Is transcervical Foley catheter actually slower than prostaglandins in ripening the cervix? A randomized study

[Prostaglandins or cervical balloon for the induction of labor for cervical ripening: A literature review]

OBJECTIVE

Induction of labor in France concerns one birth out of four with 70% of induction starting by cervical ripening, either with a pharmacological (prostaglandins) or a mechanical (balloon) method. This review aims to compare these two methods within current knowledge, using the PRISMA methodology.

METHODS

Trials comparing these two methods, published or unpublished up to July 2023, in French or English were searched for in the PubMed, Cochrane Library and ClinicalTrial.govs datasets. Fifty articles including 10,689 women were selected. The outcomes of interest were those from the Core Outcome Set for trails on Induction of Labour (COSIOL) list: mode of delivery, time from induction-to-birth, maternal and neonatal morbidity, and maternal satisfaction.

RESULT

No differences were observed between the two methods for the mode of delivery or neonatal and maternal morbidity. The time from induction-to-birth was longer for mechanical methods. Those were also associated with a greater need for oxytocin, less uterine hyperstimulation and less instrumental deliveries. Maternal satisfaction was assessed in only nine trials using various scales which made the interpretation of maternal satisfaction.

CONCLUSION

The efficacy of these two induction methods is similar for vaginal delivery, but it remains to be seen which one best meets women's satisfaction criteria.

Time matters: Cervical ripening balloon for 6 versus 12 h-Retrospective comparison between two protocols

OBJECTIVE

Recently, two randomized controlled trials compared removal of cervical ripening balloon (CRB) after 6 versus 12 h. Their results showed similar Bishop score changes in both groups and a shorter time to delivery in the 6-h group. Neither of the studies was powered to show difference in mode of delivery. The aim of this study was to compare mode of delivery when the CRB was removed after 6 versus 12 h.

METHODS

A historical control study comparing induction of labor with a CRB between two time periods, one in which the CRB was removed after 12 h (12-h group), and the other in which it was removed after 6 h (6-h group). We included term pregnancies with a singleton fetus in vertex presentation. We excluded patients with a previous cesarean delivery, failed ripening with prostaglandins prior to CRB insertion, and any contraindication for vaginal delivery. The primary outcome was mode of delivery. Secondary outcomes included delivery within 24 h and other maternal and neonatal outcomes.

RESULTS

We included 1704 patients, 914 in the 12-h group, and 717 in the 6-h group. Removal after 6 h was associated with a lower rate of cesarean and instrumental deliveries (28.6% vs 22.5%, and 12% vs 6.2%, respectively) and a higher rate of vaginal delivery within 24 h. All differences were statistically significant.

CONCLUSION

Removing a cervical ripening balloon after 6 rather than 12 h is associated with reduced cesarean and instrumental delivery rates, and should be considered as a reasonable, and potentially superior alternative in labor induction protocols with intracervical ripening balloon.

Evidence Based Management of Labor

Importance

Induction of labor (IOL) is a common obstetric intervention. Augmentation of labor and active management of the second stage is frequently required in obstetric practice. However, techniques around labor and induction management vary widely. Evidence-based practice regarding induction and labor management can reduce birth complications such as infection and hemorrhage and decrease rates of cesarean delivery.

Objective

To review existing evidence on IOL and labor management strategies with respect to preparing for induction, cervical ripening, induction and augmentation, and second stage of labor techniques.

Evidence acquisition

Review of recent original research, review articles, and guidelines on IOL using PubMed (2000-2022).

Results

Preinduction, pelvic floor training and perineal massage reduce postpartum urinary incontinence and perineal trauma, respectively. Timely membrane sweeping (38 weeks) can promote spontaneous labor and prevent postterm inductions. Outpatient Foley bulb placement in low-risk nulliparous patients with planned IOL reduces time to delivery. Inpatient Foley bulb use beyond 6 to 12 hours shows no benefit. When synthetic prostaglandins are indicated, vaginal misoprostol should be preferred. For nulliparous patients and those with obesity, oxytocin should be titrated using a high-dose protocol. Once cervical dilation is complete, pushing should begin immediately. Warm compresses and perineal massage decrease risk of perineal trauma.

Conclusion and relevance

Several strategies exist to assist in successful IOL and promote vaginal delivery. Evidence-based strategies should be used to improve outcomes and decrease risk of complications and cesarean delivery. Recommendations should be shared across interdisciplinary team members, creating a model that promotes safe patient care.

Six compared with 12 hours of Foley balloon placement for labor induction in nulliparous women with unripe cervices: a randomized controlled trial

BACKGROUND

Compared with a planned 12-hour placement of a double-balloon catheter, a planned 6-hour placement of a double-balloon catheter shortens the labor induction to delivery interval. The Foley catheter is low cost. Moreover, it has at least comparable effectiveness to the proprietary double-balloon labor induction devices. Of note, a 6-hour placement of a Foley balloon catheter in nulliparas has not been evaluated.

OBJECTIVE

This study aimed to evaluate 6- vs 12-hour Foley balloon placement for cervical ripening in the labor induction of nulliparas.

STUDY DESIGN

A randomized controlled trial was conducted at the Universiti Malaya Medical Centre from January 2022 to August 2022. Nulliparas aged ≥18 years, with a term, singleton pregnancy in cephalic presentation, with intact membranes, with reassuring fetal heart rate tracing, with an unripe cervix, and without any significant contractions, were recruited at admission for labor induction. Participants were randomized after successful Foley balloon insertion, for the balloon to be left passively in place for 6 or 12 hours and then removed to check for a ripened cervix. Amniotomy was performed once the cervix had ripened, followed by titrated oxytocin infusion to expedite labor and delivery. The primary outcome was the labor induction to delivery interval. The secondary outcomes were mostly from the core outcome set for trials on labor induction of labor trial reporting, such as change in the Bishop score after the intervention, use of an additional method for cervical ripening, time to delivery after double-balloon device removal, mode of delivery, indication for cesarean delivery, duration of oxytocin infusion, blood loss during delivery, presence of a third- or fourth-degree perineal tear, maternal infection, maternal satisfaction regional analgesia in labor, length of hospital stay, intensive care unit admission, cardiorespiratory arrest, need for hysterectomy. The neonatal outcomes were Apgar score at 1 and 5 minutes, neonatal intensive care unit admission, cord pH, neonatal sepsis, fetal birthweight, birth trauma, hypoxic-ischemic encephalopathy, or need for therapeutic hypothermia. Data were analyzed using the t test, Mann-Whitney U test, chi-square test, and Fisher exact test, as appropriate for the data type.

RESULTS

Overall, 240 women were randomized, 120 to each arm. The median labor induction to delivery intervals were 21.3 hours (interquartile range, 16.2-27.9) for the 6-hour balloon catheter placement and 26.0 hours (interquartile range, 21.5-30.9) for the 12-hour balloon catheter placement (P<.001). Of the secondary outcomes, for 6- vs 12-hour balloon catheter placement, the sequential use of additional cervical ripening agent (mostly Foley reinsertion) was 33 of 119 (27.5%) vs 17 of 120 (14.2%) (relative risk, 1.94; 95% confidence interval, 1.15-3.29; P=.011), Bishop score increase was 3 (interquartile range, 2.00-3.75) vs 3 (2.25-4.00) (P=.002), and the rate of recommendation to a friend was 83 of 118 (70.3%) vs 101 of 119 (84.9%) (relative risk, 0.83; 95% confidence interval; 0.72-0.95; P=.007), respectively. Cesarean delivery rates were 52 of 119 (43.7%) for the 6-hour balloon catheter placement and 64 of 120 (53.3%) for the 12-hour balloon catheter placement (relative risk, 0.82; 95% confidence interval, 0.63-0.07; P=.136), and maternal satisfaction scores (0-10 numerical rating scale) were 7 (interquartile range, 6-9) for the 6-hour balloon catheter placement and 7 (interquartile range, 7-9) for the 12-hour balloon catheter placement (P=.880).

