Comparison of sublingual versus vaginal misoprostol for the induction of labour: a systematic review

Directive clinique no 432c : Déclenchement artificiel du travail

OBJECTIFS

Présenter des données probantes et des recommandations sur la maturation cervicale et le déclenchement artificiel du travail. Fournir de l'information aux professionnels accoucheurs et aux personnes enceintes sur les soins périnataux optimaux et la prévention des interventions obstétricales inutiles.

POPULATION CIBLE

Toutes les patientes enceintes. BéNéFICES, RISQUES ET COûTS: La mise en application interprofessionnelle et cohérente de la présente directive, l'équipement adéquat et le personnel compétent améliorent la sécurité des soins per partum. Les personnes enceintes et leurs personnes de soutien doivent être informées des risques et bénéfices du déclenchement artificiel du travail. DONNéES PROBANTES: La littérature publiée jusqu'en mars 2022 a été passée en revue. Une recherche a été effectuée dans les bases de données PubMed, CINAHL et Cochrane Library pour répertorier des revues systématiques, des essais cliniques randomisés et des études observationnelles sur la maturation cervicale et le déclenchement artificiel du travail. La littérature grise (non publiée) a été obtenue à l'aide de recherches menées dans des sites Web d'organismes s'intéressant à l'évaluation des technologies dans le domaine de la santé et d'organismes connexes, dans des collections de directives cliniques, des registres d'essais cliniques et des sites Web de sociétés de spécialité médicale nationales et internationales. MéTHODES DE VALIDATION: Les auteurs ont évalué la qualité des données probantes et la force des recommandations en utilisant le cadre méthodologique GRADE (Grading of Recommendations, Assessment, Development, and Evaluation). Voir l'annexe A en ligne (tableau A1 pour les définitions et tableau A2 pour l'interprétation des recommandations fortes et conditionnelles [faibles]). PROFESSIONNELS CONCERNéS: Tous les fournisseurs de soins obstétricaux. DÉCLARATIONS SOMMAIRESMISOPROSTOL: OCYTOCINE: RECOMMANDATIONS.

Guideline No. 432c: Induction of Labour

OBJECTIVES

This guideline presents evidence and recommendations for cervical ripening and induction of labour. It aims to provide information to birth attendants and pregnant individuals on optimal perinatal care while avoiding unnecessary obstetrical intervention.

TARGET POPULATION

All pregnant patients.

BENEFITS, RISKS, AND COSTS

Consistent interprofessional use of the guideline, appropriate equipment, and trained professional staff enhance safe intrapartum care. Pregnant individuals and their support person(s) should be informed of the benefits and risks of induction of labour.

EVIDENCE

Literature published to March 2022 was reviewed. PubMed, CINAHL, and the Cochrane Library were used to search for systematic reviews, randomized control trials, and observational studies on cervical ripening and induction labour. Grey (unpublished) literature was identified by 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.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and conditional [weak] recommendations).

INTENDED AUDIENCE

All providers of obstetrical care.

SUMMARY STATEMENTS

Misoprostol OXYTOCIN: RECOMMENDATIONS.

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).

Sublingual misoprostol vs. oral misoprostol solution for induction of labor: A retrospective study

Introduction

Induction of labor (IOL) is one of the most common obstetrical procedures, with an increasing rate. The prostaglandin E1 analogue misoprostol is frequently used as a primary method of labor induction. The optimal dose and route of administration is yet to be ascertained.

Aim

To compare efficiacy and safety between a regimen of sublingually administered misoprostol and a regimen of orally administered misoprostol, with cesarean delivery as primary outcome.

Methods

A retrospective study was conducted including women carrying a live, singleton fetus in a cephalic position with labor induced at >37 + 0 gestational weeks at Skåne University hospital, Lund, between January 1st 2013 to December 31st 2017. Data was obtained from computerized obstetrical charts.

Results

Totally 2,404 women were included; 974 induced with sublingual misoprostol and 1,430 with oral solution. In primiparous women the cesarean delivery rate was lower in primiparous women induced with oral compared to sublingual misoprostol (20.5% vs. 28.6%, p < 0.001), whereas in parous women the rates did not differ significantly 4.9% vs. 7.5%; NS). The increased risk of caesarean remained after controlling for potential confounding factors (adjusted odds ratio 1.49 (1.14–1.95). Women induced with sublingual misoprostol had a shorter time to vaginal delivery when compared to oral solution (primiparous median 16.7 h vs. 21.7 h; p < 0.001, parous median 9.9 h vs. 13.3 h; p = 0.01), and a higher rate of vaginal delivery within 24 h (primiparas 77.7% vs. 63.3%, p < 0.001, parous 93.2% vs. 84.2%; p = 0.01).

