Misoprostol for induction of labour at term: a more effective agent than dinoprostone vaginal gel

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.

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.

Comparing birth experience and birth outcome of vaginal births between induced and spontaneous onset of labour: a prospective study

PURPOSE

In developed countries, around 25% of all births involve labour induction. Studies have indicated that labour induction negatively influences the birth experience as well as the birth process. However, the impact of labour induction when only considering vaginal deliveries has not been studied yet, which was the purpose of the present study.

METHODS

186 women who gave birth vaginally took part in this prospective study. 95 women gave birth after spontaneous onset of labour (SL-group) and 91 women received a labour induction (LI-group). Eight to 72 h after birth, the women filled in the revised version of the standardised Childbirth Experience Questionnaire, which examines the birth experience in four dimensions (Own Capacity, Perceived Safety, Participation and Professional Support). Medical details regarding birth and fetal outcomes were taken from the medical records.

RESULTS

Birth outcomes (the number of epidural anaesthesia, the duration of birth, birth risks and childbirth injuries) as well as fetal outcomes (APGAR after 1 and 5 min and arterial cord pH) did not differ between the groups. Regarding the subjective birth experience, the LI-group indicated significantly lower values for Perceived Safety and Participation compared to the SL-group, while there were no differences for the dimensions Own Capacity and Professional Support.

DISCUSSION

Successful labour induction resulting in a vaginal birth did not negatively influence birth and fetal outcomes and only partly affected the women's birth experience. The negative impact of labour induction on the dimensions Perceived Safety and Participation should sensitize midwives in order to provide optimal support.

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.

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.

Feasibility, acceptability, and programme effectiveness of misoprostol for prevention of postpartum haemorrhage in rural bangladesh: a quasiexperimental study

We explored the feasibility of distributing misoprostol tablets using two strategies in prevention of postpartum haemorrhage (PPH) among women residing in the Abhoynagar subdistrict of Bangladesh. We conducted a quasiexperimental study with a posttest design and nonequivalent comparison and intervention groups. Paramedics distributed three misoprostol tablets, one delivery mat (Quaiyum's delivery mat), a packet of five standardized sanitary pads, and one lidded plastic container with detailed counseling on their use. All materials except misoprostol were also provided with counseling sessions to the control group participants. Postpartum blood loss was measured by paramedics using standardized method. This study has demonstrated community acceptability to misoprostol tablets for the prevention of PPH that reduced overall volume of blood loss after childbirth. Likewise, the delivery mat and pad were found to be useful to mothers as tools for assessing the amount of blood loss after delivery and informing care-seeking decisions. Further studies should be undertaken to explore whether government outreach health workers can be trained to effectively distribute misoprostol tablets among rural women of Bangladesh. Such a study should explore and identify the programmatic requirements to integrate this within the existing reproductive health program of the Government of Bangladesh.

Comparative evaluation of 50 microgram oral misoprostol and 25 microgram intravaginal misoprostol for induction of labour at term: a randomized trial

OBJECTIVES

To assess and compare the efficacy and safety of 50 µg oral misoprostol and 25 µg intravaginal misoprostol for induction of labour at term.

METHODS

This non-blinded, randomized clinical trial included 228 pregnant women at term with obstetric or medical indications for induction of labour. Women either took 50 µg misoprostol orally (two 25 µg tablets) or had one 25 µg tablet of misoprostol inserted in the posterior vaginal fornix. In each group, misoprostol administration was repeated every four hours in the same dose until regular uterine contractions were established or to a maximum of five doses. Time to delivery and outcome data for each group were compared.

RESULTS

Of the 228 women, eight (3.5%) were excluded from the analysis as they withdrew their consent after randomization. Mean induction-to-delivery interval was similar in both groups (21.22 hours in the oral group vs. 20.15 hours in the vaginal group; P = 0.58). There was no significant difference between the groups with respect to the number of women who delivered within 24 hours or who required oxytocin augmentation of labour, the mode of delivery, and neonatal outcomes (P > 0.05). Uterine hyperstimulation occurred in two women who received misoprostol vaginally, but not in any of the women in the oral misoprostol group.