CONCLUSION

Compared with a planned 12-hour Foley balloon catheter placement, a planned 6-hour Foley balloon placement shortens the time to birth, despite less cervical ripening at Foley balloon catheter removal and more additional cervical ripening agent use. However, the 6-hour balloon catheter placement was less likely to be recommended to a friend than the 12-hour balloon catheter placement.

Six vs 12 hours of Foley catheter balloon placement in the labor induction of multiparas with unfavorable cervixes: a randomized controlled trial

BACKGROUND

Planned 6- vs 12-hour placement of the double-balloon catheter for cervical ripening in labor induction hastens delivery. The Foley catheter is low-priced and typically performs at least as well as the proprietary double-balloon devices in labor induction. Maternal satisfaction with labor induction is usually inversely related to the speed of the process.

OBJECTIVE

This study aimed to compare Foley balloon placement for 6 vs 12 hours in the labor induction of multiparas with unfavorable cervixes.

STUDY DESIGN

A randomized controlled trial was conducted in a university hospital in Malaysia from January to October of 2022. Eligible multiparous women admitted for induction of labor for various indications were enrolled. Participant inclusion criteria were multiparity (at least 1 previous vaginal delivery of ≥24 weeks' gestation), age ≥18 years, term pregnancy >37 weeks' gestation, singleton pregnancy, cephalic presentation, intact membranes, normal fetal heart rate tracing, no significant contractions (< 2 in 10 minutes), and unfavorable cervix (Bishop score < 6). Participants were randomized after successful Foley balloon insertion for the balloon to be left in place for 6 or 12 hours of passive ripening before removal to check cervical suitability for amniotomy. The primary outcomes were the induction-to-delivery interval and maternal satisfaction with the allocated intervention assessed using a visual numerical rating scale (0-10). Secondary outcomes were derived in part from the core outcome set for trials on induction of labor (Core Outcomes in Women's and Newborn Health [CROWN]). Maternal outcomes were change in first Bishop score after intervention, use of additional method for cervical ripening, time to delivery after balloon removal, mode of delivery, indication for cesarean delivery, duration of oxytocin infusion, blood loss during delivery, presence of third- or fourth-degree perineal tear, maternal infection, use of regional analgesia in labor, length of hospital stay, intensive care unit (ICU) admission, cardiorespiratory arrest, and need for hysterectomy. The secondary neonatal outcomes were Apgar score at 1 and 5 minutes, neonatal intensive care unit (NICU) admission, cord blood pH, neonatal sepsis, birthweight, birth trauma, hypoxic-ischemic encephalopathy, or need for therapeutic hypothermia. Analyses were conducted with the t-test, Mann-Whitney U test, chi-square test, and Fisher exact test, as appropriate.

RESULTS

A total of 220 women were randomized (110 to each intervention). Regarding the 2 primary outcomes, the induction-to-delivery intervals were a median (interquartile range) of 15.9 (12.0-24.0) and 21.6 (17.3-26.0) hours (P<.001), and maternal satisfaction scores were 7 (6-8) and 7 (6-8) (P=.734) for 6- and 12-hour placement, respectively. The following rates were observed for 6- and 12-hour placement, respectively: sequential use of additional cervical ripening agent (Foley reinsertion)-29 per 110 (26.4%) and 13 per 110 (11.8%) (relative risk, 2.23; 95% confidence interval, 1.23-4.10; P=.006); spontaneous balloon expulsion-22 per 110 (20.0%) and 37 per 110 (33.6%) (relative risk, 0.60; 95% confidence interval, 0.38-0.94; P=.022); and recommendation of the allocated intervention to a friend-61 per 110 (73.6%) and 87 per 110 (79.1%) (relative risk, 0.90; 95% confidence interval, 0.80-1.08; P=.341). Other secondary outcomes, including cesarean delivery, were not significantly different.

CONCLUSION

Foley balloon placement for 6 hours for cervical ripening in parous women hastens birth but does not increase maternal satisfaction relative to 12-hour placement. Foley reinsertion for additional ripening was more frequent in the 6-hour group.

Induction of labor via Foley balloon catheter placement for 6 vs 12 hours in women with 1 previous cesarean delivery and unfavorable cervices: a randomized controlled trial

BACKGROUND

Induction of labor in women with 1 previous cesarean delivery and unripe cervices is a high-risk process, carrying an increased risk of uterine rupture and the need for cesarean delivery. Balloon ripening is often chosen as prostaglandin use is associated with an appreciable risk of uterine rupture in vaginal birth after cesarean delivery. A shorter duration of placement of the balloon typically expedites delivery; however, this has not been evaluated in induction of labor after 1 previous cesarean delivery.

OBJECTIVE

This study aimed to compare Foley balloon catheter placement for 6 vs 12 hours in induction of labor after 1 previous cesarean delivery.

STUDY DESIGN

A randomized controlled trial was conducted in a university hospital in Malaysia from January 2022 to February 2023. Eligible women with 1 previous cesarean delivery admitted for induction of labor were enrolled. Participants were randomized after balloon catheter insertion for 6 or 12 hours of passive ripening before balloon deflation and removal to check cervical status for amniotomy. The primary outcome was the induction of labor to delivery interval. The secondary outcomes were largely derived from the core outcome set for trials on induction of labor (Core Outcomes in Women's and Newborn Health [CROWN]). The Student t test, Mann-Whitney U test, chi-square test, and Fisher exact test were used as appropriate for the data.

RESULTS

Overall, 126 women were randomized, 63 to each intervention. The mean induction of labor to delivery intervals were 23.0 (standard deviation, ±8.9) in the 6-hour arm and 26.6 (standard deviation, ±7.1) in the 12-hour arm (mean difference, -3.5 hours; 95% confidence interval, -6.4 to -0.7; P=.02). The median induction of labor (Foley balloon catheter insertion) to Foley balloon catheter removal intervals were 6.0 hours (interquartile range, 6.0-6.3) in the 6-hour arm and 12.0 hours (interquartile range, 12.0-12.5) in the 12-hour arm (P<.001). The median induction of labor to amniotomy intervals were 14.1 hours (interquartile range, 9.3-21.8) in the 6-hour arm and 19.0 hours (interquartile range, 15.9-22.0) in the 12-hour arm (P=.02). The usage rates of epidural analgesia in labor were 46.0% (29/63) in the 6-hour arm and 65.1% (41/63) in the 12-hour arm (relative risk, 0.71; 95% confidence interval, 0.51-0.98; P=.03). Spontaneous balloon catheter expulsion rates were 22.2% (14/63) in the 6-hour arm and 17.5% (11/63) in the 12-hour arm (relative risk, 1.27; 95% confidence interval, 0.63-2.58; P=.50), and additional ripening use rates (Foley reinsertion) were 46.0% (29/63) in the 6-hour arm and 31.7% (20/63) in the 12-hour arm (relative risk, 1.45; 95% confidence interval, 0.92-2.27; P=.10). The results were not different. Moreover, maternal satisfaction scores (0-10 numerical rating scale) of 9 (range, 8-10) in the 6-hour arm and 9 (range, 8-10) in the 12-hour arm (P=.41) were not different. Other secondary maternal and neonatal outcomes were not significantly different either.

CONCLUSION

Foley balloon catheter placement for 6 hours hastened birth and reduced epidural analgesia use in labor without a change in maternal satisfaction.

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.

Induction of Labor in Women with Previous Cesarean Section and Unfavorable Cervix: A Retrospective Cohort Study

Background: The efficacy and safety of a cervical ripening balloon (CRB) in women with a previous cesarean section (CS) and unfavorable Bishop score are still controversial. Methods: A retrospective cohort study was performed across six tertiary hospitals from 2015 to 2019. Women with one previous transverse CS, singleton cephalic term pregnancy and BS < 6 were included if submitted to labor induction with a CRB. The main outcome was the rate of vaginal birth after cesarean (VBAC) after CRB ripening. Secondary outcomes were abnormal composite fetal and maternal outcomes. Results: Of the 265 women included, 57.3% had successful vaginal birth. Augmentation improved vaginal delivery (32.2% vs. 21.2%). Intrapartum analgesia was associated with an increased VBAC rate (58.6% vs. 34.5%). Maternal BMI ≥30 and age ≥40 years increased emergency CS rate (11.8% vs. 28.3% and 7.2 vs. 15.9%). Composite adverse maternal outcome occurred in 4.8% of CRB group women and increased to 17.6% when associated with oxytocin. Uterine rupture occurred in one case (0.4%) in the CRB-oxytocin group. Poorer fetal outcome occurred after emergency CS, if compared to successful VBAC (12.4% vs. 3.3%). Conclusions: In women with a previous CS and unfavorable Bishop score, induction of labor with a CRB can be considered safe and effective.

