A benefit-risk assessment of misoprostol for cervical ripening and labour induction

Comparison of Vaginal and Oral Doses of Misoprostol for Labour Induction in Post-Term Pregnancies

INTRODUCTION

Considering maternal complications, it is preferred to induce labour after 40 weeks. Labour induction is a procedure used to stimulate uterine contractions during pregnancy before the beginning of the labour.

AIM

The aim of this study was to compare oral misoprostol with vaginal misoprostol for induction of labour in post-term pregnancies.

MATERIALS AND METHODS

This double blind clinical-trial study was performed on 180 post-term pregnant women who were admitted to the labour ward of Besat Hospital Sanandaj, Iran in 2013-2014. Participants were equally divided into three groups using block randomization method. The induction was performed for the first group with 100 μg of oral misoprostol, for the second group with 50 μg of oral misoprostol, and for the third group with 25 μg of vaginal misoprostol. Vaginal examination and FHR was done before repeating each dose to determine Bishop Score. Induction time with misoprostol to the start of uterine contractions, induction time to delivery, and mode of delivery, systolic tachycardia, hyper stimulation and fetal outcomes were studied as well.

RESULTS

First minute Apgar scores and medication dosage of the study groups were significantly different (p=0.0001). But labour induction, induction frequency, mode of delivery, complications, and 5 minutes Apgar score in the groups had no significant difference (p>0.05). The risk of fetal distress and neonatal hospitalization of the groups were statistically significant (p=0. 02). There was no significant difference between the three groups in terms of mean time interval from the administration of misoprostol to the start of uterine contractions (labour induction), the time interval from the start of uterine contractions to delivery and taking misoprostol to delivery. From the administration of misoprostol to start of the uterine contractions the mean difference between time intervals in the three groups were not statistically significant.

CONCLUSION

Based on our findings it can be concluded that prescribing 100μg oral misoprostol is effective than 50 μg oral or 25 μg vaginal misoprostol in terms of induction time, maternal and neonatal outcomes in post- term pregnancy. However, the best dose and route should be decided according to evidence based information.

Low-dose oral misoprostol for induction of labor: a systematic review

OBJECTIVE

To estimate the efficacy and safety of low-dose oral misoprostol compared with dinoprostone (PGE2), vaginal misoprostol, and oxytocin for labor induction in women with a viable fetus.

DATA SOURCES

We conducted electronic database searches of PubMed, MEDLINE, EMBASE, and the Cochrane Library for articles published before January 2008 using the keywords misoprostol, labor, induction, randomized controlled trials, dinoprostone, oxytocin, pregnancy, and maternal and fetal side effects.

METHODS OF STUDY SELECTION

We included randomized controlled trials comparing 20-25 micrograms oral misoprostol with vaginal misoprostol, dinoprostone or oxytocin given to women at 32-42 weeks of gestation for labor induction. From 401 citations identified, results from nine studies were finally analyzed using the Review Manager software. Relative risk (RR) and 95% confidence intervals (CIs) were calculated using fixed and random-effects models.

TABULATION, INTEGRATION, AND RESULTS

Nine articles with 2,937 women met the inclusion criteria. The five trials comparing oral misoprostol and dinoprostone showed significantly fewer women requiring cesarean delivery in the misoprostol group (20% compared with 26%; RR 0.82, 95% CI 0.71-0.96). There were no statistically significant differences in risks of uterine hyperstimulation or need for oxytocin augmentation. Two trials compared oral with vaginal low-dose misoprostol. Women using oral misoprostol were significantly less likely to experience uterine hyperstimulation with fetal heart rate changes (2% compared with 13%; RR 0.19, 95% CI 0.08-0.46), but there were no significant differences in other outcomes.

CONCLUSION

Low-dose oral misoprostol solution (20 micrograms) administered every 2 hours seems at least as effective as both vaginal dinoprostone and vaginal misoprostol, with lower rates of cesarean delivery and uterine hyperstimulation, respectively.

