A 2025 Clinical Practice Guideline from the American College of Obstetricians and Gynecologists (ACOG) extensively evaluates contemporary methods for cervical ripening in term, singleton, vertex pregnancies with intact membranes. The panel highlighted that commonly used pharmacologic agents for cervical ripening include misoprostol, a prostaglandin E1 analogue, and dinoprostone, a prostaglandin E2 preparation. Both are recommended options, with oral or vaginal misoprostol supported by strong recommendations and high quality evidence, and vaginal dinoprostone supported by strong recommendations with moderate quality evidence. Misoprostol may be administered orally or vaginally in a range of dosing regimens, whereas dinoprostone is available as a vaginal gel or a 10 mg vaginal insert. Misoprostol is contraindicated in patients with a history of uterine surgery, including cesarean delivery, because of the risk of uterine rupture, and selection of any agent should consider patient characteristics, preferences, and clinical context. [1]
Comparative data suggest differences in efficacy and resource utilization. A 2010 Cochrane review of 38 trials including 7,022 participants found that vaginal misoprostol was associated with a lower rate of failure to achieve vaginal delivery within 24 hours and reduced need for oxytocin augmentation compared with vaginal dinoprostone, without differences in cesarean delivery or tachysystole with fetal heart rate changes. A separate review comparing the 10 mg sustained-release dinoprostone vaginal insert with vaginal misoprostol tablets reported a lower incidence of vaginal delivery within 24 hours and greater need for oxytocin augmentation in the dinoprostone group, with no differences in cesarean or tachysystole rates. An individual participant data meta analysis in 2024 including 4,180 participants found low dose vaginal misoprostol to be equivalent to vaginal dinoprostone in achieving vaginal delivery, with similar composite adverse perinatal outcomes, and a lower incidence of a composite adverse maternal outcome with misoprostol. In comparisons of oral misoprostol with vaginal dinoprostone, a 2021 Cochrane review of 13 trials including 9,676 participants found a reduced risk of cesarean delivery with oral misoprostol, particularly at lower initial doses, with no differences in reported neonatal outcomes. The overall available data indicate both agents are effective options, with variations in time to delivery, need for oxytocin, and certain maternal outcomes observed across studies. [1]
The World Health Organization (WHO) recommends oral misoprostol (25 mcg every 2 hours) for labor induction, and this recommendation is classified as a “strong” recommendation, and the quality of evidence is stated to be moderate. It also provides a strong recommendation for low doses of vaginal prostaglandins for labor induction based on moderate-quality evidence. It is stated that low-dose vaginal misoprostol (25 mcg every 6 hours) is also a viable option; however, the strength of recommendation is weak. Of note, it recommends against using misoprostol in those with a history of cesarean section, and it is classified as a strong recommendation. [2]
In their summary of the evidence, it notes that vaginal misoprostol has demonstrated efficacy in achieving vaginal delivery, lower rates of cesarean section delivery, Apgar score being less than 7 at five minutes of life when compared to placebo, expectant management, oxytocin monotherapy, or other prostaglandins. However, it has been associated with a higher rate of uterine hyperstimulation with fetal heart rate (FHR) changes when compared to other prostaglandins, although the risk appears to be lower with lower doses (25 mcg every 6 hours). Oral misoprostol also has demonstrated comparable or favorable outcomes compared to placebo, expected managements, oxytocin, or other prostaglandins in labor induction and relative outcomes. When the two formulations are compared, oral formulation has been associated with a lower risk of Apgar score being less than 7 at five minutes of life compared to vaginal formulations. It notes that misoprostol can also be administered buccally or sublingually; however, there is insufficient evidence to recommend these routes of administration. [2]
A 2022 guideline from the WHO on induction of labor at or beyond term only recommends induction when there are clear indications that continuing with a pregnancy poses a greater risk to the mother or baby than the risk of inducing labor. These are not significantly different than the 2011 guidelines on general labor induction. No specific medication is preferred, and women receiving oxytocin, misoprostol, or other prostaglandins should never be left unattended. [3]
The benefits of using oral misoprostol for labor induction are that it is low in cost, noninvasive, stable at room temperature, and is associated with lower cesarean rates than other induction methods. Additionally, it may lead to less uterine hyperstimulation with FHR changes as compared to vaginal misoprostol. However, despite its benefits, it notes that the optimal dose for safety is yet to be determined. Compared to the oral route, benefits of vaginal misoprostol are similar, with additional benefit of achieving a higher plasma level. It is also stated to be more efficacious at cervical ripening and induction of labor compared to oxytocin and dinoprostone. However, it is noted that vaginal misoprostol is associated with more uterine hyperstimulation and meconium-stained fluid when compared to other vaginal induction methods. Furthermore, slow or erratic absorption can occur with vaginal misoprostol, which may result in inaccurate dosing. A stated advantage of using dinoprostone vaginal insert is that it is able to be removed quickly in the case of FHR changes, which may resolve within 15 minutes after removing the insert. It is noted, however, that vaginal dinoprostone is associated with a 5% chance of uterine hyperstimulation one hour after administration. [4]
