Randomized comparison between intravaginal misoprostol and dinoprostone for cervical ripening and induction of labor

Safety of misoprostol vs dinoprostone for induction of labor: A systematic review and meta-analysis

OBJECTIVE

Pharmacological agents such as prostaglandins (dinoprostone and misoprostol) are commonly used to reduce the duration of labor and promote vaginal delivery. However, key safety considerations with its use include an increased risk of uterine rupture, tachysystole and hyperstimulation of pregnant women, which could potentially lead to a non-reassuring fetal heart rate and to fetal hypoxemia. The aim of this systematic review was to assess maternal and fetal outcomes between misoprostol group (PGE1) and dinoprostone group (PGE2) STUDY DESIGN: We search on MEDLINE (PubMed), CINHAL (EBSCOhost), EMBASE, Scopus (Ovid), CENTRAL (January 1, 1998, to December 31, 2022). Patients were eligible if they presented at greater than 36 weeks gestation with an indication for induction of labor and a single live cephalic fetus. We conducted a meta-analysis of data for both primary (cesarean section rate, instrumental deliveries rate, tachysystole, uterine rupture, post-partum haemorrage; chorionamiositis) and secondary outcomes (Apgar at 5 min <7, meconium-stained liquor, NICU admission, infant death) using odds-ratio (OR) as a measure of effect-size. Risk of bias assessment was performed with RoB-I. We performed statistical analyses using Cochrane RevMan version 5.4 software.

RESULTS

We found 39 RCTs comparing the outcomes of interest between misoprostol and dinoprostone. The pooled effect showed no statistically significant difference between the two groups in terms of cesarean section rate [OR: 0.94; 95% CI 0.84-1.05], instrumental deliveries rate [OR: 1.04; 95% CI: 0.90-1.19; p = 0.62], tachysystole [OR: 1.21; 95% CI: 0.91-1.60; p = 0.19], post-partum hemorrhage [OR: 0.85; 95% CI: 0.62-1.15p = 0.30], chorioamnionitis [OR: 0.94; 95% CI: 0.76-1.17p = 0.59], Apgar at 5 min < 7 [OR: 0.83; 95% CI: 0.61-1.12, p = 0.21], meconium-stained liquor [OR: 1.11; 95% CI: 0.97-1.27p = 0.59], NICU admission group [OR: 0.91; 95% CI: 0.77-1.09], infant death [OR: 0.57; 95% CI: 0.22-1.44]. After performing a sub-group analysis based on the type of prostaglandins administrations (oral, vaginal gel, vaginal pessary), results did not change substantially.

CONCLUSIONS

This systematic review and meta-analysis demonstrate that misoprostol and dinoprostone appear to have a similar safety profile.

A Comparative Study of the Efficacy and Safety of Oral Misoprostol, Intravenous Oxytocin, and Intravaginal Dinoprostone for Labor Induction in Pakistani Women

INTRODUCTION

A frequent medical procedure to accelerate labor is the induction of labor. There are different methods of labor induction, including the use of medications such as misoprostol, oxytocin, and dinoprostone.

OBJECTIVE

This research compared the effectiveness and safety of oral misoprostol, intravenous oxytocin, and intravaginal dinoprostone for labor induction in Pakistani women.

METHODOLOGY

A study was conducted in the Department of Obstetrics and Gynaecology, Hayatabad Medical Complex-Medical Teaching Institute (MTI) and Lady Reading Hospital-MTI, Peshawar, Pakistan, over two years. It included 378 women between 38 and 42 gestational weeks, divided into three groups of 126 women each. The oral misoprostol group was given a maximum of six doses of a 25 μg oral misoprostol solution (oral misoprostol tablet of 200 μg dissolved in 200 ml) at intervals of two hours. The drip rate for the intravenous oxytocin group ranged from 6 mIU/minute to 37 mIU/minute. The intravaginal dinoprostone group received a controlled-release vaginal insert containing 10mg of intravaginal dinoprostone, which was left in place for 12 hours.

