Abstract
Background:
Vaginal birth after cesarean (VBAC) is a safe option for selected women, but success rates are influenced by maternal characteristics and obstetric history. This study aimed to evaluate the success of trial of labor after cesarean (TOLAC) and identify factors associated with successful VBAC among women with one previous cesarean scar.
Materials and Methods:
A retrospective observational study was conducted on 377 women with a single prior cesarean scar. Among them, 126 women were eligible for TOLAC. Data on maternal age, parity, previous vaginal delivery, prior TOLAC, and primary indications for cesarean were collected and analyzed. VBAC success rates were calculated, and associations between maternal factors and outcomes were assessed.
Results:
Overall, 22.2% of women eligible for TOLAC achieved successful VBAC. Women with a persisting indication for previous cesarean had a VBAC success rate of 16.0%, compared with 6.8% among those with a nonpersisting indication. Notably, women with a history of previous TOLAC had the highest success rate at 64.7%, while only 4.7% of women with a single cesarean scar achieved VBAC. Maternal age was significantly associated with success, with women aged ≥30 years having higher VBAC rates than those aged 20–29 years (9.5% vs. 2.6%, p = 0.018). Parity and previous vaginal delivery were strong predictors, with multiparous women achieving 31.9% success versus 3.9% among primiparous women, and 33.3% of women with prior vaginal births delivering successfully compared with 3.6% without.
Conclusions:
VBAC success is influenced by prior TOLAC, maternal age, parity, previous vaginal delivery, and cesarean indication. Individualized assessment of these factors is crucial for counseling women considering TOLAC and optimizing vaginal birth outcomes.
Keywords
Introduction
The incidence of cesarean sections is increasing worldwide, without a corresponding decrease in maternal or neonatal morbidity or mortality. 1 Offering women the option of a vaginal birth after cesarean (VBAC), defined as a vaginal delivery following a previous cesarean, is an important strategy to improve maternal and neonatal outcomes. Successful VBAC is generally less costly and associated with fewer complications for both mother and child. 2
In the United States, VBAC rates have fluctuated over the past few decades. After peaking at 28.3% in 1996, rates declined sharply to 9.2% by 2004, largely due to concerns regarding uterine rupture and changing clinical guidelines. 3 More recent data from 2010 to 2019, covering over 4 million term deliveries, indicate a gradual increase in trial of labor after cesarean (TOLAC) participation from 14.4% to 19.6% and improvement in VBAC success rates from 68.5% to 74.3%. 4 Women with a single prior cesarean consistently demonstrated higher TOLAC (21.9%) and VBAC success (73.5%) rates compared with those with multiple prior cesareans. A history of prior vaginal delivery significantly improved both TOLAC participation and VBAC success.
In Western nations, repeat cesarean sections following a prior cesarean remain prevalent despite associated negative health consequences. 5 In the United Arab Emirates (UAE), VBAC success rates and the factors influencing outcomes vary across studies. A 2018–2019 cohort at a Joint Commission International-accredited hospital found that among Emirati and Omani women eligible for TOLAC, 86% opted for a trial of labor, with a high success rate of 83% (126 of 152). 6
Several maternal, obstetric, and clinical factors influence VBAC success. Maternal age is important: a large retrospective cohort demonstrated that women aged 15–20 years were 27% less likely than those aged 21–34 to experience VBAC failure, while women aged ≥35 years were 14% more likely to fail and 39% more likely to experience operative complications. 7 Gestational age also plays a role; successful VBAC rates have shown a bimodal distribution, peaking at 34 weeks (76.6%) and 41 weeks (71.6%), with uterine rupture rates rising from 0.08% at 34 weeks to 0.51% at 42 weeks. 8
Labor characteristics also differ in VBAC cases. A study from Greece comparing women with a prior cesarean attempting VBAC to women without a previous cesarean found that VBAC was associated with longer labor durations (27% vs. 10.3% for 481–720 minutes), higher rates of episiotomy (20.7% vs. 7.9%), and more frequent use of epidural analgesia (68.4% vs. 10%). 9 Data from Iraq indicated that 64.1% of women attempted TOLAC, with an overall VBAC success rate of 39.2% (61.2% among TOLAC cases); older age, longer interpregnancy intervals, and prior vaginal delivery or VBAC were associated with higher success. 10 Another study confirmed that vaginal birth is a strong predictor of successful VBAC. 11
