Safety and efficacy of titrated oral misoprostol solution versus vaginal dinoprostone for induction of labor: A single-center randomized control trial

Methods for the induction of labor: efficacy and safety

This review assessed the efficacy and safety of pharmacologic agents (prostaglandins, oxytocin, mifepristone, hyaluronidase, and nitric oxide donors) and mechanical methods (single- and double-balloon catheters, laminaria, membrane stripping, and amniotomy) and those generally considered under the rubric of complementary medicine (castor oil, nipple stimulation, sexual intercourse, herbal medicine, and acupuncture). A substantial body of published reports, including 2 large network meta-analyses, support the safety and efficacy of misoprostol (PGE1) when used for cervical ripening and labor induction. Misoprostol administered vaginally at doses of 50 μg has the highest probability of achieving vaginal delivery within 24 hours. Regardless of dosing, route, and schedule of administration, when used for cervical ripening and labor induction, prostaglandin E2 seems to have similar efficacy in decreasing cesarean delivery rates. Globally, although oxytocin represents the most widely used pharmacologic agent for labor induction, its effectiveness is highly dependent on parity and cervical status. Oxytocin is more effective than expectant management in inducing labor, and the efficacy of oxytocin is enhanced when combined with amniotomy. However, prostaglandins administered vaginally or intracervically are more effective in inducing labor than oxytocin. A single 200-mg oral tablet of mifepristone seems to represent the lowest effective dose for cervical ripening. The bulk of the literature assessing relaxin suggests this agent has limited benefit when used for this indication. Although intracervical injection of hyaluronidase may cause cervical ripening, the need for intracervical administration has limited the use of this agent. Concerning the vaginal administration of nitric oxide donors, including isosorbide mononitrate, isosorbide, nitroglycerin, and sodium nitroprusside, the higher incidence of side effects with these agents has limited their use. A synthetic hygroscopic cervical dilator has been found to be effective for preinduction cervical ripening. Although a pharmacologic agent may be administered after the use of the synthetic hygroscopic dilator, in an attempt to reduce the interval to vaginal delivery, concomitant use of mechanical and pharmacologic methods is being explored. Combining the use of a single-balloon catheter with dinoprostone, misoprostol, or oxytocin enhances the efficacy of these pharmacologic agents in cervical ripening and labor induction. The efficacy of single- and double-balloon catheters in cervical ripening and labor induction seems similar. To date, the combination of misoprostol with an intracervical catheter seems to be the best approach when balancing delivery times with safety. Although complementary methods are occasionally used by patients, given the lack of data documenting their efficacy and safety, these methods are rarely used in hospital settings.

[Comparison of vaginal prostaglandins with oral misoprostol as a second line of cervical ripening after using a cervical balloon catheter]

OBJECTIVE

To compare vaginal prostaglandins with oral misoprostol as a second line of cervical ripening after using a cervical balloon catheter.

MATERIAL AND METHODS

This is a retrospective monocentric study (Lille, France), according to a "before"/"after" design. The inclusion criteria were a singleton pregnancy, with a fetus in cephalic presentation, a term >37 WA, with a cervix having a Bishop score lower than 6 after a first line of maturation by cervical balloon catheter. Two groups were formed: "before" corresponding to the continuation of maturation by vaginal prostaglandins, from March 2019 to November 2019, and "after": corresponding to the continuation of maturation by oral misoprostol, from June 2020 to December 2020. The primary outcome was vaginal delivery rate.

RESULTS

One hundred women were included in each group. The rate of vaginal delivery was similar between the 2 groups (76% vs 81%, p=0.39), as were the times between the start of induction and the birth and between the start of induction and the transition to birth room. There was no difference in the indication for caesarean section, with in particular an identical rate of caesarean sections for induction failure (p=0.52). Subgroup analysis in obese women showed a significantly higher rate of vaginal delivery in the "after" group (OR=4.17;95% CI [1.02;17.07]).

CONCLUSION

The vaginal delivery rate is similar when using vaginal prostaglandins or oral misoprostol as second line cervical ripening after use of a cervical balloon catheter.

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.

Guideline No. 432b: Cervical Ripening

OBJECTIVE

This guideline presents evidence and recommendations for cervical ripening and induction of labour. It aims to provide information to birth attendants and pregnant individuals on optimal perinatal care while avoiding unnecessary obstetrical intervention.

TARGET POPULATION

All pregnant patients.

BENEFITS, HARMS, AND COSTS

Consistent interprofessional use of the guideline, appropriate equipment, and trained professional staff enhance safe intrapartum care. Pregnant individuals and their support person(s) should be informed of the benefits and risks of induction of labour.