RESULTS

More women in the oral misoprostol group (n=94; 74.6%) had successful inductions when compared to the intravaginal dinoprostone (n=83; 65.9%) and intravenous oxytocin (n = 77; 64.71%) groups. Oral misoprostol had the greatest proportion of normal vaginal deliveries (n=62; 65.95%), followed by intravaginal dinoprostone (n=47; 56.63%), and intravenous oxytocin had the lowest rate (n=33; 42.85%). Cesarean section rates were greatest in the intravenous oxytocin group (n=31; 40.26%), followed by the intravaginal dinoprostone group (n=29; 34.94%), and lowest in the oral misoprostol group (n=24; 25.53%).

CONCLUSION

Oral misoprostol induces labor in women safely and effectively, resulting in the lowest percentage of cesarean deliveries and the highest percentage of normal vaginal deliveries, respectively. Intravaginal dinoprostone showed the lowest rate of side effects, followed by oral misoprostol while intravenous oxytocin had the highest rate of side effects.

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.

Isosorbide Mononitrate a Nitric Oxide Donor: A Study of Its Efficacy and Safety as an Agent for Cervical Ripening

OBJECTIVE

To study the efficacy and safety profile of isosorbide mononitrate (IMN) as an agent for cervical ripening.

METHODOLOGY

This study was conducted in the Department of Obstetrics and Gynecology, M Y Hospital & M G M Medical College Indore from September 2011 to February 2013. Pregnant women attending the antenatal clinics were screened for possible participation in the study after explaining the nature of the study. This study was conducted on 150 patients. An initial dose of 40 mg IMN was applied in the posterior vaginal fornix, and the same dose was repeated after 6 h. Cervical ripening was assessed by the change in Bishop Score 12 h after the initial application.

RESULTS

In a study of 150 cases, mean maternal age was 22.2 ± 2.6 years (range 19-35 years) and mean gestational age was 40.5 ± 1.07 (range 40-42 weeks). 52 women were primigravidas, while 98 were multigravidas. The mean Bishop Score-before drug administration was 1.94 ± 1.3 (range 0-5), and mean fetal heart rate was 137 ± 6.2 bpm. The mean of Bishop scores before IMN administration was 1.94 ± 1.3, while mean of Bishop score after drug administration was 6.7 ± 2.2; mean difference was equal to 4.76. P value was equal to 0.0001. By conventional criteria, this difference is considered to be statistically significant. The mode of delivery 96 (64 %) delivered vaginally, while 54 (36 %) were delivered by Cesarean section. Mean Apgar score at 1 min was 8.2 ± 0.9 SD (range 7-10), while mean Apgar score at 5 min was 9.4 ± 0.6 (range 8-10). The only side effect noted was headache, and 30 cases (20 %) complained of headache.

CONCLUSION

IMN seems to be effective, safe, inexpensive, and well-tolerated agent for cervical ripening. It is cost effective and safe with minimal side effects.

Labor Induction with 50 μg Vaginal Misoprostol: Can We Reduce Induction-Delivery Intervals Safely?

OBJECTIVE

To compare the efficacy and safety profile of two methods of labor induction i.e., intracervical dinoprostone gel (0.5 mg 8 h) and misoprostol (50 μg 4 h) for induction of labor in women with a poor Bishop's score.

DESIGN

Observational study.

STUDY PERIOD

January 1st, 2009 to December 31st, 2010.

POPULATION

A total of 329 women with unfavorable cervices induced at or near term.

METHODS

Two cervical ripening agent study arms were used: dinoprostone gel (193 women) and misoprostol (137 women).

MAIN OUTCOME MEASURES

Induction to delivery interval, cesarean section, incidence of meconium stained liquor, FHR pattern, incidence of uterine hyperstimulation, and neonatal outcomes.

RESULTS

The induction to delivery interval was significantly shorter in the misoprostol group as compared to the dinoprostone group (p < 0.001). There was no difference in cesarean section rates between the two groups (dinoprostone gel 43 %; misoprostol 33 %; p = 0.144). The incidence of non-reassuring fetal heart rate pattern, meconium stained liquor, and uterine hyperstimulation were equivalent in both the groups (p = 0.529; 0.733; and 0.321, respectively). The neonatal outcomes in both the groups were comparable in terms of Apgar scores at birth (p = 0.160) and NICU admissions (p = 0.951).

CONCLUSIONS

Labor induction in women with unfavorable cervices results in high caesarean section rates. However, the use of misoprostol significantly reduces the induction to delivery interval, without adversely affecting the caesarean section rates and neonatal outcomes. Hence it may become a cost-effective alternative to dinoprostone gel in resource-poor settings like India.

