Attempted vaginal birth after cesarean section: a multicenter comparison of outpatient prostaglandin E(2) gel with expectant management

Outpatient cervical ripening and labor induction with low-dose vaginal misoprostol reduces the interval to delivery: a systematic review and network meta-analysis

OBJECTIVE

Several systematic reviews and meta-analyses have summarized the evidence on the efficacy and safety of various outpatient cervical ripening methods. However, the method with the highest efficacy and safety profile has not been determined conclusively. We performed a systematic review and network meta-analysis of published randomized controlled trials to assess the efficacy and safety of cervical ripening methods currently employed in the outpatient setting.

DATA SOURCES

With the assistance of an experienced medical librarian, we performed a systematic search of the literature using MEDLINE, Embase, Scopus, Web of Science, Cochrane Library, and ClinicalTrials.gov. We systematically searched electronic databases from inception to January 14, 2020.

STUDY ELIGIBILITY CRITERIA

We considered randomized controlled trials comparing a variety of methods for outpatient cervical ripening.

METHODS

We conducted a frequentist random effects network meta-analysis employing data from randomized controlled trials. We performed a direct, pairwise meta-analysis to compare the efficacy of various outpatient cervical ripening methods, including placebo. We employed ranking strategies to determine the most efficacious method using the surface under the cumulative ranking curve; a higher surface under the cumulative ranking curve value implied a more efficacious method. We assessed the following outcomes: time from intervention to delivery, cesarean delivery rates, changes in the Bishop score, need for additional ripening methods, incidence of Apgar scores <7 at 5 minutes, and uterine hyperstimulation.

RESULTS

We included data from 42 randomized controlled trials including 6093 participants. When assessing the efficacy of all methods, 25 μg vaginal misoprostol was the most efficacious in reducing the time from intervention to delivery (surface under the cumulative ranking curve of 1.0) without increasing the odds of cesarean delivery, the need for additional ripening methods, the incidence of a low Apgar score, or uterine hyperstimulation. Acupressure (surface under the cumulative ranking curve of 0.3) and primrose oil (surface under the cumulative ranking curve of 0.2) were the least effective methods in reducing the time to delivery interval. Among effective methods, 50 mg oral mifepristone was associated with the lowest odds of cesarean delivery (surface under the cumulative ranking curve of 0.9).

CONCLUSION

When balancing efficacy and safety, vaginal misoprostol 25 μg represents the best method for outpatient cervical ripening.

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.

Pharmacological and mechanical interventions for labour induction in outpatient settings

BACKGROUND

Induction of labour is carried out for a variety of indications and using a range of methods. For women at low risk of pregnancy complications, some methods of induction of labour or cervical ripening may be suitable for use in outpatient settings.

OBJECTIVES

To examine pharmacological and mechanical interventions to induce labour or ripen the cervix in outpatient settings in terms of effectiveness, maternal satisfaction, healthcare costs and, where information is available, safety.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 November 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials examining outpatient cervical ripening or induction of labour with pharmacological agents or mechanical methods. Cluster trials were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We assessed evidence using the GRADE approach.

