Simplifying oral misoprostol protocols for the induction of labour

Development and validation of a stability-indicating method, structural elucidation of new degradation products from misoprostol by LC-MS time-of-flight, and an ex vivo study of vaginal permeation

Misoprostol (MSP) is commonly prescribed in obstetrics and gynecology clinical practice for labor induction, cervical ripening, first-trimester pregnancy termination, and the treatment of postpartum hemorrhage. Furthermore, there is a lack of comprehensive discussion evaluating how different commercially available formulations influence the overall efficacy of MSP, even though reports indicate issues with the quality of these formulations, particularly regarding stability and vaginal absorption processes. This study investigates the stability of MSP under acidic conditions and its in vitro permeation using swine vaginal mucosa. A forced degradation study was conducted using 0.2 M HCl, and a high-efficiency LC method was developed. Three degradation products were identified and characterized using electrospray ionization-high-resolution quadrupole-time-of-flight-MS, with respective m/z values of 391.2508, 405.2705, and 387.2259, respectively. These results suggest that the degradation mechanism involves dehydration of the β-hydroxy ketone moiety, followed by isomerization to its most resonance-stable form and de-esterification. Finally, the in vitro permeation study revealed that the esterified form of MSP was unable to permeate the mucosa and required prior degradation for any component to be detected in the receptor fluid.

Timing of cesarean delivery for fetal heart rate abnormalities in hypertensive pregnancies induced with oral misoprostol or Foley catheter: Secondary analysis of a randomized clinical trial

OBJECTIVE

The study aims to assess how oral misoprostol for cervical ripening affects the time of cesarean delivery (CD) for fetal heart rate (FHR) abnormalities in pre-eclampsia patients. Secondary goals include determining the role of uterine hyperstimulation, comparing misoprostol with Foley catheter, and identifying risk factors for FHR abnormalities associated with CD.

METHODS

A previously published randomized clinical trial was subjected to a secondary analysis (NCT01801410). We conducted a time-dependent analysis, stratifying the population based on the final mode of induction used (low-dose oral misoprostol vs Foley catheter).

RESULTS

There was no CD for FHR abnormalities within 2 h of starting misoprostol. At 5 h, the cumulative incidence of CD for FHR abnormalities in the misoprostol group was 2.10%, while it was 1.00% in the Foley group (P = 0.565). After 25 h, the CD risk for FHR abnormalities remained constant in both groups at 21.00% (95% confidence interval [CI] 15.00%-28.00%). Within 5 h of misoprostol induction, the risk of uterine hyperstimulation was similar in both groups (0.33% in misoprostol vs 0.34% in Foley group, P = 0.161). The risk of CD for FHR abnormalities was unaffected by newborn weight centiles.

CONCLUSION

There was no significant difference in CD risk for FHR abnormalities between misoprostol and Foley catheter induction. Nonetheless, the cumulative incidence of CD for FHR abnormalities increased faster in the misoprostol group, indicating that FHR monitoring timing should be tailored to the induction method.

Factors of Non-Compliance with a Protocol for Oral Administration of Misoprostol (Angusta®) 25 Micrograms to Induce Labor: An Observational Study

We set out to identify factors of non-compliance with a protocol for the oral administration of misoprostol 25 µg (Angusta^®) every 2 h (up to eight tablets), for the induction of labor (IOL). We conducted a retrospective study on IOL at term, on singleton pregnancies from 2019 to 2021, in a university hospital. The study included 195 patients, comprising 144 compliant protocols. Pain was statistically more frequent in the non-compliance group (92.2% vs. 62.5%, p < 0.001), and when a midwife was unavailable (15.7% vs. 0.7%, p < 0.001). A multivariable analysis found factors of good response (defined as going into labor before the administration of the median number of tablets, i.e., six) to be an indication for PROM (OR: 12.03, 95% CI: 5.42-26.71), and gestational age at induction (OR: 1.54, 95% CI: 1.19-2.01), independently of BMI, initial Bishop score, and parity. Patients with pain who were able to follow the protocol delivered 9 h earlier than patients with pain who interrupted the protocol and 16 h earlier than patients who experienced no pain. We identified two key elements that favored compliance: (i) providing the next tablet in advance; and (ii) offering patients early epidural analgesia when in pain in order to continue the protocol and go into labor promptly.

