Sublingual compared with vaginal misoprostol for labour induction at term: a randomised controlled trial

Methods for the induction of labor: efficacy and safety

This review assessed the efficacy and safety of pharmacologic agents (prostaglandins, oxytocin, mifepristone, hyaluronidase, and nitric oxide donors) and mechanical methods (single- and double-balloon catheters, laminaria, membrane stripping, and amniotomy) and those generally considered under the rubric of complementary medicine (castor oil, nipple stimulation, sexual intercourse, herbal medicine, and acupuncture). A substantial body of published reports, including 2 large network meta-analyses, support the safety and efficacy of misoprostol (PGE1) when used for cervical ripening and labor induction. Misoprostol administered vaginally at doses of 50 μg has the highest probability of achieving vaginal delivery within 24 hours. Regardless of dosing, route, and schedule of administration, when used for cervical ripening and labor induction, prostaglandin E2 seems to have similar efficacy in decreasing cesarean delivery rates. Globally, although oxytocin represents the most widely used pharmacologic agent for labor induction, its effectiveness is highly dependent on parity and cervical status. Oxytocin is more effective than expectant management in inducing labor, and the efficacy of oxytocin is enhanced when combined with amniotomy. However, prostaglandins administered vaginally or intracervically are more effective in inducing labor than oxytocin. A single 200-mg oral tablet of mifepristone seems to represent the lowest effective dose for cervical ripening. The bulk of the literature assessing relaxin suggests this agent has limited benefit when used for this indication. Although intracervical injection of hyaluronidase may cause cervical ripening, the need for intracervical administration has limited the use of this agent. Concerning the vaginal administration of nitric oxide donors, including isosorbide mononitrate, isosorbide, nitroglycerin, and sodium nitroprusside, the higher incidence of side effects with these agents has limited their use. A synthetic hygroscopic cervical dilator has been found to be effective for preinduction cervical ripening. Although a pharmacologic agent may be administered after the use of the synthetic hygroscopic dilator, in an attempt to reduce the interval to vaginal delivery, concomitant use of mechanical and pharmacologic methods is being explored. Combining the use of a single-balloon catheter with dinoprostone, misoprostol, or oxytocin enhances the efficacy of these pharmacologic agents in cervical ripening and labor induction. The efficacy of single- and double-balloon catheters in cervical ripening and labor induction seems similar. To date, the combination of misoprostol with an intracervical catheter seems to be the best approach when balancing delivery times with safety. Although complementary methods are occasionally used by patients, given the lack of data documenting their efficacy and safety, these methods are rarely used in hospital settings.

Comparison of the Efficacy and Safety of Sublingual Versus Oral Misoprostol for the Induction of Labor: A Randomized Open-Label Study

Introduction Misoprostol (prostaglandin E1 analog) is being used for the induction of labor by vaginal, oral, and sublingual routes. Oral misoprostol is the preferred route for induction of labor, but the use of sublingual misoprostol appears promising due to a faster onset of action. This study was done to compare the efficacy and safety of oral and sublingual misoprostol for induction of labor in term pregnancy. Materials and methods One hundred and sixty patients were randomly allocated to one of the two groups to receive 50 micrograms of oral and sublingual misoprostol four hourly for a maximum of six doses. Primigravida at 37-42 weeks of gestation with singleton pregnancy, cephalic presentation, Bishop score (<5), and reassuring fetal heart rate were included in the study. Misoprostol dose was withheld if the active phase of labor was reached or if the cervix was favorable for amniotomy (Bishop score greater than or equal to eight). The change in the Bishop score with misoprostol was studied along with adverse effects and neonatal outcomes. Results The mean number of 50 mcg misoprostol doses required was significantly less in the sublingual group (2.94±0.97 versus 2.13±0.92; p<0.0001). The rate of change of the mean Bishop score was faster in the sublingual group. After four hours of the first dose, the mean Bishop score changed to 3.52±2.14 versus 4.68±2.34 (p=0.001), and, similarly, after eight hours, it was 10.48±2.59 versus 11.39±2.06, and this difference was statistically significant (p=0.015). The mean induction delivery interval was significantly lower in the sublingual group. The need for labor augmentation, mode of delivery, and adverse effects were similar in both groups. The incidence of meconium-stained liquor and NICU admission was also similar in both groups. Conclusion Sublingmisoprostolstol has a short induction delivery interval and comparable side effects when compared to omisoprostolstol. Sublingmisoprostolstol is recommended for induction of labor at term.