MAIN RESULTS

This updated review included 34 studies of 11 different methods for labour induction with 5003 randomised women, where women received treatment at home or were sent home after initial treatment and monitoring in hospital.Studies examined vaginal and intracervical prostaglandin E₂ (PGE₂), vaginal and oral misoprostol, isosorbide mononitrate, mifepristone, oestrogens, amniotomy and acupuncture, compared with placebo, no treatment, or routine care. Trials generally recruited healthy women with a term pregnancy. The risk of bias was mostly low or unclear, however, in 16 trials blinding was unclear or not attempted. In general, limited data were available on the review's main and additional outcomes. Evidence was graded low to moderate quality. 1. Vaginal PGE₂ versus expectant management or placebo (5 studies)Fewer women in the vaginal PGE₂ group needed additional induction agents to induce labour, however, confidence intervals were wide (risk ratio (RR) 0.52, 95% confidence interval (CI) 0.27 to 0.99; 150 women; 2 trials). There were no clear differences between groups in uterine hyperstimulation (with or without fetal heart rate (FHR) changes) (RR 3.76, 95% CI 0.64 to 22.24; 244 women; 4 studies; low-quality evidence), caesarean section (RR 0.80, 95% CI 0.49 to 1.31; 288 women; 4 studies; low-quality evidence), or admission to a neonatal intensive care unit (NICU) (RR 0.32, 95% CI 0.10 to 1.03; 230 infants; 3 studies; low-quality evidence).There was no information on vaginal birth within 24, 48 or 72 hours, length of hospital stay, use of emergency services or maternal or caregiver satisfaction. Serious maternal and neonatal morbidity or deaths were not reported. 2. Intracervical PGE₂ versus expectant management or placebo (7 studies) There was no clear difference between women receiving intracervical PGE₂ and no treatment or placebo in terms of need for additional induction agents (RR 0.98, 95% CI 0.74 to 1.32; 445 women; 3 studies), vaginal birth not achieved within 48 to 72 hours (RR 0.83, 95% CI 0.68 to 1.02; 43 women; 1 study; low-quality evidence), uterine hyperstimulation (with FHR changes) (RR 2.66, 95% CI 0.63 to 11.25; 488 women; 4 studies; low-quality evidence), caesarean section (RR 0.90, 95% CI 0.72 to 1.12; 674 women; 7 studies; moderate-quality evidence), or babies admitted to NICU (RR 1.61, 95% CI 0.43 to 6.05; 215 infants; 3 studies; low-quality evidence). There were no uterine ruptures in either the PGE₂ group or placebo group.There was no information on vaginal birth not achieved within 24 hours, length of hospital stay, use of emergency services, mother or caregiver satisfaction, or serious morbidity or neonatal morbidity or perinatal death. 3. Vaginal misoprostol versus placebo (4 studies)One small study reported on the rate of perinatal death with no clear differences between groups; there were no deaths in the treatment group compared with one stillbirth (reason not reported) in the control group (RR 0.34, 95% CI 0.01 to 8.14; 77 infants; 1 study; low-quality evidence).There was no clear difference between groups in rates of uterine hyperstimulation with FHR changes (RR 1.97, 95% CI 0.43 to 9.00; 265 women; 3 studies; low-quality evidence), caesarean section (RR 0.94, 95% CI 0.61 to 1.46; 325 women; 4 studies; low-quality evidence), and babies admitted to NICU (RR 0.89, 95% CI 0.54 to 1.47; 325 infants; 4 studies; low-quality evidence).There was no information on vaginal birth not achieved within 24, 48 or 72 hours, additional induction agents required, length of hospital stay, use of emergency services, mother or caregiver satisfaction, serious maternal, and other neonatal, morbidity or death.No substantive differences were found for other comparisons. One small study found that women who received oral misoprostol were more likely to give birth within 24 hours (RR 0.65, 95% CI 0.48 to 0.86; 87 women; 1 study) and were less likely to require additional induction agents (RR 0.60, 95% CI 0.37 to 0.97; 127 women; 2 studies). Women who received mifepristone were also less likely to require additional induction agents (average RR 0.59, 95% CI 0.37 to 0.95; 311 women; 4 studies; I² = 74%); however, this result should be interpreted with caution due to high heterogeneity. One trial each of acupuncture and outpatient amniotomy were included, but few review outcomes were reported.

AUTHORS' CONCLUSIONS

Induction of labour in outpatient settings appears feasible and important adverse events seem rare, however, in general there is insufficient evidence to detect differences. There was no strong evidence that agents used to induce labour in outpatient settings had an impact (positive or negative) on maternal or neonatal health. There was some evidence that compared to placebo or no treatment, induction agents administered on an outpatient basis reduced the need for further interventions to induce labour, and shortened the interval from intervention to birth.We do not have sufficient evidence to know which induction methods are preferred by women, the interventions that are most effective and safe to use in outpatient settings, or their cost effectiveness. Further studies where various women-friendly outpatient protocols are compared head-to-head are required. As part of such work, women should be consulted on what sort of management they would prefer.

