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.

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.

Composite thermoresponsive hydrogel with auranofin-loaded nanoparticles for topical treatment of vaginal trichomonad infection

Trichomonas vaginalis is responsible for the most common non-viral sexually-transmitted disease worldwide. Standard treatment is with oral nitro-heterocyclic compounds, metronidazole or tinidazole, but resistance to these drugs is emerging and adverse effects can be problematic. Topical treatment offers potential benefits for increasing local drug concentrations and efficacy, while reducing systemic drug exposure, but no topical strategies are currently approved for trichomoniasis. The anti-rheumatic drug, auranofin (AF), was recently discovered to have significant trichomonacidal activity, but has a long plasma half-life and significant adverse effects. Here, we used this drug as a model to develop a novel topical formulation composed of AF-loaded nanoparticles (NP) embedded in a thermoresponsive hydrogel for intravaginal administration. The AF-NP composite gel showed sustained drug release for at least 12 h, and underwent sol-gel transition with increased viscoelasticity within a minute. Intravaginal administration in mice showed excellent NP retention for >6 h and markedly increased local AF levels, but reduced plasma and liver levels compared to oral treatment with a much higher dose. Furthermore, intravaginal AF-NP gel greatly outperformed oral AF in eliminating vaginal trichomonad infection in mice, while causing no systemic or local toxicity. These results show the potential of the AF-NP hydrogel formulation for effective topical therapy of vaginal infections.

Clinical application of low-dose misoprostol in the induced labor of 16 to 28 weeks pathological pregnancies (a STROBE-compliant article)

Oral mifepristone combined with rivanol lactate (rivanol) is commonly used in second-trimester pregnancy termination. However, rivanol is not suitable to premature rupture of membranes and oligohydramnios because amniocentesis is difficult. Mifepristone combined with misoprostol is suitable for the patients with oligohydramnios. In accordance with the misoprostol dosing recommendations by the International Federation of Gynecology and Obstetrics (FIGO), the incidences of uterine rupture and cervical laceration are relatively high in Chinese pregnant women. The aim of our study was to optimize misoprostol dosing regimen in terms of efficacy and safety in Chinese pregnant women.We modified the Bishop Score, and then gave patients low-dose misoprostol according to the modified Bishop score. Based on the amniotic fluid volume (AFV) indicated by type-B ultrasonic instrument, the cases with AFV ≤2 cm receiving low-dose misoprostol combined with mifepristone and the cases with amniocentesis failure followed by receiving low-dose misoprostol combined with mifepristone were enrolled into study group, and the cases with AFV >2 cm receiving rivanol combined with mifepristone were enrolled into control group. The start time of uterine contractions, time of fetal expulsion, birth process, hospital day, successful induced labor rate, complete induced labor rate, and incomplete induced labor rate were observed and compared between the 2 groups.There were significant differences in the start time of uterine contractions, time of fetal expulsion, birth process, and hospital day between the control group and the study group (all P < .05). The successful induced labor rate, complete induced labor rate, and incomplete induced labor rate were also significantly different between the 2 groups (all P < .05).In the induced labor of 16 to 28 weeks pathological pregnancy, low-dose misoprostol can markedly improve the successful induced labor rate and complete induced labor rate, shorten the birth process and hospital day, and decrease uterine curettage rate and uterine rupture risk. Low-dose misoprostol combined with mifepristone is suitable to the induced labor of 16 to 28 weeks pathological pregnancy in Chinese women.

The efficacy of misoprostol vaginal insert compared with oral misoprostol in the induction of labor of nulliparous women: A randomized national multicenter trial

INTRODUCTION

Our objective was to compare the efficacy of a 200-μg misoprostol vaginal insert vs oral misoprostol regarding the cesarean section rate and the time interval to vaginal delivery in nulliparous women with unfavorable cervix.

MATERIAL AND METHODS

In this prospective multicenter trial, 283 nulliparous women at term with Bishop score <6 were randomized to induction of labor with either a misoprostol vaginal insert (n = 140) or oral misoprostol (n = 143). In the oral misoprostol group, a 50-μg dose of oral misoprostol was administered every 4 hours up to three times during the first day; during the second day, the dose was increased to 100-μg every 4 hours up to three times during the first day, if necessary. Primary outcome was the cesarean section rate. Secondary outcomes were the time from induction of labor to vaginal delivery, the rate of other induction methods needed, labor augmentation with oxytocin and/or amniotomy, use of tocolytics and adverse neonatal and maternal events.

RESULTS

In the misoprostol vaginal insert group, median time to vaginal delivery was shorter (24.5 hours vs 44.2 hours, P < 0.001), whereas no difference was found in the cesarean section rate (33.8% vs 29.6%, odds ratio [OR] 1.21, 95% confidence interval [CI] 0.66-1.91, P = 0.67). Other induction methods and labor augmentation with oxytocin and/or amniotomy were less frequent in the misoprostol vaginal insert group (OR 0.32, 95% CI 0.18-0.59 and OR 0.56, 95% CI 0.32-0.99, respectively). Need for tocolysis and meconium-stained amniotic fluid were more common in the misoprostol vaginal insert group (OR 3.63, 95% CI 1.12-11.79 and OR 2.38, 95% CI 1.32-4.29, respectively). Maternal and neonatal adverse events did not differ between groups.

CONCLUSIONS

Misoprostol vaginal insert proved to shorten the time to vaginal delivery and to reduce the use of other methods of labor induction and augmentation, but it did not reduce the cesarean section rate compared with oral misoprostol. The benefit of more rapid delivery associated with misoprostol vaginal insert should be weighed against the greater risks for uterine hyperstimulation and meconium-stained amniotic fluid.