Efficacy and safety of oral and sublingual versus vaginal misoprostol for induction of labour: a systematic review and meta-analysis

Objective

Misoprostol is a synthetic PGE1 analogue that is used for induction of labour. Current guidelines support the use of doses that do not exceed 25 mcg in order to limit maternal and neonatal adverse outcomes. The present meta-analysis investigates the efficacy and safety of oral compared to vaginally inserted misoprostol in terms of induction of labor and adverse peripartum outcomes.

Methods

We searched Medline, Scopus, the Cochrane Central Register of Controlled Trials CENTRAL, Google Scholar, and Clinicaltrials.gov databases from inception till April 2022. Randomized controlled trials that assessed the efficacy of oral misoprostol (per os or sublingual) compared to vaginally inserted misoprostol. Effect sizes were calculated in R. Sensitivity analysis was performed to evaluate the possibility of small study effects, p-hacking. Meta-regression and subgroup analysis according to the dose of misoprostol was also investigated. The methodological quality of the included studies was assessed by two independent reviewers using the risk of bias 2 tool. Quality of evidence for primary outcomes was evaluated under the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework, ranging from very low to high.

Results

Overall, 57 studies were included that involved 10,975 parturient. Their risk of bias ranged between low-moderate. There were no differences among the routes of intake in terms of successful vaginal delivery within 24 h (RR 0.90, 95% CI 0.80) and cesarean section rates (RR 0.92, 95% CI 0.82, 1.04). Sublingual misoprostol was superior compared to vaginal misoprostol in reducing the interval from induction to delivery (MD – 1.11 h, 95% CI – 2.06, – 0.17). On the other hand, per os misoprostol was inferior compared to vaginal misoprostol in terms of this outcome (MD 3.45 h, 95% CI 1.85, 5.06). Maternal and neonatal morbidity was not affected by the route or dose of misoprostol.

Conclusion

The findings of our study suggest that oral misoprostol intake is equally safe to vaginal misoprostol in terms of inducing labor at term. Sublingual intake seems to outperform the per os and vaginal routes without increasing the accompanying morbidity. Increasing the dose of misoprostol does not seem to increase its efficacy.

Clinical trial registration

Open Science Framework (https://doi.org/10.17605/OSF.IO/V9JHF).

Misoprostol administered sublingually at a dose of 12.5 μg versus vaginally at a dose of 25 μg for the induction of full-term labor: a randomized controlled trial

Background

Labor induction is defined as any procedure that stimulates uterine contractions before labor begins spontaneously. The vaginal and oral routes of administration of misoprostol are those most used for the induction of labor in routine practice, with the recommended dose being 25 μg. Nevertheless, the sublingual route may reduce the number of vaginal examinations required, increasing patient comfort and lowering the risk of maternal and fetal infection. Based on a previous systematic review, the objective of this study was to compare the frequency of tachysystole as the main outcome measure when misoprostol is administered sublingually at the dose of 12.5 μg versus vaginally at a dose of 25 μg to induce labor in a full-term pregnancy with a live fetus.

Methods

A randomized, placebo-controlled, triple-blind clinical trial was conducted at two maternity hospitals in northeastern Brazil. Two hundred patients with a full-term pregnancy, a live fetus, Bishop score ≤ 6 and an indication for induction of labor were included. Following randomization, one group received 12.5 μg misoprostol sublingually and a vaginal placebo, while the other group received a sublingual placebo and 25 μg misoprostol vaginally. The primary outcome was the frequency of tachysystole. Student’s t-test, the chi-square test of association and Fisher’s exact test were used, as appropriate. Risk ratios and their 95% confidence intervals were calculated.