Cervical ripening as an outpatient procedure in the pandemic - minimizing the inpatient days and lowering the socioeconomic costs

OBJECTIVES

With an increasing incidence of labor induction the socioeconomic costs are increasing and the burden on hospital capacities is rising. In addition, the worldwide SARS-CoV-2 pandemic asks for improvements in patient care during pregnancy and delivery while decreasing the patient-staff contact. Here, we are retrospectively analyzing and comparing a mechanical ripening device that is utilized as an outpatient procedure to misoprostol and dinoprostone as inpatient induction methods in a low risk cohort.

METHODS

This is a retrospective comparative analysis of obstetric data on patients who presented for cervical ripening and labor induction. Ninety-six patients received a mechanical ripening agent as an outpatient procedure. As a control group, we used 99 patients with oral misoprostol (PGE1) and 42 patients with vaginal dinoprostone (PGE2) for cervical ripening in an inpatient setting. Data from 2016 until 2020 were analysed.

RESULTS

Baseline characteristics showed no significant differences. Delivery modes were similar in all groups. The time period from patient admission to onset of labor was significantly shorter in the outpatient group (p<0.001): 10.9 h/0.5 days (±13.6/0.6) for osmotic dilator vs. 17.9 h/0.7 days (±13.1/0.5) for oral misoprostol vs. 21.8 h/0.8 days (±15.9/0.7) for vaginal dinoprostone. With 20.4 h/0.8 days (±14.3/0.6) the osmotic dilator group displayed significantly the shortest inpatient stay from admission to delivery (p=0.027). The patient subgroup of misoprostol had 25.7 h/1.1 days (±14.9/0.6) of inpatient stay from admission to delivery and the patient group of dinoprostone 27.5 h/1.1 days (±16.0/0.7). There were fewer hospital days in the outpatient group: 84.9 h/3.5 days vs. 88.9 h/3.7 days vs. 93.6 h/3.9 days (outpatient osmotic dilator vs. inpatient misoprostol and dinoprostone, respectively).

CONCLUSIONS

New approaches are required to decrease individual contacts between patients and staff while maintaining a high quality patient care in obstetrics. This analysis reveals that outpatient mechanical cervical ripening can be as safe and effective as inpatient cervical ripening with PGE1/PGE2, while lowering patient-staff contact and total hospital stays and therefore decreasing the socioeconomic costs.

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.

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

OBJECTIVE

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

DATA SOURCES

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

STUDY ELIGIBILITY CRITERIA

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

METHODS

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

RESULTS

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

Cervical ripening after cesarean section: a prospective dual center study comparing a mechanical osmotic dilator vs. prostaglandin E2

OBJECTIVES

Worldwide, the overall cesarean section is rising. Trial of labor after cesarean (TOLAC) is an overall safe option with an immediate impact on neonatal and maternal short- and long-term health. Since the use of prostaglandins in cervical ripening is associated with an increased risk of uterine rupture, mechanical methods as balloon catheters or osmotic dilators have been suggested for cervical ripening prior to induction of labour. Here we are analyzing and comparing the VBAC rate, as well as maternal and fetal outcome in cervical ripening prior to TOLAC.

METHODS

This prospective dual center study analyses maternal and neonatal outcomes of TOLAC in women with an unfavorable cervix requiring cervical ripening agent. The prospective application of an osmotic dilator (Dilapan-S, n=104) was analysed in comparison to the retrospective application of off-label dinoprostone (n=102).

RESULTS

The overall fetal and neonatal outcome revealed no significant differences in both groups. Patients receiving cervical ripening with the osmotic dilator delivered vaginally/by ventouse in 52% of cases, compared to 53% when using dinoprostone (p=0.603). The interval between application to onset of labor was significantly higher in the osmotic dilator group (37.9 vs.20.7 h, p=<0.001). However, time from onset of labor to delivery was similar in both groups (7.93 vs. 7.44 h, p=0.758). There was one case of uterine rupture in the dinoprostone group.

CONCLUSIONS

Our data shows that the application of the osmotic dilator leads to similar outcomes in VBAC rate and time from onset of labor to delivery as well as safety in both groups compared to off-label use dinoprostone. Cervical ripening using the mechanical dilator is a viable and effective option, without the risk of uterine hyperstimulation.

Dinoprostone vaginal insert (DVI) versus adjunctive sweeping of membranes and DVI for term induction of labor

AIM

To compare the efficacy and safety of dinoprostone vaginal insert (DVI) alone versus DVI with adjunctive sweeping of membranes (ASM) for induction of labor (IOL).

METHODS

Single-center, prospective, randomized controlled trial; women with singleton term pregnancies, cervical dilation ≥1 and <3 cm, intact membranes allocated to either DVI or DVI with ASM. The primary outcome was vaginal delivery within 24 h of insertion. Secondary outcomes included mean time from insertion to delivery, tachysystole, operative delivery for non-reassuring fetal status (NRFS), tocolytics, fetal outcomes, pain information, and subject satisfaction.

RESULTS

One hundred and four received DVI (Group 1) alone and 104 DVI with ASM (Group 2). The rate of vaginal delivery within 24 h was 53% versus 56%, cesarean rate 8.7% versus 10.6% in Groups 1 and 2 respectively. Although the duration of labor was similar in both groups, about 6% of women required additional ripening with dinoprostone vaginal tablets in Group 2 compared to 11.5% in Group 1 (p-value = 0.2). The frequency of hyperstimulation syndrome, failed induction, analgesic requirements, and fetal outcomes were comparable. The majority (83%-86%) in either cohort were satisfied with their labor experience. Multivariate logistic regression demonstrated a slightly better chance for vaginal delivery within 24 h (odds ratio [OR] 1.22 [95% confidence interval, CI 0.65-2.29]; p-value 0.53] for DVI with ASM, although statistically insignificant. Younger maternal age and multiparity (OR 10.36 [95% CI 4.88-23.67]; p-value <0.0001) contributed to successful IOL.

CONCLUSION

DVI with ASM is at least as efficacious as DVI for cervical ripening with no increase in morbidity. Although DVI with ASM group less often needed additional dinoprostone tablets to complete the process of IOL (p-value = 0.2), adjunctive sweeping has not been shown to have a significant impact on the duration of labor or mode of delivery.

Six versus twelve hours of single-balloon catheter placement with oxytocin administration for labor induction: a randomized controlled trial

BACKGROUND

Induction of labor is common in the United States. Multiple previous studies have tried to outline a faster time to delivery to improve maternal and fetal outcomes.

OBJECTIVE

This study aimed to evaluate whether women who undergo induction of labor with a single-balloon catheter and oxytocin have a shorter time to delivery with planned removal of the catheter at 6 vs 12 hours.

STUDY DESIGN

In this randomized controlled trial, induction of labor was performed using a combination of single-balloon catheter and oxytocin. Term women, both nulliparous and multiparous, aged 18 to 50 years old with cephalic singletons were included if they were undergoing induction of labor with a Bishop score of <6 and cervical dilation of <2 cm. Women were randomized to planned removal of the single-balloon catheter at 6 hours vs 12 hours. The primary outcome was time from catheter insertion to delivery. We were powered to show a 4-hour time difference with a sample size of 89 women per group (n=178). Planned sensitivity analyses were performed to account for cesarean delivery in labor.