Oral motor assessment in individuals with Moebius syndrome

BACKGROUND

Moebius syndrome (MS) is a rare congenital condition that is characterised by facial hypomimia and congenital strabismus caused by complete or partial impairment of the 6th and 7th cranial nerves. MS may be further associated with other nerves or malformations, mainly involving the extremities. The objective of this study was to quantify the decrease in oral motor performance in people with MS compared with normoreactive individuals using the Oral Motor Assessment Scale (OMAS).

METHODS

The study group comprised 33 subjects between the ages of 2 and 20 years (average age: 10 ± 5 years) with MS along with 46 age- and gender-matched control subjects.

RESULTS

The study group displayed a lower average functional score than the control group (P < 0.0001). A significant lack of lip closure (P = 0.03) and anterior lingual seal during swallowing (P = 0.03) occurred in the study group; in most cases, the individuals with MS were classified as 'subfunctional'. In addition, individuals with MS in the older age group displayed better functional scores than those in the younger group (P = 0.05).

CONCLUSIONS

Functional damage to oral motor function in individuals with MS is evident, but differs among patients with respect to severity and the movements that are compromised. However, overall, improvements in the functional patterns of these individuals can be observed as they mature in age.

Misoprostol for term labor induction: a randomized controlled trial

OBJECTIVES

The aim of this study was to compare the efficacy of vaginal misoprostol with vaginal dinoprostone for term labor induction.

MATERIAL AND METHODS

It was a randomized controlled trial done in the Obstetrics Department, Shifa Community Health Centre, Shifa International Hospital (Teaching Hospital of Shifa College of Medicine, Islamabad). All pregnant women at term pregnancy coming for induction of labor were enrolled. 246 women fulfilled the inclusion criteria. Out of them 208 women consented to be part of the study. These women were then randomized to receive either Treatment A (vaginal misoprostol) or Treatment B (vaginal dinoprostone). Data were completed for 200 women. These included induction labor and induction-delivery interval, fetal and maternal complications, and baby apgar score.

RESULTS

Out of 200 women in the study, 100 were in Group A and 100 in Group B. Labor commenced in a mean of 6.67 hours (± 3.63) in Group A whereas it took a mean of 8.41 hours (± 5.13) in Group B (p=0.00). Actual induction to delivery (of the baby) interval was a mean of 11.68 hours (± 4.55) for misoprostol and 15.37 hours (± 5.30) for dinoprostone group (p=0.00). There were no cases of uterine rupture in both groups; however, there were 10 cases of uterine hyperstimulation in Group A and 4 in Group B (p=0.09).

CONCLUSIONS

It is time to re-evaluate the role of misoprostol for term labor induction. It is an efficacious and cost-effective alternative to the presently licensed treatment.

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.

Vaginal Misoprostol Administration for Cervical Ripening and Labor Induction

Intravaginal misoprostol has been shown to be an effective agent for cervical ripening and induction of labor. Vaginal application of misoprostol has been reported in over 9000 women worldwide and seems to have safety profile similar to that of endocervically and intravaginally administered dinoprostone. Concern arises with the use of higher doses of intravaginal misoprostol (50 mcg or more) and the association with uterine contractile abnormalities and for this reason, use of low-dose misoprostol regimen has been recommended by the American College of Obstetricians and Gynecologists. The recommendation is use of a 25-mcg dose of misoprostol inserted into the posterior vaginal fornix and repeated every 3 to 6 hours as needed. Misoprostol administration to women with prior cesarean births seems to increase the likelihood of uterine scar disruption and should not be used in these women. There are reports of uterine rupture in women with unscarred uteri treated with vaginally applied misoprostol. Therefore, all patients need to be monitored adequately after misoprostol administration. Although there is a growing body of data regarding the ambulatory use of intravaginal misoprostol for cervical ripening, its use for this purpose cannot be recommended outside of investigational protocols at this time because of concerns for maternal and neonatal safety.

Intravaginal glyceryl trinitrate and dinoprostone for cervical ripening and induction of labor

OBJECTIVE

This study was undertaken to evaluate the efficacy and safety of intravaginal administration of glyceryl trinitrate plus dinoprostone versus dinoprostone, for cervical ripening and induction of labor.

