in 208 women with a prior cesarean section after induction of labor with a Foley catheter in a retrospective cohort study. The Foley catheter was left in place up to 48 h, if the cervix was still unfavorable after 48 h, treatment was discontinued for 24 h, followed by cervical ripening with a Foley catheter for a maximum of another 48 h. If still unfavorable after that second period of 48 h, a cesarean section was performed on the basis of failed induction. The rate of vaginal deliveries (spontaneous and operative) was 71.5%, in 21% of the women delivered by cesarean section, this was performed because of failed induction. One uterine rupture occurred associated with perinatal death of the baby 48 h after birth.
Rate of vaginal delivery
In Table 2, the filling volume of the balloons, the exposure time, the rate of oxytocin usage and the vaginal birth rate are demonstrated in comparison with spontaneous onset of labor if available. There were only four trials , , , and  that compared the rate of vaginal delivery between spontaneous onset of labor and induction of labor with single-balloon catheter. The vaginal delivery rate was 56.4% when labor was induced mechanically and 75.0% after spontaneous of labor. Meta-analysis of these studies found a higher rate for cesarean section when labor was induced (OR 2.63, 95%CI 2.24–3.10, p > 0.0001).
Balloon catheter for cervical ripening/labor induction after previous cesarean section.
|Single-balloon catheter (Foley)||Spontaneous onset of labor|
|Author||Year||N||Filling volume (ml)||Exposure time (h)||Use of oxytocin (%)||Vaginal delivery (n, %)||Vaginal delivery (n, %)|
|1. Ravasia||2000||129||30–40||Till expulsion||118 (91.5)||79 (61.2)||1205/1544 (78.0)|
|2. Ben Aroya||2002||161||50–60||24||33 (20.5)||82 (50.9)||928/1432 (64.8)|
|3. Bujold||2004||255||50||12||233 (91.4)||142 (55.7)||1409/1806 (78.0)|
|5. Ziyauddin||2013||35||30||12||29 (82.9)||25 (71.4)||–|
|6. Jozwiak||2014||208||30||96||n.a.||148 (71.2)||–|
|7. Sananes||2014||135||30||24||n.a.||59 (43.7)||828/1045 (79.2)|
|8. Sarreaua||2014||151||30–80||24||78 (51.7)||81 (53.7)||–|
|9. Lamourdedieua||2015||39||30–60||12||n.a.||17 (43.5)||–|
|10. Souzaa||2015||39||n.a.||24||33 (84.6)||9 (23.1%)||–|
|11. Khotaba||2001||37||80||12||n.a.||24/34 (70.6)||–|
|12. Miller||2005||8||60||12||4 (50.0)||2 (25.0)||–|
|13. Ferradas||2013||32||30–80||12||n.a.||18 (56.3)||–|
|14. Ebeid||2013||17||80||12||14 (82.0)||9 (52.9)||–|
|15. Rossarda||2013||39||80||n.a.||n.a.||25 (64.1)||–|
|16. Cheuk||2015||24||40–60||12||18 (75.0)||18 (75.0)||–|
|Total||1447||629||560/819 (68.4)||738/1309 (56.4)||4370/5827 (75.0)|
|Meta-analysis of studies , , , and  comparing risk for cesarean section between induction of labor with spontaneous onset of labor||OR 2.63, 95%CI 2.24–3.10, p > 0.0001|
a Manuscript not in English, only assessment of the abstract.
N: number of women included in the study.
In the largest study by Bujold et al.  including 255 women labor induction with the Foley catheter was compared with spontaneous onset of labor. The single balloon catheter was filled with 50 ml and removed after 12 h. Most of the women received oxytocin for induction or augmentation (91.4%). The rate of vaginal delivery was significantly lower in women induced with the Foley catheter compared to women with spontaneous onset of labor (55.7 vs 78.0%, p < 0.001), the corresponding odds ratio for vaginal delivery was 0.68 (95%CI 0.41–1.15).
In the retrospective study by Ravasia et al.  almost all women induced with the Foley catheter needed oxytocin for induction or augmentation (91.5%). The probability for not achieving vaginal delivery was significantly higher when labor was induced (RR 1.77, 95%CI 1.39–2.24). The rate of vaginal delivery was seen 61.2% and 79.0%, respectively.
