Induction of labour is one of the most common obstetric procedures that are conducted worldwide and is done in instances where the benefits of preterm birth outweigh the risks of carrying a pregnancy. Maternal obesity has been on the rise in the last couple of years, which has complicated obstetric care even more, particularly the results of induction. It is already known that women with high body mass index (BMI) experience distorted physiological reactions to labour-inducing agents, which lead to prolonged labour, increased rate of intervention and maternal and neonatal risks. Misoprostol (a prostaglandin E1 analogue) and prostaglandin E2 (dinoprostone) are the most commonly used pharmacological agents; nevertheless, their relative efficacy in obese individuals is currently under research (1). It has been demonstrated that maternal BMI is a significant factor that determines the success of labour induction, especially in primigravida women, with higher BMI levels being linked to lower cervical favourability and slower labour.

Obesity also leads to hormonal imbalances, changes in uterine contractility, and inflammatory mediators, which can decrease responsiveness to induction agents. Clinically, it has been established that the high BMI groups have lower successful vaginal births and high induction failure, hence a need to establish induction guidelines that are specific to this high-risk group (2). Besides influencing the success of induction, high BMI is closely linked to high rates of cesarean section especially when induction techniques based on prostaglandin are employed. Comparative studies have revealed that obese women who are induced using drugs like dinoprostone have high rates of operative delivery than women with normal BMI or spontaneous labour onset. This highlights the need to choose the best induction agent to reduce the number of surgical interventions and complications (3). Various approaches to labour induction in obese women have been investigated, such as oral and vaginal prostaglandins, mechanical techniques and a combination of both.

Recent multicenter studies indicate that both misoprostol and prostaglandin E2 are effective, but their effectiveness can differ with maternal BMI, dosage and route of action. Especially misoprostol has been in the limelight of attention owing to its low cost, simple administration and strong uterotonic effects, which have made it a viable alternative in resource constrained environments (4). The safety of misoprostol in high-risk pregnancies and obesity has also been extensively investigated. Evidence exists to suggest that vaginal misoprostol inserts are safe to be used in obese women with acceptable rates of uterine hyperstimulation and good maternal outcomes. However, obese patients are likely to have abnormal drug absorption and response rate and, therefore, need special dosing schedules (5).

Comparative randomized trials of misoprostol and prostaglandin E2 have offered interesting information about the relative effectiveness of these two drugs. Research has shown that misoprostol is equal or less than prostaglandin E2 in terms of successful vaginal birth, and the induction-to-delivery ratio is comparable or shorter. The findings are especially applicable in the obese population where the long labour process may elevate the chances of developing complications like infection, hemorrhage, or fetal distress (6). Subsequent studies have suggested the synergistic effect of maternal age and BMI on induction outcomes, showing that increased BMI does not only extend labour, but also increases the risk of failed induction. Even in the high-risk groups, oral misoprostol has been demonstrated to be effective but the outcomes can be different based on the patient characteristics and clinical guidelines (7).

New methods of labour induction among obese women have been aimed at ensuring that there is an optimization of the delivery system of the drugs, including the controlled-release vaginal misoprostol inserts. These methods are designed to achieve stable drug concentrations and enhance the success rates of induction and reduce the adverse effects. This is especially significant in light of the increasing prevalence of obesity among obstetric populations around the globe (8). Prostaglandin induction failure is still a major clinical problem, which can result in maternal morbidity and neonatal complications. Retrospective cohort studies have demonstrated that failure of induction using prostaglandin agents is linked with an increased incidence of emergency cesarean section and poor perinatal outcomes, and thus more effective and predictable induction methods are required (9). Direct comparisons of misoprostol and prostaglandin E2 have always shown a discrepancy in effectiveness with some studies showing a higher success rate and less time spent in labour when using misoprostol.

These results indicate that misoprostol could be a more effective induction agent, especially in those populations with a higher BMI where cervical ripening is necessary and quick (10). The time and dose of prostaglandin E2 also contribute significantly to success of induction. Slow or insufficient response to dinoprostone can lengthen labour and raise intervention rates, particularly in already obese women with low uterine sensitivity. Induction protocol optimization is thus necessary to enhance clinical outcomes (11). The effectiveness of misoprostol has been further supported by meta-analyses of randomized controlled trials comparing oral misoprostol and vaginal dinoprostone. These studies indicate that it can shorten induction-delivery time and raise the chances of vaginal delivery, with no appreciable impact on adverse maternal or neonatal outcomes (12).