A meta-analysis of 94 observational studies (239,006 women) identified additional factors affecting VBAC outcomes. Higher success was associated with favorable Bishop scores, a prelabor scoring system assessing cervical readiness for vaginal delivery based on dilation, effacement, station, consistency, and position prior to vaginal birth (especially previous VBAC), white race, and nonrecurrent indications for prior cesarean. Lower success was linked to advanced maternal age, obesity, diabetes, hypertensive disorders, labor induction, macrosomia, and prior cesareans due to cephalopelvic disproportion, dystocia, or failed induction. 12
However, the determinants of VBAC success may vary across populations due to differences in health care practices, cultural attitudes, and selection criteria for TOLAC. In the UAE, data on VBAC outcomes remain limited, especially in diverse tertiary care settings where both local and expatriate populations are managed. This study aimed to analyze the maternal characteristics and obstetric outcomes associated with successful VBAC among women with one prior cesarean section who attempted TOLAC at a tertiary hospital in the UAE. By identifying key predictors of VBAC success, the study seeks to provide evidence that may guide clinicians in counseling eligible women, support informed decision-making, and optimize obstetric care in this region.
Methodology
Study area and period
This study was conducted at Thumbay University Hospital, located in Al Jurf, Ajman, UAE, from January 2024 to January 2025. Thumbay University Hospital is a tertiary care center that conducts approximately 5,000 deliveries annually and serves as a referral center for high-risk obstetric cases.
Study design
An institution-based retrospective record review descriptive study design was employed.
Population
All women who had undergone a TOLAC at Thumbay University Hospital during the study period and had had at least one prior cesarean section.
Eligibility criteria
Inclusion criteria were women with one previous cesarean section who presented with labor pain or complications between January 2024 and January 2025. Women who opted for elective repeat cesarean delivery or had incomplete medical records were excluded.
Study variables
The primary outcome variable was the success of trial of labor after cesarean (VBAC). Independent variables included sociodemographic factors such as maternal age, parity, and gravidity; obstetric history variables including previous vaginal delivery, prior TOLAC, and interdelivery interval; as well as the indication for the primary cesarean section and maternal complications during the current delivery.
Data collection tool and procedure
A structured proforma was developed to extract relevant data from the hospital’s electronic medical records. The tool captured maternal demographic information, obstetric history, labor and delivery details, and maternal outcomes. The proforma was content validated by three physicians. Data extraction was performed by trained personnel under supervision to ensure completeness and accuracy.
Data management and analysis
Microsoft Excel was used to enter the data, while SPSS version 28 was used for analysis. Tables and graphs were used to display descriptive statistics. The chi-square test or Fisher’s exact test, if applicable, was used to assess relationships between independent factors and TOLAC performance. P-values less than 0.05 were regarded as statistically significant.
Ethical clearance
Ethical approval was obtained from the Institutional Review Board (IRB) of Gulf Medical University. Administrative permission to access medical records was secured from the hospital director. Informed consent was obtained from patients included in the study. Patient confidentiality was strictly maintained by anonymizing data and restricting access to the research team, IRB, and the statistician. As this was a record-based study, there was no direct risk to participants.
Feasibility and data storage
The study was feasible, as it did not require laboratory investigations, payments, or direct participant contact. All data will be securely stored in the Department of Community Medicine, Gulf Medical University, for a minimum of 3 years in compliance with university policy.
Results
Among 377 women with a previous cesarean section and a single lower segment scar, 126 were deemed eligible and counseled for a TOLAC based on institutional criteria. Of these, 28 (22.2%) achieved a successful VBAC, while 98 (77.8%) required repeat cesarean delivery following an unsuccessful trial of labor (Fig. 1).
