Misoprostol versus low-dose oxytocin for cervical ripening: a prospective, randomized, double-masked trial

Effect of misoprostol versus oxytocin on delivery outcomes after labour induction in pregnant women: A systematic review and meta-analysis of randomized controlled trials

A large number of randomized controlled trials (RCTs) have been published on the effects of oral/vaginal misoprostol and oxytocin on delivery outcomes; however, data from these RCTs are conflicting. Although some meta-analyses summarized available findings in this regard, several eligible RCTs have been published since the release of those meta-analyses. Therefore, the current updated systematic review and meta-analysis of RCTs was conducted to compare the effects of oral/vaginal misoprostol and oxytocin on delivery and neonatal outcomes. A systematic search, using relevant keywords, was done in the online databases of PubMed/Medline, Scopus, and ISI Web of Science, up to April 2023, to identify eligible articles investigating the effect of oral/vaginal misoprostol and oxytocin on delivery outcomes including maternal [cesarean/vaginal delivery within 24 h after labour induction, Tachysystole, hypertonicity, hyper-stimulation, postpartum hemorrhage (PPH)] and neonatal outcomes [mean Apgar score, admission to neonatal intensive care unit (NICU), and death]. In total, 45 RCTs with a total sample size of 8406 participants were included. Meta-analysis revealed that vaginal misoprostol administration, compared with oxytocin, resulted in a significant reduction in the rate of cesarean and a significant increase in the rate of vaginal delivery and Tachysystole risk. Also, oral misoprostol was associated with a significant reduction in the rate of cesarean and a significant increase in the risk of hypertonicity compared with oxytocin. However, oral misoprostol had no significant effect on vaginal delivery compared with oxytocin. For other outcomes including hyper-stimulation, perinatal death, NICU admission, and mean Apgar score among newborns, we found no significant difference between oral/vaginal misoprostol and oxytocin. In total, vaginal/oral misoprostol might be a better method for labour induction compared with oxytocin. PROSPERO registration: CRD42023412325.

Labor induction with oxytocin in pregnant rats is not associated with oxidative stress in the fetal brain

Despite the widespread use of oxytocin for induction of labor, mechanistic insights into fetal/neonatal wellbeing are lacking because of the absence of an animal model that recapitulates modern obstetric practice. Here, we create and validate a hi-fidelity pregnant rat model that mirrors labor induction with oxytocin in laboring women. The model consists of an implantable preprogrammed microprocessor-controlled infusion pump that delivers a gradually escalating dose of intravenous oxytocin to induce birth at term gestation. We validated the model with molecular biological experiments on the uterine myometrium and telemetry-supported assessment of changes in intrauterine pressure. Finally, we applied this model to test the hypothesis that labor induction with oxytocin would be associated with oxidative stress in the newborn brain. Analysis of biomarkers of oxidative stress and changes in the expression of associated genes were no different between oxytocin-exposed and saline-treated pups, suggesting that oxytocin-induced labor was not associated with oxidative stress in the developing brain. Collectively, we provide a viable and realistic animal model for labor induction and augmentation with oxytocin that would enable new lines of investigation related to the impact of perinatal oxytocin exposure on the mother-infant dyad.

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.

First experiences with neuropsychological effects of oxytocin administration in childhood-onset craniopharyngioma

PURPOSE

The hypothalamic hormone oxytocin plays a major role in regulation of behavior and body composition. Quality of survival is frequently impaired in childhood craniopharyngioma patients due to sequelae such as behavioral deficits and severe obesity caused by tumor or treatment-related hypothalamic lesions.

METHODS

In our pilot cross-sectional study, we analyzed emotion recognition abilities and oxytocin concentrations in saliva and urine before and after single nasal administration of 24 IU oxytocin in 10 craniopharyngioma patients. Four craniopharyngioma presented with grade I lesions (limited to anterior hypothalamic areas) and 6 craniopharyngioma with grade II lesions (involving mammillary bodies and posterior hypothalamic areas). Emotional tasks were assessed before and after administration of oxytocin using the Geneva multimodal emotion portrayals corpus and the Multidimensional Mood Questionnaire.

