Controlled-Release Misoprostol Vaginal Insert in Parous Women for Labor Induction

Safety of misoprostol vaginal insert for labor induction using standard vs. adjusted retrieval criteria: a comparative cohort study

Objective To compare the safety of misoprostol vaginal insert (MVI) for labor induction using standard and adjusted criteria. Methods This was a single-center, comparative cohort study of 138 pregnant women ≥37/0 weeks undergoing labor induction with MVI using standard (69 women; administration for up to 24 h; MVI-24) or adjusted (69 women; administration for up to 10 h; MVI-10) criteria in a tertiary academic center in Germany. The main maternal safety outcomes were the rate of tachysystole and rate of tachysystole requiring tocolysis. Neonatal safety assessments included Apgar score at 5 min and postpartum arterial fetal pH. Results Uterine tachysystole occurred in more women in the MVI-24 group compared with the MVI-10 group [47.8% vs. 25.5%; P = 0.001; relative risk (RR) 2.36 (95% confidence interval [CI]: 1.39-4.00)] and as did uterine tachysystole requiring tocolysis [MVI-24: 26.1% vs. MVI-10: 11.6%; P = 0.049; RR 2.25 (95% CI: 1.05-4.83)]. The mean 5-min Apgar scores were 9.64 for the MVI-24 group and 9.87 for the MVI-10 (P = 0.016). Low postpartum umbilical arterial pH values occurred more often in the MVI-24 compared with the MVI-10 group (pH 7.10-7.19: 26.1% vs. 20.3% and pH <7.10: 4.4% vs. 0.0%, respectively). Conclusion Adjusted retrieval criteria for MVI of up to 10 h exposure instead of the standard 24 h reduced uterine tachysystole and improved the neonatal outcome.

Do we need a 200 μg misoprostol vaginal insert? A retrospective cohort study comparing the misoprostol vaginal insert to oral misoprostol

AIM

The misoprostol vaginal insert (MVI) was reported to be more effective than dinoprostone but discussed critically because of high rates of fetal heart rate changes due to uterine tachysystole. The aim of this study was to investigate the outcome of induced labor using the MVI compared to off-label orally-administered misoprostol (OM).

METHODS

Retrospective study including a total of 401 patients with singleton pregnancies in whom labor was induced at ≥36 0/7 gestational weeks with MVI (203) or OM (198). Primary outcomes were the time from induction to delivery, vaginal delivery in 24 h and the mode of delivery and the neonatal outcome.

RESULTS

Median time until any delivery was 833 min (645-1278) for MVI and 1076.5 min (698-1686.3) for OM group; 83.7% of the patients in the MVI group gave birth within 24 h versus 63.6% in the OM group. The MVI group needed significantly less pre-delivery oxytocin (29%). Tachysystole (6.4%) and pathological CTG (30.5%) occurred at a significantly higher frequency in the MVI group. The cesarean section rate was significantly higher in the MVI group amounting to 21.7% versus 14.6% in the OM group (P < 0.05). Neonatal outcome did not differ between the groups.

CONCLUSION

The MVI might be an option if you are in need for an approved and faster method to induce labor. Although we observed a significantly higher rate of fetal heart rate changes and cesarean sections in the MVI group this did not affect the neonatal outcome.

Standard and adjusted criteria for the use of the misoprostol vaginal insert for labor induction: a comparative cohort study

Objective To compare the efficacy of misoprostol vaginal insert (MVI) for labor induction using standard and adjusted criteria. Methods A single-center, comparative cohort study using a consecutive series of pregnant women ≥37/0 weeks undergoing labor induction with either standard criteria for MVI (administration for up to 24 h; MVI-24) or with adjusted criteria (MVI administration for a maximum of 10 h; MVI-10) conducted at a tertiary academic center in Germany. The primary outcomes were the time from start of induction to any delivery and cesarean delivery rate. Results A total of 138 women were included in the study, 69 in each group. The mean time from MVI administration to any delivery showed no significant difference between the MVI-24 and MVI-10 groups (954 vs. 969 min, respectively; P = 0.679). The cesarean delivery rate was proportionally lower for the MVI-10 group [39.1% (27/69) vs. 24.6% (17/69); P = 0.10]. Conclusion The time from induction to delivery with MVI was similar when using standard criteria of up to 24 h of exposure vs. adjusted criteria of up to 10 h of exposure. Although the threshold for statistical significance for cesarean section was not attained, there is nonetheless a considerable difference between the MVI-24 and MVI-10 groups.

Induction of labor using one dose vs multiple doses of misoprostol: a randomized controlled trial

BACKGROUND

Misoprostol is a common agent that is used to ripen the cervix and induce labor, yet there is no clear evidence of the optimal number of doses needed to achieve a higher rate of vaginal delivery.

OBJECTIVE

Our primary objective was to compare the rate of vaginal delivery within 24 hours between a 1-dose and a multiple-dose regimen of misoprostol for the induction of labor.