Obstetric comorbidities like gestational diabetes and hypertension also complicate pregnancy induction in obese women. Comparative studies on dinoprostone versus misoprostol in such groups have demonstrated mixed results, but generally indicate that misoprostol is a good and effective alternative even in high-risk clinical situations (13). Other induction methods such as oxytocin and low dose misoprostol have been investigated as well especially when the membranes rupture prematurely. The strategies are meant to achieve the efficacy and safety balance, minimizing the likelihood of complications like postpartum bleeding and ensuring that labour proceeds effectively (14). Cervical ripening techniques have a major impact on the rate of cesarean birth in obese women, and some studies suggest that some pharmacological agents are more effective than others. Comparative studies of various induction techniques have shown that personalized techniques are required to minimize operative births and enhance maternal outcomes (15).

Comparative systematic reviews of oral and vaginal misoprostol have shown that both methods are effective, but differences in onset and duration of action could affect clinical decision-making. These findings are in favor of the adaptability of misoprostol application in various clinical environments and patient groups (16). Lastly, maternal obesity has been found to increase the period of labour stages especially in the case of dinoprostone induction. This extension increases the risk of maternal fatigue, fetal distress, and delivery by surgery, which again underscores the necessity to decide on the most appropriate induction agent to apply in obese individuals (17). Overall, the growing body of evidence suggests that misoprostol and prostaglandin E2 may be employed to induce labour, but their effects may differ dramatically in women with high BMI. These disparities are paramount to understand so as to optimise clinical guidelines, improve maternal and neonatal outcomes and address the burden of increasing obesity in pregnancy.

Purpose

To determine the effectiveness, safety and results of misoprostol versus prostaglandin E2 labour induction in high-BMI pregnant women in terms of delivery success, duration and complications.

Study Design A Prospective comparative study. Study Setting The research was done at Saidu Group of Teaching Hospitals & Temergara Teaching Hospital Temergara. Study Period November 2025 to April 2026. Sample Size 100 pregnant women (50 in each group) were used. Sampling Technique Non-probability consecutive sampling technique was employed. Inclusion criteria: Pregnant women aged 18 to 40 years, singleton term pregnancy (37 weeks and above), cephalic presentation, BMI 30kg/m2 and presence of induction of labour were included. Only patients who had reassuring fetal status and intact or ruptured membranes were eligible. Exclusion Criteria Women who had delivered their babies via cesarean section, multiple pregnancies, placenta previa, fetal distress, contraindication to vaginal delivery or those known to be hypersensitive to prostaglandins were excluded. Methods The eligible participants were divided into two groups. Group A: Oral/vaginal misoprostol (PGE1) was used and Group B: Prostaglandin E2 (dinoprostone) was used according to the protocols of the hospital. Basic demographic data, BMI, Bishop score, and obstetric history were recorded. Patients were monitored in terms of cervical ripening, induction-to-delivery interval, mode of delivery, neonatal and maternal outcomes. Continuous fetal monitoring was used to measure fetal well-being. The primary outcome was a successful vaginal birth within 24 hours, and the secondary outcomes were the cesarean section rate, failure of induction, uterine hyperstimulation, postpartum bleeding, and neonatal Apgar scores. The data was analyzed using SPSS version 26.0. Continuous variables were discussed with the help of mean and standard deviation, and categorical variables were discussed with the help of frequencies and percentages. The significant p-value was considered to be 0.05

This was achieved by enrolling 100 pregnant women with BMI of 30 kg/m 2 and 50 women per group (Misoprostol vs Prostaglandin E2). The baseline and demographic data of the two groups were similar and there was no significant difference in terms of age, BMI, gestational age or initial Bishop score that proved the homogeneity of the two groups of the study.