RESULTS

From February 2019 to June 2020, 237 women were screened, 178 women were randomized, and 177 women were included in the final analysis (89 women in the 6-hour group and 88 women in the 12-hour group). Insertion to delivery time was significantly shorter in the 6-hour group (19.2 vs 24.3 hours; P=.04), and the proportion of women delivered by 24 hours was significantly greater in the 6-hour group (67.4% vs 47.4%; P<.01). There was no difference in the Bishop score at removal of the catheter or secondary maternal or neonatal outcomes. In a Cox proportional-hazards model censoring for cesarean delivery, the 6-hour group had a significantly shorter insertion to delivery time (hazard ratio, 0.67; P=.02).

CONCLUSION

Induction of labor with a single-balloon catheter and oxytocin with planned removal of the catheter at 6 hours rather than 12 hours results in a shorter time from insertion to delivery without increasing the rate of cesarean delivery. Decreasing the length of time a single-balloon catheter is in place should be considered in clinical protocols.

Induction of labor using Foley catheter with weight attached versus without weight attached: A randomized control trial

OBJECTIVE

To assess the effectiveness in preventing cesarean section for failed induction by using Foley catheter for cervical ripening in comparison to Foley catheter with a weight attached to it.

METHODS

A randomized control trial conducted between November 2018 and July 2020, which looked at induction of labor with 30-ml Foley catheter in one arm and the Foley placed with a 500 ml weight attached to it in the other arm. Primary outcome was the cesarean section rate.

RESULTS

We randomized 399 women. Modes of delivery were similar in both groups. Numbers undergoing cesarean section for failed induction were higher in the group that underwent induction with Foley with weight but this was not statistically significant (45.7% vs 26.5%, P = 0.1). There was a shorter time to expulsion of the Foley with weight attached (mean ± standard deviation: 2.6 ± 3.3 h vs 10.9 ± 3.2 h, P < 0.001) but this did not translate into a difference in time to active labor or time to delivery.

CONCLUSION

Placing a weight at the end of the Foley catheter for induction of labor does not affect the time to delivery or the rate of cesarean deliveries, although there is faster expulsion of the Foley. Clinical trial registration no.: CTRI/2018/10/016154.

Efficacy and safety of controlled-release dinoprostone vaginal delivery system (PROPESS) in Japanese pregnant women requiring cervical ripening: Results from a multicenter, randomized, double-blind, placebo-controlled phase III study

AIM

To evaluate the efficacy and safety of dinoprostone vaginal insert (PROPESS) in pregnant post-term Japanese women requiring cervical ripening.

METHODS

This randomized, double-blind, placebo-controlled study included 114 pregnant Japanese women at term (41 weeks of gestation) requiring cervical ripening (baseline Bishop score (BS) ≤ 4). The primary end-point was the proportion of subjects with successful cervical ripening defined as BS ≥ 7 or vaginal delivery in 12 h. The secondary end-points were changes in BS, proportion of women with vaginal delivery, proportion of women receiving mechanical cervical ripening procedure and use of oxytocic drugs.

RESULTS

PROPESS administration for a maximum of 12 h showed significantly higher successful cervical ripening rate (47.4% vs 14.3%, respectively; treatment contrast [TC]: 33.1%; P = 0.0002). The median time from administration to vaginal delivery was significantly shorter in the PROPESS group than in the placebo group (26.18 h vs 33.02 h; OR 2.51; 95% CI [1.60-3.92]; P < 0.0001). In the PROPESS group, the dosage of uterotonic drugs, such as oxytocin, decreased, and the number of patients who used these drugs also decreased.

CONCLUSION

PROPESS administration for a maximum of 12 h was an effective and well-tolerated treatment for pregnant Japanese women post-term requiring cervical ripening.

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

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

Retrospective Comparison of PGE2 Vaginal Insert and Foley Catheter for Outpatient Cervical Ripening

OBJECTIVE

To compare the efficacy of two methods of outpatient cervical ripening (CR): an intracervical Foley catheter and a prostaglandin E₂ (PGE)₂ slow-release vaginal insert.

METHODS

All records of women receiving outpatient CR at a tertiary care hospital from January 2017 to June 2018 were retrospectively reviewed. We compared time from insertion of first CR agent until delivery between groups using a Cox proportional hazards (CPH) model. Exclusion criteria included age <18 years, multiple gestation, or contraindication to either CR method. Secondary outcomes included time from removal of agent and time from admission until delivery, additional CR used, uterine tachysystole, labour and delivery complications, type of delivery, and adverse neonatal outcomes.

RESULTS

A total of 153 patients were included (82 Foley; 71 PGE₂). Baseline characteristics were comparable except for lower dilation in the PGE₂ group (16% vs. 38% <1cm dilated; P < 0.05). In the CPH model, time from insertion to delivery was not different between PGE₂ and Foley catheter groups (median 27 vs. 33 h), controlling for parity, gestational age, initial dilation, and use of oxytocin (HR 1.13, 95% confidence interval 0.77-1.68). Patients in the PGE₂ group were more likely to experience uterine tachysystole (9% vs. 0%; P < 0.01) and require another method of CR (34% vs. 1%; P < 0.001). There were no differences in neonatal or maternal adverse outcomes between groups.

CONCLUSION

Our results suggest that outpatient Foley catheter and PGE₂ CR are comparable in time from insertion to delivery; however, PGE₂ inserts are associated with higher rates of tachysystole and the need for second CR method. A prospective study is warranted to further investigate these findings.

Mechanical methods for induction of labour

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

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

BACKGROUND

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

Interest of cervical ripening using double balloon catheters for labour induction in term nulliparous women

OBJECTIVE

To compare the efficiency of double balloon catheters with that of intravaginal prostaglandins alone for the labor induction of unfavourable cervices in term nulliparous women.

METHODS

50 nulliparous patients induced with a double balloon device were compared to 53 patients induced using intravaginal prostaglandins alone. The main outcome measure was labour induction failure, characterized by the absence of active labour. The secondary outcome measures were the improvement of the Bishop score, the average durations of ripening and labour induction, the average time to active labour, the need for a second cervical ripening agent, the total dose of prostaglandins used in each group, the use of oxytocins, as well as the rates of vaginal delivery, abnormal foetal heart rate during labour and perinatal maternal infection.

RESULTS

The rate of failed labour induction was of 28% in the double balloon group, against 13% in the prostaglandins group. The average durations of ripening and labour induction, as well as the time to active labour were higher in the double balloon group. The improvement of the Bishop score was significantly lower in the double balloon group.

DISCUSSION AND CONCLUSION

In our study, the use of double balloon catheters does not seem to reduce the rate of failed labour induction in nulliparous women when compared to the use of prostaglandins alone. In addition, it could lengthen the labour induction duration, although more powerful studies would be necessary not to recommend its use for nulliparous women.

Induction of labor in patients with an unfavorable cervix after a cesarean using an osmotic dilator versus vaginal prostaglandin

BACKGROUND

Trial of labor after cesarean (TOLAC) is a viable option for safe delivery. In some cases cervical ripening and subsequent labor induction is necessary. However, the commonly used prostaglandins are not licensed in this subgroup of patients and are associated with an increased risk of uterine rupture.

METHODS

This cohort study compares maternal and neonatal outcomes of TOLAC in women (n=82) requiring cervical ripening agents (osmotic dilator vs. prostaglandins). The initial Bishop scores (BSs) were 2 (0-5) and 3 (0-5) (osmotic dilator and prostaglandin group, respectively). In this retrospective analysis, Fisher's exact test, the Kruskal-Wallis rank sum test and Pearson's chi-squared test were utilized.

RESULTS

Vaginal birth rate (including operative delivery) was 55% (18/33) in the osmotic dilator group vs. 51% (25/49) in the dinoprostone group (P 0.886). Between 97% and 92% (32/33 and 45/49) (100%, 100%) of neonates had an Apgar score of >8 after 1 min (5, 10 min, respectively). The time between administration of the agent and onset of labor was 36 and 17.1 h (mean, Dilapan-S® group, dinoprostone group, respectively). Time from onset of labor to delivery was similar in both groups with 4.4 and 4.9 h (mean, Dilapan-S® group, dinoprostone group, respectively). Patients receiving cervical ripening with Dilapan-S® required oxytocin in 97% (32/33) of cases. Some patients presented with spontaneous onset of labor, mostly in the dinoprostone group (24/49, 49%). Amniotomy was performed in 64% and 49% (21/33 and 24/49) of cases (Dilapan-S® group and dinoprostone group, respectively).