Sananes et al.  included 135 women after previous cesarean section with labor induction using a Foley catheter. The filling volume was only 30 ml and the catheter was removed after 24 h. Vaginal delivery was only achieved in 43.7% of women with the Foley catheter and in 79.2% after spontaneous onset of labor. In the multivariate analysis, the use of the Foley catheter for labor induction was an independent risk factor for not achieving vaginal delivery (OR 3.73, 95%CI 2.47–5.62).
Need for oxytocin to induce or augment labor
Nine of the 16 studies reported on the use of oxytocin with balloon catheters for inducing or augmenting labor (Table 2) , , , , , , , , and . In some of these trials, it was unclear whether oxytocin was used for induction or augmentation of labor , , and . The standard protocol after removal or expulsion of the balloon catheter was often artificial rupture of the membranes and oxytocin application. The average proportion of women requiring oxytocin was 68.4% ranging from 20.5%  to 91.5%  (Table 2).
Rate of intrapartum fever
In 13 of the reviewed studies, there was no information on intrapartum fever or infection , , , , , , , , , , , , , and . Jozwiak et al.  found intrapartum infection, defined as body temperature >38.0 °C and start of broad spectrum antibiotics during labor, in 5%, and postpartum infection in 1% of cases, neonatal suspected and proven infections occurred in 5% and 3%, respectively. Sarreau et al.  reported on intrapartum fever in 5.3% of patients with the Foley catheter, there were no cases of postpartum endometritis, and one case with suspected chorioamnionitis (0.6%). Ferradas et al.  defined intrapartum fever as a body temperature ≥37.7 °C during labor, and chorioamnionitits was diagnosed on histological analysis of the placenta. Seven out of 32 women with the double-balloon catheter (18.8%) had intrapartum fever and 3 patients (9.4%) revealed chorioamnionitis, while in women treated with oxytocin only the rate of intrapartum fever and chorioamnionitis was 31.3% and 14.6%, respectively. The differences between both groups were statistically not significant (p = 0.21 and p = 0.73).
Induction of labor with balloon catheters has shown to be as effective as prostaglandins in women with an unfavorable cervix and without a previous cesarean section , , and . The most important advantages of balloon catheters over prostaglandins are their wide availability, the low costs of the devices, especially Foley catheters, and the significantly lower rates of uterine hyperstimulation associated with a potentially lower risk of uterine rupture in women with a scarred uterus. The disadvantages are the higher proportion of women requiring oxytocin for labor induction or augmentation and the potential risk for increased maternal or neonatal infectious morbidity.
Labor induction in women with a history of cesarean section remains a challenge to obstetricians, especially when the cervix is unripe. Nearly 25% of these women require induction of labor because of medical indications. Balloon catheters may be an appropriate alternative to prostaglandins in women with a previous cesarean section, since prostaglandins are associated with a higher risk for uterine rupture (2–6%) , , , , and . However, data with balloon catheters are limited up to now. There are no randomized controlled trials comparing balloon catheters with prostaglandins on which to base clinical decisions regarding the optimal method for cervical ripening and labor induction in patients with a previous cesarean section . Nearly all published trials (except one prospective study) are retrospective cohort or observational studies, most of them with small patient number. There is a great heterogeneity among these studies regarding definition of uterine rupture, filling volume and the exposure time of balloon catheters as well as the necessity of oxytocin use for labor induction or augmentation.
Rate of uterine rupture
Uterine rupture is a major concern when undertaking a TOLAC, especially when labor is induced. Numerous studies showed a higher rate of uterine rupture in women with induction of labor compared to women who went into spontaneous labor , , , and . In a recent secondary analysis of data from the Eunice Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Unit Network Cesarean Registry, Palatnik and Grobman  compared obstetric outcomes between women undergoing induction of labor and those undergoing expectant management ≥39 weeks of gestation. Induction of labor ≥39 weeks was associated with a significantly higher rate of vaginal delivery (73.8% vs 61.3%, p < 0.001) but also with a higher rate of uterine rupture (1.4% vs 0.5%, p = 0.006) compared to expectant management. A prospective four-year observational study showed that mechanical induction of labor, e.g., with balloon catheters, has a lower risk for uterine rupture in comparison with oxytocin and prostaglandins . The present review underlines that induction of labor with balloon catheters in women with a previous cesarean section is associated with a moderately higher rate for uterine rupture (OR = 2.45) compared to spontaneous onset of labor, if all studies are considered for analysis. If one excludes the criticized study by Hoffman et al.  our meta-analysis of the remaining studies shows no significant difference in the rate for uterine rupture between both procedures (OR 1.23, 95%CI 0.48–3.14, p = 0.6042).