CONCLUSION

Oral misoprostol in a dose of 50 µg every four hours, to a maximum of five doses, has the potential to induce labour as safely and effectively as 25 µg misoprostol administered vaginally every four hours.

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.

Electron microscopic visualization of the filament binding mode of actin-binding proteins

A large number of actin-binding proteins (ABPs) regulate various kinds of cellular events in which the superstructure of the actin cytoskeleton is dynamically changed. Thus, to understand the actin dynamics in the cell, the mechanisms of actin regulation by ABPs must be elucidated. Moreover, it is particularly important to identify the side, barbed-end or pointed-end ABP binding sites on the actin filament. However, a simple, reliable method to determine the ABP binding sites on the actin filament is missing. Here, a novel electron microscopic method for determining the ABP binding sites is presented. This approach uses a gold nanoparticle that recognizes a histidine tag on an ABP and an image analysis procedure that can determine the polarity of the actin filament. This method will facilitate future study of ABPs.

A randomised controlled trial of low-dose misoprostol and dinoprostone vaginal pessaries for cervical priming

OBJECTIVE

We studied the efficacy of 25-microg misoprostol pessaries as either single or double dose compared with a 3-mg dinoprostone pessary for cervical priming.

DESIGN AND SETTING

A randomised controlled trial in Singapore.

POPULATION

One hundred and seventy-one women with term pregnancies and modified Bishop scores (mBS) < or =6 from 2003 to 2004.

METHOD

Patients were randomised to single misoprostol dose, double misoprostol dose or the current dinoprostone regimen.

MAIN OUTCOME MEASURES

Primary outcome was number of women who achieved favourable mBS >6 or active labour by day 2. Secondary outcomes were time interval from insertion to delivery, cardiotocographic abnormalities, delivery and neonatal outcome.

RESULTS

More women in the misoprostol double-dose group (96.6%) and dinoprostone group (93%) achieved the primary outcome compared with the single-dose group (77.8%) (P = 0.003 and P = 0.03, respectively). There was no difference in secondary outcomes. More multiparous women achieve primary outcome compared with nulliparous women (odds ratio 0.21, 95% confidence interval 0.06-0.77).

CONCLUSION

Double-dose misoprostol 25 microg is as effective as dinoprostone 3 mg inserts for cervical priming; both are more efficacious than a single-dose misoprostol pessary. Parity prognosticates the success of induction.

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.

Which route of misoprostol application is more advantageous prior to fractional curettage in postmenopausal patients?

PURPOSE

To determine the effectiveness and potential side effects of oral, vaginal, and sublingual intake of misoprostol on cervical dilatation prior to fractional curettage in patients with postmenopausal bleeding.

METHODS

Seventy-six patients with postmenopausal bleeding during a period of 18 months were included in this randomized controlled trial. Patients were given 400 microg of misoprostol through the vaginal, oral, and sublingual routes, 12 h prior to the fractional curettage procedure. The degree of cervical dilatation, duration of the procedure, the side effects and complications were noted.

RESULTS

When compared with the control group, misoprostol administered orally or sublingually was found to have a significant effect on cervical dilatation (P < 0.05). Of the three groups, nausea was found to be more common in the orally administered misoprostol group.

CONCLUSIONS

We conclude that the oral or sublingual application of misoprostol prior to fractional curettage in patients with postmenopausal bleeding decreases the need for cervical dilatation.

Labor induction in preeclampsia: is misoprostol more effective than dinoprostone?

OBJECTIVE

To compare the efficacy of vaginal misoprostol versus dinoprostone for induction of labor (IOL) in patients with preeclampsia according to the WHO criteria.