RESULTS

All patients presented with detectable levels of oxytocin before administration. Nasal administration of oxytocin was well-tolerated and resulted in increased oxytocin concentrations in saliva and urine. After oxytocin administration, craniopharyngioma patients with postsurgical lesions limited to the anterior hypothalamus area showed improvements in emotional identifications compared to craniopharyngioma patients with lesions of anterior and posterior hypothalamic areas. Focusing on correct assignments to positive and negative emotion categories, craniopharyngioma patients improved assignment to negative emotions.

CONCLUSIONS

Oxytocin might have positive effects on emotion perception in craniopharyngioma patients with specific lesions of the anterior hypothalamic area. Further studies on larger cohorts are warranted.

Induction of Labor in Women with Oligohydramnios: Misoprostol Compared with Prostaglandin E2

Objective To compare perinatal outcomes in women with oligohydramnios and an unfavorable cervix undergoing labor induction with misoprostol to prostaglandin E2. Study Design We conducted a secondary analysis of women with oligohydramnios undergoing labor induction in the Consortium on Safe Labor study (2002-2008). Oligohydramnios was recorded in the medical chart. We evaluated perinatal outcomes. We limited the analysis to women with an unfavorable cervix defined by simplified Bishop score ≤ 4. Misoprostol was compared with prostaglandin E2. Women could have received oxytocin, underwent mechanical dilation, or had artificial rupture of membranes, but women who underwent induction with both misoprostol and prostaglandin E2 were excluded. We calculated adjusted odds ratios with 95% confidence intervals, controlling for maternal age, maternal body mass index (kg/m²), parity, and mechanical dilation. Results Among women with oligohydramnios and an unfavorable cervix who underwent induction of labor, 141 (39.4%) received misoprostol and 217 (60.6%) received prostaglandin E2. There were no significant differences in cesarean delivery, chorioamnionitis, postpartum hemorrhage, transfusion, neonatal intensive care unit (NICU) admission, NICU stay > 72 hours, mechanical ventilation, and neonatal sepsis. Conclusion In women with oligohydramnios and an unfavorable cervix, induction of labor with misoprostol was comparable to prostaglandin E2.

Induction of labor--pharmacology methods

Pharmacologic methods for induction of labor have been used for many decades. Pharmacologic agents have an advantage over mechanical methods in that they can be used during both the initial cervical ripening stage of induction and throughout the second stage of labor. Pharmacologic induction agents such as prostaglandins and oxytocin are commonly used for labor and delivery floors and are well established for use in cervical ripening. Nitric oxide donors and mifepristone are known agents in medicine but are new and actively studied in the area of cervical ripening. These agents are introduced and analyzed in this review.

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 versus high dose of oxytocin for labor induction: a comparative study

To compare the efficacy and complications of intravaginal Misoprostol with oxytocin for induction of labor this study was carried out. One hundred and ten term pregnant women with Bishop score of < or = 4 were randomized into two groups. Fifty five patients received 50 microg intravaginal Misoprostol 2 times at 6 h intervals (Misoprostol group), the second group received oxytocin infusion (6 mu min(-1)) for induction of labor (oxytocin group n = 55). The time from induction to delivery, the route of delivery, fetal outcome and maternal complications were recorded. There was no statistically significant difference regarding demographic or clinical characteristics between two groups. Induction success within the first 12 h were 80 and 33.3% for Misoprostol and oxytocin groups respectively (p<0.05). The average time from induction to delivery was 10. 6 +/- 3.7 and 17 +/- 7.2 h in the Misoprostol and oxytocin administered groups, respectively (p<0.05). The rate of vaginal delivery was significantly higher in misoprostol group (72.7%) when compared with oxytocin group (45.5%). Low Apgar score, meconium stain amniotic fluid, abnormal FHR and precipitating labor was similar in both groups (p>0.05). We concluded misoprostol 50 microg vaginally (every 6 h, up to 100 microg) safely and effectively induces labor and it is recommended for parturient women with Bishop score < or = 4 and the use of this drug could produce several beneficial effects, particularly a decrease in the incidence of cesarean delivery.