Precision-guided long-acting analgesia by Gel-immobilized bupivacaine-loaded microsphere

Peripheral nerve blockade (PNB) is a conventional strategy for the management of acute postoperative pain. However, the short duration of the associated analgesia and the potential systemic toxicity due to the low molecular weights of local anesthetics limit their application. Methods: An in situ forming injectable Gel-microsphere (Gel-MS) system consisting of PLGA-PEG-PLGA Gel (Gel) and Gel-immobilized bupivacaine-loaded microsphere (MS/BUP) was prepared for precision-guided long-acting analgesia. A series of in vitro characterizations, such as scanning electron microscopy, rheology analysis, confocal laser scanning microscopy, drug release, and erosion and degradation, were carried out. After that, the in vivo analgesia effect of the Gel-MS system, the immobilization effect of Gel on the MS, and biocompatibility of the system were evaluated using a sciatic nerve block model. Results: The BUP release from the Gel-MS system was regulated by both the inner MS and the outer Gel matrix, demonstrating sustained BUP release in vitro for several days without an initial burst release. More importantly, incorporation of the Gel immobilized the MS and hindered the diffusion of MS from the injection site because of its in situ property, which contributed to a high local drug concentration and prevented systemic side effects. In vivo, a single injection of Gel-MS/BUP allowed rats to maintain sensory and motor blockade significantly longer than treatment with MS/BUP (P < 0.01) or BUP-loaded Gel (Gel-BUP, P < 0.01). Histopathological results demonstrated the excellent biodegradability and biocompatibility of the Gel-MS system without neurotoxicity. Conclusion: This precision-guided long-acting analgesia, which provides an in situ and sustained release of BUP, is a promising strategy for long-acting analgesia, and could represent a potential alternative for clinical pain management.

Misoprostol vaginal insert versus misoprostol vaginal tablets for the induction of labour: a cohort study

Background

Misoprostol vaginal insert for induction of labor has been recently reported to be superior to dinoprostone vaginal insert in a phase III trial, but has never been compared to vaginal misoprostol in another galenic form. The aim of this study was to compare misoprostol vaginal insert (MVI) with misoprostol vaginal tablets (MVT) for induction of labor in term pregnancies.

Methods

In this retrospective cohort study we compared 200 consecutive women induced with 200-μg misoprostol 24-h vaginal insert (Misodel®) with a historical control of 200 women induced with Misoprostol 25-μg vaginal tablets (Cytotec®) every 4-6 h. Main outcomes variables included induction-to-delivery interval, vaginal delivery within 24-h, incidence of tachysystole, mode of delivery, and neonatal outcome. A subanalysis in the MVI group was performed in order to identify predictive factors for tachysistole and vaginal delivery within 24 h.

Results

The time from induction to vaginal delivery was 1048 ± 814 min in the MVI group and 1510 ± 1043 min in the MVT group (p < 0.001). Vaginal delivery within 24-h occurred in 127 (63.5%) patients of the MVI group and in 110 (55%) patients of the MVT group (p < 0.001). Tachysystole was more common in the MVI group (36% vs. 18%; p < 0.001). However, no significant predictors of uterine tachysystole in MVI group have been identified in crude and fully adjusted logistic regression models. Bishop score was the only predictor for vaginal delivery within 24 h (p < 0.001) in MVI group. Caesarean delivery rate (27% vs. 20%) and vaginal-operative deliveries (15.5% vs. 15.5%) did not differ significantly between the two groups. Neonatal outcomes were similar in both groups.

Conclusions

MVI achieves a more vaginal delivery rate within 24 h and Tachysystole events compared to MVT. However, no differences in caesarean section, operative vaginal delivery, and neonatal outcomes are reported. No predictors of tachysistole after MVI administration have been identified. Bishop score and parity are the only predictors of vaginal delivery within 24 h after MVI administration.

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.

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.

Misoprostol vaginal insert and time to vaginal delivery: a randomized controlled trial

OBJECTIVE

To compare the efficacy and safety of a 200-microgram misoprostol vaginal insert with a 10-mg dinoprostone vaginal insert for reducing the time to vaginal delivery.

METHODS

In a phase III, double-blind, multicenter study, women being induced with a modified Bishop score of 4 or less were randomly assigned to receive either a 200-microgram misoprostol vaginal insert or a 10-mg dinoprostone vaginal insert. Coprimary end points were time to vaginal delivery and rate of cesarean delivery. Secondary end points included time to any delivery mode, time to onset of active labor, and oxytocin use.

RESULTS

A total of 1,358 women were randomized to receive the 200-microgram misoprostol vaginal insert (n=678) or dinoprostone vaginal insert (n=680). Women receiving the misoprostol vaginal insert had a significantly shorter median time to vaginal delivery compared with patients receiving the dinoprostone vaginal insert (21.5 hours compared with 32.8 hours, P<.001). Cesarean delivery occurred in 26.0% and 27.1% of women receiving the misoprostol vaginal insert and dinoprostone vaginal insert, respectively. A significant reduction in time to any delivery (18.3 hours compared with 27.3 hours), time to onset of active labor (12.1 hours compared with 18.6 hours), and proportion of women requiring predelivery oxytocin (48.1% compared with 74.1%) was observed with the misoprostol vaginal insert compared with dinoprostone vaginal insert (P<.001 for each). Uterine tachysystole requiring intervention occurred in 13.3% and 4.0% of participants receiving the misoprostol vaginal insert and dinoprostone vaginal insert, respectively (P<.001).

CONCLUSION

Use of a 200-microgram misoprostol vaginal inset significantly reduced times to vaginal delivery and active labor with reduced need for oxytocin compared with the dinoprostone vaginal insert. Cesarean delivery rates were similar with both treatments. Tachysystole was more common in women receiving the 200-microgram misoprostol vaginal insert.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT01127581.

LEVEL OF EVIDENCE

I.