Preliminary results of a large prospective cohort study in 53 hospitals in the Netherlands (The PROBAAT-S study) have been published recently as abstract (not listed in Table 1) . The aim of the study was to evaluate the effectiveness and safety of induction of labor vs elective repeat cesarean section in women with prior cesarean section and indications for delivery. If the cervix was unfavorable (Bishop Score < 6) women were either induced by prostaglandins (n = 121) or by the Foley catheter (filling volume 30 ml, n = 1014); in the latter group, amniotomy and oxytocin infusion was started when the Foley catheter fall out and Bishop score was >6. The rate of uterine rupture was 2.5% and 1.3%, respectively (p = 0.29), and the rate of vaginal deliveries was 64% and 56% (p = 0.12). Of note, in women with a favorable cervix and oxytocin augmentation uterine rupture occurred in 2.7% of cases. When comparing the Foley catheter with the double balloon device the rates of uterine rupture were 1.3% and 0.85%, respectively.
Rate of vaginal delivery
The vaginal delivery rate after spontaneous onset of labor was higher when compared with labor induction (56.5% [25.0–75.0%] vs 75.0% [64.8–79.2%]) in this review. Observational studies have consistently shown that women with a scarred uterus who are induced have a 15–20% lower chance of achieving vaginal birth , , and . However, some authors criticized this comparison and stated that the actual alternative to induction is not spontaneous labor but expectant management , , , and . In fact, when induction of labor in women with a scarred uterus has been compared with expectant management instead of spontaneous labor, meta-analysis of observational studies has revealed that the risk of cesarean section was 12% lower with labor induction (pooled RR 0.88, 95%CI 0.84–0.93) .
Need for oxytocin to induce or augment labor
Balloon catheters are associated with a significantly higher need for oxytocin (induction and augmentation) compared to prostaglandins for induction of labor in women with an unscarred uterus (75% vs 50%; RR 1.51; 95%CI 1.15–1.97) . The balloon catheter alone induced onset of labor in 23.5–31% of these women  and . As shown in our analysis, the average proportion of women requiring oxytocin for induction or augmentation of labor was 68.4% (20.5–91.5%) in women with a previous cesarean section. The number of women with onset of labor induced by the balloon catheter alone was not specified in the reviewed trials. The standard protocol after removal or expulsion of the balloon catheter was artificial rupture of the membranes and oxytocin application in nearly all of trials with and without previous cesarean section. This high need for oxytocin use explains the increased rate of oxytocin administration compared to prostaglandins. On the other hand, the increased rate of oxytocin application in women with an unfavorable cervix is associated with an increased risk for cesarean section compared to its use in women with a favorable cervix . Recently, the sequential use of the balloon catheter and prostaglandin E2 has been investigated for induction of labor in women with and without a previous cesarean section  and . In a prospective multicenter study, sequential use of the double-balloon catheter and vaginally applied prostaglandin E2 gel (1 mg/2 mg) was evaluated. Prostaglandin E2 was only administered if there were no uterine contractions within 12 h after placement of the balloon catheter. There was no uterine rupture in 98 cases, and the vaginal delivery rate was 58% .
Rate of intrapartum fever
None of the published meta-analyses have shown an increased risk for serious maternal side effects or complications associated with the use of balloon catheters , , and , however, the risk of infection was not specifically considered. The intracervical placement of a balloon catheter as a ‘foreign material’ may theoretically increase the risk of uterine infection. According to the meta-analysis by Heinemann et al.  which specifically evaluated the infectious morbidity associated with mechanical methods, the Foley catheter was associated with a significantly higher rate of maternal infections, defined as fever, endometritis or chorioamnionitis, compared to the use of prostaglandins or oxytocin for induction of labor (7.6% vs 5%, pooled OR 1.5, 95%CI 1.07–2.09). On the other hand, a recently published Cochrane Review  came to the conclusion that according to the limited data available, there is no evidence of an increased risk of infectious morbidity with balloon catheters, but recommended to interpret published data with caution. In the PROBAAT-trial , comparing the Foley catheter with the use of vaginal prostaglandin E2 gel, the rate of intrapartum infection was significantly lower in women with the Foley catheter (1% vs 3%, p = 0.035). Two other trials evaluating labor induction with balloon catheters after rupture of the membranes did not show an increased risk for maternal infection  and .