Conclusion

IOL with oral misoprostol solution was associated with a significantly higher vaginal delivery rate when compared to sublingual misoprostol, whereas sublingual misoprostol was associated with a significantly shorter time from induction to vaginal delivery. Oral administration is considered the most safe and efficient administration of misoprostol, although more studies are needed to find the optimal route and dosage of misoprostol for IOL.

Labour Induction with Misoprostol in German Obstetric Clinics: What Are the Facts on Such Use?

Subject While the synthetic prostaglandin E1 analogue misoprostol is the most effect labour induction agent, its use is off-label for the most part. For this reason, and in view of its potential adverse effects and varying approaches to its administration, the drug has recently once again become a focus of critical attention. The objective of this survey was thus to establish a record of labour induction with misoprostol in German clinics and determine the impact of the negative reporting on everyday obstetric practice. Material and Methods In this cross-sectional study, 635 obstetrics and gynaecology departments in Germany were requested by email to participate in our survey in February/March 2020. Online responses to 19 questions were requested regarding the clinic, use of misoprostol before and after the critical reporting, use of misoprostol (sourcing, method of administration, dosage, monitoring) and other labour induction methods. Results A total of 262 (41.3%) of the clinics solicited for the survey completed the questionnaire. There were no differences regarding the care level (Perinatal Centre Level I, Perinatal Centre Level II, Clinic with Perinatal Focus or Obstetric/Private Clinic; p = 0.2104) or birth counts (p = 0.1845). In most cases, misoprostol was prepared in the clinic's own pharmacy (54%) or imported from another country (46%) and administered orally in tablet form (95%). Misoprostol dosage levels varied (25 µg [48%], 50 µg [83%], 75 µg [6%], 100 µg [47%] and > 100 µg [5%]). Most of the clinics used premanufactured tablets/capsules (59%), although Cytotec tablets were also divided (35%) or dissolved in water (5%). Misoprostol administration intervals were mainly every 4 hours (64%) or every 6 hours (30%). CTG checks were run in most cases before and after administration of a dose of misoprostol (78% and 76%) and before and after administration of a dose of prostaglandin E2 (both 88%). Presence of contractions led to no misoprostol (59%) or no prostaglandin E2 (64%) being administered in most cases. The critical reporting resulted in discontinuation of use of misoprostol in 17% of the clinics - mainly smaller obstetric/private clinics with fewer than 1000 births. Labour cocktails were used mainly in obstetric and private clinics (61%). Conclusion Misoprostol is an established agent for labour induction in German clinics. The dosing schemes used vary. Improvements of currently common management practices are required, especially in the area of labour induction (CTG checks before and after administration of labour-inducing medication, no administration of prostaglandin if contractions are ongoing). The discussion of use of misoprostol in the media resulted in stoppage of its use mainly in smaller clinics.

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.

Induction of labour in nulliparous women- quick or slow: a cohort study comparing slow-release vaginal insert with low-dose misoprostol oral tablets

Background

This study was undertaken with the objective of comparing efficacy and safety for two different regimens using misoprostol for induction of labour.

Methods

The study was set in two different hospitals in the region of Zeeland, Denmark, and designed as a prospective cohort study. Nulliparous women with unripe cervix, eligible for vaginal delivery and medical induction of labour were included. Exclusion criteria were a previous uterine scar, suspicion of growth restriction of the fetus and prelabour rupture of membranes.

One department used 25 mcg oral misoprostol tablets and the other department used 200 mcg slow-release misoprostol vaginal insert, for induction of labour.

Primary outcomes were predefined as frequency of cesarean section, tachysystole and delivery within 24 h. Secondary outcomes were: time from induction to delivery, use of additional methods for induction, postpartum hemorrhage, anal sphincter rupture, epidural, pyrexia (rectal temperature >  38.5 °C), prolonged rupture of membranes, and use of tocolysis.

Results

No significant differences in women achieving vaginal delivery was found. However, a significantly increased risk of tachysystole for the vaginal administration route was observed; 28.4% compared with 2.3%. There were no events of serious neonatal asphyxia. Half of the women induced with vaginal insert delivered within 24 h, compared with 16.8% of the women induced with oral misoprostol.