STUDY DESIGN

Ninety-eight patients were retrospectively analyzed. A total of 47 patients received 3 mg dinoprostone suppositories every 6 h (max. 6 mg/24 h) whereas 51 patients in the misoprostol group received either 50 mug misoprostol vaginally every 12 h, or 25 mug every 6 h (max. 100 mug/24 h). Primary outcomes were vaginal delivery within 24 and 48 h, respectively.

RESULTS

The probability of delivering within 48 h was more than three-fold higher in the misoprostol than in the dinoprostone group: odds ratio (OR)=3.48; 95% confidence interval (CI) 1.24, 10.30, whereas no significant difference was observed within 24 h (P=0.34). No correlation was seen between a ripe cervix prior to IOL and delivery within 24/48 h (P=0.33 and P=1.0, respectively). More cesarean sections were performed in the dinoprostone group due to failed IOL (P=0.0009). No significant differences in adverse maternal outcome were observed between both study groups, whereas more neonates (12 vs. 6) of the dinoprostone group were admitted to the NICU (P=0.068).

CONCLUSION

This study suggests that misoprostol may have some advantages compared to dinoprostone, including improved efficacy and lower cost of the drug, even in cases of preeclampsia.

Misoprostol compared with prostaglandin E2 for labour induction in women at term with intact membranes and unfavourable cervix: a systematic review*

BACKGROUND

Misoprostol is a commonly used prostaglandin to induce labour. A potential risk of induction, however, is caesarean delivery, especially in women with an unfavourable cervix.

OBJECTIVES

To evaluate the use of misoprostol, compared with prostaglandin E2 (PgE2), for labour induction in women at term with an unfavourable cervix and intact membranes.

SEARCH STRATEGY

PubMed, Medline, EMBASE and the Cochrane Library were searched for articles published in any language from January 1987 to December 2005, using the keywords 'misoprostol', 'labour/labor' and 'induction'.

SELECTION CRITERIA

We identified randomised trials of women at term (> or =37 weeks of gestation) with intact membranes and unfavourable cervix, undergoing labour induction with misoprostol, orally, vaginally, sublingually or buccally, compared with PgE2 vaginally or intracervically.

DATA COLLECTION AND ANALYSIS

Caesarean delivery was the primary outcome, with tachysystole and hyperstimulation as secondary outcomes. The primary analysis compared any misoprostol with any PgE2 for all women, with a subgroup analysis for nulliparous women. Secondary analyses compared different routes and doses of misoprostol (oral or vaginal and 25 microgram or >25 microgram) and PgE2 (intracervical or vaginal). Relative risks (RR) and 95% confidence intervals (CI) were calculated using random effects models. Main results Fourteen of 611 articles identified met the criteria for systematic review, with three providing information for nulliparous women. There was no difference in the risk of caesarean delivery between misoprostol and PgE2 groups (RR = 0.99, 95% CI = 0.83-1.17). Any misoprostol was associated with higher risks of tachysystole and hyperstimulation compared with any PgE2 (RR = 1.86, 95% CI = 1.01-3.43 and RR = 3.71, 95% CI = 2.00-6.88, respectively). There was a higher rate of vaginal delivery within 24 hours among all vaginal deliveries with any misoprostol compared with any PgE2 (RR = 1.14, 95% CI = 1.00-1.31), and among all deliveries, a lower rate of oxytocin use (RR = 0.71, 95% CI = 0.60-0.85) but a trend towards increased meconium staining was observed (RR = 1.22, 95% CI = 0.96-1.55). The use of misoprostol at starting dosages >25 microgram had similar findings to the primary analysis. Studies of lower misoprostol dosing (starting dose of 25 microgram) did not show any differences in the outcomes of interest, but the sample size of this secondary analysis was small (304 women, 155 receiving misoprostol).

AUTHOR'S CONCLUSIONS

Although misoprostol in women at term with an unfavourable cervix and intact membranes was more effective than PgE2 in achieving vaginal delivery within 24 hours, misoprostol does not reduce the rate of caesarean delivery either in all women or in the subgroup of nulliparous women, and it increases the rates of tachysystole and hyperstimulation. Further studies of misoprostol using a starting dose of 25 microgram may be warranted.