EVIDENCE

Literature published to March 2022 was reviewed. PubMed, CINAHL, and the Cochrane Library were used to search for systematic reviews, randomized controlled trials, and observational studies on cervical ripening and induction of labour. Grey (unpublished) literature was identified by searching the websites of health technology assessment and health technology related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and conditional [weak] recommendations).

INTENDED AUDIENCE

All providers of obstetrical care.

RECOMMANDATIONS

Directive clinique no 432b : Maturation cervicale

OBJECTIF

Présenter des données probantes et des recommandations sur la maturation cervicale et le déclenchement artificiel du travail. Fournir de l'information aux professionnels accoucheurs et aux personnes enceintes sur les soins périnataux optimaux et la prévention des interventions obstétricales inutiles.

POPULATION CIBLE

Toutes les patientes enceintes. BéNéFICES, RISQUES ET COûTS: La mise en application interprofessionnelle et cohérente de la présente directive, l'équipement adéquat et le personnel compétent améliorent la sécurité des soins per partum. Les personnes enceintes et leurs personnes de soutien doivent être informées des risques et bénéfices du déclenchement artificiel du travail. DONNéES PROBANTES: La littérature publiée jusqu'en mars 2022 a été passée en revue. Une recherche a été effectuée dans les bases de données PubMed, CINAHL et Cochrane Library pour répertorier des revues systématiques, des essais cliniques randomisés et des études observationnelles sur la maturation cervicale et le déclenchement artificiel du travail. La littérature grise (non publiée) a été obtenue à l'aide de recherches menées dans des sites Web d'organismes s'intéressant à l'évaluation des technologies dans le domaine de la santé et d'organismes connexes, dans des collections de directives cliniques, des registres d'essais cliniques et des sites Web de sociétés de spécialité médicale nationales et internationales. MéTHODES DE VALIDATION: Les auteurs ont évalué la qualité des données probantes et la force des recommandations en utilisant le cadre méthodologique GRADE (Grading of Recommendations Assessment, Development and Evaluation). Voir l'annexe A en ligne (tableau A1 pour les définitions et tableau A2 pour l'interprétation des recommandations fortes et conditionnelles [faibles]). PROFESSIONNELS CONCERNéS: Tous les fournisseurs de soins obstétricaux.

RECOMMANDATIONS

Evaluating misoprostol and mechanical methods for induction of labour: Scientific Impact Paper No. 68 April 2022

Increasingly, births around the world are started artificially using medications or other methods. This process is known as induction of labour. As it becomes more common, methods are needed to meet the different clinical needs and birth preferences of women. Induction of labour typically includes a combination of the medication dinoprostone inserted into the vagina, artificial rupture of membranes ('releasing the waters'), and synthetic oxytocin (hormone given via a drip). This paper reviews some of the methods less commonly used for induction in the UK, namely a drug called misoprostol, which can be given orally or vaginally, and 'mechanical' methods, where labour is started by stretching the cervix (neck of the womb), most commonly with a soft silicone tube with a balloon near the tip, filled with water. Low-dose oral misoprostol tablets are now commercially available in the UK. Other methods for labour induction are not reviewed in detail in this paper. The evidence suggests mechanical induction of labour (using a balloon catheter) and misoprostol are both at least as safe and effective as using the standard drug, dinoprostone. There is evidence to suggest a balloon catheter may reduce the chance of serious negative outcomes for babies when compared with dinoprostone, and that giving low-dose oral misoprostol results in fewer caesarean births. Where possible and after informed consent, the method of induction of labour should be personalised to suit the individual woman, her clinical condition, and the setting in which she is giving birth. Local contexts and resources also need to be taken into account. To date, research into women's perspectives and experiences of induction of labour have been significantly lacking.

Titrated oral misoprostol versus static regimen of oral misoprostol for induction of labour: a systematic review and meta-analysis