STUDY DESIGN

A prospective, double-blind, placebo-controlled, randomized clinical trial was conducted among 196 singleton low-risk nullipara women with term pregnancies and unfavorable cervices who were randomly assigned to receive intravaginal glyceryl trinitrate plus dinoprostone or placebo plus dinoprostone. The main outcome variables were time from application to active phase of labor and to delivery. Secondary outcomes were change in Bishop score, fetal and maternal morbidity, and incidence of cesarean deliveries.

RESULTS

The interval from application of the initial dose to the beginning of active phase of labor was 868 +/- 582 and 1136 +/- 692 minutes (P = .004) and from initial dose to delivery was 1339 +/- 826 and 1620 +/- 975 minutes (P = .03) for the glyceryl trinitrate and placebo groups, respectively. There were no significant differences in Bishop score change, cesarean section rate, and in the incidence of hypersystole and hyperstimulation. The incidence of tachysystole was significantly lower in the glyceryl trinitrate group (4% vs 15%, P < or = .02). No maternal and neonatal adverse effects were noted.

CONCLUSION

The association of glyceryl trinitrate with dinoprostone is more effective than dinoprostone alone for labor induction in low-risk patients at term with unfavorable cervices.

Induction of labor

The rate of labor induction continues to rise significantly in the United States because of a growing use of labor induction for postterm pregnancies and elective induction of labor. Although different types and doses of prostaglandins used for cervical ripening often initiate uterine activity, the principal role of these agents is to soften the unripe cervix independent of uterine activity. Several systematic reviews with meta-analyses have shown that prostaglandins are superior to placebo and oxytocin alone in ripening of the cervix. Numerous studies and meta-analyses have assessed misoprostol's efficacy and safety as a labor induction agent. The most appropriate dose and route of administration has not yet been confirmed.

Dinoprostone versus misoprostol: a randomized study of nulliparous women undergoing induction of labor

BACKGROUND

The objectives of the study were to compare the efficacy and safety of intravaginal misoprostol and intravaginal dinoprostone for induction of labor and to quantify the clinical response to suspicious cardiotocographic (CTG) readings.

METHODS

One hundred and ninety-one patients were randomized to receive either 50 micro g misoprostol initially then a further identical dose 6 h later or 2 mg dinoprostone initially followed by 1 mg 6 h later, over a period of 24 h. If not in labor after 24 h, then both arms of the study would thereafter receive dinoprostone alone as per hospital protocol.

RESULTS

The induction to delivery interval (1047 vs. 1355 min, p = 0.01), delivery within 12 h (35.4% vs. 18.9%, p = 0.02) and delivery within 24 h (83.3% vs. 63.3%, p = 0.01) were all shorter in the misoprostol arm. There were no differences in rates of oxytocin augmentation (p = 0.47), tachysystole (p = 0.32) and hyperstimulation syndrome (p = 0.82). There was an increase in the median number of times a doctor was called to advise on a suspicious CTG in the misoprostol group (1 vs. 2 occasions, p = 0.052), but there was no difference in neonatal outcome.

CONCLUSIONS

Intravaginal misoprostol led to a shorter, more efficient labor, and although there was more anxiety related to the CTG, there was no increase in neonatal adverse effects.

Misoprostol and dinoprostone therapy for labor induction: a Doppler comparison of uterine and fetal hemodynamic effects

OBJECTIVE

To compare the effect of misoprostol (PGE(1)) versus dinoprostone (PGE(2)) on blood flow in uteroplacental circulation during labor induction.

STUDY DESIGN

Eighty-four women with indications for induction of labor were assigned to receive either misoprostol 50 microg per vagina every 4 h as needed or 0.5 mg doses of dinoprostone given intra-cervically every 6 h by means of a randomization table generated by computer. Doppler velocimetry of umbilical, uterine and arcuate arteries was performed immediately before and 2-3 h after the administration of misoprostol or dinoprostone. The SAS system was used to perform statistical analysis.

RESULTS

There were no significant changes of pulsatility index (PI), resistance index (RI) and systolic/diastolic (S/D) ratio in umbilical arteries after both prostaglandin compounds. Vaginal application of misoprostol significantly increased all ratios in arcuate artery and S/D ratio in uterine artery. Intra-cervically dinoprostone significantly increased PI, RI and S/D ratio in arcuate and uterine arteries.

