Comparison of 25 and 50 microg vaginally administered misoprostol for preinduction of cervical ripening and labor induction

Comparison of the effect of oral and vaginal misoprostol on labor induction: updating a systematic review and meta-analysis of interventional studies

OBJECTIVES

This study is aimed to compare the effect of oral misoprostol with vaginal misoprostol to induce labor as a systematic review and meta-analysis.

METHODS

Electronic databases including PubMed [Medline], Scopus, Web of science, Embase, Ovid, Cochrane library, and ClinicalTrials.gov were searched using the relevant keywords. All RCTs comparing the effect of oral vs vaginal misoprostol on labor induction were considered. The Cochrane Risk of Bias checklist was used for assessing quality of included RCTs. All statistical analyses were completed using STATA (Version 16) and Revman (Version 5).

RESULTS

Thirty-three RCTs with 5162 patients (1560 in oral and 2602 in vaginal groups) were included in this meta-analysis. Labor induction length did differ significantly between the two routes of misoprostol administration [Standardized Mean Difference: 0.40 h, 95% confidence interval (CI) 0.34, 0.46; I²: 66.35%; P = 0.04]. In addition, the risk of neonatal death, tachysystole, uterine hyperstimulation, preeclampsia, non-FHR and abortion was lower in the oral misoprostol group and the risk of hypertonus, PROM, oxytocin need and cesarean fever was higher in this group than the vaginal misoprostol group.

CONCLUSIONS

Based on results of this meta-analysis, it can be inferred that currently, clinical specialists can decide to use this drug orally or vaginally on a case-by-case basis, depending on the condition of the pregnant mother and the baby.

Which method is best for the induction of labour? A systematic review, network meta-analysis and cost-effectiveness analysis

BACKGROUND

More than 150,000 pregnant women in England and Wales have their labour induced each year. Multiple pharmacological, mechanical and complementary methods are available to induce labour.

OBJECTIVE

To assess the relative effectiveness, safety and cost-effectiveness of labour induction methods and, data permitting, effects in different clinical subgroups.

METHODS

We carried out a systematic review using Cochrane methods. The Cochrane Pregnancy and Childbirth Group's Trials Register was searched (March 2014). This contains over 22,000 reports of controlled trials (published from 1923 onwards) retrieved from weekly searches of OVID MEDLINE (1966 to current); Cochrane Central Register of Controlled Trials (The Cochrane Library); EMBASE (1982 to current); Cumulative Index to Nursing and Allied Health Literature (1984 to current); ClinicalTrials.gov; the World Health Organization International Clinical Trials Registry Portal; and hand-searching of relevant conference proceedings and journals. We included randomised controlled trials examining interventions to induce labour compared with placebo, no treatment or other interventions in women eligible for third-trimester induction. We included outcomes relating to efficacy, safety and acceptability to women. In addition, for the economic analysis we searched the Database of Abstracts of Reviews of Effects, and Economic Evaluations Databases, NHS Economic Evaluation Database and the Health Technology Assessment database. We carried out a network meta-analysis (NMA) using all of the available evidence, both direct and indirect, to produce estimates of the relative effects of each treatment compared with others in a network. We developed a de novo decision tree model to estimate the cost-effectiveness of various methods. The costs included were the intervention and other hospital costs incurred (price year 2012-13). We reviewed the literature to identify preference-based utilities for the health-related outcomes in the model. We calculated incremental cost-effectiveness ratios, expected costs, utilities and net benefit. We represent uncertainty in the optimal intervention using cost-effectiveness acceptability curves.

RESULTS

We identified 1190 studies; 611 were eligible for inclusion. The interventions most likely to achieve vaginal delivery (VD) within 24 hours were intravenous oxytocin with amniotomy [posterior rank 2; 95% credible intervals (CrIs) 1 to 9] and higher-dose (≥ 50 µg) vaginal misoprostol (rank 3; 95% CrI 1 to 6). Compared with placebo, several treatments reduced the odds of caesarean section, but we observed considerable uncertainty in treatment rankings. For uterine hyperstimulation, double-balloon catheter had the highest probability of being among the best three treatments, whereas vaginal misoprostol (≥ 50 µg) was most likely to increase the odds of excessive uterine activity. For other safety outcomes there were insufficient data or there was too much uncertainty to identify which treatments performed 'best'. Few studies collected information on women's views. Owing to incomplete reporting of the VD within 24 hours outcome, the cost-effectiveness analysis could compare only 20 interventions. The analysis suggested that most interventions have similar utility and differ mainly in cost. With a caveat of considerable uncertainty, titrated (low-dose) misoprostol solution and buccal/sublingual misoprostol had the highest likelihood of being cost-effective.