Methods of term labour induction for women with a previous caesarean section

BACKGROUND

Women with a prior caesarean delivery have an increased risk of uterine rupture and for women subsequently requiring induction of labour it is unclear which method is preferable to avoid adverse outcomes. This is an update of a review that was published in 2013.

OBJECTIVES

To assess the benefits and harms associated with different methods used to induce labour in women who have had a previous caesarean birth.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (31 August 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing any method of third trimester cervical ripening or labour induction, with placebo/no treatment or other methods in women with prior caesarean section requiring labour induction in a subsequent pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion and trial quality, extracted data, and checked them for accuracy.

MAIN RESULTS

Eight studies (data from 707 women and babies) are included in this updated review. Meta-analysis was not possible because studies compared different methods of labour induction. All included studies had at least one design limitation (i.e. lack of blinding, sample attrition, other bias, or reporting bias). One study stopped prematurely due to safety concerns. Vaginal PGE2 versus intravenous oxytocin (one trial, 42 women): no clear differences for caesarean section (risk ratio (RR) 0.67, 95% confidence interval (CI) 0.22 to 2.03, evidence graded low), serious neonatal morbidity or perinatal death (RR 3.00, 95% CI 0.13 to 69.70, evidence graded low), serious maternal morbidity or death (RR 3.00, 95% CI 0.13 to 69.70, evidence graded low). Also no clear differences between groups for the reported secondary outcomes. The GRADE outcomes vaginal delivery not achieved within 24 hours, and uterine hyperstimulation with fetal heart rate changes were not reported. Vaginal misoprostol versus intravenous oxytocin (one trial, 38 women): this trial stopped early because one woman who received misoprostol had a uterine rupture (RR 3.67, 95% CI 0.16 to 84.66) and one had uterine dehiscence. No other outcomes (including GRADE outcomes) were reported. Foley catheter versus intravenous oxytocin (one trial, subgroup of 53 women): no clear difference between groups for vaginal delivery not achieved within 24 hours (RR 1.47, 95% CI 0.89 to 2.44, evidence graded low), uterine hyperstimulation with fetal heart rate changes (RR 3.11, 95% CI 0.13 to 73.09, evidence graded low), and caesarean section (RR 0.93, 95% CI 0.45 to 1.92, evidence graded low). There were also no clear differences between groups for the reported secondary outcomes. The following GRADE outcomes were not reported: serious neonatal morbidity or perinatal death, and serious maternal morbidity or death. Double-balloon catheter versus vaginal PGE2 (one trial, subgroup of 26 women): no clear difference in caesarean section (RR 0.97, 95% CI 0.41 to 2.32, evidence graded very low). Vaginal delivery not achieved within 24 hours, uterine hyperstimulation with fetal heart rate changes, serious neonatal morbidity or perinatal death, and serious maternal morbidity or death were not reported. Oral mifepristone versus Foley catheter (one trial, 107 women): no primary/GRADE outcomes were reported. Fewer women induced with mifepristone required oxytocin augmentation (RR 0.54, 95% CI 0.38 to 0.76). There were slightly fewer cases of uterine rupture among women who received mifepristone, however this was not a clear difference between groups (RR 0.29, 95% CI 0.08 to 1.02). No other secondary outcomes were reported. Vaginal isosorbide mononitrate (IMN) versus Foley catheter (one trial, 80 women): fewer women induced with IMN achieved a vaginal delivery within 24 hours (RR 2.62, 95% CI 1.32 to 5.21, evidence graded low). There was no difference between groups in the number of women who had a caesarean section (RR 1.00, 95% CI 0.39 to 2.59, evidence graded very low). More women induced with IMN required oxytocin augmentation (RR 1.65, 95% CI 1.17 to 2.32). There were no clear differences in the other reported secondary outcomes. The following GRADE outcomes were not reported: uterine hyperstimulation with fetal heart rate changes, serious neonatal morbidity or perinatal death, and serious maternal morbidity or death. 80 mL versus 30 mL Foley catheter (one trial, 154 women): no clear difference between groups for the primary outcomes: vaginal delivery not achieved within 24 hours (RR 1.05, 95% CI 0.91 to 1.20, evidence graded moderate) and caesarean section (RR 1.05, 95% CI 0.89 to 1.24, evidence graded moderate). However, more women induced using a 30 mL Foley catheter required oxytocin augmentation (RR 0.81, 95% CI 0.66 to 0.98). There were no clear differences between groups for other secondary outcomes reported. Several GRADE outcomes were not reported: uterine hyperstimulation with fetal heart rate changes, serious neonatal morbidity or perinatal death, and serious maternal morbidity or death. Vaginal PGE2 pessary versus vaginal PGE2 tablet (one trial, 200 women): no difference between groups for caesarean section (RR 1.09, 95% CI 0.74 to 1.60, evidence graded very low), or any of the reported secondary outcomes. Several GRADE outcomes were not reported: vaginal delivery not achieved within 24 hours, uterine hyperstimulation with fetal heart rate changes, serious neonatal morbidity or perinatal death, and serious maternal morbidity or death.