STUDY DESIGN

A randomized controlled trial was conducted from March 2016 to March 2017 that compared a single dose to up to 4 doses of misoprostol. Randomization was stratified by parity. Women with a singleton pregnancy ≥37 weeks gestation with intact membranes who had been admitted for labor induction with a Bishop score ≤6 were included. Our primary outcome was the rate of vaginal delivery within 24 hours. Secondary outcomes included time to vaginal delivery, cesarean delivery rate, and maternal and neonatal morbidity. Based on a power of 80%, an alpha of .05, and the assumption that 50% of women in the multiple-misoprostol group would deliver vaginally in 24 hours, a sample size of 220 patients was needed to detect a 20% increase in vaginal delivery rate within 24 hours in the 1-misoprostol group. Continuous variables were compared with the use of the Mann-Whitney test. Categoric variables were compared with the use of the Fisher's exact test. Probability values <.05 were considered statistically significant.

RESULTS

Two hundred fifty women were assigned randomly. Demographics and clinical characteristics were similar between groups. In the univariate analysis, there was no difference in the rate of vaginal delivery within 24 hours between the 1-misoprostol group and the multiple-dose group (41.7% vs 44.7%, respectively; P=.698) or time to vaginal delivery (1187 min vs 1321 min, respectively; P=.202). The 1-misoprostol group had a greater cesarean delivery rate (35.8% vs 22.8%; P=.034). In a Poisson regression that controlled for Bishop score before the initiation of oxytocin, parity, gestational age, body mass index, estimated fetal weight, artificial rupture of membrane at <6 cm, and Foley balloon placement, the treatment group was no longer associated with cesarean delivery rate. Instead, a Bishop score of <4 before the initiation of oxytocin and nulliparity were associated significantly with cesarean delivery rate.

CONCLUSION

In this first randomized controlled trial in the literature to compare a single with a multiple dosing of misoprostol, we found that the 1-dose regimen is an acceptable alternative for the induction for labor, especially for multiparous women and for patients with a Bishop score >4 after the first dose.

The misoprostol vaginal insert compared with oral misoprostol for labor induction in term pregnancies: a pair-matched case-control study

AIM

To compare the efficacy and safety of the misoprostol vaginal insert (MVI) with an off-label use of oral misoprostol (OM).

METHODS

Pair-matched case-control study comparing the induction of labor with a retrievable MVI to OM. The primary outcomes were the time from induction to delivery and the cesarean section rate. Secondary outcomes included uterine tachysystole, tocolysis, fetal scalp blood testing, meconium-stained amniotic fluid, umbilical arterial pH, and Apgar score.

RESULTS

One hundred and thirty eight women ≥37/0 weeks pregnant undergoing labor induction with misoprostol were included. The mean time from application to delivery was significantly shorter and the caesarean section rate significantly higher in the MVI group (P<0.01) with an odds ratio of 2.75 (95% CI: 1.21-6.25) in favor of vaginal delivery in the OM group. The mean 5-min Apgar scores and arterial cord pH values were significantly lower in the MVI group. An arterial pH value of 7.10-7.19 was found in 26.1% and 15.9%, and a value <7.10 was found in 4.3% and 0% of MVI and OM cases, respectively.

CONCLUSION

The MVI compared with OM significantly shortened the time from application to delivery at the expense of a higher cesarean section rate and negative effects on neonatal outcomes.

A critical appraisal of the misoprostol removable, controlled-release vaginal delivery system of labor induction

BACKGROUND

Induction of labor is a major issue in pregnancy management. Finding strategies to increase rate and decrease time to vaginal delivery is an important goal, but maternal or neonatal safety must remain the primary objective. Misoprostol is a synthetic analogue of prostaglandin used off label to ripen the cervix and induce labor. The misoprostol vaginal insert (MVI) was designed to allow a controlled-release delivery of misoprostol (from 50 to 200 μg) with a removal tape. The objective of this review was to make a critical appraisal of this device referring to the literature.

METHODS

A literature search was performed in the PubMed and Cochrane databases using the keywords "vaginal misoprostol insert".

RESULTS

Several studies compared different doses of MVI (50, 100, 150, and 200 μg) with the 10 mg dinoprostone insert. The 100 μg MVI compared with the dinoprostone vaginal insert (DVI) showed similar efficacy and no significant differences in cesarean delivery rate. MVI 200 μg compared with DVI showed a reduced time to vaginal delivery and oxytocin need but had an increased risk of uterine hyperstimulation. The rate of hyperstimulation syndrome was two to three times more frequent with the 200 μg MVI than the 100 μg.

CONCLUSION

Current data suggest that the 100 μg MVI would provide the best balance between efficacy and safety. Further studies should be performed to evaluate this dose, especially in high-risk situations needing induction of labor.

Misoprostol for induction of labor

Labor-induction rates have increased considerably in the United States as well as around the world. With up to half of all induced labors requiring cervical ripening, prostaglandins have been utilized to increase induction success and achieve vaginal delivery. Misoprostol, a synthetic prostaglandin E1 analog has the ability to mimic the changes of spontaneous labor and has been used off label for over 30 years as a labor-induction agent. In the following article, cervical ripening and induction of labor with misoprostol will be discussed. The risks and benefits of misoprostol for ripening and induction and routes of administration will be reviewed, as well as future directions and new developments for its use.