Table 1: Demographic and Baseline Characteristics of Participants

Table 1 shows that the average age of the misoprostol group subjects was 27.8 ± 3.9 years compared to 28.4 ± 4.1 years in the PGE2 group (p=0.421). The mean BMI was 32.4 ± 2.3 kg/m² and 32.9 ± 2.6 kg/m² in the misoprostol and PGE2 groups, respectively (p=0.389). Mean gestational age and Baseline Bishop score were also similar across the groups, which was adequate randomization

Table 2: Labour Outcomes

The cumulative success rate of successful vaginal delivery within 24 hours was much better in the misoprostol group, 36/50 patients (72%) successful vaginal delivery vs. 30/50 patients (60%), in the PGE2 group (p=0.041). The misoprostol group also recorded lower cesarean section rate of 28% compared to PGE2 group of 40% (p=0.038). The induction-delivery time of the misoprostol group (14.1 + 3.4 hours) was much shorter than the PGE2 group (17.9 + 4.0 hours) (p<0.001). There were 5 cases (10 percent) of failed induction and 9 cases (18 percent) in the misoprostol group and 5 cases (18 percent) in the PGE2 group respectively, which is statistically significant (p=0.048).

Table 3: Maternal Complications

There was measurement of maternal complications in the two groups. In the misoprostol, 4 patients (8%) and in the PGE2, 2 patients (4) experienced uterine hyperstimulation but was not found significant (p=0.392). There was 3 patient (6%), and 4 patient (8%) incidence of postpartum hemorrhage in the misoprostol and PGE2 groups, respectively (p=0.694). Similar rates of infection were also found, 2 cases (4% in the misoprostol group and 3 cases (6% in the PGE2 group) (p=0.647). In general, maternal complications were both medically manageable. There was similarity in the neonatal outcomes of the two groups.

Table 4: Neonatal Outcomes

The mean Apgar score at 1 minute was 7.3 ± 0.7 in the misoprostol group versus 7.0 ± 0.8 in the PGE2 group (p=0.214), while at 5 minutes the scores were 8.9 ± 0.5 and 8.7 ± 0.6, respectively (p=0.167). The NICU admissions of PGE2 group were marginally more, 7 cases (14%) versus 4 cases (8) of misoprostol group, but it was not significant (p=0.341). These results show that neither of the induction agents had any negative impact on the well-being of the neonates. In general, misoprostol was found to be more effective in induction of labour in high-BMI obese women, vaginal delivery rates, reduced induction-delivery time, reduced cesarean delivery and failed induction rates compared to prostaglandin E2.

The current research was carried out to compare the results of labour induction with misoprostol and prostaglandin E2 in high BMI women, which is a growing population in the obstetric practice. The results of this research showed that misoprostol had a higher success rate of vaginal birth within 24 hours, the induction-delivery time was reduced and the rate of cesarean section was lower than that of prostaglandin E2. These findings are in line with the recent literature that has emphasized the role of maternal BMI on the efficacy of induction agents and the necessity of optimized protocols in obese women. The increased vaginal births in the misoprostol group in this study is consistent with the results of Socha et al. who found better induction rates with oral misoprostol in women with a higher BMI (1).

This improved uterotonic effect of misoprostol could be the reason behind its better performance as physiological alterations associated with obesity, such as the change in myometrial responsiveness and hormonal balance, have the potential to decrease the efficacy of traditional induction agents. Thus, it can be helpful to choose an agent that has a more potent pharmacological effect in order to address these difficulties. Conversely, the comparatively low success rate of prostaglandin E2 in this study is in line with previous studies that show that obese women are less responsive to dinoprostone (2). Greater adiposity is linked with reduced cervical ripening efficiency and an increased duration of labour, which could be a factor in the higher incidence of induction failure and operative delivery in this group. These results highlight the significance of personalized treatment of obese patients, in which the general induction guidelines might fail to provide the best outcomes.

Another important finding of this study is the much shorter induction-to-delivery interval in the misoprostol group. Extended labour is linked to maternal discomfort, risk of infection and complications in the newborns. Past research has also shown that misoprostol is capable of shortening the labour period since it has a fast-acting effect and prolonged uterine contractions (3). This is especially helpful in obese women, where delayed labour progression is generally noticed. The rate of cesarean section was significantly greater in the group of prostaglandin E2, mainly because of the failure of induction and fetal distress. This is in line with reports that obese women who were induced through the use of prostaglandins are more likely to deliver by operation (4). The decrease in cesarean rates is an urgent objective in obstetrics because surgical birth is associated with increased risks of bleeding, infection, and postpartum, particularly in obese women.