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.

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.

Intravaginal misoprostol versus Foley catheter for cervical ripening and induction of labor

OBJECTIVE

To compare the efficacy and safety of 100 microg of intravaginal misoprostol with intracervical Foley catheter for cervical ripening and induction of labor.

METHOD

One hundred women being induced in the Lagos University Teaching Hospital, Nigeria, were randomized to receive a single 100 microg dose of misoprostol intravaginally or intracervical insertion of Foley catheter. Data analyses were by the Student's t-test and chi-square test.

RESULT

Misoprostol was more effective in terms of induction to delivery interval (11.84+/-5.43 versus 20.03+/-4.68 h, P<0.05), change in Bishop score, and number delivered within 24 h, in patients with a one-time successful induction. Uterine hyperactivity and rupture were more frequent in the misoprostol group.

CONCLUSION

A single 100 microg dose of intravaginal misoprostol is more efficacious than intracervical insertion of Foley catheter for cervical ripening and induction of labor. Further studies using lower doses are needed to determine the safest dose.

A randomised controlled trial comparing low dose vaginal misoprostol and dinoprostone vaginal gel for inducing labour at term

OBJECTIVE

To compare the efficacy of low dose vaginal misoprostol and dinoprostone vaginal gel for induction of labour at term.

DESIGN

A single-blind randomised controlled trial.

SETTING

Antenatal and labour ward of a UK district general hospital.

PARTICIPANTS

Two hundred and sixty-eight women requiring induction of labour at term (>37 weeks of gestation) with no significant fetal or medical condition, no previous uterine surgery and no contraindication to prostaglandin.

METHODS

Misoprostol 25 microg (one-quarter of a 100 microg tablet) was inserted into the posterior vaginal fornix every 4 hours (to a maximum of six doses) or dinoprostone vaginal gel 1-2 mg 6 hourly (maximum of 3 mg in 24 hours).

MAIN OUTCOME MEASURE

Induction-to-vaginal delivery interval.

SECONDARY OUTCOME MEASURES

Requirements for oxytocin, mode of delivery, number of women delivering < 24 hours, incidence of uterine contraction abnormalities, incidence of abnormal cardiotocograph (CTG) recordings, 5-minute Apgar scores, umbilical cord pH recordings, analgesia requirements, admission to NICU and blood loss at delivery.

RESULTS

There were no significant differences between the two groups in induction-to-vaginal delivery interval, mode of delivery, number of women delivering within 24 hours and neonatal outcomes. The incidence of uterine contraction abnormalities (tachysystole and hyperstimulation) and the incidence of abnormal CTG recordings were also similar for both groups.

CONCLUSION

Low dose vaginal misoprostol is as effective as dinoprostone gel for inducing labour at term. There would be substantial cost savings, estimated at around 3.9 million UK pounds per annum, for maternity services if low dose misoprostol became the agent of choice for inducing labour in the UK.

The vagina as a route for systemic drug delivery

Exhaustive efforts have been made toward the administration of drugs, via alternative routes, that are poorly absorbed after the oral administration. The vagina as a route of drug delivery has been known since ancient times. In recent years, the vaginal route has been rediscovered as a potential route for systemic delivery of peptides and other therapeutically important macromolecules. However, successful delivery of drugs through the vagina remains a challenge, primarily due to the poor absorption across the vaginal epithelium. The rate and extent of drug absorption after intravaginal administration may vary depending on formulation factors, vaginal physiology, age of the patient and menstrual cycle. Suppositories, creams, gels, tablets and vaginal rings are commonly used vaginal drug delivery systems. The purpose of this communication is to provide the reader with a summary of advances made in the field of vaginal drug delivery. This report, therefore, summarizes various vaginal drug delivery systems with an introduction to vaginal physiology and factors affecting drug absorption from the vaginal route.