CONCLUSIONS

This pilot study examines the application of an osmotic dilator for cervical ripening to promote vaginal delivery in women who previously delivered via cesarean section. In our experience, the osmotic dilator gives obstetricians a chance to perform induction of labor in these women.

Which method is best for the induction of labour? A systematic review, network meta-analysis and cost-effectiveness analysis

BACKGROUND

More than 150,000 pregnant women in England and Wales have their labour induced each year. Multiple pharmacological, mechanical and complementary methods are available to induce labour.

OBJECTIVE

To assess the relative effectiveness, safety and cost-effectiveness of labour induction methods and, data permitting, effects in different clinical subgroups.

METHODS

We carried out a systematic review using Cochrane methods. The Cochrane Pregnancy and Childbirth Group's Trials Register was searched (March 2014). This contains over 22,000 reports of controlled trials (published from 1923 onwards) retrieved from weekly searches of OVID MEDLINE (1966 to current); Cochrane Central Register of Controlled Trials (The Cochrane Library); EMBASE (1982 to current); Cumulative Index to Nursing and Allied Health Literature (1984 to current); ClinicalTrials.gov; the World Health Organization International Clinical Trials Registry Portal; and hand-searching of relevant conference proceedings and journals. We included randomised controlled trials examining interventions to induce labour compared with placebo, no treatment or other interventions in women eligible for third-trimester induction. We included outcomes relating to efficacy, safety and acceptability to women. In addition, for the economic analysis we searched the Database of Abstracts of Reviews of Effects, and Economic Evaluations Databases, NHS Economic Evaluation Database and the Health Technology Assessment database. We carried out a network meta-analysis (NMA) using all of the available evidence, both direct and indirect, to produce estimates of the relative effects of each treatment compared with others in a network. We developed a de novo decision tree model to estimate the cost-effectiveness of various methods. The costs included were the intervention and other hospital costs incurred (price year 2012-13). We reviewed the literature to identify preference-based utilities for the health-related outcomes in the model. We calculated incremental cost-effectiveness ratios, expected costs, utilities and net benefit. We represent uncertainty in the optimal intervention using cost-effectiveness acceptability curves.

RESULTS

We identified 1190 studies; 611 were eligible for inclusion. The interventions most likely to achieve vaginal delivery (VD) within 24 hours were intravenous oxytocin with amniotomy [posterior rank 2; 95% credible intervals (CrIs) 1 to 9] and higher-dose (≥ 50 µg) vaginal misoprostol (rank 3; 95% CrI 1 to 6). Compared with placebo, several treatments reduced the odds of caesarean section, but we observed considerable uncertainty in treatment rankings. For uterine hyperstimulation, double-balloon catheter had the highest probability of being among the best three treatments, whereas vaginal misoprostol (≥ 50 µg) was most likely to increase the odds of excessive uterine activity. For other safety outcomes there were insufficient data or there was too much uncertainty to identify which treatments performed 'best'. Few studies collected information on women's views. Owing to incomplete reporting of the VD within 24 hours outcome, the cost-effectiveness analysis could compare only 20 interventions. The analysis suggested that most interventions have similar utility and differ mainly in cost. With a caveat of considerable uncertainty, titrated (low-dose) misoprostol solution and buccal/sublingual misoprostol had the highest likelihood of being cost-effective.

LIMITATIONS

There was considerable uncertainty in findings and there were insufficient data for some planned subgroup analyses.

CONCLUSIONS

Overall, misoprostol and oxytocin with amniotomy (for women with favourable cervix) is more successful than other agents in achieving VD within 24 hours. The ranking according to safety of different methods was less clear. The cost-effectiveness analysis suggested that titrated (low-dose) oral misoprostol solution resulted in the highest utility, whereas buccal/sublingual misoprostol had the lowest cost. There was a high degree of uncertainty as to the most cost-effective intervention.

FUTURE WORK

Future trials should be powered to detect a method that is more cost-effective than misoprostol solution and report outcomes included in this NMA.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013005116.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Risk of maternal, fetal and neonatal complications associated with the use of the transcervical balloon catheter in induction of labour: A systematic review

Induction of labour is one of the most frequently applied obstetrical interventions globally. Many studies have compared the use of balloon catheters with pharmacological agents. Although the safety of the balloon catheter is often mentioned, little has been written about the total spectrum of maternal and fetal morbidity associated with induction of labour using a balloon catheter. We evaluated the safety of labour induction with a transcervical balloon catheter by conducting a literature review with pooled risk assessments of the maternal, fetal and neonatal morbidity. We searched Medline, EMBASE and CINAHL as well as the Cochrane database using the Keywords 'induction of labour', 'cervical ripening', 'transcervical balloon', 'balloon catheter' and 'Foley balloon'. We did not use language or date restrictions. Randomized and quasi-randomized controlled trials as well as observational studies that contained original data on occurrence of maternal, fetal or neonatal morbidity during induction of labour with the balloon catheter were included. Studies were excluded if the balloon catheter was used concurrently with oxytocin and concurrently or consecutively with misoprostol, dinoprostone or extra-amniotic saline infusion. Study selection and quality assessment was performed by two authors independently using a standardized critical appraisal instrument. Outcomes were reported as weighted mean rates. We detected 84 articles reporting on 13,791 women. The overall risk of developing intrapartum maternal infection was 11.3% (912 of 8079 women), 3.3% (151 of 4538 women) for postpartum maternal infection and 4.6% (203 of 4460 women) for neonatal infection. Uterine hypercontractility occurred in 2.7% (148 of 5439) of the women. Uterine rupture after previous caesarean section occurred in 1.9% of women (26 of 1373), while other major maternal complications had an occurrence rate of <1%. The risk for developing minor maternal complications was <2%. The risk of developing a non-reassuring fetal heart rate was 10.8% (793 of 7336 women), 10.1% (507 of 5008 women) for fetal distress and 14.0% (460 of 3295 women) for meconium stained liquor. Neonatal death occurred in 0.29% (6 of 2058) of the deliveries and NICU admission in 7.2% (650 of 9065 deliveries). This review shows that labour induction with a balloon catheter is a safe intervention, with intrapartum maternal infection being the only reasonable risk above 10%.

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.

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

BACKGROUND

Cervical ripening of an unfavorable cervix can be achieved by placement of a transcervical catheter. Advantages of this method include both lower cost and lower risk of tachysystole than other methods. Despite widespread use with varying degrees of applied tension, an unanswered question is whether there is an advantage to placing the transcervical catheter to tension compared with placement without tension.

OBJECTIVE

The purpose of this study was to determine whether tension placed on a transcervical balloon catheter that is inserted for cervical ripening results in a faster time to delivery.

STUDY DESIGN

This was a prospective, randomized controlled trial; 140 women who underwent cervical ripening (Bishop score, ≤6) were assigned randomly to a balloon catheter with applied tension vs no tension. Tension was created when the catheter was taped to the patient's thigh and tension was reapplied in 30-minute increments. There were 67 patients in the tension group and 73 patients in the no tension group. Low-dose oxytocin (maximum, 6 mU/min) was administered after catheter placement. The primary outcome was time from catheter insertion to delivery. A secondary outcome was time from insertion to catheter expulsion. The Kolmogorov-Smirnov test was used to determine whether the data were distributed normally. Survival curves that used lifetables were constructed from time of catheter insertion to delivery and from time of catheter insertion to catheter expulsion and were compared with the use of the Wilcoxon (Gehan) Breslow statistic. A probability value of <.05 was set to denote statistical significance.

RESULTS

Baseline characteristics were similar between groups. The median time from catheter insertion to delivery was not significantly different between the tension group and the no tension group (16.2 vs 16.9 hours; P=.814). The median time from catheter insertion to expulsion, however, was significantly less in the tension group vs the no tension group (2.6 vs 4.6 hours; P<.001), respectively. Vaginal delivery within 24 hours was not significantly different between the tension and no tension groups (41/52 [79%] vs 37/52 [71%]; P=.365) nor were there significant differences in cesarean delivery rates between the tension and no tension groups (17/67 [25%] vs 27/73 [37%]; P=.139).