Oral misoprostol tablets (25 µg) for induction of labor: a targeted literature review and cost analysis

BACKGROUND

Various methods exist for the induction of labor (IOL), and there is limited consensus as to optimal methods. Off-label misoprostol is recommended by the World Health Organization (WHO) for IOL but preparing it into doses suitable for IOL lacks precision, with potential adverse outcomes if dosing is inaccurate. This study explores potential outcomes and costs associated with increased uptake of a low-dose (25 µg) oral misoprostol formulation (Angusta; Norgine BV, Amsterdam) approved for IOL, in France, Belgium, and the Netherlands.

METHODS

A literature review was undertaken to derive probabilities of delivery outcomes (vaginal, instrumental, and cesarean sections) for IOL methods, from published meta-analyses. Outcomes for oral misoprostol tablets (25 µg) were unavailable in the meta-analyses, so were estimated using data from two published retrospective cohort studies. A model was developed to predict the frequency of IOL outcomes and associated costs at the national level, across multiple scenarios. Scenarios were tested using a moderate, medium, and high increase in oral misoprostol tablet (25 µg) uptake. Market shares, costs, and induction rates were defined for each country using multiple data sources.

RESULTS

Increased uptake of oral misoprostol tablets (25 µg) was estimated to be associated with a slightly increased rate of routine vaginal deliveries, and concurrent decreases in instrumental vaginal deliveries and cesarean sections. Since routine vaginal deliveries are less costly than other delivery outcomes, increased uptake of oral misoprostol tablets (25 µg) within the IOL market has the potential to be cost-saving. These trends were predicted using 25 µg oral misoprostol tablet outcomes informed by both retrospective studies.

CONCLUSION

Preliminary outcomes suggest that oral misoprostol tablets at 25 µg per dose may improve outcomes in IOL and be cost-saving. Further study is required to validate these findings and assess the comparative efficacy of IOL methods, including oral misoprostol tablets (25 µg).

Cervical Ripening and Labor Induction and Augmentation, 5th Edition

Cervical ripening and induction and augmentation of labor are common procedures in labor and birth units. The potential risks and benefits for the procedure should be explained to women so that they can make informed decisions. Clinicians should be knowledgeable about the methods and medications used and be skilled in maternal-fetal assessment. Adequate nurse staffing is required to monitor the mother and fetus to promote the best possible outcomes. This practice monograph includes information on mechanical and pharmacologic methods for cervical ripening; labor induction and augmentation with oxytocin, a high alert drug; and nurse staffing levels and skills needed to provide safe and effective care during cervical ripening and labor induction and augmentation.

Cervical Ripening and Labor Induction and Augmentation, 5th Edition

Cervical ripening and induction and augmentation of labor are common procedures in labor and birth units. The potential risks and benefits for the procedure should be explained to women so that they can make informed decisions. Clinicians should be knowledgeable about the methods and medications used and be skilled in maternal-fetal assessment. Adequate nurse staffing is required to monitor the mother and fetus to promote the best possible outcomes. This practice monograph includes information on mechanical and pharmacologic methods for cervical ripening; labor induction and augmentation with oxytocin, a high alert drug; and nurse staffing levels and skills needed to provide safe and effective care during cervical ripening and labor induction and augmentation.

An audit of oral administration of Angusta® (misoprostol) 25 µg for induction of labor in 976 consecutive women with a singleton pregnancy in a university hospital in Denmark

INTRODUCTION

Induction of labor (IOL) is used to improve the outcome of pregnancy for mother and child. Since 2013, oral misoprostol has been used for IOL at Aarhus University Hospital, Denmark. The purpose of the present paper is to describe our experience of the use of a new, 25-µg misoprostol tablet commercially manufactured for the purpose of IOL regarding efficacy and outcome for mother and neonate in both an inpatient and an outpatient regimen.