The two groups had similar maternal complications, and no statistically significant differences existed. Uterine hyperstimulation was a little more common in the misoprostol group, but it was not significant and the difference was within acceptable clinical ranges. The same has been observed in other studies that have tested the safety of misoprostol in high-risk pregnancies and indicated that it is safe to use provided that it is monitored (5). The similarity of the neonatal outcomes of the two groups also supports the safety profile of the two induction agents. There were no significant differences in Apgar scores and NICU admission rates, which means that both drugs did not have a negative impact on the well-being of the neonatal unit. This is in line with randomized controlled trials that have compared misoprostol and prostaglandin E2 with no significant differences in the outcomes of the neonatal despite differences in the characteristics of maternal labour (6).

The other factor is the effects of BMI on labour progression and induction success. Research has indicated that there is a correlation between increased BMI and extended labour time and failed induction (7). The results of this study support this association and indicate that misoprostol can be more appropriate to overcome these obstacles because of its pharmacodynamic characteristics. New developments in induction methods, including controlled-release misoprostol vaginal inserts have also enhanced the predictability and success of labour induction in obese women (8). These inventions are meant to offer uniformity in drug delivery and reduce the variability in response especially in patients with altered drug metabolism. Failed induction is a major cause of maternal morbidity and the fact that it is more prevalent in the prostaglandin E2 group in the study is interesting. Past studies have associated unsuccessful induction of prostaglandins with risks of emergency cesarean delivery and poor perinatal outcomes (9).

Thus, the choice of a more trustworthy induction agent may significantly influence the general obstetric results. This study is also supported by comparative studies that have shown greater efficacy of misoprostol than prostaglandin E2 in regards to labour progression and delivery outcomes (10). Moreover, the timing and dosage of prostaglandin E2 is also a significant determinant of its efficacy and inadequate administration can also lead to worse results in obese women (11). Meta-analyses have always indicated that oral misoprostol is related to shorter induction times and higher vaginal delivery rates than vaginal dinoprostone (12). These results reinforce the evidence base to use misoprostol as a first-line agent in inducing labour in obese populations. The comorbid conditions like gestational diabetes and hypertension that occur more frequently in obese women may also complicate the labour induction (13).

In spite of these, misoprostol has proved to be effective consistently in various clinical situations and as such, it is a flexible agent. Other induction methods such as low dose regimens and combination therapies have been considered to enhance safety and efficacy (14). The ease and affordability of misoprostol however, render it especially appealing in resource constrained environments like those in state-run hospitals. Moreover, the type of cervical ripening technique has a great impact on the cesarean rates among obese women (15). The effectiveness of cervical ripening with misoprostol could be the reason behind its low operative delivery rates in this study.  The overall effectiveness and versatility of oral and vaginal misoprostol have been confirmed by comparative systematic reviews of the two agents (16). This adaptability allows clinicians to tailor induction regimens depending on patient factors and institutional capacities. Finally, the long labour time during the use of prostagland in E2 in obese women has been well established (17), which coincides with the longer induction to delivery time in this study. This is also a reason why misoprostol should be used in such patients. This study demonstrates that misoprostol is superior to prostaglandin E2 in labour induction in high BMI women and that higher vaginal delivery rates, less labour time, and equivalent safety profiles are observed. These results highlight the importance of the appropriate choice of induction agents to optimize the maternal and neonatal outcomes of obese pregnancy.,

The conclusion of this study is that misoprostol is a better agent than prostaglandin E2 in labour induction in high BMI women. It demonstrated a high success rate of vaginal birth, less induction-delivery time, and a lower rate of cesarean section with an equivalent safety profile. Although the rate of uterine hyperstimulation was slightly higher with misoprostol, it was not significant and could be managed in clinical practice. The number of neonatal outcomes was not different between the two groups, and this indicates that misoprostol does not adversely affect the fetus. In light of the rising incidences of maternal obesity and the complications associated with obstetrics, misoprostol is an effective, economical and viable choice in labour induction. Therefore, it is recommended that misoprostol should be considered as a first line induction drug in obese pregnant women, particularly in resource limited settings, and appropriate follow-up must be done to ensure maternal and neonatal safety

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