CONCLUSION

Application of tension did not result in faster delivery times but did result in faster times to catheter expulsion.

Misoprostol Vaginal Insert in Labor Induction: A Cost-Consequences Model for 5 European Countries-An Economic Evaluation Supported with Literature Review and Retrospective Data Collection

Introduction

The present study aimed to assess the costs and consequences of using an innovative medical technology, misoprostol vaginal insert (MVI), for the induction of labor (IOL), in place of alternative technologies used as a standard of care.

Methods

This was a retrospective study on cost and resource utilization connected with economic model development. Target population were women with an unfavorable cervix, from 36 weeks of gestation, for whom IOL is clinically indicated. Data on costs and resources was gathered via a dedicated questionnaire, delivered to clinical experts in five EU countries. The five countries participating in the project and providing completed questionnaires were Austria, Poland, Romania, Russia and Slovakia. A targeted literature review in Medline and Cochrane was conducted to identify randomized clinical trials meeting inclusion criteria and to obtain relative effectiveness data on MVI and the alternative technologies. A hospital perspective was considered as most relevant for the study. The economic model was developed to connect data on clinical effectiveness and safety from randomized clinical trials with real life data from local clinical practice.

Results

The use of MVI in most scenarios was related to a reduced consumption of hospital staff time and reduced length of patients’ stay in hospital wards, leading to lower total costs with MVI when compared to local comparators.

Conclusions

IOL with the use of MVI generated savings from a hospital perspective in most countries and scenarios, in comparison to alternative technologies.

Funding

Sponsorship, article processing charges, and the open access charge for this study were funded by Ferring Pharmaceuticals Poland.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-016-0397-3) contains supplementary material, which is available to authorized users.

Foley catheter placement for induction of labor with or without stylette: a randomized clinical trial

BACKGROUND

Foley catheters are used for cervical ripening during induction of labor. Previous studies suggest that use of a stylette (a thin, rigid wire) to guide catheter insertion decreases insertion failure. However, stylette effects on insertion outcomes have been sparsely studied.

OBJECTIVE

The purpose of this study was to compare catheter insertion times, patient-assessed pain levels, and insertion failure rates between women who received a digitally placed Foley catheter for cervical ripening with the aid of a stylette and women who received the catheter without a stylette.

STUDY DESIGN

We conducted a randomized clinical trial of women aged ≥ 18 years who presented for induction of labor. Inclusion criteria were singletons with intact membranes and cephalic presentation. Women received a computer-generated random assignment of a Foley catheter insertion with a stylette (treatment group, n = 62) or without a stylette (control group, n = 61). For all women, a standard insertion technique protocol was used. Three primary outcomes were of interest, including the following: (1) insertion time (total minutes to successful catheter placement), (2) patient-assessed pain level (0-10), and (3) failure rate of the randomly assigned insertion method. Treatment control differences were first examined using the Pearson's test of independence and the Student t test. Per outcome, we also constructed 4 regression models, each including the random effect of physician and fixed effects of stylette use with patient nulliparity, a history of vaginal delivery, cervical dilation at presentation, or postgraduate year of the performing resident physician.

RESULTS

Women who received the Foley catheter with the stylette vs without the stylette did not differ by age, race/ethnicity, body mass index, or any of several other characteristics. Regression models revealed that insertion time, patient pain, and insertion failure were unrelated to stylette use, nulliparity, and history of vaginal delivery. However, overall insertion time and failure were significantly influenced by cervical dilation, with insertion time decreasing by 21% (95% confidence interval [CI], 5-34%) and odds of failure decreasing by 71% (odds ratio, 0.29; 95% CI, 0.10-0.86) per 1 cm dilation. Resident postgraduate year also significantly influenced insertion time, with greater time required of physicians with less experience. Mean insertion time was 51% (95% CI, 23-69%) shorter for fourth-year than second-year residents. Statistically nonsignificant but prominent patterns in outcomes were also observed, suggesting stylette use may lengthen the overall insertion procedure but minimize variability in pain levels and decrease insertion failure.

CONCLUSIONS

The randomized trial suggests that, even after accounting for nulliparity, history of vaginal delivery, cervical dilation, and physician experience, Foley catheter insertions with and without a stylette are equivalent in insertion times, patient pain levels, and failure of catheter placement.

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.

Controlled-release dinoprostone insert versus Foley catheter for labor induction: a meta-analysis

OBJECTIVE

To compare the effectiveness and safety of controlled-release dinoprostone insert with Foley catheter balloon for cervical ripening and labor induction.

METHODS

PubMed, Cochrane Central Register of Controlled Trials, Web of Science, and China Knowledge Resource Integrated Database were searched. Only randomized controlled trials comparing controlled-release dinoprostone insert with Foley catheter balloon were included. Risk ratio (RR) or mean difference (MD) with 95% confidence interval (CI) was calculated.

RESULTS

Six studies were included with 731 women received dinoprostone insert and 722 Foley catheter. Time from induction to delivery was significantly shortened in dinoprostone insert group compared to Foley catheter group (MD 5.73 h, 95% CI 1.26-10.20). There were no significant differences in vaginal delivery within 24 h (RR 0.75, 95% CI 0.43-1.30) or cesarean section (RR 0.94, 95% CI 0.80-1.12) between two ripening methods. Dinoprostone insert was related with increased rate of excessive uterine contraction (RR 0.07, 95% CI 0.03-0.19), but less oxytocin use (RR 1.86, 95% CI 1.25-2.77) when compared with Foley catheter.

CONCLUSIONS

Induction of labor with controlled-release dinoprostone insert seems to be more effective than Foley catheter. However, the former method causes excessive uterine contraction more frequently.

Foley Catheter for Induction of Labor at Term: An Open-Label, Randomized Controlled Trial

Objective

This study aimed to determine the optimal Foley catheter balloon volume (30-mL vs. 80-mL) and the maximum time for cervical ripening (12 hours vs. 24 hours) to improve vaginal delivery rate within 24 hours of induction.

Methods

We conducted an open-label, randomized controlled trial in a teaching hospital in China. Women with a term singleton pregnancy, cephalic presentation, intact membrane and an unfavorable cervix (Bishop score <6) were randomly allocated, in 1:1:1:1 ratio, to receive either one of the four treatments: (1) 30-mL balloon for a maximum of 12 hours, (2) 30-mL balloon for a maximum of 24 hours, (3) 80-mL balloon for a maximum of 12 hours, and (4) 80-mL balloon for a maximum of 24 hours. The primary outcome was vaginal delivery within 24 hours. Secondary outcomes included cesarean section rate and maternal/neonatal morbidity. Data were analyzed on a per-protocol basis.

Results

Five hundred and four women were recruited and randomized (126 women in each group); nine women did not receive the assigned intervention. More women achieved vaginal delivery within 24 hours in 12-hour Foley catheter groups than in the 24-hour Foley catheter groups (30-mL/12 hours: 54.5%, 30-mL/24 hours: 33.1%, 80-mL/12 hours: 46.4%, 80-mL/24 hours: 24.0%, p < 0.001). Cesarean section rates and the incidence of chorioaminonitis were comparable among four groups. After adjustment for confounding factors, both ripening time and balloon size did not affect the proportion of women delivered vaginally within 24 hours of induction.

Conclusion

For women with an unfavorable cervix at term, induction of labor with a Foley catheter is safe and effective. Higher balloon volume (80-mL vs. 30-mL) and longer ripening time (24 hours vs. 12 hours) would not shorten induction to delivery interval or reduce cesarean section rate.

Trial Registration

Chinese Clinical trial registry (ChiCTR-TRC-13003044)

Direct electrical stimulation softens the cervix in pregnant and nonpregnant rats

OBJECTIVE

The objective of the study was to determine the effects of electrical stimulation (ES) on cervical ripening in pregnant and nonpregnant rats.