We aimed to conduct a systematic review and meta-analysis to compare the efficacy and safety of titrated oral misoprostol versus static oral misoprostol for labour induction. We searched for the available randomised clinical trials (RCTs) in the Cochrane Library, PubMed, ISI web of science, Scopus, and ClinicalTrials.gov. We included RCTs compared titrated oral misoprostol versus static regimen of oral misoprostol during labour induction. Our main outcomes were vaginal and caesarean delivery rates, uterine tachysystole, misoprostol side effects, and neonatal adverse events. Three RCTs met our inclusion criteria with a total number of 360 patients. The vaginal delivery rate did not significantly differ between both groups (p = 0.49). Titrated oral misoprostol was associated with significant increase in the caesarean delivery rate compared to static oral misoprostol (p = 0.04). Moreover, titrated oral misoprostol led to significant increase in the uterine tachysystole and misoprostol side effects (p = 0.01 & p = 0.003, respectively). There were no differences among both groups regarding different neonatal adverse events. In conclusion, titrated oral misoprostol increases the incidence of caesarean delivery, uterine tachysystole, and misoprostol side effects with a similar vaginal delivery rate compared to static dose misoprostol. Thus, static oral misoprostol should be used instead of titrated oral misoprostol during labour induction. Impact StatementWhat is already known on this subject? Different studies have evaluated titrated oral misoprostol administration for induction of labour and proved their efficacy in comparison with other induction methods. However, there is controversy among the published studies between titrated oral misoprostol and static oral misoprostol during induction of labour. A recent study concluded that hourly titrated misoprostol and static oral misoprostol are equally safe and effective when utilised for induction of labour with no fear of any adverse events. However, another study recommended static oral misoprostol administration for labour induction as it was linked to a lower caesarean section incidence, fewer drug side effects, and decline in complication rates in comparison with titrated oral misoprostol.What the results of this study add? Titrated oral misoprostol increases the incidence of caesarean delivery, uterine tachysystole, and misoprostol side effects with a similar vaginal delivery rate compared to static dose misoprostol.What the implications are of these findings for clinical practice and/or further research? Static oral misoprostol should be used instead of titrated oral misoprostol during labour induction. More future trials are required to confirm our findings.

[Efficacy and safety of oral misoprostol 25μg vs. vaginal dinoprostone in induction of labor at term]

OBJECTIVE

To compare the efficacy and safety of oral misoprostol 25μg compared to vaginal dinoprostone in the induction of labor at term.

METHODS

Analytic, retrospective study of patients induced at term by prostaglandins with an unfavorable cervix, over two consecutive periods from 01/01/2019 to 19/02/2020 and from 20/02/2020 to 07/04/2021, within a regional level III university hospital center. We compared the safety and the efficacy between the oral misoprostol Angusta® used since 20/02/2020 and the vaginal dinoprostone previously used in gel or diffuser. The primary endpoint was the rate of vaginal deliveries within 24h. Secondary endpoints were cesarean section rate, indications for cesarean section, uterine contractility abnormalities and neonatal outcomes.

RESULTS

Our study found no difference in terms of efficacy with similar rates of vaginal deliveries within 24h (51.88% vs. 51.25%; P=0.87) and caesarean sections (misoprostol group: 19.42% vs. dinoprostone group: 16.62%; P=0.33). However, the tolerance criteria revealed in the dinoprostone group an increase in tachysystole (misoprostol group: 9.28% vs. dinoprostone group: 16.90%; P=0.003) and acidosis (arterial pH<7.10, misoprostol group: 3.83% vs. dinoprostone group: 9.29%; P=0.006).

CONCLUSION

No difference in efficacy was found between the two induction techniques. Oral misoprostol 25μg seems to be better tolerated from a maternal and fetal point of view.

Low-dose oral misoprostol for induction of labour

BACKGROUND

Misoprostol given orally is a commonly used labour induction method. Our Cochrane Review is restricted to studies with low-dose misoprostol (initially ≤ 50 µg), as higher doses pose unacceptably high risks of uterine hyperstimulation.

OBJECTIVES

To assess the efficacy and safety of low-dose oral misoprostol for labour induction in women with a viable fetus in the third trimester of pregnancy.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov,  the WHO International Clinical Trials Registry Platform (14 February 2021) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised trials comparing low-dose oral misoprostol (initial dose ≤ 50 µg) versus placebo, vaginal dinoprostone, vaginal misoprostol, oxytocin, or mechanical methods; or comparing oral misoprostol protocols (one- to two-hourly versus four- to six-hourly; 20 µg to 25 µg versus 50 µg; or 20 µg hourly titrated versus 25 µg two-hourly static).

DATA COLLECTION AND ANALYSIS

Using Covidence, two review authors independently screened reports, extracted trial data, and performed quality assessments. Our primary outcomes were vaginal birth within 24 hours, caesarean section, and hyperstimulation with foetal heart changes.

