In clinical medicine, term pregnancy delivery is defined as delivery occurring from 37 completed weeks (259 days) to less than 42 weeks (294 days) of gestation [1]. The initiation mechanism of this physiological process involves a complex multifactorial regulatory system, encompassing the activation of the fetal hypothalamic-pituitary-adrenal (HPA) axis, dynamic changes in placental hormones, alterations in uterine myometrial sensitivity, and a cascade of inflammatory factor reactions, among others [2, 3]. Any abnormality in any of these links may prevent the normal initiation of the delivery mechanism. However, in clinical practice, many terms pregnant women are unable to naturally progress into the labor stage due to various physiological, psychological, or pathological factors and must rely on artificial intervention methods to induce labor [4]. Otherwise, a series of severe problems, such as placental aging or dysfunction, fetal distress, and neonatal asphyxia, may arise, thereby posing a threat to the life safety of both the mother and the infant [5]. Labor induction at term refers to the process of accelerating uterine contractions and initiating the delivery process through various methods, such as pharmacological or mechanical means, after 37 completed weeks of gestation and before the onset of spontaneous uterine contractions, aiming to achieve an effect similar to that of natural childbirth [6]. The primary objective of labor induction is to facilitate timely delivery from an unfavorable intrauterine environment and to alleviate or resolve maternal comorbidities or pregnancy-related complications [7]. The success of labor induction is closely associated with cervical maturity. The more mature the cervix is, the higher the success rate of labor induction [8].

Cervical ripening is an important physiological change that occurs in women during the late stages of pregnancy. Essentially, it involves a series of biochemical and morphological alterations in cervical tissue under the regulation of endogenous hormones. These changes include the degradation of collagen fibers, a significant increase in the content of glycosaminoglycans such as hyaluronic acid in the extracellular matrix, and an increase in water retention. Ultimately, these processes lead to cervical softening, shortening, and enhanced dilatation capacity, thereby creating the necessary conditions for normal childbirth [9]. This process is not only crucial for spontaneous labor but also as a prerequisite for successful induction [10]. Clinical interventions aimed at promoting cervical ripening attempt to replicate this physiological process through pharmacological or mechanical methods. Their mechanisms including promoting the synthesis of endogenous prostaglandins, enhancing collagenase activity, and altering the physicochemical properties of the extracellular matrix [11]. Ideally, interventions to promote cervical ripening should achieve biological effects similar to those of natural ripening, effectively improving cervical compliance while maintaining normal uterine contraction rhythms and avoiding complications such as tetanic contractions, birth canal injuries, or inadequate placental perfusion [12]. It is noteworthy that insufficient cervical ripening significantly affects the outcome of labor induction, not only prolonging labor and increasing maternal physical exertion but also potentially leading to failed induction and subsequent emergency cesarean section, thereby increasing risks for both mother and neonate [13]. Consequently, the selection of safe, effective, and highly predictable methods for promoting cervical ripening has become a critical issue in optimizing delivery management and improving pregnancy outcomes.

Misoprostol, a synthetic analog of prostaglandin E1, is a widely used drug in the fields of pregnancy termination and labor induction due to its significant pharmacological effects [14]. By activating prostaglandin receptor–mediated signaling pathways, misoprostol promotes cervical connective tissue remodeling, enhances collagen degradation, and increases cervical compliance. Additionally, it sensitizes uterine smooth muscle to oxytocin, facilitating the initiation of effective uterine contractions [15]. Misoprostol acts rapidly and offers remarkable cost-effectiveness, making it well-suited for use in healthcare institutions at all levels [16]. Cervical balloon placement is a commonly used mechanical method for labor induction [17]. The balloon is a double-lumen catheter made of silicone. It is inserted into the cervical canal, and physiological saline is injected into the balloon. The mechanical expansion of the balloon stimulates the cervix, promoting cervical ripening and dilation [18]. This method does not directly stimulate uterine smooth muscle contraction but instead applies mechanical pressure to the cervix, mimicking the pressure exerted by the fetal head on the cervix during natural childbirth, thereby achieving the effect of labor induction [19]. In clinical obstetric practice, oral misoprostol solution administration and cervical balloon placement, as two commonly used methods for promoting cervical ripening, have been widely applied in the labor induction process for pregnant women with unfavorable cervical conditions. Common indications for induction in such cases include, but are not limited to, hypertensive disorders of pregnancy (e.g., preeclampsia), gestational diabetes mellitus requiring delivery, oligohydramnios, post-term gestation ($\ge$41 weeks), suspicion of fetal growth restriction, and non-reassuring fetal status in the absence of acute emergencies. However, there is currently no consensus in the academic community regarding the comparative clinical efficacy and safety of these two intervention methods. Some research data indicate that oral misoprostol solution demonstrates a more significant advantage in shortening the interval from induction to delivery, with a significantly higher rate of delivery completion within 24 hours compared to the balloon group. It may also reduce the cesarean section rate by more effectively promoting cervical ripening [20]. Nevertheless, other research findings suggest that the cervical balloon may have greater safety advantages, as its mechanical expansion avoids the risk of uterine hyperstimulation that may be associated with pharmacological interventions, whereas misoprostol may increase the incidence of uterine hyperstimulation [21]. This controversy has created confusion for clinicians when selecting labor induction methods and underscores the need for systematic and comprehensive comparative studies on these two approaches.