Randomized trial of preinduction cervical ripening: misoprostol vs oxytocin

OBJECTIVE

The purpose of this study was to compare the vaginal delivery rate in women who undergo labor induction with preinduction misoprostol or oxytocin alone.

STUDY DESIGN

Women with singleton pregnancies and Bishop scores <5 with labor induction at > or = 24 weeks of gestation were eligible; they were assigned randomly to oxytocin alone or preinduction cervical ripening with misoprostol. Labor characteristics, maternal complications, and neonatal outcomes were analyzed.

RESULTS

One hundred sixty-three women received oxytocin, and 164 women received misoprostol. Maternal demographics, pretreatment Bishop scores, and labor analgesia were similar between groups. Vaginal delivery rates were also similar: 87% (n = 141) for oxytocin and 81% (n = 133) for misoprostol. Mean time from treatment to delivery was shorter for the oxytocin group, compared with the misoprostol group (13.1 vs 16.3 hours; P = .005). There was no difference in maternal complications or neonatal outcomes between groups.

CONCLUSION

Preinduction cervical ripening with misoprostol did not improve the vaginal delivery rate and resulted in longer intervals to active labor and delivery. Preinduction cervical ripening with misoprostol may not be necessary.

The impact of duration of labor induction on cesarean rate

OBJECTIVE

We sought to determine maternal factors that influence success of labor induction and whether the probability of cesarean delivery changed with time during induction.

STUDY DESIGN

We performed a retrospective cohort study of 1650 singleton pregnancies induced at a gestation of 37 weeks or longer, with birthweights of 2500 g or greater, and without congenital anomalies. We used multivariate logistic regression to calculate odds ratios for cesarean.

RESULTS

Nulliparity (odds ratio [OR] 7.8, 95% confidence interval [CI] 5.7 to 11), hypertension (OR 1.4, 95% CI 1.1 to 1.8), diabetes (OR 2.2, 95% CI 1.6 to 3.1), maternal age 28.8 years old or older (OR 1.3, 95% CI 1.2 to 1.4), and birthweight of 3441 g or greater (OR 1.6, 95% CI 1.2 to 2.0) were significantly associated with cesarean. Cesarean risk increased linearly with time by an average of 3.8% per 6 hours.

CONCLUSION

Risk of cesarean increases over the duration of induction but does not reach clinical certainty. Cesarean probability is greater with nulliparity, hypertension, diabetes, older maternal age, or higher birthweight. Inductions without stated indications may not carry an increased risk of cesarean.

[Efficacy and safety of misoprostol in obstetrics]

OBJECTIVE

To review the efficacy and safety of misoprostol for indications not included in the prescription information given for the product, including abortion, labor induction, treatment and prevention of postpartum bleeding, and hysteroscopy preparation.

METHOD

Pubmed was searched for controlled, randomized, blinded clinical trials of misoprostol in obstetrics from 1999 through 2004.

RESULTS

Nineteen clinical trials were found. The efficacy for abortion in association with mifepristone at a dosage of 400 microg/6 h is superior versus both placebo and gemeprost, but misoprostol is more painful and less effective than dilation and subsequent evacuation. Regarding the administration route, trials show similar efficacy for the vaginal and oral approaches. In the prevention and treatment of postpartum hemorrhage, misoprostol was not any better than oxytocin. When used as a labor inducing agent, results are best with doses of 50 microg/3-8 h, but no controlled clinical trials were found. Although its use for hysteroscopy facilitates the procedure versus placebo, it entails a higher frequency of adverse events. No controlled clinical trials were found for other options.

CONCLUSIONS

The efficacy of misoprostol for indications reviewed in this paper is controversial, and studies found are heterogeneous. Designing and conducting further clinical trials to investigate appropriate dosage and administration routes, as well as the drug s adverse effect profile under such circumstances is essential, and would potentially allow an application for approval to be filed with health authorities regarding its use in obstetric practice.

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.