Distribution of TOLAC outcomes, illustrating the proportion of successful VBACs versus unsuccessful trials among eligible women. TOLAC, trial of labor after cesarean; VBAC, vaginal birth after cesarean.
Figure 2 illustrates the relationship between the primary indication for cesarean and VBAC outcomes. Among women with a persisting indication, 16.0% achieved a successful VBAC, whereas 84.0% proceeded to elective cesarean. In contrast, women with a nonpersisting indication had a slightly lower VBAC success rate of 6.8%, with 93.2% undergoing elective cesarean.
Primary maternal indications for previous cesarean section.
From Table 1, maternal age was found to be significantly associated with VBAC outcomes. Women aged 30 years and above demonstrated a higher likelihood of successful VBAC compared with younger women aged 20–29 years (9.5% vs. 2.6%, p = 0.018). Parity was another strong determinant of VBAC success. Multiparous women had significantly higher success rates than primiparous women, with 31.9% of multiparous women achieving VBAC compared with only 3.9% of primiparous women (p < 0.001). A history of previous vaginal delivery also emerged as a key predictor. Among women with at least one prior vaginal birth, 33.3% successfully achieved VBAC, whereas only 3.6% of women with no previous vaginal deliveries were successful (p < 0.001). Maternal indication for TOLAC further influenced outcomes. Women who had previously undergone a trial of labor after cesarean demonstrated the highest success rate, with 64.7% achieving VBAC, in contrast to only 4.7% of women whose only history was a single cesarean scar (p < 0.001).
Factors Associated with Successful VBAC
TOLAC, trial of labor after cesarean; VBAC, vaginal birth after cesarean.
Discussion
A successful VBAC was attained by 22.2% of the 126 women in our study who qualified for TOLAC. This success rate is lower than reported in other studies, where VBAC success has varied widely—for example, 52.2% in a population-based study in England, 13 85.3% in a cross-sectional study of 150 women, 14 and 83% among Emirati and Omani women. 5 The lower success in our cohort likely reflects the higher-risk nature of our tertiary referral population, differences in patient selection, intrapartum management, and institutional thresholds for proceeding to cesarean delivery. These findings underscore that VBAC success is influenced by both population and institutional factors, which may account for the variability observed across studies.
According to our data, the VBAC success rate among women with persistent cesarean indications was 16.0%, while those with nonpersisting indications had a success rate of only 6.8%. This finding appears counterintuitive, as previous studies generally report higher VBAC success rates among women with nonrecurrent or nonpersisting indications, such as fetal distress or malpresentation. A possible explanation for this discrepancy in our cohort is that the majority of women with nonpersisting indications opted for an elective repeat cesarean rather than attempting a trial of labor, resulting in a smaller number of women undergoing VBAC in that group. In contrast, women with persisting indications who were carefully selected for a trial of labor may have represented a subgroup with more favorable obstetric characteristics, thus explaining their relatively higher success rate.
Supporting literature shows that, when attempted, VBAC tends to be more successful in women with nonrecurrent indications. For instance, studies have demonstrated that with appropriate selection and close intrapartum monitoring, VBAC success can reach 70%–80% in such cases.12,15 Conversely, recurrent causes such as cephalopelvic disproportion or labor dystocia are associated with reduced success rates. Therefore, our observed difference likely reflects differences in the proportion of women attempting trial of labor rather than true differences in biological success potential between the two groups.
Based on our findings, maternal age was significantly associated with VBAC success, with women aged 30 years and above demonstrating higher success rates than younger women aged 20–29 years (9.5% vs. 2.6%, p = 0.018). In contrast, a cohort of 100 women with a previous cesarean reported increasing VBAC success rates with advancing age—60.7% (<30 years), 68.6% (30–34 years), and 77.8% (>35 years)—although this trend was not statistically significant (p = 0.524). 16 Conversely, a larger cohort study of 2,493 women observed that successful vaginal delivery decreased with increasing maternal age, particularly among those with a prior vaginal delivery; after adjusting for confounders, maternal age ≥35 years was significantly associated with a lower likelihood of achieving VBAC, suggesting that older women may have a higher risk of TOL failure. 17 Similarly, a study from Ethiopia reported that women aged less than 25 years and 25–29 years had nearly nine and five times higher odds, respectively, of a successful VBAC compared with those aged ≥30 years. 18 Advanced maternal age has been associated with lower VBAC success in previous studies, and age is often correlated with parity, previous vaginal deliveries, and prior TOLAC, which are all strong predictors of successful VBAC. Due to our sample size, we were unable to perform multivariable analyses to adjust for these confounding factors, which represents an important limitation of our study. Future research with larger cohorts should incorporate stratified and adjusted analyses to more accurately assess the independent effect of maternal age on VBAC outcomes and to better inform clinical counseling.