Conclusions

Induction with vaginal slow-release misoprostol leads to quicker delivery with an increased risk of tachysystole but with similar perinatal outcomes and rates of cesarean sections. Low-dose oral misoprostol appears to be safe, however it leads to an increased use of secondary methods and a tendency of more intrapartum pyrexia.

Trial registration

Clinicaltrials.gov ID: NCT02693587 on February 262,016.

EudraCT number 2020–000366-42 on 23 January 2020, retrospectively registered.

A comparison of vaginal versus buccal misoprostol for cervical ripening in women for labor induction at term (the IMPROVE trial): a triple-masked randomized controlled trial

BACKGROUND

Cervical ripening is commonly needed for labor induction. Finding an optimal route of misoprostol dosing for efficacy, safety, and patient satisfaction is important and not well studied for the buccal route.

OBJECTIVE

To compare the efficacy and safety of vaginal and buccal misoprostol for women undergoing labor induction at term.

STUDY DESIGN

The IMPROVE trial was an institutional review board-approved, triple-masked, placebo-controlled randomized noninferiority trial for women undergoing labor induction at term with a Bishop score ≤6. Enrolled women received 25 mcg (first dose), then 50 mcg (subsequent doses) of misoprostol by assigned route (vaginal or buccal) and a matching placebo tablet by the opposite route. The primary outcomes were time to delivery and the rate of cesarean delivery performed urgently for fetal nonreassurance. A sample size of 300 was planned to test the noninferiority hypothesis.

RESULTS

The trial enrolled 319 women, with 300 available for analysis, 152 in the vaginal misoprostol group and 148 in the buccal. Groups had similar baseline characteristics. We were unable to demonstrate noninferiority. The time to vaginal delivery was lower for the vaginal misoprostol group (median [95% confidence interval] in hours: vaginal: 20.1 [18.2, 22.8] vs buccal: 28.1 [24.1, 31.4], log-rank test P = .006, P_{noninferiority} = .663). The rate of cesarean deliveries for nonreassuring fetal status was 3.3% for the vaginal misoprostol group and 9.5% for the buccal misoprostol group (P = .033). The rate of vaginal delivery in <24 hours was higher in the vaginal group (58.6% vs 39.2%, P = .001).

CONCLUSION

We were unable to demonstrate noninferiority. In leading to a higher rate of vaginal deliveries, more rapid vaginal delivery, and fewer cesareans for fetal issues, vaginal misoprostol may be superior to buccal misoprostol for cervical ripening at term.

Buccal versus Vaginal Misoprostol for Term Induction of Labor: A Retrospective Cohort Study

OBJECTIVE

To compare the efficacy of similar buccal and vaginal misoprostol doses for induction of labor.

STUDY DESIGN

Retrospective chart review of 207 consecutive women undergoing term induction of labor with misoprostol. Misoprostol route and dosing were collected. Time to delivery and other labor outcomes (e.g., vaginal delivery less than 24 hours) were compared between women receiving buccal and vaginal misoprostol.

RESULTS

There was no significant difference in time to delivery for women receiving buccal (median 18.2 hour, 95% confidence interval [CI] = [14.9, 21.5]) versus vaginal (median 18.3 hour, 95% CI = [15.0, 20.4]) misoprostol (p = 0.428); even after adjusting for covariates (p = 0.381). Women who presented with premature rupture of membranes were more likely to receive buccal misoprostol (92.7% received buccal vs. 7.3% received vaginal, p < 0.001). A similar number of women delivered vaginally in the buccal group (88.2%) and vaginal misoprostol group (86.8%, p = 0.835). The proportion of women who experienced uterine tachysystole or chorioamnionitis did not significantly differ by route of administration.

CONCLUSION

We found no significant differences in time to delivery or other labor outcomes between buccal or vaginal dosing of misoprostol in women undergoing labor induction at term.

Labor Induction Techniques: Which Is the Best?

Induction of labor is a common procedure undertaken whenever the benefits of prompt delivery outweigh the risks of expectant management. Cervical assessment is essential to determine the optimal approach. Indication for induction, clinical presentation and history, safety, cost, and patient preference may factor into the selection of methods. For the unfavorable cervix, several pharmacologic and mechanical methods are available, each with associated advantages and disadvantages. In women with a favorable cervix, combined use of amniotomy and intravenous oxytocin is generally the most effective approach. The goal of labor induction is to ensure the best possible outcome for mother and newborn.