Prospective randomised controlled trial to compare safety and efficacy of intravaginal Misoprostol with intracervical Cerviprime for induction of labour with unfavourable cervix

A randomised prospective trial was carried out to compare the efficacy and safety of intravaginal Misoprostol with intracervical dinoprostone gel for induction of labour in cases of unfavourable cervix. One hundred women with an unfavourable cervix requiring induction of labour were randomised to receive either 25 microm vaginal Misoprostol 4-hourly or 0.5 mg of intracervical dinoprostone 12 hourly. The outcome measured was change in Bishop's score, percentage of women going into labour, induction to delivery interval, need for oxytocin, mode of delivery and complications. The parity, mean period of gestation and Bishop's score were similar in both the groups. The improvement in Bishop's score at 12 h was significantly better in the Misoprostol group. Induction to delivery interval was shorter in the Misoprostol group, 16.59 +/- 5.13 h vs 27.77 +/- 12.71 h. The rate of complications was comparable. Vaginal Misoprostol 25 microg 4-hourly is safe and effective for induction of labour with shorter induction to delivery interval.

A randomised controlled trial of intravaginal dinoprostone, intravaginal misoprostol and transcervical balloon catheter for labour induction

OBJECTIVE

To compare the efficacy and safety of induction of labour by vaginal application of dinoprostone or misoprostol or transcervical insertion of a balloon (Bard) catheter.

DESIGN

A non-blinded, randomised, controlled trial.

SETTING

A tertiary level Swedish hospital.

POPULATION

A total of 592 women who had undergone full-term pregnancies, not previously been subjected to a caesarean section, and required induction of labour for common, routine indications.

METHODS

Women were randomly assigned to induction of labour using intravaginal dinoprostone (2 mg once every 6 hours) or misoprostol (25 micrograms once every 4 hours) or a transcervical balloon catheter.

MAIN OUTCOME MEASURES

The time interval between induction to delivery in general and vaginal delivery in particular, the mode of delivery, maternal and neonatal parameters of outcome.

RESULTS

Of the 588 subjects included in the final intention-to-treat analysis, 191 were assigned to treatment with dinoprostone, 199 with misoprostol and 198 with the balloon catheter. The shortest mean induction-to-delivery interval was obtained with the catheter (12.9 hours versus 16.8 and 17.3 hours for dinoprostone and misoprostol, respectively). The efficacies of the two prostaglandins were similar. The maternal and neonatal outcomes associated with each of the three procedures were similar.

CONCLUSIONS

Induction of labour with a transcervical balloon catheter is effective and safe and can be recommended as the first choice. The two prostaglandins, dinoprostone and misoprostol, were shown to be equally effective and safe, while misoprostol costs significantly less and is easier to store.

The routine use of oxytocin after oral misoprostol for labour induction in women with an unfavourable cervix is not of benefit

BACKGROUND

Induction of labour with misoprostol is often augmented with oxytocin with the possible consequence of uterine hypercontractility. It is important to determine whether the use of oxytocin in this circumstance has benefit as well as risk.

AIM

To compare two regimens for labour induction in women with an unfavourable cervix: oral misoprostol vs. oral misoprostol routinely followed by oxytocin.

METHODS

A prospective randomised trial in which 200 women with an unfavourable cervix received either oral misoprostol 25 microg every 3 h (group 1, n = 100) or two such doses routinely followed by oxytocin (group 2, n = 100). Outcomes included change in Bishop score, induction delivery interval, oxytocin requirement, contraction abnormalities, mode of delivery and neonatal outcome.

RESULT

The improvement in Bishop score with two misoprostol doses in all 200 women was highly significant (2.9 +/- 1.5 to 6.6 +/- 1.9, P < 0.0001). The induction delivery interval, Caesarean delivery rate, vaginal delivery rate within 24 h, contraction abnormalities and neonatal outcome were similar in both groups. Contraction abnormalities were remarkably low with either regimen (1%). Routine addition of oxytocin 3 h after the second misoprostol dose (group 2) resulted in the maximum oxytocin dose (64 mU/min) being given to more women (66% in group 2; 36% in group 1).