Against this background, there remains a lack of consensus and limited robust comparative evidence regarding the efficacy and safety of oral misoprostol solution versus cervical balloon placement for labor induction in this specific population. Therefore, this study aimed to compare the labor induction effects and safety of oral misoprostol solution and cervical balloon placement in full-term pregnant women with unfavorable cervical conditions.

Induction of labor is an important intervention for terminating pregnancy, especially in full-term pregnancies with unfavorable cervical conditions. The selection of an appropriate induction method is therefore crucial for ensuring maternal and neonatal safety and improving the quality of childbirth [25]. In recent years, with the continuous advances in medical technology, multiple induction methods have been widely applied in clinical practice. Among these, oral misoprostol solution and cervical balloon placement are two commonly used induction techniques. However, controversy remains regarding the comparative effectiveness and safety in the induction of full-term pregnancies, and robust evidence-based data are still limited. This study conducted a retrospective analysis of the clinical data from 610 parturients who underwent full-term pregnancy induction at our hospital between January 2023 and January 2025. The aim was to comprehensively evaluate the clinical value of oral misoprostol solution and cervical balloon placement for inducing labor in women with unfavorable cervical conditions and to provide a scientific basis for clinical practice.

For pregnant women with unfavorable cervical conditions, successful vaginal delivery during the induction process is an important indicator for evaluating the effectiveness of induction. Misoprostol, through its prostaglandin E1 activity, can soften the cervix and increase its dilatability, thereby creating more favorable conditions for natural childbirth [26]. In contrast, although cervical balloons can facilitate cervical ripening to some extent, their effect is less pronounced than that of misoprostol. The results of this study demonstrated that the vaginal delivery rate in the misoprostol group (57.42%) was significantly higher than that in the cervical balloon group (47.67%), while the cesarean section rate was lower (42.58% vs. 52.33%). These findings indicate that misoprostol has a clear advantage in promoting natural childbirth. Consistent with our results, Kemper et al. [27] conducted a systematic search of randomized controlled trials (RCTs) comparing catheters with oral misoprostol for the induction of labor in full-term singleton pregnancies from inception to April 2019, including four trials providing individual participant data with a total of 2815 subjects. The results showed that for women undergoing induction, the effectiveness of catheters was lower than that of oral misoprostol, with a slightly reduced likelihood of vaginal delivery among subjects using catheters (Risk Ratio = 0.95, 95% CI = 0.91–0.99), supporting the conclusions of this study. This difference may be attributable to the distinct pharmacological mechanism of misoprostol. Misoprostol directly acts on uterine smooth muscle and cervical tissue, increasing the frequency and intensity of uterine contractions while softening and dilating the cervix [28]. In contrast, cervical balloon primarily functions through physical compression and dilation of the cervical canal, with a relatively weaker regulatory effect on uterine contractions [29]. Additionally, the delivery rate within 24 hours was significantly higher in the misoprostol group than in the cervical balloon group, and the labor duration was shorter. This suggests that misoprostol can more effectively shorten the time interval from induction to delivery. From a clinical perspective, reducing labor duration not only alleviates the suffering of parturients but also reduce the risk of maternal and neonatal complications associated with prolonged labor. By enhancing the coordination and intensity of uterine contractions, misoprostol promotes more rapid cervical dilation and accelerates the labor process. In contrast, the physical mechanism of cervical balloon dilation is relatively slow in achieving effective cervical ripening, often necessitating artificial rupture of membranes to strengthen contractions and expedite labor. Notably, this study showed that the incidence of poor progress during the first stage of labor reached 49.68% in the cervical balloon group, suggesting that mechanical dilation may lack coordination between cervical ripening and the onset of contractions, increasing the risk of labor stagnation. Misoprostol, by directly stimulating uterine smooth muscle to produce regular contractions while simultaneously promoting cervical softening, enabling contractile forces to be more effectively translated into the power for cervical dilation. In contrast, reliance on mechanical dilation with cervical balloons may lead to cervical tissue edema, increasing uterine contraction resistance, which is also an important reason for its high incidence of poor progress in the first stage of labor [30].