Another review article suggests that when comparing intravaginal misoprostol to intracervical dinoprostone in women with an unfavorable cervix at term, misoprostol was more efficacious at resulting in delivery within 24 hours (risk ratio [RR] 1.27; 95% confidence interval [CI] 1.10 to 1.48; p= 0.002; I2= 0%;) and required less use of oxytocin as an augmentation strategy (RR 0.62; 95% CI 0.54 to 0.72; p<0.00001; I2= 40%). On the other hand, misoprostol use was associated with increased uterine hyperstimulation (RR 3.15; 95% CI,1.58 to 6.28; p= 0.001; I2= 0% ) and tachysystole (RR 2.02; 95% CI 1.28 to 3.19; p= 0.003; I2= 44%). There was no significant difference in the rate of cesarean delivery (p= 0.66), the incidence of neonatal intensive care unit (NICU) admission (p= 0.80), and Apgar scores at 1 and 5 minutes (1 min: p= 0.90; 5 min: p= 0.89). [5]
A 2025 meta-analysis assessed the effectiveness and safety of oral misoprostol compared with vaginal dinoprostone for labor induction. The analysis incorporated individual participant data from five randomized controlled trials, encompassing 1892 participants, to provide a comprehensive evaluation. The study employed an intention-to-treat approach using a two-stage random-effects model, which facilitated a detailed comparison of primary outcomes such as vaginal delivery rates and composite measures of both maternal and perinatal adverse outcomes. The research extended its scope by conducting an aggregate-data meta-analysis on an additional seven randomized controlled trials (RCTs) that adhered to the Trustworthiness in RAndomised Clinical Trials (TRACT) criteria, further strengthening the conclusions. The findings indicated comparable rates of vaginal delivery following induction of labor with either oral misoprostol or vaginal dinoprostone, with an odds ratio of 0.99 (95% CI, 0.80 to 1.22; I²= 0%). Additionally, the incidence of composite adverse perinatal and maternal outcomes did not significantly differ between the groups, with adjusted odds ratios of 1.02 (95% CI, 0.61 to 1.72) and 1.39 (95% CI, 0.72 to 2.69), respectively. Furthermore, the meta-analysis underscored the robustness of the results by highlighting the importance of assessing data trustworthiness and integrity, as evidenced by the disparities observed in studies that failed to meet the stringent TRACT criteria. The analysis provides valuable insights for clinical decision-making in obstetric practices, promoting evidence-based approaches to labor induction. [6]
A 2024 systematic review and meta-analysis examined the efficacy and safety of intravaginal misoprostol compared to dinoprostone for labor induction at term. This analysis involved eight RCTs with a total of 1,801 participants, including 937 women in the misoprostol group and 864 in the dinoprostone group. The study population consisted of singleton pregnant women with live intrauterine gestations and unfavorable cervices, ranging from 37 to 42 weeks of gestation. The primary objective was to analyze key maternal and neonatal outcomes, such as the rates of vaginal delivery within 24 hours, cesarean delivery, and the necessity for oxytocin augmentation. Misoprostol was associated with a significantly reduced need for oxytocin augmentation compared to dinoprostone (risk ratio [RR] 0.83; 95% CI 0.71 to 0.97; p= 0.02). However, other outcomes, including cesarean delivery rates, uterine tachysystole, hyperstimulation, NICU admissions, and Apgar scores, showed no significant differences between the two groups, suggesting similar safety and efficacy profiles. Notably, the analysis revealed no significant heterogeneity among studies regarding vaginal delivery within 24 hours, cesarean delivery, and instrumental delivery. Despite varying dosages and administration regimens across trials, the authors suggest that intravaginal misoprostol is an effective and safe alternative to dinoprostone for labor induction in clinical settings, offering the advantage of requiring less oxytocin augmentation. [7]
Another 2024 systematic review and updated meta-analysis involving 53 RCTs (N= 10,455 patients) assessed the efficacy and safety of oral and vaginal misoprostol compared to dinoprostone for labor induction in women. Vaginal misoprostol showed a statistically significant higher success rate for labor induction compared to vaginal dinoprostone (RR 1.14; 95% CI 1.08 to 1.21; p<0.00001; I2= 69%), with less need for additional oxytocin (RR 0.67; 95% CI 0.59 to 0.76; p<0.00001; I2= 82%). However, vaginal misoprostol was associated with a higher incidence of uterine hyperstimulation, tachysystole, and abnormal cardiotocography compared to dinoprostone. There were no significant differences in cesarean section rates or neonatal intensive care unit admissions between the groups. Interestingly, oral misoprostol was found to have comparable safety profiles to vaginal dinoprostone, providing similar efficacy without increased risks of adverse outcomes, making it a potential alternative for labor induction. These findings suggest that while vaginal misoprostol is effective, its safety profile must be carefully considered, and oral misoprostol may offer a safer, equally effective option. [8]