CONCLUSION

There was no benefit of routine addition of oxytocin after two doses of misoprostol. Reduced oxytocin requirement was observed when it was added only if needed. Both regimens achieved 85-87% vaginal deliveries with low incidence of hypercontractility.

Misoprostol for Labor Induction in Women With Term Premature Rupture of Membranes

OBJECTIVE

To systematically review published data evaluating the comparative use of misoprostol with placebo/expectant management or oxytocin for labor induction in women with term (> or = 36 weeks of gestation) premature rupture of membranes.

DATA SOURCES

PubMed (1966-2005), Ovid (1966-2005), CINAHL, The Cochrane Library, ACP Journal Club, OCLC, abstracts from scientific forums, and bibliographies of published articles were searched using the following keywords: premature rupture of membranes, misoprostol, labor induction, and cervical ripening. Primary authors were contacted directly if the data sought were unavailable or only published in abstract form.

METHODS OF STUDY SELECTION

Only randomized controlled trials evaluating the efficacy and safety of misoprostol in comparison with placebo or expectant management (n = 6) and oxytocin (n = 9) published in either article or abstract form were analyzed and included in the meta-analysis.

TABULATION, INTEGRATION, AND RESULTS

Studies were reviewed independently by all authors. Meta-analysis was performed, and the relative risks (RRs) were calculated and pooled for each study outcome. Misoprostol, compared with placebo, significantly increased vaginal delivery less than 12 hours (RR 2.71, 95% confidence interval [CI] 1.87-3.92, P < .001). Misoprostol was similar to oxytocin with respect to vaginal delivery less than 24 hours (RR 1.07, 95% CI 0.88-1.31, P = .50) and less than 12 hours (RR 0.98, 95% CI 0.71-1.35, P = .90). Misoprostol was not associated with an increased risk of tachysystole, hypertonus, or hyperstimulation syndrome when compared with oxytocin and had similar risks for adverse neonatal and maternal outcomes.

CONCLUSION

Misoprostol is an effective and safe agent for induction of labor in women with term premature rupture of membranes. When compared with oxytocin, the risk of contraction abnormalities and the rate of maternal and neonatal complications were similar among the 2 groups.

Oral misoprostol versus intracervical dinoprostone for induction of labor

OBJECTIVES

To compare oral misoprostol with dinoprostone for induction of labor and their effects on the fetal heart rate patterns.

METHODS

In a randomized controlled trial, 200 patients received either misoprostol 50 mug orally for every 4 h, or dinoprostone 0.5 mg intracervically for every 6 h. Cardiotocographic recordings, in 10-min windows 30, 60, and 80 min after prostaglandin administration during induction and continuously during labor, were compared between the two groups. Primary outcome for effectiveness and safety was assessed in terms of the number of vaginal deliveries within 24 h and fetal heart rate abnormalities during induction and labor respectively.

RESULTS

Data from 96 patients in the misoprostol group and 95 in the dinoprostone group were analyzed. There were no significant differences in respect of the number of vaginal deliveries within 24 h (RR 1.12; 95% CI 0.88-1.42). The frequency of suspicious and pathological fetal heart rate patterns did not differ significantly but significantly more cardiotocographs in the dinoprostone group had non-reassuring baseline variability 60 min after dose administration (RR 0.33; 95% CI 0.14-0.77). Maternal and neonatal outcomes did not differ significantly.

CONCLUSION

Oral misoprostol is as effective as intracervical dinoprostone for induction of labor with no difference in the frequency of fetal heart rate abnormalities.