Data on balloon catheters for labor induction after previous cesarean section are limited by small sample size, retrospective analyses, and different protocols. Single- or double-balloon catheter, little (30 ml) or high filling volume (80 ml), different exposure times (12–96 h), and the various use of oxytocin for induction or augmentation of labor are significant factors which may influence the rate of vaginal delivery and are contributed to the risk for uterine rupture , , , , , and . In view of conflicting data, increased infectious morbidity associated with balloon catheters remains an ongoing matter of debate. Therefore, prospective randomized controlled trials are needed to give evidence-based recommendations for the use of balloon catheters in women with a previous cesarean section. A national ongoing prospective observational cohort study in the Netherlands which plans to include 1500 women (PROBAAT-S Trial) currently compares the application of single-balloon catheter with prostaglandins for labor induction after previous cesarean section . The results of this trial are awaited full of suspense and may influence future guideline recommendations.
Based on the available current evidence (observational studies), in women with previous cesarean section, the risk for uterine rupture with balloon catheters compared to spontaneous onset of labor is increased (OR = 2.45, NNH = 186). For more strong evidence based recommendations, further randomized controlled trials with adequate statistical power are needed.
-  M. Jozwiak, J.M. Dodd. Methods of term labour induction for women with a previous caesarean section. Cochrane Database Syst Rev. 2013;3:CD009792
-  A. Locatelli, A.L. Regalia, A. Ghidini, E. Ciriello, A. Biffi, J.C. Pezzullo. Risks of induction of labour in women with a uterine scar from previous low transverse caesarean section. BJOG. 2004;111(12):1394-1399 Crossref
-  J.R. Scott. Intrapartum management of trial of labour after caesarean delivery: evidence and experience. BJOG. 2014;121(2):157-162 Crossref
-  M.B. Landon, J.C. Hauth, K.J. Leveno, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004;351(25):2581-2589 Crossref
-  G.A. Macones, J. Peipert, D.B. Nelson, et al. Maternal complications with vaginal birth after cesarean delivery: a multicenter study. Am J Obstet Gynecol. 2005;193(5):1656-1662 Crossref
-  I. Al-Zirqi, B. Stray-Pedersen, L. Forsen, S. Vangen. Uterine rupture after previous caesarean section. BJOG. 2010;117(7):809-820 Crossref
-  W.A. Grobman. Predictors of induction success. Semin Perinatol. 2012;36(5):344-347 Crossref
-  E.N. Schoorel, S. Melman, S.M. van Kuijk, et al. Predicting successful intended vaginal delivery after previous caesarean section: external validation of two predictive models in a Dutch nationwide registration-based cohort with a high intended vaginal delivery rate. BJOG. 2014;121(7):840-847 (discussion 7) Crossref
-  E.N. Schoorel, S.M. van Kuijk, S. Melman, et al. Vaginal birth after a caesarean section: the development of a Western European population-based prediction model for deliveries at term. BJOG. 2014;121(2):194-201 (discussion) Crossref
-  M.M. Costantine, K.A. Fox, L.D. Pacheco, et al. Does information available at delivery improve the accuracy of predicting vaginal birth after cesarean? Validation of the published models in an independent patient cohort. Am J Perinatol. 2011;28(4):293-298 Crossref
-  L.M. Harper, G.A. Macones. Predicting success and reducing the risks when attempting vaginal birth after cesarean. Obstet Gynecol Surv. 2008;63(8):538-545 Crossref
-  M. Lydon-Rochelle, V.L. Holt, T.R. Easterling, D.P. Martin. Risk of uterine rupture during labor among women with a prior cesarean delivery. N Engl J Med. 2001;345(1):3-8 Crossref