MAIN RESULTS

We included 61 trials involving 20,026 women. GRADE assessments ranged from moderate- to very low-certainty evidence, with downgrading decisions based on imprecision, inconsistency, and study limitations. Oral misoprostol versus placebo/no treatment (four trials; 594 women) Oral misoprostol may make little to no difference in the rate of caesarean section (risk ratio (RR) 0.81, 95% confidence interval (CI) 0.59 to 1.11; 4 trials; 594 women; moderate-certainty evidence), while its effect on uterine hyperstimulation with foetal heart rate changes is uncertain (RR 5.15, 95% CI 0.25 to 105.31; 3 trials; 495 women; very low-certainty evidence). Vaginal births within 24 hours was not reported. In all trials, oxytocin could be commenced after 12 to 24 hours and all women had pre-labour ruptured membranes. Oral misoprostol versus vaginal dinoprostone (13 trials; 9676 women) Oral misoprostol probably results in fewer caesarean sections (RR 0.84, 95% CI 0.78 to 0.90; 13 trials, 9676 women; moderate-certainty evidence). Subgroup analysis indicated that 10 µg to 25 µg (RR 0.80, 95% CI 0.74 to 0.87; 9 trials; 8652 women) may differ from 50 µg (RR 1.10, 95% CI 0.91 to 1.34; 4 trials; 1024 women) for caesarean section. Oral misoprostol may decrease vaginal births within 24 hours (RR 0.93, 95% CI 0.87 to 1.00; 10 trials; 8983 women; low-certainty evidence) and hyperstimulation with foetal heart rate changes (RR 0.49, 95% CI 0.40 to 0.59; 11 trials; 9084 women; low-certainty evidence). Oral misoprostol versus vaginal misoprostol (33 trials; 6110 women) Oral use may result in fewer vaginal births within 24 hours (average RR 0.81, 95% CI 0.68 to 0.95; 16 trials, 3451 women; low-certainty evidence), and less hyperstimulation with foetal heart rate changes (RR 0.69, 95% CI 0.53 to 0.92, 25 trials, 4857 women, low-certainty evidence), with subgroup analysis suggesting that 10 µg to 25 µg orally (RR 0.28, 95% CI 0.14 to 0.57; 6 trials, 957 women) may be superior to 50 µg orally (RR 0.82, 95% CI 0.61 to 1.11; 19 trials; 3900 women). Oral misoprostol probably does not increase caesarean sections overall (average RR 1.00, 95% CI 0.86 to 1.16; 32 trials; 5914 women; low-certainty evidence) but likely results in fewer caesareans for foetal distress (RR 0.74, 95% CI 0.55 to 0.99; 24 trials, 4775 women). Oral misoprostol versus intravenous oxytocin (6 trials; 737 women, 200 with ruptured membranes) Misoprostol may make little or no difference to vaginal births within 24 hours (RR 1.12, 95% CI 0.95 to 1.33; 3 trials; 466 women; low-certainty evidence), but probably results in fewer caesarean sections (RR 0.67, 95% CI 0.50 to 0.90; 6 trials; 737 women; moderate-certainty evidence). The effect on hyperstimulation with foetal heart rate changes is uncertain (RR 0.66, 95% CI 0.19 to 2.26; 3 trials, 331 women; very low-certainty evidence). Oral misoprostol versus mechanical methods (6 trials; 2993 women) Six trials compared oral misoprostol to transcervical Foley catheter. Misoprostol may increase vaginal birth within 24 hours (RR 1.32, 95% CI 0.98 to 1.79; 4 trials; 1044 women; low-certainty evidence), and probably reduces the risk of caesarean section (RR 0.84, 95% CI 0.75 to 0.95; 6 trials; 2993 women; moderate-certainty evidence). There may be little or no difference in hyperstimulation with foetal heart rate changes (RR 1.31, 95% CI 0.78 to 2.21; 4 trials; 2828 women; low-certainty evidence). Oral misoprostol one- to two-hourly versus four- to six-hourly (1 trial; 64 women) The evidence on hourly titration was very uncertain due to the low numbers reported. Oral misoprostol 20 µg hourly titrated versus 25 µg two-hourly static (2 trials; 296 women) The difference in regimen may have little or no effect on the rate of vaginal births in 24 hours (RR 0.97, 95% CI 0.80 to 1.16; low-certainty evidence). The evidence is of very low certainty for all other reported outcomes.

AUTHORS' CONCLUSIONS

Low-dose oral misoprostol is probably associated with fewer caesarean sections (and therefore more vaginal births) than vaginal dinoprostone, and lower rates of hyperstimulation with foetal heart rate changes. However, time to birth may be increased, as seen by a reduced number of vaginal births within 24 hours. Compared to transcervical Foley catheter, low-dose oral misoprostol is associated with fewer caesarean sections, but equivalent rates of hyperstimulation. Low-dose misoprostol given orally rather than vaginally is probably associated with similar rates of vaginal birth, although rates may be lower within the first 24 hours. However, there is likely less hyperstimulation with foetal heart changes, and fewer caesarean sections performed due to foetal distress. The best available evidence suggests that low-dose oral misoprostol probably has many benefits over other methods for labour induction. This review supports the use of low-dose oral misoprostol for induction of labour, and demonstrates the lower risks of hyperstimulation than when misoprostol is given vaginally. More trials are needed to establish the optimum oral misoprostol regimen, but these findings suggest that a starting dose of 25 µg may offer a good balance of efficacy and safety.