Induction of labor (IOL) is defined as the artificial initiation of uterine contractions before the onset of spontaneous labor, with the goal of achieving vaginal delivery. It is frequently indicated in various obstetric conditions such as post-term pregnancy, gestational hypertension, intrauterine growth restriction, and premature rupture of membranes, among others. The prevalence of IOL has steadily increased over the years and now accounts for approximately 20% of term pregnancies in developed countries, with rising trends seen globally as well [1].

Cervical ripening is a crucial step in the success of labor induction, especially when the cervix is unfavorable (Bishop score <6). Two primary modalities are employed for this purpose: mechanical and pharmacological methods. The Foley catheter, a mechanical method, induces ripening by exerting direct pressure on the internal os and stimulating endogenous prostaglandin release [2]. It is cost-effective, widely accessible, and associated with fewer systemic side effects, making it a popular choice, particularly in low-resource settings [3].

On the other hand, misoprostol, a synthetic prostaglandin E1 analogue, is commonly used for pharmacologic induction due to its efficacy, stability at room temperature, and low cost. Administered vaginally or orally, it facilitates both cervical ripening and initiation of uterine contractions [4]. However, concerns about uterine hyperstimulation and its effects on fetal well-being have prompted debates over its routine use [5, 6].

Several studies have compared the effectiveness and safety of Foley catheter versus misoprostol for cervical ripening, but the results remain inconclusive. While misoprostol has demonstrated faster induction-to-delivery intervals, mechanical methods like the Foley catheter are associated with lower rates of uterine hyperstimulation and comparable neonatal outcomes [7, 8].

Given these observations, this study was designed as a prospective randomized controlled trial to compare the maternal and fetal outcomes of labor induction using Foley catheter versus vaginal misoprostol in term pregnancies, aiming to determine the more effective and safer method for routine clinical use.

A total of 200 pregnant women with singleton, term gestation (≥37 weeks) requiring induction of labor were enrolled. Inclusion criteria included cephalic presentation, intact membranes, and a Bishop score ≤6. Women with previous cesarean section, malpresentation, multiple gestation, antepartum hemorrhage, or known hypersensitivity to prostaglandins were excluded.

Participants were randomly assigned into two groups of 100 each using a computer-generated randomization list. Group A received cervical ripening with a Foley catheter (16F), which was inserted into the endocervical canal under aseptic precautions and inflated with 30 mL of sterile saline. The catheter was left in place for a maximum of 12 hours or until spontaneous expulsion occurred. Group B received vaginal misoprostol, 25 µg every 4 hours, up to a maximum of 4 doses, or until the onset of active labor.

Maternal monitoring included regular assessment of uterine contractions, fetal heart rate (FHR), and vital signs. Vaginal examinations were performed periodically to assess Bishop score and cervical dilation. Labor progress was managed according to institutional protocols, and oxytocin augmentation was used if required.

Primary outcome measures included time from induction to delivery, mode of delivery (vaginal or cesarean), and improvement in Bishop score. Secondary outcomes were maternal complications such as uterine hyperstimulation, postpartum hemorrhage (PPH), and fetal outcomes including Apgar scores at 1 and 5 minutes, meconium-stained liquor, and NICU admissions.

Data were collected using a structured proforma and entered into Microsoft Excel. Statistical analysis was performed using SPSS version 25.0. Continuous variables were expressed as mean ± standard deviation and compared using Student’s t-test. Categorical data were analyzed using chi-square or Fisher’s exact test. A p-value <0.05 was considered statistically significant.

A total of 200 women were enrolled and equally divided into two groups: Group A (Foley catheter) and Group B (vaginal misoprostol). The baseline demographic characteristics such as age, parity, gestational age, and Bishop score were comparable between both groups (Table 1).

Table 1: Baseline Characteristics of Participants

Labor outcomes showed a statistically significant reduction in induction-to-delivery interval in the misoprostol group (9.4 ± 2.1 hours) compared to the Foley group (12.6 ± 3.5 hours, p<0.001). Vaginal delivery occurred in 82% of women in Group B compared to 74% in Group A; however, this difference was not statistically significant (p=0.17). The rate of cesarean section was slightly higher in Group A (26%) than in Group B (18%) (Table 2).