AUTHORS' CONCLUSIONS

RCT evidence on methods of induction of labour for women with a prior caesarean section is inadequate, and studies are underpowered to detect clinically relevant differences for many outcomes. Several studies reported few of our prespecified outcomes and reporting of infant outcomes was especially scarce. The GRADE level for quality of evidence was moderate to very low, due to imprecision and study design limitations.High-quality, adequately-powered RCTs would be the best approach to determine the optimal method for induction of labour in women with a prior caesarean birth. However, such trials are unlikely to be undertaken due to the very large numbers needed to investigate the risk of infrequent but serious adverse outcomes (e.g. uterine rupture). Observational studies (cohort studies), including different methods of cervical ripening, may be the best alternative. Studies could compare methods believed to provide effective induction of labour with low risk of serious harm, and report the outcomes listed in this review.

Methods of term labour induction for women with a previous caesarean section

BACKGROUND

Induction of labour is a common obstetric intervention, with between 20% and 30% of births reported to occur following induction of labour. Women with a prior caesarean delivery have an increased risk of uterine rupture, particularly when labour is induced. For women who have had a previous caesarean birth and who require induction of labour in a subsequent pregnancy, it is unclear which method of cervical ripening and labour induction is preferable.

OBJECTIVES

To assess the benefits and harms associated with different methods used to induce labour in women who have had a previous caesarean birth and require induction of labour in a subsequent pregnancy.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 July 2012) and reference lists of retrieved studies.

SELECTION CRITERIA

All randomised controlled trials comparing any method of third trimester cervical ripening or labour induction, with placebo/no treatment or other methods in women with prior caesarean section requiring labour induction in a subsequent pregnancy were included.Methods of cervical ripening or labour induction could include: prostaglandin medication (including oral or vaginal prostaglandin E2 (PGE2) and misoprostol); mifepristone; mechanical methods (including Foley catheters and double balloon catheters); oxytocin, or placebo.

DATA COLLECTION AND ANALYSIS

The two review authors independently assessed studies for inclusion and trial quality. Any disagreement was resolved by discussion. Both review authors independently extracted data and data were checked for accuracy.

