Randomized clinical trial between hourly titrated and 2 hourly static oral misoprostol solution for induction of labor

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.

A re-analysis of 150 women's health trials to investigate how the Bayesian approach may offer a solution to the misinterpretation of statistical findings

OBJECTIVE

To investigate whether a Bayesian interpretation might help prevent misinterpretation of statistical findings and support authors to differentiate evidence of no effect from statistical uncertainty.

DESIGN

A Bayesian re-analysis to determine posterior probabilities of clinically important effects (e.g., a large effect is set at a 4 percentage point difference and a trivial effect to be within a 0.5 percentage point difference). Posterior probabilities greater than 95% are considered as strong statistical evidence, and less than 95% as inconclusive.

SAMPLE

150 major women's health trials with binary outcomes.

MAIN OUTCOME MEASURES

Posterior probabilities of large, moderate, small and trivial effects.

RESULTS

Under frequentist methods, 48 (32%) were statistically significant (p-value ≤ 0.05) and 102 (68%) statistically non-significant. The frequentist and Bayesian point estimates and confidence intervals showed strong concordance. Of the statistically non-significant trials (n = 102), the Bayesian approach classified the majority (94, 92%) as inconclusive, neither able to confirm or refute effectiveness. A small number of statistically non-significant findings (8, 8%) were classified as having strong statistical evidence of an effect.

CONCLUSIONS

Whilst almost all trials report confidence intervals, in practice most statistical findings are interpreted on the basis of statistical significance, mostly concluding evidence of no effect. Findings here suggest the majority are likely uncertain. A Bayesian approach could help differentiate evidence of no effect from statistical uncertainty.

Effect of Oxytocin Combined with Different Volume of Water Sac in High-Risk Term Pregnancies

Objective

The study estimated the impacts of water sac of different capacities combined with oxytocin (OXT) on pregnant women with high-risk term pregnancies.

Methods

Women with high-risk term pregnancies who received OXT were enrolled to perform labor induction using 30  mL (group A), 80 mL (group B), and 150  mL (group C), followed by the comparisons regarding to the success rate of labor induction, cesarean section rate, duration of induced labor to labor, duration of the first stage of labor, postpartum blood loss, the incidence of adverse reactions, and the assessment of cervical ripening using Bishop Score. Besides, neonatal weight, Apgar score, as well as psychological status, and satisfaction of patients were compared among these groups.

Results

As compared with group A, the success rate of induced labor was higher in groups B and C with lower cesarean section rate and shorter duration of induced labor to labor, but the duration of the first stage of labor in group B was the shortest among the three groups. The amount of postpartum hemorrhage decreased stepwise from groups A to B to C. In addition, groups A and B showed a reduced incidence of adverse reactions than group C, but the highest level of cervical ripening and highest patient satisfaction was revealed in group C and group B, respectively. Furthermore, the highest patient satisfaction was found in group B.

Conclusion

The usage of an 80  mL water sac combined with OXT  in high-risk term pregnancy has ideal induction effects, which can guarantee maternal cervical maturity and shorten the time of the first stage of labor.

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.

American College of Nurse-Midwives Clinical Bulletin Number 18: Induction of Labor

Induction of labor is an increasingly common component of intrapartum care in the United States. This rise is fueled by a nationwide escalation in both medically indicated and elective inductions at or beyond term, supported by recent research showing some benefits of induction over expectant management. However, induction of labor medicalizes the birth experience and may lead to a complex cascade of interventions. The purpose of this Clinical Bulletin is twofold: (1) to guide clinicians on the use of person-centered decision-making when discussing induction of labor and (2) to review evidence-based practice recommendations for intrapartum midwifery care during labor induction.

Misoprostol for labour induction

Oral and vaginal misoprostol are effective induction methods, but there is a delicate balance between a quicker labour and avoiding side effects. In randomised comparisons with balloon catheters, oral misoprostol resulted in more vaginal births in the first 24 h as well as fewer caesarean sections without an increase in hyperstimulation events. Vaginal misoprostol was most effective when used concurrently with a balloon catheter. In comparison with dinoprostone, oral misoprostol had lower rates of caesarean section and uterine hyperstimulation with foetal heart rate changes, but fewer babies were born vaginally within 24 h. In contrast, vaginal misoprostol resulted in more vaginal births within 24 h, with no significant differences in caesarean section rates. There were no differences in perinatal adverse events with either route. When oral and vaginal misoprostol were compared, vaginal misoprostol resulted in more vaginal births in the first 24 h, but with more maternal and neonatal complications.