The present study also demonstrated that the oxytocin usage rate and the duration of oxytocin infusion were significantly lower in the misoprostol group than in the balloon group. It is important to note that the induction of the labor process carries significant clinical risks, which are particularly prominent in medical settings that lack electronic oxytocin infusion pumps and fetal electronic monitoring equipment. A major challenge in such settings is the difficulty in precisely regulating uterine contraction intensity. Insufficient stimulation may prolong labor and increase the failure rate of induction, whereas excessive stimulation can markedly elevate the risk of fetal distress [31]. From a mechanistic perspective, cervical balloons have a pharmacological advantage of not directly inducing uterine contractions during the cervical ripening phase. By physically stimulating the cervix, cervical balloons promote the synthesis and secretion of endogenous prostaglandins, leading to cervical softening and dilation, ultimately facilitating natural childbirth. This mechanism avoids direct stimulation of the uterus and fetus by drugs, reducing the risks of overly strong or uncoordinated contractions, as well as adverse reactions caused by improper drug use [32]. However, clinical observations from this study revealed that approximately 80% of parturients still required intravenous oxytocin infusion during subsequent labor stages. This indicates that while cervical balloons are effective for cervical ripening, they still rely on oxytocin to maintain and enhance uterine contractions to ensure successful delivery. This reliance poses significant fetal safety risks in medical settings lacking precise infusion equipment. For example, improper dosage control of oxytocin can lead to overly strong or irregular contractions, increasing the risks of fetal distress in utero and even uterine rupture [33]. Therefore, the safety advantages of cervical balloons during the cervical ripening phase may be offset by the risks associated with subsequent oxytocin infusion. In contrast, misoprostol exhibits dual pharmacological effects by both inducing uterine contractions and promoting cervical ripening. This dual action allows a greater proportion of parturients to achieve vaginal delivery without reliance on oxytocin infusion, thereby suggesting potential safety advantages. Notably, the incidence of meconium-stained amniotic fluid was higher in the misoprostol group, which may be attributable to pharmacological stimulation of fetal intestinal smooth muscle [34]. In the absence of continuous electronic fetal heart rate monitoring, meconium-stained amniotic fluid, as an important clinical indicator of fetal distress, may itself constitute an indication for cesarean section. Although meconium staining is not directly causally associated with fetal hypoxia, considering the potential risk of meconium aspiration syndrome, this phenomenon remains clinically significant. It is worth noting that the introduction of electronic fetal heart rate monitoring in cases with meconium staining may further reduce the cesarean section rate in the misoprostol group, thereby potentially amplifying the observed differences in clinical efficacy between the two induction methods.