LIMITATIONS

There was considerable uncertainty in findings and there were insufficient data for some planned subgroup analyses.

CONCLUSIONS

Overall, misoprostol and oxytocin with amniotomy (for women with favourable cervix) is more successful than other agents in achieving VD within 24 hours. The ranking according to safety of different methods was less clear. The cost-effectiveness analysis suggested that titrated (low-dose) oral misoprostol solution resulted in the highest utility, whereas buccal/sublingual misoprostol had the lowest cost. There was a high degree of uncertainty as to the most cost-effective intervention.

FUTURE WORK

Future trials should be powered to detect a method that is more cost-effective than misoprostol solution and report outcomes included in this NMA.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013005116.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

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.

Labour induction with 25 micrograms versus 50 micrograms intravaginal misoprostol in full term pregnancies

We undertook this study in order to compare the efficacy of 25 microg versus 50 microg of intravaginal misoprostol for cervical ripening and labour induction at term. The study population consisted of 120 women with term singleton pregnancies in vertex presentation booked for caesarean section. They had a Bishop scoring of <6 and a reactive fetal heart rate tracing. They were randomized into two groups, A and B, to receive 25 microg and 50 microg of vaginal misoprostol, respectively, 4 hourly with a maximum of five doses until the patient had three contractions in 10 minutes. There was no significant difference in the induction delivery interval between the two groups (12.52+/- 7.05 h in the 25 microg group versus 11.72+/- 6.74 h in the 50 microg group; P = 0.58). Of the women in the 25 microg group, 83.3% delivered vaginally as did 71.67% of those in the 50 microg group, but the difference was not statistically significant (P = 0.128). There were significantly more women requiring oxytocin augmentation in the 25 microg group than in the 50 microg group (P = 0.03). However, there were no significant differences in the rates of caesarean and operative vaginal delivery, meconium stained liquor, fetal distress or in the incidences of hyperstimulation between the two groups. Neonatal outcomes were similar. The intravaginal administrations of 25 microg, as well as 50 microg of misprostol, are equally efficacious in inducing labour. The 25 microg group more often required oxytocin as an adjunct.

Induction of labor in great grandmultipara with misoprostol

OBJECTIVE

To compare the efficacy and complications of intravaginal misoprostol application with oxytocin infusion for induction of labor in great grandmultiparous pregnancies with a Bishop score of <6.

STUDY DESIGN

Sixty-four great grandmultiparous (delivering the tenth, or greater, infant) pregnant patients with a Bishop score of <6 were randomized in two groups with 32 patients receiving 50 microg intravaginal misoprostol four times with 4h intervals, and 32 patients receiving oxytocin infusion for induction of labor starting from 2 mIU/min, increasing it every 30 min with 2 mIU/min increments up to maximum of 40 mIU/min. The time from induction to delivery, the route of delivery, fetal outcome and maternal complications were recorded. Statistical analyses were performed using Mann-Whitney U-test, Chi-Square test and hypothesis test about differences for two proportions (t-test) to determine differences between the two groups. P < or = 0.05 was considered significant.

RESULT

The mean time from induction to delivery was 9.91+/-4.30 and 10.88+/-4.72 h in the misoprostol and oxytocin administered group, respectively, with no significant difference between the groups. The rate of vaginal delivery was 84.4 and 87.5% in the misoprostol and oxytocin administered group, respectively, with no significant difference between the groups (P = 0.72). The rates of placental abruption and postpartum hemorrhage were similar in both groups and no case of uterine rupture occurred. The 1 and 5 min mean Apgar scores were 6.91+/-1.57-8.88+/-1.39 and 7.22+/-1.24-9.06+/-0.84 in the misoprostol and oxytocin administered group with no significant differences between the groups (P = 0.38 and 0.51). No case of asphyxia was present. The rate of admission to neonatal intensive care unit was higher in the misoprostol administered group, but the difference was not significant.

CONCLUSION

Intravaginal misoprostol is an alternative method to oxytocin in induction of labor in great grandmultiparous pregnant women with low Bishop scores, as it is effective, cheap and easy to use. Safety about rare complications and neonatal morbidity needs clarifications with further studies.

Labor induction post-term with 25 micrograms vs. 50 micrograms of intravaginal misoprostol

OBJECTIVES

To compare the effectiveness of 25 microg vs. 50 microg of intravaginal misoprostol for cervical ripening and labor induction beyond 41 weeks' gestation.