-  E. Ophir, M. Odeh, Y. Hirsch, J. Bornstein. Uterine rupture during trial of labor: controversy of induction’s methods. Obstet Gynecol Surv. 2012;67(11):734-745 Crossref
-  L. Sanchez-Ramos, F.L. Gaudier, A.M. Kaunitz. Cervical ripening and labor induction after previous cesarean delivery. Clin Obstet Gynecol. 2000;43(3):513-523 Crossref
-  A.C. Rossi, F. Prefumo. Pregnancy outcomes of induced labor in women with previous cesarean section: a systematic review and meta-analysis. Arch Gynecol Obstet. 2015;291(2):273-280 Crossref
-  M. Jozwiak, K.W. Bloemenkamp, A.J. Kelly, B.W. Mol, O. Irion, M. Boulvain. Mechanical methods for induction of labour. Cochrane Database Syst Rev. 2012;3:CD001233
-  Z. Vaknin, Y. Kurzweil, D. Sherman. Foley catheter balloon vs locally applied prostaglandins for cervical ripening and labor induction: a systematic review and metaanalysis. Am J Obstet Gynecol. 2010;203(5):418-429 Crossref
-  N.S. Fox, D.H. Saltzman, A.S. Roman, C.K. Klauser, E. Moshier, A. Rebarber. Intravaginal misoprostol versus Foley catheter for labour induction: a meta-analysis. BJOG. 2011;118(6):647-654 Crossref
-  E. Krause, S. Malorgio, A. Kuhn, C. Schmid, M. Baumann, D. Surbek. Off-label use of misoprostol for labor induction: a nation-wide survey in Switzerland. Eur J Obstet Gynecol Reprod Biol. 2011;159(2):324-328 Crossref
-  F. Voigt, T.W. Goecke, L. Najjari, U. Pecks, N. Maass, W. Rath. Off-label use of misoprostol for labor induction in Germany: a national survey. Eur J Obstet Gynecol Reprod Biol. 2015;187:85-89 Crossref
-  C.M. Huisman, M. Jozwiak, J.W. de Leeuw, B.W. Mol, K.W. Bloemenkamp. Cervical ripening in the Netherlands: a survey. Obstet Gynecol Int. 2013;2013:745159
-  S. Bel, A. Gaudineau, L. Zorgnotti, N. Sananes, G. Fritz, B. Langer. Survey on cervical ripening practices in France. Gynecol Obstet Fertil. 2014;42(5):301-305 Crossref
-  Z. Ben-Aroya, M. Hallak, D. Segal, M. Friger, M. Katz, M. Mazor. Ripening of the uterine cervix in a post-cesarean parturient: prostaglandin E2 versus Foley catheter. J Matern Fetal Neonatal Med. 2002;12(1):42-45
-  E. Bujold, S.C. Blackwell, R.J. Gauthier. Cervical ripening with transcervical foley catheter and the risk of uterine rupture. Obstet Gynecol. 2004;103(1):18-23 Crossref
-  M.K. Hoffman, A. Sciscione, M. Srinivasana, D.P. Shackelford, L. Ekbladh. Uterine rupture in patients with a prior cesarean delivery: the impact of cervical ripening. Am J Perinatol. 2004;21(4):217-222 Crossref
-  M. Jozwiak, H.A. van de Lest, N.B. Burger, M.G. Dijksterhuis, J.W. De Leeuw. Cervical ripening with Foley catheter for induction of labor after cesarean section: a cohort study. Acta Obstet Gynecol Scand. 2014;93(3):296-301 Crossref
-  D.J. Ravasia, S.L. Wood, J.K. Pollard. Uterine rupture during induced trial of labor among women with previous cesarean delivery. Am J Obstet Gynecol. 2000;183(5):1176-1179 Crossref
-  N. Sananes, M. Rodriguez, C. Stora, et al. Efficacy and safety of labour induction in patients with a single previous caesarean section: a proposal for a clinical protocol. Arch Gynecol Obstet. 2014;290(4):669-676 Crossref
-  F. Ziyauddin, S. Hakim, S. Beriwal. The transcervical foley catheter versus the vaginal prostaglandin e2 gel in the induction of labour in a previous one caesarean section—a clinical study. J Clin Diagn Res. 2013;7(1):140-143
-  Q.K. Cheuk, T.K. Lo, C.P. Lee, A.P. Yeung. Double balloon catheter for induction of labour in Chinese women with previous caesarean section: one-year experience and literature review. Hong Kong Med J. 2015;21(3):243-250
-  S. Khotaba, M. Volfson, L. Tarazova, et al. Induction of labor in women with previous cesarean section using the double balloon device. Acta Obstet Gynecol Scand. 2001;80(11):1041-1042