Results

The frequency of tachysystole was lower in the group using 12.5 μg misoprostol sublingually compared to the group using 25 μg misoprostol vaginally (RR = 0.15; 95%CI: 0.02–0.97; p = 0.002). Failure to achieve vaginal delivery within 12 and 24 h was similar in both groups. Sublingual administration was preferred to vaginal administration by women in both groups; however, the difference was not statistically significant.

Conclusion

The effectiveness of labor induction with low-dose sublingual misoprostol was similar to that achieved with vaginal administration of the recommended dose; however, the rate of tachysystole was lower in the sublingual group, and this route of administration may prove a safe alternative.

Trial registration

Registration number: NCT01406392, ClinicalTrials.gov. Date of registration: August 1, 2011.

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.

Comparison of the efficacy and safety of sublingual misoprostol with that of vaginal misoprostol for labour induction at term

OBJECTIVE

To compare the efficacy and safety of 50 mcg of sublingual misoprostol with 25 mcg of vaginal misoprostol for induction of labour at term.

METHOD

Non blinded randomized prospective control study. 200 women with singleton term pregnancy, admitted for induction of labour, were randomized to receive either 25 mcg of vaginal misoprostol or 50 mcg of sublingual misoprostol. Outcome measures compared were the number of vaginal deliveries, induction-delivery interval, caesarean section for foetal distress, oxytocin for acceleration, number of doses required, side effects and neonatal outcome.

RESULT

Mean dose was smaller and induction to delivery interval was significantly shorter in the sublingual group (13.1 ± 4.1 h) compared with the vaginal group (17.9 ± 5.4 h), p value 0.001. There were no statistically significant differences in the other secondary outcome measures.

CONCLUSION

50 mcg of sublingual misoprostol was more effective than and as safe as 25 mcg vaginal misoprostol for labour induction at term.

Induction of labour

OBJECTIVE

To review the most current literature in order to provide evidence-based recommendations to obstetrical care providers on induction of labour.

OPTIONS

Intervention in a pregnancy with induction of labour.

OUTCOMES

Appropriate timing and method of induction, appropriate mode of delivery, and optimal maternal and perinatal outcomes.

EVIDENCE

Published literature was retrieved through searches of PubMed, CINAHL, and The Cochrane Library in 2010 using appropriate controlled vocabulary (e.g., labour, induced, labour induction, cervical ripening) and key words (e.g., induce, induction, augmentation). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to the end of 2010. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The evidence in this document was rated using criteria described in the Report of the Canadian Task Force on Preventative Health Care (Table 1). SUMMARY STATEMENTS: 1. Prostaglandins E(2) (cervical and vaginal) are effective agents of cervical ripening and induction of labour for an unfavourable cervix. (I) 2. Intravaginal prostaglandins E(2) are preferred to intracervical prostaglandins E(2) because they results in more timely vaginal deliveries. (I).

A randomised controlled trial of intravaginal dinoprostone, intravaginal misoprostol and transcervical balloon catheter for labour induction

OBJECTIVE

To compare the efficacy and safety of induction of labour by vaginal application of dinoprostone or misoprostol or transcervical insertion of a balloon (Bard) catheter.

DESIGN

A non-blinded, randomised, controlled trial.

SETTING

A tertiary level Swedish hospital.

POPULATION

A total of 592 women who had undergone full-term pregnancies, not previously been subjected to a caesarean section, and required induction of labour for common, routine indications.

METHODS

Women were randomly assigned to induction of labour using intravaginal dinoprostone (2 mg once every 6 hours) or misoprostol (25 micrograms once every 4 hours) or a transcervical balloon catheter.

MAIN OUTCOME MEASURES

The time interval between induction to delivery in general and vaginal delivery in particular, the mode of delivery, maternal and neonatal parameters of outcome.

RESULTS

Of the 588 subjects included in the final intention-to-treat analysis, 191 were assigned to treatment with dinoprostone, 199 with misoprostol and 198 with the balloon catheter. The shortest mean induction-to-delivery interval was obtained with the catheter (12.9 hours versus 16.8 and 17.3 hours for dinoprostone and misoprostol, respectively). The efficacies of the two prostaglandins were similar. The maternal and neonatal outcomes associated with each of the three procedures were similar.