STUDY DESIGN

Timed pregnant and nonpregnant Sprague-Dawley rats (n = 6-7/group) were used. Cervical ES for pregnant rats was performed in vivo on day 15 of gestation by inserting an electrical probe into the vagina in contact with the cervix. Parameters of ES varied from 0.1 to 0.2 mA, 10 pulses per second, 20 milliseconds pulse duration, and repeating pulses for 15, 30, 60, and 120 minutes for pregnant ES groups and similar times for sham control groups with electrode but without ES. Nonpregnant ES groups were stimulated with only 0.2 mA for 30 minutes. Cervical collagen was measured in controls and following ES at various times using light-induced fluorescence (LIF) of collagen. Photographs were taken following ES, and some rats were killed, the cervices were isolated, and cervical extensibility was estimated.

RESULTS

LIF values of pregnant rats are significantly lower (P < .001) and extensibility greater (P < .05) in the ES treatment groups compared with the control groups on days 16 and 17 of pregnancy. Similarly LIF is lower (P < .05) and extensibility values greater (P < .05) in nonpregnant rats treated with ES. No adverse effects, including altered delivery time, pup weights, or damage to cervix, were produced by low current levels of ES needed to soften the cervix.

CONCLUSION

The following conclusions were reached: (1) application of ES rapidly produces softening and ripening of the cervix in pregnant and nonpregnant rats; (2) ES treatment does not produce early delivery; (3) the exact mechanism for ES ripening is not yet known; and (4) ES might be used clinically to ripen the cervix when needed.

A comparison of inpatient with outpatient balloon catheter cervical ripening: a pilot randomized controlled trial

Background

One in four Australian births are induced. If cervical ripening using a prostaglandin is required, a pre-labour overnight hospitalisation and separation from family and support companions is necessary. Recent evidence shows that balloon catheter cervical ripening is just as effective as prostaglandins, but does not cause uterine stimulation. For women with low risk pregnancies, this offers the possibility of undergoing the overnight ripening process in their own home. We conducted a pilot randomised trial to assess the outcomes, clinical pathways and acceptability to both women and clinicians of outpatient balloon catheter ripening compared with usual inpatient care.

Methods

Forty-eight women with low risk term pregnancies were randomised (2:1) to either outpatient (n = 33) or inpatient double-balloon catheter (n = 15) cervical ripening. Although not powered for statistically significant differences, the study explored potential direction of effect for key clinical outcomes such as oxytocin use, caesarean section and morbidities. Feedback on acceptability was sought from women at catheter insertion and 4 weeks after the birth, and from midwives and doctors, at the end of the study.

Results

Clinical and perinatal outcomes were similar. Most women required oxytocin (77 %). The outpatient group were 24 % less likely to require oxytocin (risk difference −23.6 %, 95 % CI −43.8 to −3.5). There were no failed inductions, infections or uterine hyperstimulation attributable to the catheter in either group. Most women in both groups reported discomfort with insertion and wearing the catheter, but were equally satisfied with their care and felt the baby was safe (91 % both groups). Outpatient women reported feeling less isolated or emotionally alone. Most midwives and doctors (n = 90) agreed that they are more comfortable in sending home a woman with a catheter than prostaglandins and 90 % supported offering outpatient ripening to eligible women.

Conclusions

Outpatient balloon catheter ripening should be further investigated as an option for women in an adequately powered randomised trial.

Trial registration

Prospectively registered, Australian New Zealand Clinical Trials Registry ACTRN12612001184864.

[Double-balloon device and intravaginal dinoprostone for cervical ripening in women with unfavourable cervix]

OBJECTIVES

To compare the efficiency of a double cervical ripening (mechanical agent and dinoprostone) to a dinoprostone-only ripening in women with an unfavourable cervix.

METHODS

In a retrospective study from January 2008 to October 2013, 96 patients were included with the following criteria: pregnancies over 37 weeks, singleton, vertex presentation, medical indication for induction of labor, no premature rupture of membranes and very unfavourable cervix (Bishop score ≤ 3). Patients were classified into 2 groups: intravaginal dinoprostone for 24h (prostaglandin group, n=38) and double-balloon device for 12h followed by intravaginal dinoprostone for 24h (balloon+prostaglandin group, n=58).

RESULTS

There was no difference in vaginal delivery rates between the 2 groups (balloon+prostaglandin group 51.7%, prostaglandin group 50%, P=0.87). The Bishop score after cervical ripening was significantly higher in the balloon+prostaglandin group (4.4 versus 2.4, P<0.0001), but the interval between the induction and the delivery was longer (33.6h versus 24.9h, P=0.0044). There was no significant difference for maternal and neonatal complications.

CONCLUSION

A double cervical ripening (with mechanical agent and dinoprostone) allows the Bishop score to be improved without increasing the rate of vaginal delivery, for patients with a Bishop score ≤ 3.

[Cervical ripening: is there an advantage for a double-balloon device in labor induction?]

OBJECTIVES

To compare efficiency of a double-balloon to vaginal prostaglandins for cervical ripening in patients with unfavourable cervix.

PATIENTS AND METHODS

Fifty patients induced with a double-balloon were compared to 50 patients receiving vaginal prostaglandins. Matching criteria were age, parity, history of uterine scar, gestational age and Bishop score. The primary outcome was failure induction. Secondary outcomes included improvement in Bishop score, ripening-to-delivery interval, caesarean section rate, maternal and neonatal morbidity.

RESULTS

Risk of failed induction (16% in the double-balloon group vs. 14% in the prostaglandins group) and caesarean section rate (28% vs. 36%) were similar in the two groups. The proportion of favourable cervix and the time to obtain a better Bishop score were similar with the two methods. Maximal pain score during cervical ripening was significantly lower in the double-balloon group (P<0.001). Ripening-to-delivery interval (30.4 h ± 15.6h vs. 28.9 h ± 20.5h) was not different between the two groups. There was no difference about maternal and neonatal outcomes.

DISCUSSION AND CONCLUSION

The double-balloon was as efficient as vaginal prostaglandins. The ripening-to-delivery interval was not different between the two groups. The main advantage of this device could be a better tolerance favourishing patient satisfaction.

A simplified cervix model in response to induction balloon in pre-labour

BACKGROUND

Induction of labour is poorly understood even though it is performed in 20% of births in the United States. One method of induction, the balloon dilator applied with traction to the interior os of the cervix, engages a softening process, permitting dilation and effacement to proceed until the beginning of active labour. The purpose of this work is to develop a simple model capable of reproducing the dilation and effacement effect in the presence of a balloon.

METHODS

The cervix, anchored by the uterus and the endopelvic fascia was modelled in pre-labour. The spring-loaded, double sliding-joint, double pin-joint mechanism model was developed with a Modelica-compatible system, MapleSoft MapleSim 6.1, with a stiff Rosenbrock solver and 1E-4 absolute and relative tolerances. Total simulation time for pre-labour was seven hours and simulations ended at 4.50 cm dilation diameter and 2.25 cm effacement.

RESULTS

Three spring configurations were tested: one pin joint, one sliding joint and combined pin-joint-sliding-joint. Feedback, based on dilation speed modulated the spring values, permitting controlled dilation. Dilation diameter speed was maintained at 0.692 cm·hr-1 over the majority of the simulation time. In the sliding-joint-only mode the maximum spring constant value was 23800 N·m-1. In pin-joint-only the maximum spring constant value was 0.41 N·m·rad-1. With a sliding-joint-pin-joint pair the maximum spring constants are 2000 N·m-1 and 0.41 N·m·rad-1, respectively.

CONCLUSIONS

The model, a simplified one-quarter version of the cervix, is capable of maintaining near-constant dilation rates, similar to published clinical observations for pre-labour. Lowest spring constant values are achieved when two springs are used, but nearly identical tracking of dilation speed can be achieved with only a pin joint spring. Initial and final values for effacement and dilation also match published clinical observations. These results provide a framework for development of electro-mechanical phantoms for induction training, as well as dilator testing and development.

Inner thigh taping vs traction for cervical ripening with a Foley catheter: a randomized controlled trial

OBJECTIVE

To assess the effectiveness of inner thigh "Taping" compared with "Traction" using a weighted bag when an intracervical Foley catheter is used for cervical ripening.