-  T.D. Miller, G. Davis. Use of the Atad catheter for the induction of labour in women who have had a previous Caesarean section—a case series. Aust N Z J Obstet Gynaecol. 2005;45(4):325-327 Crossref
-  E. Ebeid, N. Nassif. Induction of labor using double balloon cervical device in women with previous cesarean section: experience and review. Open J Obstet Gynecol. 2013;3:301-305 Crossref
-  E. Ferradas, I. Alvarado, M. Gabilondo, I. Diez-Itza, J. García-Adanez. Double balloon device compared to oxytocin for induction of labour after previous caesarean section. Open J Obstet Gynecol. 2013;3:212-216 Crossref
-  L. Rossard, C. Arlicot, H. Blasco, et al. Cervical ripening with balloon catheter for scared uterus: a three-year retrospective study. J Gynecol Obstet Biol Reprod (Paris). 2013;42(5):480-487 Crossref
-  C. Lamourdedieu, A. Gnisci, M. Marcelli, H. Heckenroth, M. Gamerre, A. Agostini. Cervical ripening after previous cesarean section with Foley catheter: a prospective study of 41 patients. J Gynecol Obstet Biol Reprod (Paris). 2015;44(5):426-432 Crossref
-  M. Sarreau, L. Leufflen, E. Monceau, et al. Balloon catheter for cervical ripening on scarred uterus with unfavorable cervix: multicenter retrospective study of 151 patients. J Gynecol Obstet Biol Reprod (Paris). 2014;43(1):46-55 Crossref
-  A.S. Souza, M. Medeiros Junior Wde, B.B. de Araujo, I.C. Coelho, G.V. Guerra. Mechanical method of induction of labor in high-risk pregnant women with previous cesarean section. Rev Bras Ginecol Obstet. 2015;37(3):127-132 Crossref
-  Wing D. Cervical ripening and induction of labor in women with a prior cesarean delivery, http://wwwuptodatecom/contents/cervical-ripening-and-induction-of-labor-in-women-with-a-prior-cesarean-delivery?source=see_link§ionName=RISK+OF+RUPTURE&anchor=H3#H3; 2015 [Version 25.0].
-  A. Palatnik, W.A. Grobman. Induction of labor versus expectant management for women with a prior cesarean delivery. Am J Obstet Gynecol. 2015;212(3):358 e1–e6
-  C. Huisman, K. Rengerink, M. Jozwiak, et al. Effectiveness and safety of different methods for induction of labor in women with a previous cesarean section. Am J Obstet Gynecol. 2014;210(Suppl. 1):S333-S334 Crossref
-  E.J. Sims, R.B. Newman, T.C. Hulsey. Vaginal birth after cesarean: to induce or not to induce. Am J Obstet Gynecol. 2001;184(6):1122-1124 Crossref
-  M.B. Landon, S. Leindecker, C.Y. Spong, et al. The MFMU Cesarean Registry: factors affecting the success of trial of labor after previous cesarean delivery. Am J Obstet Gynecol. 2005;193(3 Pt. 2):1016-1023 Crossref
-  A.B. Caughey, J.M. Nicholson, Y.W. Cheng, D.J. Lyell, A.E. Washington. Induction of labor and cesarean delivery by gestational age. Am J Obstet Gynecol. 2006;195(3):700-705 Crossref
-  S. Osmundson, R.J. Ou-Yang, W.A. Grobman. Elective induction compared with expectant management in nulliparous women with an unfavorable cervix. Obstet Gynecol. 2011;117(3):583-587 Crossref
-  S.J. Stock, E. Ferguson, A. Duffy, I. Ford, J. Chalmers, J.E. Norman. Outcomes of elective induction of labour compared with expectant management: population based study. BMJ. 2012;344:e2838 Crossref
-  E. Mishanina, E. Rogozinska, T. Thatthi, R. Uddin-Khan, K.S. Khan, C. Meads. Use of labour induction and risk of cesarean delivery: a systematic review and meta-analysis. CMAJ. 2014;186(9):665-673 Crossref
-  S. Kehl, J. Ziegler, E. Schleussner, et al. 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. BJOG. 2015;122(1):129-136 Crossref
-  A. Cromi, F. Ghezzi, M. Agosti, et al. Is transcervical Foley catheter actually slower than prostaglandins in ripening the cervix? A randomized study. Am J Obstet Gynecol. 2011;204(4):338 e1–e7