A novel misoprostol delivery system for induction of labor: clinical utility and patient considerations

Induction of labor is one of the most commonly performed obstetric procedures and will likely become more common as the reproductive population in developed nations changes. As the proportion of women undergoing induction grows, there is a constant search for more efficacious ways to induce labor while maintaining fetal and maternal safety as well as patient satisfaction. With almost half of induced labors requiring cervical ripening, methods for achieving active labor and vaginal delivery are constantly being investigated. Prostaglandins have been shown to be effective induction agents, and specifically vaginal misoprostol, used off-label, have been widely utilized to initiate cervical ripening and active labor. The challenge is to administer this medication accurately while maintaining the ability to discontinue the medication when needed. The misoprostol vaginal insert initiates cervical ripening utilizing a delivery system that controls medication release and can be rapidly removed. This paper reviews the design, development, and clinical utility of the misoprostol vaginal insert for induction of labor as well as patient considerations related to the delivery system.

Misoprostol vaginal insert for induction of labor: a delivery system with accurate dosing and rapid discontinuation

Labor induction and cervical ripening are widely utilized and new methods are constantly being investigated. Prostaglandins have been shown to be effective labor induction agents and, in particular, were compared with other prostaglandin preparations; vaginal misoprostol used off-label was associated with reduced failure to achieve vaginal delivery. The challenge is to provide this medication with the correct dosing for this indication and with the ability to discontinue the medication if needed, all while ensuring essential maternal and neonatal safety. The misoprostol vaginal insert initiates cervical ripening using a delivery system that controls misoprostol release and can be rapidly removed. This article reviews the development, safety and efficacy of the misoprostol vaginal insert for induction of labor and cervical ripening, and will focus on vaginally administered prostaglandins.

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 Comparison of Vaginal vs. Oral Misoprostol for Induction of Labor-Double Blind Randomized Trial

OBJECTIVE

To compare efficacy and safety of 50 μgm misoprostol vaginal with oral for labor induction.

METHODS

110 women at term gestation, Bishop score ≤4, with various indications for labor induction were randomized and double blinded. After decoding 51 women had received misoprostol orally and 52 vaginally, four hourly (maximum six doses) or till woman went into active labor.

RESULTS

Statistical analysis was done with SPSS 11.0. In vaginal misoprostol group induction delivery interval was significantly less (9.79 vs. 16.47 h) and successful induction was significantly higher (90.38 vs. 74.51%) than oral group, with in 24 h of induction. As for as dose required is concerned in vaginal group 40.38% women needed two doses for delivery, in contrast 35.29% in oral group maximum six doses were required.

CONCLUSION

Vaginal route of misoprostol is more effective labor inducing agent than oral.

Vaginal misoprostol for cervical ripening and induction of labour

BACKGROUND

Misoprostol (Cytotec, Searle) is a prostaglandin E1 analogue widely used for off-label indications such as induction of abortion and of labour. This is one of a series of reviews of methods of cervical ripening and labour induction using standardised methodology.

OBJECTIVES

To determine the effects of vaginal misoprostol for third trimester cervical ripening or induction of labour.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group's Trials Register (November 2008) and bibliographies of relevant papers. We updated this search on 30 April 2010 and added the results to the awaiting classification section.

SELECTION CRITERIA

Clinical trials comparing vaginal 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

We developed a strategy to deal with the large volume and complexity of trial data relating to labour induction. This involved a two-stage method of data extraction.We used fixed-effect Mantel-Haenszel meta-analysis for combining dichotomous data.If we identified substantial heterogeneity (I² greater than 50%), we used a random-effects method.

MAIN RESULTS

We included 121 trials. The risk of bias must be kept in mind as only 13 trials were double blind.Compared to placebo, misoprostol was associated with reduced failure to achieve vaginal delivery within 24 hours (average relative risk (RR) 0.51, 95% confidence interval (CI) 0.37 to 0.71). Uterine hyperstimulation, without fetal heart rate (FHR) changes, was increased (RR 3.52 95% CI 1.78 to 6.99).Compared with vaginal prostaglandin E2, intracervical prostaglandin E2 and oxytocin, vaginal misoprostol was associated with less epidural analgesia use, fewer failures to achieve vaginal delivery within 24 hours and more uterine hyperstimulation. Compared with vaginal or intracervical prostaglandin E2, oxytocin augmentation was less common with misoprostol and meconium-stained liquor more common.Lower doses of misoprostol compared to higher doses were associated with more need for oxytocin augmentation and less uterine hyperstimulation, with and without FHR changes.We found no information on women's views.

AUTHORS' CONCLUSIONS

Vaginal misoprostol in doses above 25 mcg four-hourly was more effective than conventional methods of labour induction, but with more uterine hyperstimulation. Lower doses were similar to conventional methods in effectiveness and risks. The authors request information on cases of uterine rupture known to readers. The vaginal route should not be researched further as another Cochrane review has shown that the oral route of administration is preferable to the vaginal route. Professional and governmental bodies should agree guidelines for the use of misoprostol, based on the best available evidence and local circumstances.