Our analysis demonstrated that VBAC success was strongly influenced by parity, with multiparous women achieving significantly higher success rates compared with primiparous women (31.9% vs. 3.9%, p < 0.001). Supporting evidence from a prospective observational study indicated that women in the VBAC group were more likely to have lower parity (≤3) compared with those undergoing repeat cesarean, with 97.7% of VBAC patients falling within this category. 19 Similarly, a case–control retrospective study conducted in Samarinda reported that higher parity (2–3 previous deliveries) was strongly associated with VBAC success (p < 0.001; OR = 17.73), 20 highlighting parity as a key determinant of favorable trial of labor outcomes. 20 These findings suggest that prior childbirth experience enhances uterine efficiency and labor progression, thereby increasing the likelihood of successful VBAC in multiparous women. Conversely, primiparous women may face greater challenges during labor, which could explain their lower success rates.
In our study, a history of previous vaginal delivery emerged as a strong predictor of VBAC success, with 33.3% of women with prior vaginal births achieving VBAC compared with only 3.6% of women without such a history (p < 0.001). Supporting evidence from an observational study in Canada, which included 2,204 patients undergoing a trial of labor after a single low-transverse cesarean, reported the highest VBAC success among women with prior VBAC (93.1%), followed by those with a previous vaginal delivery before cesarean (81.8%) and those with no prior vaginal delivery (70.1%) (p < 0.001). 21 Similarly, a study from Nigeria demonstrated that both previous vaginal delivery before the first cesarean and prior successful VBAC were strongly associated with VBAC success (p < 0.001), with women having prior vaginal experience showing higher success rates. 22 These findings are consistent with our results, reinforcing that a history of vaginal delivery or prior VBAC is a significant determinant of successful trial of labor. This concordance emphasizes that prior vaginal birth is one of the most reliable predictors of favorable VBAC outcomes across diverse populations.
In the present study, several maternal and obstetric factors were found to be strongly associated with VBAC success. Women aged 30 years and above had higher success rates compared with those aged 20–29 years (9.5% vs. 2.6%, p = 0.018). Parity also played a significant role, with multiparous women achieving VBAC at a rate of 31.9% vs. 3.9% among primiparous women (p < 0.001). Moreover, a history of previous vaginal delivery was a key predictor, with 33.3% of women with at least one prior vaginal birth delivering successfully compared with 3.6% of women without prior vaginal deliveries (p < 0.001). These findings demonstrate that maternal age, parity, prior vaginal birth, and previous TOLAC are important factors influencing VBAC success.
As this was a single-center retrospective study in a tertiary referral facility, the findings may be subject to referral bias and limited generalizability. In addition, comparison between local and expatriate populations was not feasible due to limited and incomplete demographic data, which may have influenced observed TOLAC outcomes.
Conclusion
Finally, maternal variables and prior obstetric history were associated with VBAC success in this population. A successful vaginal birth following cesarean section was more likely for women who had a prior TOLAC, were older than 30, had higher parity, and had previously delivered their babies vaginally. The mother’s indication for the prior cesarean section was also important; poorer success rates were linked to persistent indications. When taking TOLAC into account, these results emphasize the value of customized evaluation. Prospective, multicenter studies should be the main focus of future research in order to validate the factors that predict VBAC success and enhance the generalizability of results across various demographics and health care environments.
Footnotes
Author Disclosure Statement
No competing financial interests exist.
Funding Information
No funding was received for this article.