-  Z. Alfirevic, A.J. Kelly, T. Dowswell. Intravenous oxytocin alone for cervical ripening and induction of labour. Cochrane Database Syst Rev. 2009;4:CD003246
-  A.B. Ande, C.M. Ezeanochie, N.B. Olagbuji. Induction of labor in prolonged pregnancy with unfavorable cervix: comparison of sequential intracervical Foley catheter-intravaginal misoprostol and intravaginal misoprostol alone. Arch Gynecol Obstet. 2012;285(4):967-971 Crossref
-  S. Kehl, C. Weiss, M. Wamsler, et al. Double-balloon catheter and sequential vaginal prostaglandin E2 versus vaginal prostaglandin E2 alone for induction of labor after previous cesarean section. Arch Gynecol Obstet. 2016;293(4):757-765
-  J. Heinemann, G. Gillen, L. Sanchez-Ramos, A.M. Kaunitz. Do mechanical methods of cervical ripening increase infectious morbidity? A systematic review. Am J Obstet Gynecol. 2008;199(2):177-187 (discussion 87–88)
-  M. Jozwiak, K.O. Rengerink, M. Benthem, et al. Foley catheter versus vaginal prostaglandin E2 gel for induction of labour at term (PROBAAT trial): an open-label, randomised controlled trial. Lancet. 2011;378(9809):2095-2103 10.1016/S0140-6736(11)61484-0 Epub 2011 Oct 24 Crossref
-  S. Kehl, A. Ehard, S. Berlit, S. Spaich, M. Sutterlin, J. Siemer. Combination of misoprostol and mechanical dilation for induction of labour: a randomized controlled trial. Eur J Obstet Gynecol Reprod Biol. 2011;159(2):315-319 Crossref
-  A.D. Mackeen, L. Walker, K. Ruhstaller, M. Schuster, A. Sciscione. Foley catheter vs prostaglandin as ripening agent in pregnant women with premature rupture of membranes. J Am Osteopath Assoc. 2014;114(9):686-692 Crossref
-  R. Salim, N. Zafran, Z. Nachum, G. Garmi, N. Kraiem, E. Shalev. Single-balloon compared with double-balloon catheters for induction of labor: a randomized controlled trial. Obstet Gynecol. 2011;118(1):79-86 Crossref
-  I. Solt, S. Ben-Harush, S. Kaminsky, V. Sosnovsky, E. Ophir, J. Bornstein. A prospective randomized study comparing induction of labor with the foley catheter and the cervical ripening double balloon catheter in nuliparous and multiparous women. Am J Obstet Gynecol. 2009;201(Suppl. 1):S124 Crossref
-  E. Mei-Dan, A. Walfisch, S. Suarez-Easton, M. Hallak. Comparison of two mechanical devices for cervical ripening: a prospective quasi-randomized trial. J Matern Fetal Neonatal Med. 2012;25(6):723-727 Crossref
-  C.E. Pennell, J.J. Henderson, M.J. O’Neill, S. McChlery, D.A. Doherty, J.E. Dickinson. Induction of labour in nulliparous women with an unfavourable cervix: a randomised controlled trial comparing double and single balloon catheters and PGE2 gel. BJOG. 2009;116(11):1443-1452 Crossref
-  E. Mei-Dan, A. Walfisch, C. Valencia, M. Hallak. Making cervical ripening EASI: a prospective controlled comparison of single versus double balloon catheters. J Matern Fetal Neonatal Med. 2014;27(17):1765-1770 Crossref
-  A. Berndl, D. El-Chaar, K. Murphy, S. McDonald. Does cervical ripening at term using a high volume foley catheter result in a lower caesarean section rate than a low volume foley catheter? A systematic review and meta-analysis. J Obstet Gynaecol Can. 2014;36(8):678-687
-  Induction of labour in women after previous caesarean delivery. The PROBAAT-S study, http://wwwstudies-obsgynnlprobaets; 2011.
a Department of Obstetrics and Gynaecology, University Hospital Erlangen, Universitätsstr. 21-23, 91054 Erlangen, Germany
b Department of Medical Statistics and Biomathematics, University Medical Center Mannheim, Heidelberg University, Germany
c Faculty of Medicine, Gynaecology and Obstetrics, University Hospital RWTH Aachen, Wendlingweg 2, 52074 Aachen, Germany
⁎ Corresponding author. Fax: +49 9131/85 33468.
⁎⁎ Corresponding author. Fax: +49 241/80 82 711.
© 2016 Elsevier Ireland Ltd, All rights reserved.