MATERIAL AND METHODS

We performed an audit from 1 April 2016, including data on all IOL in women with singleton pregnancies until 1000 consecutive women were registered. Data from 976 consecutive women with gestational age ≥37⁺⁰  weeks induced in accordance with the "Aarhus protocol" were included in the present analyses. All inductions were by oral misoprostol. Outpatient induction is standard procedure in low-risk pregnancies, that is, pregnancies with a healthy mother and no signs of placental insufficiency. In the outpatient IOL, the first dose of misoprostol is administered after a normal cardiotocography registration at the hospital. Subsequent doses are taken at home according to a predefined regimen. Following delivery, data on baseline variables and outcome variables for the mother and neonate were retrieved from the medical records.

RESULTS

In 71.9% of cases, the women were induced in an outpatient regimen. Delivery within 24 hours was achieved in 38.8% of women (nulliparous 32.3%, multiparous 50.9%) and within 48 hours in 70.1% (nulliparous 66.2%, multiparous 77.2%). Hyperstimulation during induction occurred in 0.6%. The mode of delivery was spontaneous vaginal in 75.5% of cases. The cesarean section rate was 14.9% (nulliparous 20.7%, multiparous 4.1%). Apgar <7 at 5 minutes and pH <7.0 in the umbilical artery was seen in 0.9% and 0.7%, respectively.

CONCLUSIONS

Induction of labor by a commercially produced low-dose (25 µg) misoprostol tablet for oral induction according to the "Aarhus protocol" is feasible in an outpatient as well as an inpatient regimen. Delivery was achieved within 48 hours for 70.1% of women. Few adverse events were seen; however, the audit was underpowered for safety.

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.

Oral misoprostol, low dose vaginal misoprostol, and vaginal dinoprostone for labor induction: Randomized controlled trial

OBJECTIVE

To compare effectiveness and safety of oral misoprostol (50 μg every four hours as needed), low dose vaginal misoprostol (25 to 50 μg every six hours as needed), and our established dinoprostone vaginal gel (one to two mg every six hours as needed) induction.

MATERIALS AND METHODS

Consenting women with a live term single cephalic fetus for indicated labor induction were randomized (3N = 511). Prior uterine surgery or non-reassuring fetal surveillance were exclusions. Concealed computer generated randomization was stratified and blocked. Newborns were assessed by a team unaware of group assignment. The primary outcome was time from induction at randomization to vaginal birth for initial parametric analysis. Sample size was based on mean difference of 240 minutes with α2 = 0.05 and power 95%. Non-parametric analysis was also pre-specified ranking cesareans as longest vaginal births.

RESULTS

Enrollment was from April 1999 to December 2000. Demographics were similar across groups. Analysis was by intent to treat, with no loss to follow up. Mean time (±SD) to vaginal birth was 1356 (±1033) minutes for oral misoprostol, 1530 (±3249) minutes for vaginal misoprostol, and 1208 (±613) minutes for vaginal dinoprostone (P = 0.46, ANOVA). Median times to vaginal birth were 1571, 1339, and 1451 minutes respectively (P = 0.46, Kruskal-Wallis). Vaginal births occurred within 24 hours in 44.9, 53.5 and 47.7% respectively (P = 0.27, χ2). There were no significant differences in Kaplan Meier survival analyses, cesareans, adverse effects, or maternal satisfaction. The newborn who met birth asphyxia criteria received vaginal misoprostol, as did. all three other newborns with cord artery pH<7.0 (P = 0.04, Fisher Exact).

CONCLUSION

There was no significant difference in effectiveness of the three groups. Profound newborn acidemia, though infrequent, occurred only with low dose vaginal misoprostol.

Oral Misoprostol Versus Vaginal Prostaglandin E2 Labor Induction Efficiency, Safety, and Labor Outcomes

BACKGROUND

Prostaglandin E1 (oral misoprostol) and the other Prostaglandin E2 (Dinoprostone gel) are promising agents for cervical ripening and induction of labor.

AIMS OF STUDY

To compare the efficiency and safety on maternal-fetal outcomes using 25 micrograms oral misoprostol PGE1 with 50 micrograms of intra-vaginal PGE2 for induction of labor.

METHODS

This was a retrospective study design reviewing medical records of induced labor at Al Shifa hospital in Gaza Strip.