Misoprostol and pregnancy: ever-increasing indications of effective usage

PURPOSE OF REVIEW

The subject of misoprostol in the field of reproductive health care has courted much controversy. The aim of this review is to survey the literature published in this field over the past year, and to evaluate developments in this area. This article will cover termination of pregnancy, induction of labor and the issue of postpartum hemorrhage.

RECENT FINDINGS

The use of misoprostol as a single agent remains of clinical value when mifepristone is unavailable. The sublingual and rectal routes are alternative modes of administration. For induction of labor, the optimum dose and route of misoprostol is still undetermined. Lower doses of between 20 microg to 40 microg may increase the safety profile for labor induction. Misoprostol may be a useful adjunct to the therapeutic options available for the prevention and treatment of postpartum hemorrhage.

SUMMARY

There are many potential uses for misoprostol in pregnancy. However clinicians must judge the evidence and the emotive debate surrounding this field and decide how it will influence their clinical practice depending on the priorities of their own clinical circumstances.

A randomised trial comparing low dose vaginal misoprostol and dinoprostone for labour induction

OBJECTIVE

To compare vaginal misoprostol with dinoprostone for induction of labour.

DESIGN

Randomised multicentre trial.

SETTING

Labour wards of one university hospital and two teaching hospitals.

POPULATION

Six hundred and eighty-one women with indication for labour induction at >or=36 weeks of gestation, singleton pregnancy and no previous ceasarean section.

METHODS

Misoprostol (25 mcg, hospital-prepared capsule) in the posterior vaginal fornix, every four hours, maximum three times daily or dinoprostone gel (1 mg) every four hours. Oxytocin was administered if necessary.

MAIN OUTCOME MEASURES

Primary: 'adverse neonatal outcome' (5-minute Apgar score <7 and/or umbilical cord pH <7.15). Secondary: labour duration, mode of delivery and patient satisfaction.

RESULTS

Three hundred and forty-one women received misoprostol and 340 dinoprostone. The median induction-delivery interval was longer in the misoprostol group compared with the dinoprostone group (25 versus 19 hours, P= 0.008). The caesarean section rate was lower in the misoprostol group: 16.1%versus 21%, but this difference was not statistically significant RR = 0.8 (95% CI 0.6-1.04). 'Adverse neonatal outcome' was found to be similar in both groups: 21% in the misoprostol and 23% in the dinoprostone groups. Significantly fewer neonates were admitted to NICU in the misoprostol group compared with dinoprostone 19%versus 26% (RR = 0.7, 95% CI 0.5-0.98).

CONCLUSIONS

Misoprostol in this dosing regimen is a safe method of labour induction. NICU admission rates were lower in the misoprostol group. No difference could be detected in patient satisfaction between groups.

Induction of labour with an unfavourable cervix

Labour induction is undertaken when the advantages for the mother and/or the baby are considered to outweigh the disadvantages. When the uterine cervix is unfavourable, oxytocin, with or without amniotomy, is frequently ineffective. Vaginal prostaglandin E(2) is most commonly used if it is affordable. Evidence regarding many alternative methods is discussed in this chapter. Of particular interest are misoprostol and extra-amniotic saline infusion.Misoprostol, an orally active prostaglandin E(1) analogue, has been used widely by the vaginal and oral routes for labour induction at or near term. Several recent trials have confirmed that it is highly effective. Overall Caesarean section rates appear to be reduced, despite a relative increase in Caesarean sections for fetal heart rate abnormalities. Concern remains regarding increased rates of uterine hyperstimulation and meconium-stained amniotic fluid, although data on perinatal outcome have been reassuring. Postpartum haemorrhage may be increased following labour induction with misoprostol, and isolated reports of uterine rupture, with or without previous Caesarean section, have appeared. Using small dosages appears to reduce adverse outcomes. Very large trials are needed to evaluate rare adverse outcomes.Extra-amniotic saline infusion is an effective method which appears to reduce the risk of uterine hyperstimulation that occurs with the use of exogenous uterotonics.