A 2024 individual participant data meta-analysis of randomized trials examined the effectiveness and safety of induction of labor using low-dose vaginal misoprostol compared to vaginal dinoprostone. This analysis combined data from eight trials, encompassing 4,180 women (low-dose vaginal misoprostol, n= 2,077; vaginal dinoprostone, n= 2,103) to evaluate the primary outcomes, which included vaginal delivery rates, composite adverse perinatal outcomes, and composite adverse maternal outcomes. Low-dose vaginal misoprostol and vaginal dinoprostone were observed to have comparable rates of vaginal birth and similar perinatal safety profiles. Notably, use of low-dose vaginal misoprostol was associated with a significantly lower rate of composite adverse maternal outcomes compared to vaginal dinoprostone (adjusted odds ratio [OR] 0.80; 95% CI 0.65 to 0.98; p= 0.03; I2= 0%). Despite the comparable effectiveness in achieving vaginal delivery, the distinct advantage of low-dose vaginal misoprostol lies in its better maternal safety profile, characterized by a trend toward lower maternal infection rates and reduced intensive care unit admissions among participants. Overall, low-dose vaginal misoprostol may not only be a viable alternative to vaginal dinoprostone for cervical ripening and labor induction, but also offer benefits in terms of maternal safety, particularly in resource-limited settings where cost-effectiveness is crucial. [9]
A 2023 systematic review and meta-analysis synthesized data from 39 RCTs involving 15,993 participants to evaluate the safety profiles of misoprostol and dinoprostone for labor induction in women with singleton pregnancies beyond 36 weeks' gestation. Maternal outcomes analyzed included cesarean section rate, instrumental deliveries, tachysystole, uterine rupture, postpartum hemorrhage, and chorioamnionitis. Neonatal outcomes encompassed five-minute Apgar scores of less than 7, meconium-stained amniotic fluid, NICU admissions, and infant mortality. No statistically significant differences were identified between misoprostol and dinoprostone in the primary outcomes of cesarean delivery (OR 0.94; 95% CI 0.84 to 1.05) or instrumental delivery (OR 1.04; 95% CI 0.90 to 1.19). Rates of uterine tachysystole were comparable between groups overall (OR 1.21; 95% CI 0.91 to 1.60), though a subgroup analysis revealed heightened tachysystole with vaginal misoprostol compared to dinoprostone gel (OR 1.48; 95% CI 1.09 to 2.01). There was no significant difference in postpartum hemorrhage (OR 0.85; 95% CI 0.62 to 1.15), neonatal Apgar scores <7 (OR 0.83; 95% CI 0.61 to 1.12), or NICU admissions (OR 0.91; 95% CI 0.77 to 1.09). The findings suggest a comparable safety profile between the two agents, with no clear superiority for either in any maternal or neonatal outcomes. [10]
A 2016 meta-analysis compared the efficacy and safety of intravaginal misoprostol and the dinoprostone vaginal insert for labor induction at term. A total of 8 studies with 1,669 patients (misoprostol n= 903; dinoprostone n= 763) were eligible for inclusion. Dosing regimens varied across trials, with both dinoprostone gel and insert being used. Overall, the use of misoprostol showed less oxytocin augmentation when compared with dinoprostone (RR 0.78; 95% CI 0.67 to 0.90). Yet results for other outcomes, including the risk of tachysystole, uterine hyperstimulation, vaginal delivery within 24 h, cesarean delivery, Neonatal Intensive Care Unit admission, and Apgar scores <7 in 5 min, revealed no significant differences between misoprostol and dinoprostone. Study findings are limited by small-scale trials and further studies assessing the effectiveness and safety of misoprostol and dinoprostone in selected groups of patients are warranted. [11]
A 2010 meta-analysis compared intravaginal misoprostol with dinoprostone vaginal insert for cervical ripening and labor induction. From 11 included RCTs (N= 1,572), the pooled relative risk of vaginal delivery within 12 hours between dinoprostone and misoprostol was 0.65 (95% CI 0.44 to 0.96) and vaginal delivery within 24 hours was RR of 0.83 (0.74 to 0.94). Cesarean rates for induction reported a RR of 1.01 (95% CI 0.85 to 1.19). Uterine hyperstimulation and fetal tachysystole were similar but the dinoprostone group observed a significantly increased need for oxytocin augmentation (RR 1.45; 95% CI 1.20 to 1.74). No difference in fetal outcomes was observed. [12]
A 2012 meta-analysis assessing the efficacy and safety of dinoprostone vaginal insert compared to repeated prostaglandin administration (including dinoprostone and misoprostol) in women at term included studies reporting data separately for nulliparous and/or multiparous women with unfavorable cervix and intact membranes (N= 7 RCTs; 911 patients). Dinoprostone vaginal insert was found to reduce the cesarean section rate in nulliparous women by 24% compared to other ways of administration (RR 0.76; 95% CI 0.59 to 0.98) and in multiparous women by 23% (RR 0.77; 95% CI 0.60 to 0.99). However, dinoprostone vaginal insert significantly increased the risk of uterine hyperstimulation in nulliparous (RR 2.17; 95% CI 1.08 to 4.33) and multiparous women (RR 2.23; 95% CI 1.15 to 4.32) compared to other ways of administration. [13]