METHODS

The study population consisted of 120 women not in active labor with a gestational age >41 weeks, singleton pregnancy with vertex presentation, reactive fetal heart rate tracing, amniotic fluid index >/=5, and Bishop score <5. Women were randomized to receive either 25 microg (n=60) or 50 microg (n=60) of intravaginal misoprostol. The dose was repeated every 4 h (maximum number of doses limited to six) until the patient exhibited three contractions in 10 min. The main outcome measure was the induction-vaginal delivery interval.

RESULTS

There was no significant difference between the two groups with regard to the induction-vaginal delivery interval (685+/-201 min in the 25 microg group vs. 627+/-177 min in the 50 microg group, P=0.09). The proportion of women delivering vaginally with one dose of vaginal misoprostol was significantly greater in the 50 microg group (0/49 vs. 41/47, P<0.001). There were no differences in the rates of cesarean and operative vaginal delivery rates, or in the incidences of tachysystole and hyperstimulation syndrome in the two treatment groups. Neonatal outcomes were also similar.

CONCLUSIONS

Intravaginal administration of 25 microg of misoprostol appears to be as effective as 50 microg for cervical ripening and labor induction beyond 41 weeks' gestation.

Vaginal misoprostol for cervical ripening and induction of labour

BACKGROUND

Misoprostol (Cytotec, Searle) is a prostaglandin E1 analogue marketed for use in the prevention and treatment of peptic ulcer disease. It is inexpensive, easily stored at room temperature and has few systemic side effects. It is rapidly absorbed orally and vaginally. Although not registered for such use, misoprostol has been widely used for obstetric and gynaecological 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 trials register (October 2002), the Cochrane Controlled Trials Register (The Cochrane Library, Issue 3, 2002) and bibliographies of relevant papers.

SELECTION CRITERIA

The criteria for inclusion included the following: (1) 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; (2) random allocation to the treatment or control group; (3) adequate allocation concealment; (4) violations of allocated management not sufficient to materially affect conclusions; (5) clinically meaningful outcome measures reported; (6) data available for analysis according to the random allocation; (7) missing data insufficient to materially affect the conclusions.

DATA COLLECTION AND ANALYSIS

A strategy was developed to deal with the large volume and complexity of trial data relating to labour induction. This involved a two-stage method of data extraction. The initial data extraction was done centrally, and incorporated into a series of primary reviews arranged by methods of induction of labour, following a standardised methodology. The data will be extracted from the primary reviews into a series of secondary reviews, arranged by category of woman. To avoid duplication of data in the primary reviews, the labour induction methods have been listed in a specific order, from one to 25. Each primary review includes comparisons between one of the methods (from two to 25) with only those methods above it on the list.

MAIN RESULTS

Sixty-two trials have been included. Compared to placebo, misoprostol was associated with increased cervical ripening (relative risk of unfavourable or unchanged cervix after 12 to 24 hours with misoprostol 0.09, 95% confidence interval (CI) 0.03 to 0.24). It was also associated with reduced failure to achieve vaginal delivery within 24 hours (relative risk (RR) 0.36, 95% CI 0.19 to 0.68). Uterine hyperstimulation, without fetal heart rate changes, was increased (RR 11.7 95% CI 2.78 to 49). Compared with vaginal prostaglandin E2, intracervical prostaglandin E2 and oxytocin, vaginal misoprostol labour induction 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. Compared with intracervical prostaglandin E2, unchanged or unfavourable cervix after 12 to 24 hours was less common with misoprostol. Lower doses of misoprostol compared to higher doses were associated with more need for oxytocin augmentation, less uterine hyperstimulation, with and without fetal heart rate changes, and a non-significant trend to fewer admissions to neonatal intensive care unit. Use of a gel preparation of misoprostol versus tablet was associated with less hyperstimulation and more use of oxytocin and epidural analgesia. Information on women's views is conspicuously lacking.

REVIEWER'S CONCLUSIONS

Vaginal misoprostol appears to be more effective than conventional methods of cervical ripening and labour induction. The apparent increase in uterine hyperstimulation is of concern. Doses not exceeding 25 mcg four-hourly of concern. Doses not exceeding 25 mcg four-hourly appeared to have similar effectiveness and risk of uterine hyperstimulation to conventional labour inducing methods. The studies reviewed were not large enough to exclude the possibility of rare but serious adverse events, particularly uterine rupture, which has been reported anecdotally following misoprostol use in women with and without previous caesarean section. The authors request information on cases of uterine rupture known to readers. Further research is needed to establish the ideal route of administration and dosage, and safety. Professional and governmental bodies should agree guidelines for the use of misoprostol, based on the best available evidence and local circumstances.