CONCLUSIONS

Our results indicate that vaginal misoprostol and cervical dinoprostone administration increases uteroplacental resistance but does not affect umbilical blood flow. Misoprostol would be as safe and effective agent as dinoprostone for cervical ripening and labor induction.

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.

A comparison of 100 microg oral misoprostol every 3 hours and 6 hours for labor induction: a randomized controlled trial

OBJECTIVE

To compare the efficacy and safety of 100 microg oral misoprostol for induction of labor between the regimen of 3 hour and 6 hour interval administration.

METHODS

Singleton pregnancies indicated for induction of labor between 34 and 42 weeks of gestation in the condition of unfavorable cervix (Bishop score < or = 4) and no contraindication for prostaglandins therapy were recruited into the study. All pregnant women were randomly assigned to receive 100 microg oral misoprostol every 3 hours or 6 hours until the cervix was favorable for amniotomy, spontaneous rupture of membranes or active labor occurred.

RESULTS

The mean time interval from induction to vaginal delivery was significantly shorter in the 3 hour interval group, compared with the 6 hour interval group (13.82 +/- 6.98h and 17.66 +/- 7.48h, P = 0.0019). There was no significant difference between the groups with regard to mode of delivery, analgesic requirement, maternal complication and neonatal outcome.

CONCLUSIONS

100 microg oral misoprostol every 3 hours is more effective for labor induction than every 6 hours but there was no difference in mode of delivery, analgesic requirement, maternal complications and neonatal outcome. A dose of 100 microg misoprostol orally every 3 hours seems to be the optimum regimen and the new option for labor induction. However, further study should be performed.

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

Misoprostol, a prostaglandin E(1) analogue, is widely used in the US and other countries for cervical ripening and labour induction. Its use for these indications is not approved by the US Food and Drug Administration (FDA). The manufacturer of misoprostol issued a letter to American healthcare providers in August 2000, cautioning against the use of misoprostol in pregnant women and citing a lack of safety data for its use in obstetrical practice. The only FDA-approved indication in the product labelling is the treatment and prevention of intestinal ulcer disease resulting from nonsteroidal anti-inflammatory drug use. Multiple trials have proven that when applied vaginally, misoprostol is an effective agent for cervical ripening and labour induction in term pregnancy. The use of oxytocin augmentation is reduced when intravaginal misoprostol is used compared with other agents. Misoprostol use in obstetrics carries the added benefits of temperature stability at room temperature, which is unlike other prostaglandin preparations which require refrigeration or freezing, and reduced cost. However, debate continues regarding the optimal dose, dosage regimen, and route of administration. Uterine contraction abnormalities are often found in association with higher misoprostol doses (50 microg or more) given vaginally or orally. Some trials also indicate increased frequencies of meconium passage, neonatal acidaemia and caesarean delivery for fetal distress in women receiving higher doses of vaginally applied misoprostol. However, most trials fail to demonstrate a significant change in the caesarean delivery rate with the use of misoprostol, although a recent meta-analysis indicated that the use of intravaginal misoprostol is associated with a lowering of the caesarean rate when compared with pooled controls. Low-dose misoprostol (25 microg) is an effective agent for cervical ripening and labour induction when used in a judicious and cautious fashion. There are insufficient data to support the widespread use of oral misoprostol for cervical ripening and labor induction. Some trials suggest that this approach may be effective; however, the ideal dose and administration regimen have yet to be defined.

Induction of labour with a viable infant: a randomised clinical trial comparing intravaginal misoprostol and intravaginal dinoprostone

OBJECTIVE

To compare the efficacy and safety of vaginal misoprostol (50 microg) with vaginal dinoprostone.

DESIGN

Double-blind randomised trial.

SETTING

Obstetrics Department, Poissy Hospital, France.

PARTICIPANTS

370 patients with medical indications for induction of labour.

OUTCOME MEASURES

Vaginal deliveries within 24 hours, as well as time to vaginal deliveries, caesarean rates, costs, and fetal, neonatal and maternal condition.