Management of late intrauterine death using a combination of mifepristone and misoprostol—experience of two regimens

OBJECTIVE

To determine the safety and effectiveness of managing intrauterine death after 24 weeks gestation using a combination of mifepristone and misoprostol.

STUDY DESIGN

Two regimens are compared. Twenty-nine women (group one) were managed using a combination of oral mifepristone and vaginal/oral misoprostol. After a change in dosage and route of administration, a further 20 women were managed with oral mifepristone and vaginal misoprostol (group two).

RESULTS

All women delivered vaginally. The mean induction to delivery interval in group one was 7 h compared with 10.2 h in group two. Group two experienced fewer gastrointestinal side-effects than group one.

CONCLUSION

This study confirms that the combined use of mifepristone and misoprostol is a safe and effective way of managing IUD after 24 weeks gestation. Regimen one results in a shorter induction to delivery interval but is associated with a higher incidence of gastrointestinal side-effects.

Vaginal misoprostol for cervical priming before dilatation and curettage in postmenopausal women: a randomized controlled trial

AIM

To investigate the efficacy of vaginal misoprostol for cervical priming before dilatation and curettage in postmenopausal women.

METHODS

Forty-four postmenopausal women with indication for dilatation and curettage were randomly assigned to receive either 400 micro g of misoprostol or placebo vaginally 6 h before dilatation and curettage. The main outcome measures were the number of women who required cervical dilatation, cervical width, time taken to dilate to Hegar 6 and other complications.

RESULTS

The mean cervical diameter (4.59 millimeters in the misoprostol group vs 4.41 millimeters in the placebo group) was comparable between the two groups. A similar number of women in the misoprostol group and in the placebo group required cervical dilatation (12 vs 16, P = 0.35). The operative times for both groups were similar. The incidence of side-effects was comparable in both groups. There were two uterine perforations in the misoprostol group (2 vs 0).

CONCLUSION

There was no significant benefit from applying 400 micro g vaginal misoprostol 6 h prior to dilatation and curettage in postmenopausal women.

Prediction of adverse outcome associated with vaginal misoprostol for labor induction

OBJECTIVE

To identify predictors of adverse outcome in pregnant women at term receiving 50 microg of intravaginal misoprostol for labor induction.

STUDY DESIGN

A prospective observational study was conducted of 720 pregnant women at term with an unfavorable cervix and a medical or obstetric indication for labor induction. All patients received 50 microg of intravaginal misoprostol every 4h up to three doses. The primary outcome measure was "adverse outcome" defined as: neonatal death, fetal acidemia and emergent cesarean delivery performed for non-reassuring fetal heart rate tracings. A stepwise logistic regression analysis was used to identify predictors of adverse outcome.

RESULTS

Tachysystole (frequent uterine contractions) (odds ratio (OR), 3.7; 95% confidence interval (CI), 1.2-10.8) and fetal tachycardia (OR, 4.8; 95% CI, 1.4-16.2) were determined as significant predictors of adverse outcome. The specificity of the model was 94.2%, whereas the sensitivity was 20.4%.

CONCLUSION

In the absence of tachysystole and fetal tachycardia, an uneventful delivery might be expected for women receiving 50 microg of intravaginal misoprostol.

Six hourly vaginal misoprostol versus intracervical dinoprostone for cervical ripening and labor induction

AIM

Prospective clinical trials were conducted to assess the safety and efficacy of 6-hourly vaginal misoprostol versus intracervical dinoprostone for induction of labor.

METHODS

A total of 120 pregnant women requiring induction of labor were recruited. Cases were randomized to receive either 50 microg vaginal misoprostol 6 hourly (group 1, n = 60) or 0.5 mg intracervical dinoprostone 6 hourly (group II, n = 60). Outcome measures, such as change in Bishop's score, need of oxytocin, induction delivery interval; complications like tachysystoly, hyperstimulation, abnormal fetal heart rate, and meconium passage were compared between two groups. Statistical analysis was performed by Wilcoxan's Rank sum and Student's t-test.