RESULTS

In general, the results showed that women who used oral misoprostol with an age less than 30 years and parity less than 3 was effective for delivery and safe outcomes with an odds ratio (OR) of 15.8 (CI 6.9–39.8) and OR 29.2 (CI 10.7–80.3) respectively. The most common indication for labor induction in both methods was reputure of the membrane (ROM) more than 24 hours, postdates, and a medical disorder. However, the total interval hours for both methods was 8.4 hours. The mode of delivery was similar in both groups as vaginal delivery outcome was 73.6% for oral misoprostol E1 and 75% for prostaglandin E2 cases. However, PGE2 induction showed a higher cesarean delivery 25% rate versus 18.4%. Clinically the use of oral misoprostol showed a higher percentage of birth canal injury, failed induction, uterine rupture by 9.3%, 8%, 1.3% respectively. Fetal distress was found as the most common fetal complication and the most common cause for cesarean section.

CONCLUSION

The study recommended more research is needed as present evidence does not support use of oral misoprostol versus Prostaglandin E2.

Efficacy comparison of titrated oral solution of misoprostol and intravenous oxytocin on labour induction in women with full-term pregnancy

A double-blind randomised trial was conducted on women with gestational age of 40-42 weeks of pregnancy and Bishop score of more than 5. The first group received oxytocin infusion and the second group received a titrated oral solution of misoprostol. Then, the two groups were compared by the primary outcome (the number of deliveries in the first 24 hours of intervention). The two groups did not have any significant difference in maternal and gestational age at the time of intervention, primary Bishop score, parity and neonatal weight. The number of deliveries in the first 24 hours was greater in the misoprostol group. Duration of onset of intervention to proper contractions was longer in the misoprostol group. However, the number of deliveries between 6-12 hours, 12-18 hours and 18-24 hours after induction was greater in the misoprostol group. The incidence of tachysystole and meconium was greater in the misoprostol group.Impact statementWhat is already known on this subject? Labour induction is widely used where the continuation of pregnancy might be dangerous for the mother or the baby. Of the various methods used for induction, misoprostol which is a prostaglandin E1 analogue has been reviewed more in recent years. Misoprostol has various routes of administration but in most studies only vaginal administration has been evaluated, leaving us with limited data about oral administration.What do the results of this study add? Oral misoprostol is a suitable method for labour induction and can be used as an alternative to oxytocin.What are the implications of these findings for clinical practice and/or further research? Misoprostol is not expensive, has a long shelf life, accessible in underdeveloped countries and rural areas and has several routes of administrations such as oral, sublingual and vaginal. Despite the fact that the oral route of misoprostol has a fast absorption and easier administration, there are relatively few studies assessing the the use of the oral route of misoprostol. Misoprostol is a suitable method for Labour induction and it has the potentials of being used as an alternative for oxytocin, however, the optimum dosages, the preferred route of administration, the maximum dose, the maximum time for administration, and maternal and neonatal safety should be studied more.

Oral misoprostol for induction of labor at term: a randomized controlled trial of hourly titrated and 2 hourly static oral misoprostol solution

Background: Misoprostol has been shown to be effective in induction of labor (IOL) with different dosages and routes of administration.Objectives: This study compared the efficacy and safety of hourly titrated and 2-hourly static low dose oral misoprostol for IOL in Ekiti State University Teaching Hospital, Ado-Ekiti.Methods: One hundred fifty women with singleton pregnancy at term admitted for IOL were randomized into the two groups. Oxytocin augmentation was done as necessary. The primary outcome is rate of vaginal delivery within 24 hours. Data were analyzed using SPSS.Results: Vaginal delivery was achieved within 24 hours in 40 (67.8%) women who received hourly titrated-doses oral misoprostol and 42 (70.0%) women who received 2-hourly static-dose of oral misoprostol, p > .05. The rate of vaginal delivery, oxytocin augmentation, induction delivery time and cesarean section rate were similar in both groups, p > .05. Occurrence of uterine hyperactivity did not differ significantly among the women (p > .05) and no cases of uterine rupture were recorded. There were no adverse neonatal outcomes.Conclusions: The hourly titrated oral misoprostol is as effective and safe as the 2-hourly static oral misoprostol for IOL. Both can be utilized in IOL without the fear of adverse outcomes.