RESULTS

Compared with vaginal dinoprostone, vaginal misoprostol resulted in greater efficacy in several areas: vaginal delivery within 24 hours; time to vaginal delivery; and vaginal delivery within 12 hours. There was a non-significant increase in the caesarean section rate for fetal distress in the misoprostol group, but fewer caesarean sections for failed induction. Fetal tolerance was similar in the two groups, although significantly more neonates had a cord pH <7.20 and (non-significantly) none had meconium stained amniotic fluid in the misoprostol group. The incidence of poor neonatal outcome was similar in both groups. Subgroup analysis by indication for induction showed that the higher rates of arterial cord pH <7.20 and of meconium-stained amniotic fluid with misoprostol persisted only in possible fetal compromise. Poor neonatal outcome was less frequent in the misoprostol group in cases of induction for non-fetal indications.

CONCLUSIONS

Vaginal misoprostol resulted in successful and earlier induction of labour more often than dinoprostone, but the safety of misoprostol raises some concern in potentially compromised infants. Misoprostol should be preferred to dinoprostone in cases of induction for non-fetal indications.

A comparison of oral and vaginal misoprostol for induction of labour at term: a randomised trial

OBJECTIVE

To compare the efficacy of oral with vaginal misoprostol for induction of labour at term.

DESIGN

Randomised trial.

SETTING

Tertiary Care hospital.

PARTICIPANTS

One hundred and sixty-seven women requiring induction of labour.

METHODS

The women were randomised to receive 50 microg of misoprostol orally or vaginally every 6 h until the cervix was favourable for amniotomy, spontaneous rupture of membranes, or active labour occurred. Sample size was calculated with a two-tailed alpha of 0.05 and a power of 95% to detect a 5 h difference in induction-to-delivery time. Student's t test was used for comparison of normally distributed continuous variables and the Mann-Whitney U test was used for non-Gaussian distributed continuous variables. Fisher' s exact and chi2 tests were used for comparison of categorical variables. The main outcome measure was induction to delivery time.

RESULTS

The median induction to delivery time was significantly shorter with vaginal misoprostol (15.7 h range 4.3-55.7), compared with oral misoprostol (23.0 h range 3.2-141.7, P = 0.0013). The median number of doses was also significantly less in the vaginal misoprostol group, 1 (range 1-3), compared with the oral group, 2 (range 1-8), (P < 0.0001). The significant differences in outcome held true when nulliparous and multiparous women were analysed separately. There were no differences between the two routes of administration with respect to rates of hyperstimulation or neonatal asphyxia. There were more caesarean sections in the vaginal misoprostol group, but the difference was not statistically significant.

CONCLUSIONS

Compared with oral misoprostol, vaginal misoprostol for induction of labour at term results in a shorter induction-to-delivery time, with fewer doses required per patient. Vaginal misoprostol may be associated with higher rates of caesarean section than oral misoprostol.

Labor induction

Labor induction has become commonplace in modern obstetrics. The increasing rate of labor induction has probably played a role in the increased rate of cesarean delivery observed in the United States during the past few decades. Clearly, the favorability of the cervix has a substantial impact on the potential success of any labor induction. Induction in the setting of an unfavorable cervix can result in prolonged induction, prolonged hospitalization, failed induction, and an increased cesarean delivery rate. In this modern era of healthcare reform and cost containment, the identification of therapeutic strategies to enhance the success and cost-effectiveness of labor induction are of great interest. Ongoing research is needed to advance our knowledge of the mechanisms of parturition and cervical ripening in order to direct interventions for labor induction more effectively.

Use of misoprostol in obstetrics and gynecology

Misoprostol is prostaglandin E1 analogous and marketed for prevention and treatment of peptic ulcer disease. However, it has been used widely in obstetrics and gynecology practice because of its effectiveness, low cost, stability in light and hot climate conditions, and ease of administration compared with its licensed counterparts--dinoprostone and gemeprost. A large number of studies have shown that misoprostol is effective in first and second trimester abortion, late pregnancy labor induction, and third stage of labor management (misoprostol has not been approved by the U.S. Food and Drug Administration for these indications). Because misoprostol is not registered for such use, it has not undergone the extensive testing for appropriate dosage and safety required for registration. Serious complications such as teratogenesis after failed abortions and uterine rupture during second trimester abortions and third trimester labor induction have been reported as the result of increasingly wide use of misoprostol in obstetric and gynecology practice. There is an urgent need to evaluate all the available data and organize a large randomized trial to determine the safety of its use in obstetric and gynecology practice.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader will be able to identify the various uses of misoprostol, to describe the potential complications of misoprostol use and its teratogenic effects, to compare the various routes of administration, and to define the appropriate dose.