Review of Evidence-Based Methods for Successful Labor Induction

Induction of labor is increasingly a common component of the intrapartum care. Knowledge of the current evidence on methods of labor induction is an essential component of shared decision-making to determine which induction method meets an individual's health needs and personal preferences. This article provides a review of the current research evidence on labor induction methods, including cervical ripening techniques, and contraction stimulation techniques. Current evidence about expected duration of labor following induction, use of the Bishop score to guide induction, and guidance on the use of combination methods for labor induction are reviewed.

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.

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

Objective

To compare the efficacy and safety of the hourly administration of titrated oral misoprostol solution (OMS) and vaginal dinoprostone for induction of labor.

Methods

Titrated OMS was administrated hourly for induction of labor, starting with a dose of 20 µg and terminating at a dose of 50 µg. The safety and efficacy of OMS were compared with that of vaginal dinoprostone for induction of labor.

Results

From June 2016 to October 2019, 2280 (78.3%) and 2115 (72.9%) women who received titrated OMS and vaginal dinoprostone, respectively, had a vaginal delivery (P = 0.005). Cesarean delivery was performed in 632 (21.7%) and 783 (27.0%) women who received titrated OMS and vaginal dinoprostone, respectively (P = 0.008). Tachysystole with changes in fetal heart rate (FHR) was seen in 104 (3.6%) and 249 (8.6%) women in the OMS and dinoprostone groups, respectively (P = 0.007). The frequency of non‐reassuring FHR was lower in the OMS group compared to the dinoprostone group (P = 0.006).

Conclusion

The titrated OMS has an efficacy comparable to vaginal dinoprostone. Moreover, it causes a lower incidence of cesarean delivery, lower frequency of tachysystole with changes in FHR, and non‐reassuring FHR.

Titrated oral misoprostol has a similar efficacy to dinoprostone, but with a lower incidence of cesarean delivery and lower frequency of non‐reassuring fetal heart rate.

Efficacy comparison of titrated oral solution of misoprostol and intravenous oxytocin on labour induction in women with full-term pregnancy

A double-blind randomised trial was conducted on women with gestational age of 40-42 weeks of pregnancy and Bishop score of more than 5. The first group received oxytocin infusion and the second group received a titrated oral solution of misoprostol. Then, the two groups were compared by the primary outcome (the number of deliveries in the first 24 hours of intervention). The two groups did not have any significant difference in maternal and gestational age at the time of intervention, primary Bishop score, parity and neonatal weight. The number of deliveries in the first 24 hours was greater in the misoprostol group. Duration of onset of intervention to proper contractions was longer in the misoprostol group. However, the number of deliveries between 6-12 hours, 12-18 hours and 18-24 hours after induction was greater in the misoprostol group. The incidence of tachysystole and meconium was greater in the misoprostol group.Impact statementWhat is already known on this subject? Labour induction is widely used where the continuation of pregnancy might be dangerous for the mother or the baby. Of the various methods used for induction, misoprostol which is a prostaglandin E1 analogue has been reviewed more in recent years. Misoprostol has various routes of administration but in most studies only vaginal administration has been evaluated, leaving us with limited data about oral administration.What do the results of this study add? Oral misoprostol is a suitable method for labour induction and can be used as an alternative to oxytocin.What are the implications of these findings for clinical practice and/or further research? Misoprostol is not expensive, has a long shelf life, accessible in underdeveloped countries and rural areas and has several routes of administrations such as oral, sublingual and vaginal. Despite the fact that the oral route of misoprostol has a fast absorption and easier administration, there are relatively few studies assessing the the use of the oral route of misoprostol. Misoprostol is a suitable method for Labour induction and it has the potentials of being used as an alternative for oxytocin, however, the optimum dosages, the preferred route of administration, the maximum dose, the maximum time for administration, and maternal and neonatal safety should be studied more.