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 protocol

Background

Various methods are currently used for the induction of labor. Nevertheless, the most effective method with the fewest side effects remains to be established. Misoprostol, administered vaginally, has been routinely used for this purpose; however, other forms of administration are being proposed, including the use of sublingual tablets. No studies have yet compared the effectiveness and safety of 12.5-μg misoprostol administered sublingually compared to a 25-μg vaginal dose of the drug for the induction of labor.

Methods

A triple-blind, multicenter, placebo-controlled, randomized clinical trial will be conducted in Brazil at the Instituto de Medicina Integral Prof. Fernando Figueira and at the Assis Chateaubriand Maternity Teaching Hospital of the Federal University of Ceará. A total of 140 patients with full-term pregnancies, a live fetus, a Bishop score ≤ 6 and a recommendation of induction of labor will be randomized to one of two groups. One group will receive 12.5-μg sublingual tablets of misoprostol and placebo vaginal tablets, while the other group will receive placebo sublingual tablets and vaginal tablets containing 25 μg of misoprostol. The principal endpoint is the rate of tachysystole. The secondary endpoints are vaginal delivery within 24 h of induction, uterine hyperstimulation, Cesarean section, severe neonatal morbidity or perinatal death, severe maternal morbidity or maternal death, and maternal preference regarding the route of administration of the drug. Student’s t-test, and the chi-square test of association or Fisher’s exact test, as appropriate, will be used in the data analysis. Risk ratios and their respective 95% confidence intervals will be calculated.

Discussion

Misoprostol has been identified as a safe, inexpensive, easily administered option for the induction of labor, with satisfactory results. An experimental study has shown that misoprostol administered sublingually at a dose of 25 μg appears to be effective and is associated with greater maternal satisfaction when labor is induced in women with an unfavorable cervix. Nevertheless, the rate of tachysystole remains high; therefore, further studies are required to determine the ideal dose and the ideal interval of time between doses.

Trial registration

ClinicalTrial.gov, NCT01406392.

Survey of Provider Preferences Regarding the Route of Misoprostol for Induction of Labor at Term

Objective  To survey obstetrical provider preferences regarding use of misoprostol for induction of labor (IOL). Methods  An anonymous 25-question survey was distributed at an American College of Obstetricians and Gynecologists (ACOG) joint District V and VII Meeting in 2014 to obstetrics providers. The same survey was sent electronically to local providers. A separate survey was emailed to the labor and delivery nurses at two of the teaching hospitals in Indianapolis. The surveys queried provider demographics, dosing practice for misoprostol, opinions regarding different dosing strategies, and instructions on buccal administration. Results  A total of 113 (46.5%) providers responded. Of these, 92.9% used misoprostol for IOL, 73% preferred the vaginal route, 20% preferred buccal administration, and 7% oral administration. Only resident physician and midwife providers endorsed buccal route preference. Being a midwife independently predicted a preference for using buccal misoprostol (odds ratio [OR]: 125.8, 95% confidence interval [CI]: 7.9-1992.3). Additionally, 44 nurses completed the survey regarding administration techniques of buccal misoprostol. Also, 54.5% of nurses correctly instructed their patients on buccal administration techniques. Conclusion  Although not extensively studied, one-fifth of providers, particularly nurse midwives, prefer buccal administration of misoprostol for IOL. The majority of nurses correctly administered buccal misoprostol. There may be a need for further study and education about buccal administration of misoprostol for IOL.

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.

Sublingual versus Vaginal Misoprostol for the Induction of Labor at Term: A Randomized, Triple-Blind, Placebo-Controlled Clinical Trial

BACKGROUND

We sought to compare the effectiveness and safety of sublingual versus vaginal misoprostol for the termination of pregnancy with a live full-term fetus.

METHODS

This randomized, triple-blind, placebo-controlled clinical trial was performed on 200 primiparous women with normal, singleton, full-term pregnancies candidated for the induction of labor. Sublingual and vaginal tablets containing misoprostol (25 mcg) or placebo in similar shapes were administered every 4 hours until the Bishop score reached above 8. Maternal and neonatal complications and outcomes were compared.