Table 2: Labor and Delivery Outcomes

In terms of maternal complications, uterine hyperstimulation occurred more frequently in the misoprostol group (12%) compared to the Foley group (2%), which was statistically significant (p=0.006). Postpartum hemorrhage was observed in 6% of Group A and 8% of Group B (p=0.58) (Table 3).

Table 3: Maternal Complications

Fetal outcomes, including Apgar scores and NICU admissions, were comparable between the groups. Apgar scores at 5 minutes ≥7 were seen in 96% of Group A and 93% of Group B. NICU admissions were slightly higher in the misoprostol group (14%) versus the Foley group (10%) but not statistically significant (p=0.38) (Table 4).

Table 4: Neonatal Outcomes

The results indicate that while misoprostol leads to a shorter induction-to-delivery time and higher Bishop score improvement, it is also associated with a significantly increased risk of uterine hyperstimulation (Table 2 and Table 3). Neonatal outcomes did not differ significantly between the two groups (Table 4).

This study aimed to compare maternal and fetal outcomes following induction of labor using Foley catheter versus vaginal misoprostol in term pregnancies. The findings indicate that while misoprostol resulted in a shorter induction-to-delivery interval and greater cervical ripening, it was also associated with a significantly higher incidence of uterine hyperstimulation. In contrast, the Foley catheter showed a more favorable safety profile with fewer maternal complications.

The significantly reduced induction-to-delivery interval observed in the misoprostol group is consistent with previous reports demonstrating faster onset of labor due to its potent uterotonic properties (1,2). Several randomized trials and meta-analyses have shown that vaginal misoprostol effectively shortens the duration of labor compared to mechanical methods (3,4). However, the Foley catheter, despite a relatively longer induction period, has been found to be equally effective in achieving vaginal delivery when allowed sufficient time (5).

In our study, vaginal delivery rates were slightly higher in the misoprostol group, though not statistically significant. This aligns with the findings of a Cochrane review which reported similar vaginal delivery outcomes between mechanical and pharmacological agents (6). However, the mode of delivery is influenced by multiple factors including parity, Bishop score, and labor progression, which may account for the variations across studies (7,8).

A key concern with misoprostol is the risk of uterine hyperstimulation, which was notably higher in our study compared to the Foley group. Similar findings have been reported by other investigators who caution against higher doses or repeated dosing of misoprostol due to the potential for adverse maternal and fetal outcomes (9,10). Uterine hyperstimulation has been associated with fetal heart rate abnormalities and increased NICU admissions, emphasizing the need for close fetal monitoring during misoprostol-induced labor (11).

Although the rates of NICU admissions and low Apgar scores were not significantly different between groups in our study, previous research has highlighted a slightly increased risk of neonatal morbidity with misoprostol, particularly when hyperstimulation occurs (12,13). On the other hand, mechanical methods like the Foley catheter have demonstrated a better neonatal safety profile, possibly due to their localized action and minimal systemic absorption (14).

The improvement in Bishop scores was higher in the misoprostol group, reaffirming its role as an effective pharmacologic agent for cervical ripening. However, studies have shown that the Foley catheter, despite slower initial progress, provides predictable ripening and can be combined with oxytocin for enhanced efficacy (15).

Overall, both methods are effective for labor induction in term pregnancies. Misoprostol offers advantages in terms of quicker delivery and enhanced cervical ripening but carries a higher risk of uterine overstimulation. The Foley catheter, while slower, presents fewer complications and remains a safe and reliable method, especially in women with contraindications to prostaglandins.

Both Foley catheter and vaginal misoprostol are effective methods for labor induction in term pregnancies. While misoprostol offers a shorter induction-to-delivery interval and improved cervical ripening, it is associated with a higher risk of uterine hyperstimulation. The Foley catheter, though slower, presents fewer maternal complications and remains a safer alternative, particularly in high-risk settings.