RESULTS

Bishop score rise, after 6 h of initiation of therapy was significantly higher in the misoprostol group than dinoprostone, 2.98 +/- 2.57 versus 2.05 +/- 1.83 (P = 0.04). The need of oxytocin augmentation was reduced in misoprostol versus dinoprostone group, 16.6% versus 78.3% (P = <0.001). Induction delivery interval was shorter in misoprostol; 12.8 +/- 6.4 h versus 18.53 +/- 8.5 h in dinoprostone group (P = <0.01). One case (1.6%) in misoprostol group, but none in dinoprostone had tachystole (P = 1.00). Abnormal heart rate pattern was found more in misoprostol than dinoprostone 16.6% versus 4.9% (P = 0.14) and so was the incidence of cesarean section, 26.6 versus 15%, respectively (P = 0.47). Meconium passage was the same in both groups, 10% in each group.

CONCLUSION

Vaginal misoprostol 50 microg 6-hourly is safe and effective for induction of labor with lesser need of oxytocin augmentation and shorter induction delivery interval.

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.

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.

No benefit, but increased harm from high dose (100 microg) misoprostol for induction of labour: a randomised trial of high vs. low (50 microg) dose misoprostol

Misoprostrol, a synthetic analogue of prostaglandin E(1), has been used for cervical preparation. Its ideal dose, route and frequency of administration are still under investigation. We conducted a randomised controlled trial, in a tertiary hospital in a developing country, to compare misoprostol 50 microg (low) and 100 microg (high) for effectiveness and safety in induction of labour at term. Women admitted for induction of labour with a singleton live fetus in cephalic presentation after 37 weeks' gestation were recruited. A misoprostol tablet was inserted in the posterior vaginal fornix at 8-hour intervals. Main outcomes were duration of induction, maternal and fetal complications. The mean duration of induction was 15.4 (SD 10.6) and 14.2 (SD 13.6) h in the low- and high-groups respectively (P = 0.095). There was no difference in need for augmentation with oxytocin (OR 0.82; 95% Cl 0.36-1.86) or operative delivery (OR 1.29; 95% CI 0.26-6.84). There were two uterine ruptures and four intrapartum stillbirths in the high misoprostol group. There was no difference in postpartum haemorrhage, 9.5% vs. 7.9% (P = 1.00) and admissions to the neonatal unit 18.8% vs. 17.0% (P = 0.980) in the 1ow- and high-groups) respectively. Misoprostol 50 microg was as effective as the 100 microg dose for induction of labour whereas the higher dose had an increased risk of serious complications.

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.

Randomized study of vaginal misoprostol (PGE(1)) and dinoprostone gel (PGE(2)) for induction of labor at term

OBJECTIVES

To investigate the efficacy and safety of misoprostol in the induction of labor at term by comparing this agent with the commonly used dinoprostone gel.

PATIENTS AND METHODS

A randomized clinical trial of vaginal misoprostol, 50 microg 6-hourly, and dinoprostone gel, 1-2 mg 6-hourly, in 435 women undergoing induction of labor at term. The women, 210 in the misoprostol group and 225 in the dinoprostone group, were compared to determine whether there was a significant difference in achieving vaginal delivery within 24 h, the incidence of hyperstimulation syndrome, Cesarean section rate and adverse neonatal outcome. They were also offered the option of preinduction sonographic cervical assessment.

RESULTS

Misoprostol, compared to dinoprostone gel, was associated with a significantly shorter median induction-to-delivery interval (14.6 h vs. 19.0 h; P = 0.0014), a higher incidence of vaginal delivery within 24 h of induction (65.7% vs. 54.2%; P = 0.019) and a reduced need for oxytocin augmentation during labor (20.5% vs. 29.8%; P = 0.034). The groups did not differ significantly in the rates of Cesarean section (18.1% vs. 19.1%; P = 0.88) and hyperstimulation syndrome (2.4% vs. 0.9%; P = 0.27). None of the cases of hyperstimulation required treatment with tocolysis. All nine cases of excessive uterine contractility occurred after the first dose of the drug. There were no significant differences in maternal and neonatal morbidity between the two groups. There was a significant association between preinduction cervical length and the induction-to-delivery interval in both those receiving misoprostol and those treated with dinoprostone.