MAIN RESULTS

Two studies (involving a total of 80 women) were included. However, the two included studies used different methods and thus, meta-analysis was not appropriate. The two included studies compared 2.5 mg vaginal PGE2 inserts versus oxytocin (Taylor and colleagues) and misoprostol versus oxytocin (Wing and colleagues). Risk of bias in the included studies was judged 'low' and 'unclear' respectively.Vaginal PGE2 inserts versus oxytocin - Taylor and colleagues included 42 women, equally distributed over both groups. Baseline characteristics, and reasons for labour induction were comparable between the groups. There were no significant differences in any of the outcome measures reported (caesarean section, instrumental vaginal deliveries, epidural analgesia, Apgar score, perinatal death). One uterine rupture occurred in the prostaglandin group, after the use of prostaglandins and oxytocin, while no ruptures occurred in the oxytocin group (one study, 42 women; risk ratio (RR) 3.00, 95% confidence interval (CI) 0.13 to 69.70).Misoprostol versus oxytocin - the study conducted by Wing and colleagues was stopped prematurely due to safety concerns after the inclusion of 38 women. Seventeen women had been included in the misoprostol group, and 21 women in the oxytocin group. There were no significant difference in the only outcome measure reported by the authors, uterine rupture, which occurred twice in the misoprostol group, and did not occur in the oxytocin group (one study; 38 women; RR 6.11, 95% CI 0.31 to 119.33).

AUTHORS' CONCLUSIONS

There is insufficient information available from randomised controlled trials on which to base clinical decisions regarding the optimal method of induction of labour in women with a prior caesarean birth.

Different methods for the induction of labour in outpatient settings

BACKGROUND

Induction of labour is carried out for a variety of indications and using a range of pharmacological, mechanical and other methods. For women at low risk, some methods of induction of labour may be suitable for use in outpatient settings.

OBJECTIVES

To examine pharmacological and mechanical interventions to induce labour in outpatient settings in terms of feasibility, effectiveness, maternal satisfaction, healthcare costs and, where information is available, safety. The review complements existing reviews on labour induction examining effectiveness and safety.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (December 2009) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials examining outpatient cervical ripening or induction of labour with pharmacological agents or mechanical methods.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed eligible papers for risk of bias. We checked all data after entry into review manager software.

MAIN RESULTS

We included 28 studies with 2616 women examining different methods of induction of labour where women received treatment at home or were sent home after initial treatment and monitoring in hospital.Studies examined vaginal and intracervical PGE(2), vaginal and oral misoprostol, isosorbide mononitrate, mifepristone, oestrogens, and acupuncture. Overall, the results demonstrate that outpatient induction of labour is feasible and that important adverse events are rare. There was no strong evidence that agents used to induce labour in outpatient settings had an impact (positive or negative) on maternal or neonatal health. There was some evidence that, compared to placebo or no treatment, induction agents reduced the need for further interventions to induce labour, and shortened the interval from intervention to birth. We were unable to pool results on outcomes relating to progress in labour as studies tended to measure a very broad range of outcomes.There was no evidence that induction agents increased interventions in labour such as operative deliveries. Only two studies provided information on women's views about the induction process, and overall there was very little information on the costs to health service providers of different methods of labour induction in outpatient settings.

AUTHORS' CONCLUSIONS

Induction of labour in outpatient settings appears feasible. We do not have sufficient evidence to know which induction methods are preferred by women, or the interventions that are most effective and safe to use in outpatient settings.

Intracervical prostaglandins for induction of labour

BACKGROUND

Prostaglandins have been used for cervical ripening and induction of labour since the 1970s. The goal of the administration of prostaglandins in the process of induction of labour is to achieve cervical ripening before the onset of contractions. One of the routes of administration that was proposed is intracervical. Using this route, prostaglandins are less easy to administer and the need for exposing the cervix may cause discomfort to the woman.

OBJECTIVES

To determine the effects of intracervical prostaglandins for third trimester cervical ripening or induction of labour compared with placebo/no treatment and with vaginal prostaglandins (except misoprostol).

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (August 2007) and bibliographies of relevant papers.

SELECTION CRITERIA

Clinical trials comparing intracervical prostaglandins used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed above it on a predefined list of labour induction methods (vaginal prostaglandins, except misoprostol).

DATA COLLECTION AND ANALYSIS

A strategy was developed to deal with the large volume and complexity of trial data relating to labour induction. This involved a two-stage method of data extraction.