1. Noor N, Ansari M, Ali SM, Parveen S. Foley Catheter versus Vaginal Misoprostol for Labour Induction. Int J Reprod Med. 2015;2015:845735. doi:10.1155/2015/845735.
2. Adeniji OA, Oladokun A, Olayemi O, Adeniji OI, Odukogbe AA, Ogunbode O, et al. Pre-induction cervical ripening: transcervical Foley catheter versus intravaginal misoprostol. J Obstet Gynaecol. 2005;25(2):134–9. doi:10.1080/01443610500040737.
3. Caliskan E, Dilbaz S, Gelisen O, Dilbaz B, Ozturk N, Haberal A. Unsuccessful labour induction in women with unfavourable cervical scores: predictors and management. Aust N Z J Obstet Gynaecol. 2004;44(6):562–7. doi:10.1111/j.1479-828X.2004.00321.x.
4. Kadu NA, Shiragur S. Comparison of Intracervical Foley's Catheter With Vaginal Misoprostol Versus Intravaginal Misoprostol Alone for Cervical Ripening and Induction of Labor. Cureus. 2023;15(9):e44772. doi:10.7759/cureus.44772.
5. Owolabi AT, Kuti O, Ogunlola IO. Randomised trial of intravaginal misoprostol and intracervical Foley catheter for cervical ripening and induction of labour. J Obstet Gynaecol. 2005;25(6):565–8. doi:10.1080/01443610500231450.
6. Moraes Filho OB, Albuquerque RM, Cecatti JG. A randomized controlled trial comparing vaginal misoprostol versus Foley catheter plus oxytocin for labor induction. Acta Obstet Gynecol Scand. 2010;89(8):1045–52. doi:10.3109/00016349.2010.499447.
7. Vahid Roudsari F, Ayati S, Ghasemi M, Hasanzadeh Mofrad M, Shakeri MT, Farshidi F, et al. Comparison of vaginal misoprostol with Foley catheter for cervical ripening and induction of labor. Iran J Pharm Res. 2011;10(1):149–54.
8. Sciscione AC, Nguyen L, Manley J, Pollock M, Maas B, Colmorgen G. A randomized comparison of transcervical Foley catheter to intravaginal misoprostol for preinduction cervical ripening. Obstet Gynecol. 2001;97(4):603–7. doi:10.1016/s0029-7844(00)01186-8.
9. Hofmeyr GJ, Gülmezoglu AM. Vaginal misoprostol for cervical ripening and induction of labour. Cochrane Database Syst Rev. 2003;(1):CD000941. doi:10.1002/14651858.CD000941.
10. Ten Eikelder ML, Oude Rengerink K, Jozwiak M, de Leeuw JW, de Graaf IM, van Pampus MG, et al. Induction of labour at term with oral misoprostol versus a Foley catheter (PROBAAT-II): a multicentre randomised controlled non-inferiority trial. Lancet. 2016;387(10028):1619–28. doi:10.1016/S0140-6736(16)00084-2.
11. Jagielska I, Kazdepka-Ziemińska A, Janicki R, Fórmaniak J, Walentowicz-Sadłecka M, Grabiec M. [Evaluation of the efficacy and safety of Foley catheter pre-induction of labor]. Ginekol Pol. 2013;84(3):180–5. doi:10.17772/gp/1560.
12. Kashanian M, Bahasadri S, Nejat Dehkordy A, Sheikhansari N, Eshraghi N. A comparison between induction of labor with 3 methods of titrated oral misoprostol, constant dose of oral misoprostol and Foley catheter with extra amniotic saline infusion (EASI), in women with unfavorable cervix. Med J Islam Repub Iran. 2019;33:115. doi:10.34171/mjiri.33.115.
13. Hofmeyr GJ, Gülmezoglu AM, Alfirevic Z. Misoprostol for induction of labour: a systematic review. Br J Obstet Gynaecol. 1999;106(8):798–803. doi:10.1111/j.1471-0528.1999.tb08400.x.
14. Culver J, Strauss RA, Brody S, Dorman K, Timlin S, McMahon MJ. A randomized trial comparing vaginal misoprostol versus Foley catheter with concurrent oxytocin for labor induction in nulliparous women. Am J Perinatol. 2004;21(3):139–46. doi:10.1055/s-2004-823777.
15. Garba I, Muhammed AS, Muhammad Z, Galadanci HS, Ayyuba R, Abubakar IS. Induction to delivery interval using transcervical Foley catheter plus oxytocin and vaginal misoprostol: A comparative study at Aminu Kano Teaching Hospital, Kano, Nigeria. Ann Afr Med. 2016;15(3):114–9. doi:10.4103/1596-3519.188890.