There were no significant differences between the two groups in most complications (such as postpartum hemorrhage and amniotic fluid embolism). However, a higher incidence of chorioamnionitis was observed in the cervical balloon group (6.37% vs. 1.52%; p = 0.039). While this difference reached statistical significance, the overall number of events was small (10 vs. 2 cases). This observation warrants attention and suggests a potential association between mechanical manipulation and infection risk that should be considered in clinical practice, though it requires confirmation in larger studies. In clinical practice, it is therefore essential to strictly control the timing of balloon placement, minimize the duration of catheter retention, and strengthen post-procedural monitoring of body temperature and blood parameters. Regarding neonatal infections, the misoprostol group demonstrated significant advantages, which may be attributable to the shorter duration of labor and the inherent anti-inflammatory properties of the drug. A study by Kruit and Rahkonen [35] also confirmed that, compared with oral misoprostol, the use of cervical balloons was associated with nearly a threefold increase in the incidence of chorioamnionitis and a twofold increase in neonatal infections. Nevertheless, it should be noted that excessive doses of misoprostol may lead to overly strong uterine contractions, increasing the risk of fetal distress. Accordingly, strict control of the clinical dosage is essential, with a single dose not exceeding 50 µg. The safety controversy surrounding misoprostol primarily relates to its dose-effect relationship. Early studies suggested that oral misoprostol might increase the risk of uterine rupture. Misoprostol is rapidly absorbed, with serum concentrations peaking within 30 minutes after administration and a primary metabolic half-life of approximately 120 minutes. These pharmacokinetic characteristics necessitate repeated dosing every 1–2 hours in clinical practice to ensure effective induction of uterine contractions [36]. Although frequent dosing may increase the clinical management burden, it allows for more precise dose regulation, thereby reducing the risk of uterine hyperstimulation. In contrast, a single large dose followed by prolonged observation may fail to promptly address sudden episodes of frequent contractions, increasing the risk of adverse pregnancy outcomes. In the present study, a low-dose regimen was employed, and no related adverse events were observed, indicating that the safety of misoprostol is manageable when administered at appropriate doses.

The results of this study indicate that among women in the oral misoprostol group who may require labor induction in the future, the proportion wiling to choose this method again was significantly higher than that in the cervical balloon group. Flament et al. [37] evaluated women’s satisfaction with cervical ripening methods during labor induction. The results showed that women were generally satisfied when given the autonomy to choose a method, with 95.3% of patients in the oral misoprostol group expressing satisfaction, a figure higher than the 90.5% in the cervical balloon group, which is largely consistent with the findings of our study. This may be attributed to the fact that oral misoprostol, during the initial labor induction process, avoids the discomfort vaginal examinations required for cervical balloon insertion, thereby reducing physical trauma and psychological burden [38]. Additionally, some participants were spared from oxytocin infusion, while others avoided cesarean sections. These factors may positively influence women’s preferences regarding future labor induction methods.

This study aimed to optimize labor induction strategies for pregnant women with unfavorable cervical conditions. By systematically comparing oral misoprostol solution and cervical balloon placement in terms of labor induction success rate, labor duration, cesarean section rate, and maternal-fetal complications, it confirms that misoprostol offers advantages in improving the 24-hour vaginal delivery rate, reducing the cesarean section rate and oxytocin usage, and achieving higher maternal satisfaction. These findings provide crucial evidence-based support for optimizing labor induction protocols in clinical practice, streamlining the induction process, enhancing delivery safety, and potentially reducing unnecessary cesarean sections, thereby improving maternal and neonatal outcomes. Additionally, the study results may inform the formulation and updating of clinical guidelines and contribute to the promotion of standardized obstetric care.

In conclusion, for term pregnant women with unfavorable cervical conditions, oral misoprostol solution significantly outperforms cervical balloons in terms of induction effectiveness, safety, and patient acceptability. Its primary advantages include a substantial increase in vaginal delivery rates, significant shortening of labor duration, and lower cesarean section rates and oxytocin use. When used at a reasonable dose, the risks of neonatal infection and maternal-fetal complications remain low. Moreover, this medication is cost-effective and easy to administer, which may reduce healthcare resource utilization and underscores its high clinical value.

The data supporting the findings of this study can be obtained from the corresponding author, upon request.

SL: Developed and planned the study, performed experiments, and interpreted results. Edited and refined the manuscript with a focus on critical intellectual contributions. LD, NX: Participated in collecting, assessing, and interpreting the data. Made significant contributions to data interpretation and manuscript preparation. NW, CC: Provided substantial intellectual input during the drafting and revision of the manuscript. Made substantial contributions to the design of the work; interpreted data for the work. All authors contributed to editorial changes in the manuscript. All authors read and approved the final manuscript. All authors have participated sufficiently in the work and agreed to be accountable for all aspects of the work.

The study was carried out in accordance with the guidelines of the Declaration of Helsinki, and the protocol was approved by the Affiliated Wuxi People’s Hospital of Nanjing Medical University Ethics Committee (approval number: KY23123). All patients or their families/legal guardians gave their informed consent for inclusion before they participated in the study.

Not applicable.

This research was funded by Wuxi Municipal Health Commission Maternal and Child Health Research Project (No. FYKY202202).

The authors declare no conflicts of interest.