MAIN RESULTS

Fifty-six trials (7738 women) are included. INTRACERVICAL PGE2 WITH PLACEBO/NO TREATMENT: 28 TRIALS, 3764 WOMEN: Four studies reported the number of women who did not achieve vaginal delivery within 24 hours, showing a decreased risk with PGE2 (relative risk (RR) 0.61; 95% confidence interval (CI) 0.47 to 0.79). There was a small, and statistically non-significant, reduction of the risk of caesarean section when PGE2 was used (RR 0.88; 95% CI 0.77 to 1.00). The finding was statistically significant in a subgroup of women with intact membranes and unfavourable cervix only (RR 0.82; 95% CI 0.68 to 0.98). The risk of hyperstimulation with fetal heart rate (FHR) changes was not significantly increased (RR 1.21; 95% CI 0.72 to 2.05). However, the risk of hyperstimulation without FHR changes was significantly increased (RR 1.59; 95% CI 1.09 to 2.33. INTRACERVICAL PGE2 WITH INTRAVAGINAL PGE2: 29 TRIALS, 3881 WOMEN: The risk of not achieving vaginal delivery within 24 hours was increased with intracervical PGE2 (RR 1.26; 95% CI 1.12 to 1.41). There was no change in the risk of caesarean section (RR 1.07; 95% CI 0.93 to 1.22). The risks of hyperstimulation with FHR changes (RR 0.76; 95% CI 0.39 to 1.49) and without FHR changes (RR 0.80; 95% CI 0.56 to 1.15) were non-significantly different with the two methods of PGE2 administration. Only one trial with small sample size reported on women's views, with no difference between groups. INTRACERVICAL PGE2 LOW DOSE WITH INTRACERVICAL PGE2 HIGH DOSE: TWO TRIALS, 102 WOMEN: The trials are too small to provide any useful information.

AUTHORS' CONCLUSIONS

Intracervical prostaglandins are effective compared to placebo, but appear inferior when compared to intravaginal prostaglandins.

IMOP: randomised placebo controlled trial of outpatient cervical ripening with isosorbide mononitrate (IMN) prior to induction of labour - clinical trial with analyses of efficacy, cost effectiveness and acceptability

Background

There is increasing interest in carrying out pre-induction cervical ripening on an outpatient basis. However, there are concerns about the use of prostaglandins, the agents commonly used in hospital settings for this indication, because prostaglandins induce uterine contractions that may lead to fetal hypoxia. Indeed, in a recent study we demonstrated abnormalities in 9% of fetal heart rate tracings performed following prostaglandin induced cervical ripening at term. In contrast, we confirmed in the same study that isosorbide mononitrate (IMN) (administered on an inpatient basis) was both effective in inducing cervical ripening at term, and was associated with no associated fetal heart rate abnormalities.

Methods/design

The aim of this study is to determine whether IMN self administered by women on an outpatient basis improves the process of induction of labour. Specifically, we hypothesise that the use of outpatient IMN will result in a shorter inpatient stay before delivery, decreased costs to the health service and greater maternal satisfaction with ripening and induction of labour, compared with placebo treatment.

In the study described here (the "IMOP" study), women scheduled for induction of labour at term, and who require pre-induction cervical ripening will be randomised to self-administer at home either IMN 40 mg, or a placebo, each vaginally, at 48 hours, 32 hours and 16 hours before scheduled hospital admission.

After admission to hospital, treatment will revert to the usual induction of labour protocol. We will compare the primary outcomes of the elapsed time interval from hospital admission to vaginal delivery, the costs to the health service of induction of labour, and women's experience of induction of labour in the two groups.

Discussion

This trial will provide evidence on the efficacy of outpatient IMN for pre-induction cervical ripening at term. We will study a formulation of IMN which is cheap and widely available. If the treatment is effective, acceptable to women, and cost effective, it could be implemented into obstetric practice worldwide.

Trial registration

The trial has been registered on the International Standard Randomised Controlled Trial Number Register (ISRCTN) and given the registration number ISRTN39772441.