STUDY DESIGN

We performed a randomized controlled trial at a tertiary hospital on women with a singleton pregnancy in cephalic presentation admitted for labor induction with a Bishop score ≤6. A 30 mL intracervical Foley catheter was placed for ripening. Women were randomly allocated to inner thigh Taping or to Traction with a 500 mL weighted bag of fluid. The primary outcome was time to delivery. Secondary outcomes were time to expulsion of the catheter, maternal discomfort (visual analog scale), mode of delivery, and maternal morbidities.

RESULTS

We randomized 197 women. After exclusions (4 ineligible, 2 withdrawn by provider), we analyzed 191 (96 Taping, 95 Traction) women in their assigned groups. Groups were similar regarding maternal race, age, parity, gestational age, and induction indication. Time to delivery was not significantly different (mean ± standard deviation: 19.8 ± 8.5 vs 18.8 ± 8.0 hours; P = .39). Time to catheter expulsion was shorter in the Traction Group (median, 2.6; range, 0.2-10.8 vs median, 1.5; range, 0.1-6.3 hours; P < .001). Change in Bishop and pain scores, cesarean delivery rates, clinical amnionitis, and other maternal morbidities were similar between groups. Subset analyses of those with vaginal delivery and among nulliparas, and multiparas revealed similar results.

CONCLUSION

Traction on the intracervical Foley catheter during cervical ripening shortens the time to spontaneous catheter expulsion without affecting the time to delivery.

Foley catheter or prostaglandin E2 inserts for induction of labour at term: an open-label randomized controlled trial (PROBAAT-P trial) and systematic review of literature

OBJECTIVE

To assess the safety and effectiveness of a transcervical Foley catheter compared to vaginal prostaglandin E2 inserts for term induction of labour.

STUDY DESIGN

We conducted an open-label randomized controlled trial in five hospitals in the Netherlands. Women with a singleton term pregnancy in cephalic presentation, intact membranes, unfavourable cervix, and no prior caesarean section were enrolled. Participants were randomly allocated by a web-based randomization system to induction of labour with a 30 ml Foley catheter or 10mg slow-release vaginal prostaglandin E2 inserts in a 1:1 ratio. Due to the nature of the intervention this study was not blinded. The primary outcome was the caesarean section rate. Secondary outcomes were maternal and neonatal morbidity and time from intervention to birth. Additionally, we carried out a systematic review and meta-analysis of similar studies.

RESULTS

We analyzed 226 women: 107 received a Foley catheter and 119 inserts. Caesarean section rates were comparable (20% versus 22%, RR 0.90, 95% CI 0.54-1.50). Secondary outcomes showed no differences. We observed no serious maternal or neonatal morbidity. Meta-analysis showed comparable caesarean section rates, but significantly fewer cases of hyperstimulation during the ripening phase when a Foley catheter was used.

CONCLUSIONS

We found, in this relatively small study, no differences in effectiveness and safety of induction of labour with a Foley catheter and 10mg slow release vaginal prostaglandin E2 inserts. Meta-analysis confirmed a comparable caesarean section rate, and showed fewer cases of hyperstimulation when a Foley catheter was used.

A randomized trial of preinduction cervical ripening: dinoprostone vaginal insert versus double-balloon catheter

OBJECTIVE

We sought to compare the efficacy of a double-balloon transcervical catheter to that of a prostaglandin (PG) vaginal insert among women undergoing labor induction.

STUDY DESIGN

In all, 210 women with a Bishop score ≤6 were assigned randomly to cervical ripening with either a double-balloon device or a PGE2 sustained-release vaginal insert. Primary outcome was vaginal delivery within 24 hours.

RESULTS

The proportion of women who achieved vaginal delivery in 24 hours was higher in the double-balloon group than in the PGE2 group (68.6% vs 49.5%; odds ratio, 2.22; 95% confidence interval, 1.26-3.91). There was no difference in cesarean delivery rates (23.8% vs 26.2%; odds ratio, 0.88; 95% confidence interval, 0.47-1.65). Oxytocin and epidural analgesia were administered more frequently when a double-balloon device was used. Uterine tachysystole or hypertonus occurred more frequently in the PGE2 arm (9.7% vs 0%, P = .0007).

CONCLUSION

The use of a double-balloon catheter for cervical ripening is associated with a higher rate of vaginal birth within 24 hours compared with a PGE2 vaginal insert.

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 simplicity of preservation, lower cost and reduction of the side effects.

OBJECTIVES

To determine the effects of mechanical methods for third trimester cervical ripening or induction of labour in comparison with placebo/no treatment, prostaglandins (vaginal and intracervical prostaglandin E2 (PGE2), misoprostol) and oxytocin.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 April 2011) and bibliographies of relevant papers. We updated this search on 16 January 2012 and added the 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 methods listed above it on a predefined list of methods of labour. A comparison with amniotomy will be added, should this comparison be made in future trials.Different types of intervention have been considered as mechanical methods: (1) introduction of laminaria tents, or their synthetic equivalent (Dilapan), into the cervical canal; (2) the introduction of a catheter through the cervix into the extra-amniotic space, with or without traction; (3) use of a catheter to inject fluidsin the extra-amniotic spaceIn addition, we made other comparisons: (1) specific mechanical methods (balloon catheter and laminaria tents) compared with any prostaglandins or with oxytocin; (2) addition of prostaglandins or oxytocin to mechanical methods compared with prostaglandins alone.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and assessed risk of bias. Two review authors independently extracted data.

MAIN RESULTS

For this update we have included a further 27 studies. The review includes 71 randomised controlled trials (total of 9722 women), ranging from 39 to 588 women per study. Most studies reported on caesarean section, all other outcomes are based on substantially fewer women. Four additional studies are ongoing.Mechanical methods versus no treatment: one study (48 woman) reported on women who did not achieve vaginal delivery within 24 hours (risk ratio (RR) 0.90; 95% confidence interval (CI) 0.64 to 1.26). The risk of caesarean section was similar between groups (six studies; 416 women, RR 1.00; 95% CI 0.76 to 1.30). There were no cases of severe neonatal and maternal morbidity.Mechanical methods versus vaginal PGE2 (17 studies;1894 woman): The proportion of women who did not achieve vaginal delivery within 24 hours was not significantly different (three studies; 586 women RR 1.72; 95% CI 0.90 to 3.27); however, for the subgroup of multiparous women the risk of not achieving delivery within 24 hours was higher (one study; 147 women RR 4.38, 95% CI 1.74 to 10.98), with no increase in caesarean sections (RR 1.19, 95% CI 0.62-2.29). Compared with intracervical PGE2 (14 studies;1784 women and misoprostol there was no significant difference in the proportion of women not achieving vaginal delivery within 24 hours.Mechanical methods reduced the risk of hyperstimulation with fetal heart rate changes when compared with vaginal prostaglandins: vaginal PGE2 (eight studies; 1203 women, RR 0.16; 95% CI 0.06 to 0.39) and misoprostol (3% versus 9%) (nine studies; 1615 women, RR 0.37; 95% CI 0.25 to 0.54). Risk of caesarean section between mechanical methods and prostaglandins was comparable. Serious neonatal and maternal morbidity were infrequently reported and did not differ between the groups.Mechanical methods compared with induction with oxytocin (reduced the risk of caesarean section (five studies; 398 women, RR 0.62; 95% CI 0.42 to 0.90). The likelihood of vaginal delivery within 24 hours was not reported. Hyperstimulation with fetal heart rate changes was reported in one study (200 participants), and did not differ. There were no reported cases of severe maternal or neonatal morbidity.

AUTHORS' CONCLUSIONS

Induction of labour using mechanical methods results in similar caesarean section rates as prostaglandins, for a lower risk of hyperstimulation. Mechanical methods do not increase the overall number of women not delivered within 24 hours, however the proportion of multiparous women who did not achieve vaginal delivery within 24 hours was higher when compared with vaginal PGE2. Compared with oxytocin, mechanical methods reduce the risk of caesarean section.