CONCLUSIONS

The use of misoprostol is associated with a shorter duration of labor and a higher rate of vaginal delivery within 24 h from induction without an increase in maternal and neonatal morbidity. Transvaginal sonographic measurement of cervical length is useful in the prediction of the likelihood of vaginal delivery within 24 h of induction and of the induction-to-delivery interval and may be useful in the stratification of patients participating in randomized studies that examine the effectiveness of inducing agents.

Misoprostol versus dinoprostone for cervical priming prior to induction of labour in term pregnancy: a randomised controlled trial

A prospective randomised controlled trial was performed to compare the efficacy and safety of intravaginal misoprostol to that of intravaginal dinoprostone when used for cervical priming prior to the induction of labour; 126 women were recruited to the study and randomised to receive either intravaginal dinoprostone (n = 63) or misoprostol (n = 63) for cervical priming prior to induction of labour. The mean time from insertion of the priming agent to vaginal delivery was significantly shorter in the misoprostol group (925.8 versus 1577.6 minutes), the mean duration of the active length of labour was significantly shorter in the misoprostol group (353.7 versus 496.8 minutes) and more women in the misoprostol group delivered in less than 12 hours (92% versus 76.5%). Women in the misoprostol group were less likely to require a repeated dose of prostaglandin for cervical priming and less likely to require oxytocin for augmentation of labour. There was no difference in the number of women who were delivered vaginally or by Ceasarean section between the two groups. More women developed hyperstimulation during labour in the misoprostol group; however there was no difference between the groups in neonatal outcome in respect to low cord pH or Apgar score at delivery or admission to the neonatal special care nursery.

A comparison of oral and vaginal misoprostol tablets in induction of labour at term

OBJECTIVE

To compare the efficacy of equivalent doses of orally administered with vaginally administered misoprostol in induction of labour at term.

DESIGN

A non-blinded randomised controlled trial.

SETTING

Induction and labour wards of a UK teaching hospital.

PARTICIPANTS

Two hundred and forty-five pregnant women at term, with medical or obstetric indications for labour induction and unfavourable cervices.

METHODS

The women were randomly assigned to receive 50 microgm of misoprostol orally or vaginally four hourly to a maximum of five doses.

MAIN OUTCOME MEASURES

Interval from induction to vaginal delivery, mode of delivery, oxytocic and analgesic requirements in labour, neonatal outcome, patient satisfaction and acceptability.

RESULTS

The mean induction to vaginal delivery interval was significantly shorter in the vaginal group compared with the oral group (17.8h vs 27.9h: mean difference 10.1 hrs, 95% CI 5.8-14.4). More women were delivered within 24 hours (80% vs 46.3%; RR 1.7, 95% CI 1.3-2.1) and fewer women needed oxytocin augmentation (39% vs 58.2%; RR 0.67, 95% CI 0.5-0.9) in the vaginal group. There was no difference in the mode of delivery, analgesic requirements or neonatal outcomes in the two groups. There was a higher incidence of uterine hyperstimulation in the vaginal group (4.9% vs 0.8%, RR 6, 95% CI 0.07-48.7) and more caesarean sections were performed for fetal distress in this group (13% Vs 2.4%, RR 5.3, 95% CI 1.6-17.7), although the overall operative delivery rate was similar in the two groups.

CONCLUSION

Misoprostol effectively induces labour, with the vaginal route of administration having a faster action than the oral route in equivalent doses. However, the more frequent occurrence of hyperstimulation and the higher intervention rate for fetal distress in the vaginal group could mean that the preferred route might be oral. More trials are needed to find the right oral dosage that combines efficacy with safety.

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.