RESULTS

There were 100 parturient women in each group. The mean maternal age, gestational age, and Bishop score at the commencement of misoprostol had no statistical differences between the sublingual and vaginal groups. The mean time interval between misoprostol commencement and delivery was 497.10±291.49 and 511.67±08.46 minutes for the sublingual and vaginal groups, correspondingly. Twenty-two women had Cesarean deliveries in the sublingual group versus 14 in the vaginal group. Meconium-stained amniotic fluid was seen in 12 women in the sublingual group and 4 in the vaginal group (P=0.03). Late fetal heart rate deceleration was observed in 8 women in the sublingual group and 4 in the vaginal group (P=0.22). The mean neonatal birth weight, blood gas value at birth, Apgar score, and length of admission time in the neonatal intensive care unit were not different between the 2 groups.

CONCLUSION

Sublingual and vaginal misoprostol had similar effectiveness; however, meconium-stained liquor was observed considerably more frequently with sublingual misoprostol than with vaginal misoprostol.

TRIAL REGISTRATION NUMBER

IRCT201402096541N3.

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).

The pharmacology of prostaglandins for induction of labor

Prostaglandin medications are frequently used in the process of induction of labor. Understanding the history and research that supports prostaglandin use for induction of labor is crucial for safe practice. Dinoprostone has been the standard of care for cervical ripening in term pregnancies. Misoprostol administration via various routes has been shown to be efficacious. Oral misoprostol in particular is effective and associated with reassuring maternal and fetal outcomes. In addition, cost has become a variable in decision making regarding best practice. More research is necessary to determine the safest medication, route, dose, and interval of administration. This article reviews cervical physiology and endogenous prostaglandin activity in relation to labor, and the pharmacologic profiles of synthetic prostaglandins currently used for induction of labor.

Titrated oral misoprostol solution versus vaginal misoprostol for labor induction

OBJECTIVE

To determine the efficacy and safety of a titrated oral misoprostol solution compared with vaginal misoprostol tablets for labor induction.

METHODS

A randomized, triple-blind, multicenter clinical trial was conducted between March 2010 and June 2011. Women with a single gestation (n=200) were randomized to receive a titrated oral misoprostol solution (initial misoprostol dose 20 μg/hour; dose increased by 20 μg/hour every 6 hours up to 80 μg/hour for a maximum of 48 doses) or vaginal misoprostol tablets (25 μg of misoprostol every 6 hours for a maximum of 8 doses). Risk ratios (RR) and 95% confidence intervals (CIs) were calculated for maternal and perinatal outcomes.

RESULTS

The frequencies of vaginal delivery not achieved within 12 hours (RR 0.87; 95% CI, 0.62-1.22) and within 24 hours (RR 1.11; 95% CI, 0.83-1.49) were similar in the 2 groups. No differences were found in terms of uterine hyperstimulation, unfavorable cervix at 12 and 24 hours, oxytocin augmentation, tachysystole, epidural analgesia, adverse effects, and perinatal outcome. Approximately 70% of the women preferred the oral solution.

CONCLUSION

A titrated oral misoprostol solution was as effective and safe for labor induction as vaginal misoprostol tablets. ClinicalTrial.gov: NCT00 992524.

Current pharmacotherapy options for labor induction

INTRODUCTION

Labor induction is now reported to occur in up to 30 - 40% of obstetrical patients. There are a number of pharmacological options available to facilitate labor induction, including oxytocin and analogues of prostaglandins E1 and E2, which have particular utility when labor induction necessitates cervical ripening, as when labor induction occurs in the context of an unfavorable cervix.

AREAS COVERED

This paper reviews acceptable pharmacological options for labor induction, especially when cervical ripening is required. These options include oxytocin and a number of prostaglandin formulations using dinoprostone and misoprostol. It also covers several analyses of published clinical trials (Phase-III) describing evidence of effectiveness.

EXPERT OPINION

Oxytocin is best used when labor needs to be induced in the context of a favorable cervix. When the cervix is not favorable, cervical ripening using prostaglandins should precede labor induction. Either dinoprostone or misoprostol are superior to oxytocin alone for cervical ripening. However, judicious, careful considerations need to be made at the outset of labor induction so as to balance maternal and fetal risks, and these should be guided by institutional policies that reflect the evidence-base.

Methods of induction of labour: a systematic review

BACKGROUND

Rates of labour induction are increasing. We conducted this systematic review to assess the evidence supporting use of each method of labour induction.