CONCLUSIONS

Induction of labour with a transcervical balloon catheter is effective and safe and can be recommended as the first choice. The two prostaglandins, dinoprostone and misoprostol, were shown to be equally effective and safe, while misoprostol costs significantly less and is easier to store.

A randomised comparison of patient satisfaction with vaginal and sublingual misoprostol for induction of labour at term*

OBJECTIVE

To compare patient satisfaction with two routes of misoprostol for term labour induction.

DESIGN

Prospective randomised trial.

SETTING

Tertiary care hospital.

POPULATION

A total of 170 women admitted at > or = 37 weeks of gestation for induction of labour.

METHODS

Women were randomised to receive 50 micrograms of either sublingual or vaginal misoprostol.

MAIN OUTCOME MEASURES

Patient satisfaction with the route of administration.

RESULTS

Despite a similar proportion reporting the labour induction as more painful than expected in both groups, a significantly lower proportion mentioned that the pelvic examinations were very painful in the sublingual group (19.7 versus 36.1%, relative risk [RR] 0.5, 95% CI 0.3-0.9). Request for analgesia was similar in both groups. More women in the sublingual group thought that the labour experience was better than expected (RR 2.0, 95% CI 1.2-3.3), had a positive attitude towards induction in subsequent pregnancies (RR 1.6, 95% CI 1.1-2.3) and preferred the same route in subsequent pregnancies (RR 3.1, 95% CI 2.2-4.5). Mean number of misoprostol doses, oxytocin augmentation, tachysystole and hyperstimulation, induction to vaginal delivery interval, vaginal delivery after a single dose, vaginal birth within 12 and 24 hours, and caesarean delivery rates were similar in both groups.

CONCLUSION

Sublingual misoprostol (50 micrograms) is associated with a significantly higher patient satisfaction rate compared with a similar dose of vaginal misoprostol. Sublingual administration offers additional choice to women, in particular those wishing to avoid vaginal administration.

Buccal or sublingual misoprostol for cervical ripening and induction of labour

BACKGROUND

This is one of a series of reviews of cervical ripening and labour induction using standardised methodology. Misoprostol administered by the oral and sublingual routes have the advantage of rapid onset of action, while the sublingual and vaginal routes have the advantage of prolonged activity and greatest bioavailability.

OBJECTIVES

To determine the effectiveness and safety of misoprostol administered buccally or sublingually for third trimester cervical ripening and induction of labour.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register (8 December 2003), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 4, 2003), and bibliographies of relevant papers.

SELECTION CRITERIA

Randomised controlled trials comparing buccal or sublingual misoprostol 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.

DATA COLLECTION AND ANALYSIS

A generic strategy was developed to deal with the large volume and complexity of trial data relating to labour induction. Data were extracted onto standardized forms, checked for accuracy, and analysed using RevMan software.

MAIN RESULTS

Three studies (502 participants) compared buccal/sublingual misoprostol respectively with a vaginal regimen (200 microg versus 50 microg) and with oral administration (50 versus 50 microg and 50 versus 100microg).The buccal route was associated with a trend to fewer caesarean sections than with the vaginal route (18/73 versus 28/79; relative risk (RR) 0.70; 95% confidence interval (CI) 0.42 to 1.15). There were no significant differences in any other outcomes. When the same dosage was used sublingually versus orally, the sublingual route was associated with less failures to achieve vaginal delivery within 24 hours (12/50 versus 19/50; RR 0.63, 95% CI 0.34 to 1.16), reduced oxytocin augmentation (17/50 versus 23/50; RR 0.74, 95% CI 0.45 to 1.21) and reduced caesarean section (8/50 versus 15/50; RR 0.53, 95% CI 0.25 to 1.14), but the differences were not statistically significant. When a smaller dose was used sublingually than orally, there were no differences in any of the outcomes.

REVIEWERS' CONCLUSIONS

Based on only three small trials, sublingual misoprostol appears to be at least as effective as when the same dose is administered orally. There are inadequate data to comment on the relative complications and side-effects. Sublingual or buccal misoprostol should not enter clinical use until its safety and optimal dosage have been established by larger trials.