Oral misoprostol for induction of labor at term: a randomized controlled trial of hourly titrated and 2 hourly static oral misoprostol solution

Background: Misoprostol has been shown to be effective in induction of labor (IOL) with different dosages and routes of administration.Objectives: This study compared the efficacy and safety of hourly titrated and 2-hourly static low dose oral misoprostol for IOL in Ekiti State University Teaching Hospital, Ado-Ekiti.Methods: One hundred fifty women with singleton pregnancy at term admitted for IOL were randomized into the two groups. Oxytocin augmentation was done as necessary. The primary outcome is rate of vaginal delivery within 24 hours. Data were analyzed using SPSS.Results: Vaginal delivery was achieved within 24 hours in 40 (67.8%) women who received hourly titrated-doses oral misoprostol and 42 (70.0%) women who received 2-hourly static-dose of oral misoprostol, p > .05. The rate of vaginal delivery, oxytocin augmentation, induction delivery time and cesarean section rate were similar in both groups, p > .05. Occurrence of uterine hyperactivity did not differ significantly among the women (p > .05) and no cases of uterine rupture were recorded. There were no adverse neonatal outcomes.Conclusions: The hourly titrated oral misoprostol is as effective and safe as the 2-hourly static oral misoprostol for IOL. Both can be utilized in IOL without the fear of adverse outcomes.

Contraction of the levator ani muscle during Valsalva maneuver (coactivation) is associated with a longer active second stage of labor in nulliparous women undergoing induction of labor

BACKGROUND

The Valsalva maneuver is normally accompanied by relaxation of the levator ani muscle, which stretches around the presenting part, but in some women the maneuver is accompanied by levator ani muscle contraction, which is referred to as levator ani muscle coactivation. The effect of such coactivation on labor outcome in women undergoing induction of labor has not been previously assessed.

OBJECTIVE

The aim of the study was to assess the effect of levator ani muscle coactivation on labor outcome, in particular on the duration of the second and active second stage of labor, in nulliparous women undergoing induction of labor.

STUDY DESIGN

Transperineal ultrasound was used to measure the anteroposterior diameter of the levator hiatus, both at rest and at maximum Valsalva maneuver, in a group of nulliparous women undergoing induction of labor in 2 tertiary-level university hospitals. The correlation between anteroposterior diameter of the levator hiatus values and levator ani muscle coactivation with the mode of delivery and various labor durations was assessed.

RESULTS

In total, 138 women were included in the analysis. Larger anteroposterior diameter of the levator hiatus at Valsalva was associated with a shorter second stage (r = -0.230, P = .021) and active second stage (r = -0.338, P = .001) of labor. Women with levator ani muscle coactivation had a significantly longer active second stage duration (60 ± 56 vs 28 ± 16 minutes, P < .001). Cox regression analysis, adjusted for maternal age and epidural analgesia, demonstrated an independent significant correlation between levator ani muscle coactivation and a longer active second stage of labor (hazard ratio, 2.085; 95% confidence interval, 1.158-3.752; P = .014). There was no significant difference between women who underwent operative delivery (n = 46) when compared with the spontaneous vaginal delivery group (n = 92) as regards anteroposterior diameter of the levator hiatus at rest and at Valsalva maneuver, nor in the prevalence of levator ani muscle coactivation (10/46 vs 15/92; P = .49).

CONCLUSION

Levator ani coactivation is associated with a longer active second stage of labor.

Challenges and Limitations of Clinical Trials on Labor Induction: A Review of the Literature

Induction of labor is a common obstetric procedure performed in nearly a quarter of all deliveries in the United States. Pharmacological (prostaglandins, oxytocin) and/or mechanical methods (balloon catheters) are commonly used for labor induction; however, there is ongoing debate as to which method is the safest and most effective. This narrative review discusses key limitations of published trials on labor induction, including the lack of well-designed randomized controlled trials directly comparing specific methods of induction, heterogeneous trial populations, and wide variation in the protocols used and outcomes reported. Furthermore, the majority of published trials were underpowered to detect significant differences in the most clinically relevant efficacy and safety outcomes (e.g., cesarean delivery, neonatal mortality). By identifying the limitations of labor induction trials, we hope to highlight the importance of quality published data to better inform guidelines and drive evidence-based treatment decisions.