METHODS

We listed methods of labour induction then reviewed the evidence supporting each. We searched MEDLINE and the Cochrane Library between 1980 and November 2010 using multiple terms and combinations, including labor, induced/or induction of labor, prostaglandin or prostaglandins, misoprostol, Cytotec, 16,16,-dimethylprostaglandin E2 or E2, dinoprostone; Prepidil, Cervidil, Dinoprost, Carboprost or hemabate; prostin, oxytocin, misoprostol, membrane sweeping or membrane stripping, amniotomy, balloon catheter or Foley catheter, hygroscopic dilators, laminaria, dilapan, saline injection, nipple stimulation, intercourse, acupuncture, castor oil, herbs. We performed a best evidence review of the literature supporting each method. We identified 2048 abstracts and reviewed 283 full text articles. We preferentially included high quality systematic reviews or large randomised trials. Where no such studies existed, we included the best evidence available from smaller randomised or quasi-randomised trials.

RESULTS

We included 46 full text articles. We assigned a quality rating to each included article and a strength of evidence rating to each body of literature. Prostaglandin E2 (PGE2) and vaginal misoprostol were more effective than oxytocin in bringing about vaginal delivery within 24 hours but were associated with more uterine hyperstimulation. Mechanical methods reduced uterine hyperstimulation compared with PGE2 and misoprostol, but increased maternal and neonatal infectious morbidity compared with other methods. Membrane sweeping reduced post-term gestations. Most included studies were too small to evaluate risk for rare adverse outcomes.

CONCLUSIONS

Research is needed to determine benefits and harms of many induction methods.

Fatores associados à indução do parto em gestantes com óbito fetal após a 20ª semana

OBJETIVOS: determinar os fatores associados à indução do trabalho de parto em gestantes com óbito fetal. MÉTODOS: estudo seccional, com 258 gestantes após a 20ª semana e diagnóstico ultrassonográfico de óbito fetal, no período de janeiro/2005 a dezembro/2008, na maternidade do Hospital Barão de Lucena, Recife, Brasil. Características sociodemográficas, causas e tipos de óbito fetal, antecedentes obstétricos e características do parto foram variáveis estudadas. Foram utilizados testes qui-quadrado, exato de Fisher e "t" de Student. Razão de prevalência e análise de regressão logística múltipla também foram realizados. O nível de significância foi de 5%. RESULTADOS: a indução do parto ocorreu em 83 (32,2%) gestantes. Após análise multivariada, observou-se que a idade gestacional acima da 40ª semana de gravidez (OR= 126,5; IC95%= 3,83-4.201,5) e óbito fetal tardio (OR= 6,86; IC95%= 2,55-18,47) foram fatores de risco que permaneceram associados à indução do parto. Cesariana (OR= 0,02; IC95%= 0,004-0,09), funiculopatias (OR= 0,12; IC95%= 0,02-0,68), presença de uma ou menos gestações anteriores (OR= 0,34; IC95%= 0,14-0,81) e uma ou mais cesáreas anteriores (OR= 0,16; IC95%= 0,04-0,71) foram negativamente associados à indução. CONCLUSÕES: idade gestacional acima da 40ª semana e óbito fetal tardio são fatores de risco que podem estar associados à indução do parto em gestantes com óbito fetal.

A randomised controlled trial of low-dose misoprostol and dinoprostone vaginal pessaries for cervical priming

OBJECTIVE

We studied the efficacy of 25-microg misoprostol pessaries as either single or double dose compared with a 3-mg dinoprostone pessary for cervical priming.

DESIGN AND SETTING

A randomised controlled trial in Singapore.

POPULATION

One hundred and seventy-one women with term pregnancies and modified Bishop scores (mBS) < or =6 from 2003 to 2004.

METHOD

Patients were randomised to single misoprostol dose, double misoprostol dose or the current dinoprostone regimen.

MAIN OUTCOME MEASURES

Primary outcome was number of women who achieved favourable mBS >6 or active labour by day 2. Secondary outcomes were time interval from insertion to delivery, cardiotocographic abnormalities, delivery and neonatal outcome.

RESULTS

More women in the misoprostol double-dose group (96.6%) and dinoprostone group (93%) achieved the primary outcome compared with the single-dose group (77.8%) (P = 0.003 and P = 0.03, respectively). There was no difference in secondary outcomes. More multiparous women achieve primary outcome compared with nulliparous women (odds ratio 0.21, 95% confidence interval 0.06-0.77).

CONCLUSION

Double-dose misoprostol 25 microg is as effective as dinoprostone 3 mg inserts for cervical priming; both are more efficacious than a single-dose misoprostol pessary. Parity prognosticates the success of induction.