The Association between the Indication for Previous Cesarean Delivery and the risk for Uterine Rupture in TOLAC: A Retrospective Cohort Study

Objective To determine whether the indication for a previous cesarean delivery is associated with the risk of uterine rupture among women undergoing a trial of labor after cesarean (TOLAC). Design Retrospective cohort study. Setting Single university-affiliated tertiary medical center. Population or Sample Women with a singleton pregnancy at ≥24 weeks’ gestation, one prior low-transverse cesarean delivery, and an attempted TOLAC between 2012 and 2024. Methods Previous cesarean delivery indications were categorized as antepartum indications, suspected fetal distress, first-stage dystocia, or second-stage dystocia. Cases of uterine dehiscence were excluded. Multivariable logistic regression was used to evaluate the association between prior cesarean indication and uterine rupture, adjusting for relevant maternal and intrapartum factors. Main Outcome Measures Complete uterine rupture. Results Among 147,045 deliveries, 7,340 women underwent TOLAC, of whom 91 (1.2%) experienced uterine rupture. A previous cesarean delivery performed for second-stage dystocia was significantly more common among women with uterine rupture than among those without rupture (12.1% vs 3.2%, p<0.001). In multivariable analysis, prior second-stage dystocia remained independently associated with uterine rupture (adjusted odds ratio 3.9, 95% confidence interval 1.14–13.37). No other prior cesarean indication was independently associated with rupture risk. Conclusions Among women undergoing TOLAC, a prior cesarean delivery performed for second-stage dystocia is independently associated with an increased risk of uterine rupture. Incorporating prior cesarean indication into counselling and intrapartum risk assessment may improve individualized clinical decision-making.

Cesarean delivery rates have increased markedly over the past decades and now account for 20-40% and even more in some countries worldwide (1,2). Trial of labor after cesarean (TOLAC) offers an opportunity to reduce repeat cesarean deliveries and their associated maternal morbidity. Nevertheless, it carries a small but significant risk of uterine rupture, (3-4). Although rare, uterine rupture can result in catastrophic maternal and fetal outcomes, emphasizing the importance of identifying risk factors that could influence its occurrence. Several maternal, obstetric and intrapartum factors have been identified as potential risk factors for uterine rupture among women attempting TOLAC. The most important risk factors are induction of labor, especially with prostaglandins or use of oxytocin particularly when used for prolonged periods (5-7), short inter-delivery interval (\RL5), prolonged labor duration, labor dystocia, suspected macrosomia and low bishop score (\RL7). The risk is substantially increased also in women with a history of previous uterine surgeries (\RL8), inverted T uterine incision or longitudinal (classical) uterine incision (\RL9). Indications for cesarean delivery are typically classified as potentially recurring, such as cephalopelvic disproportion, or incidental such non-reassuring fetal status. The indication for the previous cesarean delivery may influence subsequent obstetric outcomes, and higher rates of successful vaginal birth after cesarean (VBAC) have been reported following non-recurring indications compared with prior dystocia (\RL10-12). However, the relationship between previous cesarean indication and the risk of uterine rupture remains less clear. Some data suggest that cesarean section performed for second-stage labor arrest may be associated with an increased rupture risk in subsequent labor (\RL13-14), whereas others reported no independent effect (10). Guidelines by different societies, acknowledge this uncertainty and do not currently tailor TOLAC recommendations based on prior indication for the cesarean delivery (3-4). Thus, we aimed to determine whether the indication for a previous cesarean delivery is associated with the risk of uterine rupture among women undergoing TOLAC.

Study Design and Population This retrospective cohort study was conducted at a single university-affiliated tertiary medical center between January 2012 and December 2024. The study population included all women with a singleton pregnancy at ≥24 weeks of gestation only with one previous low-transverse cesarean delivery who attempted a trial of labor after cesarean (TOLAC). Cases with prior non–low-transverse uterine incision, a nonviable fetus, or those who underwent a planned elective repeat cesarean delivery without labor were excluded. Data Collection and Definitions Eligible women were identified through the institutional electronic medical record database. To ensure data accuracy regarding the indication for the previous cesarean delivery, the comparative analysis was primarily based on women whose index cesarean was performed at our institution. However, given the rarity and clinical significance of the primary outcome, all cases of uterine rupture underwent a comprehensive manual chart review to verify the primary indication and surgery reports were retrieved for all rupture cases to validate the indication. The primary outcome was complete uterine rupture, defined as a complete disruption of all uterine layers, including the serosa. Cases of uterine dehiscence (incomplete scar separation with intact serosa) were strictly excluded from the rupture group to ensure clinical specificity. Exposure Assessment Indications for the previous cesarean were categorized into four groups based on clinical criteria: 1) Antepartum indications (e.g., malpresentation, maternal request), 2) Suspected fetal distress due to non-reassuring fetal heart rate, 3) First-stage dystocia (dysfunctional labor or failed induction) and 4) Second-stage dystocia (arrest of descent). Maternal demographic characteristics and obstetric data were obtained from computerized delivery room records. The primary outcome was uterine rupture, defined as disruption of the uterine muscle extending to and involving the uterine serosa (3,4). Potential confounders, including maternal age, parity, gestational age at delivery, inter-delivery interval, induction of labor, and prior vaginal delivery, were evaluated Approval for this retrospective study was obtained from the local Institutional Review Board (IRB - 0474-24). Statistical analysis Univariate analyses were performed to compare groups using Student’s t-test or Mann–Whitney U test for continuous variables and χ² or Fisher’s exact test for categorical variables. Variables with significant univariate associations were entered into a multivariable logistic regression model to identify independent predictors of uterine rupture. Analyses were conducted using SPSS (version 21.0; SPSS Inc., Chicago IL, USA). A two-tailed p-value <0.05 was considered statistically significant. This study used anonymized data; therefore, informed consent was not required.

During the study period, 147,045 women delivered at our center. Of these, 7,340 women underwent a trial of labor after cesarean (TOLAC) following one previous low-transverse cesarean delivery. Among the TOLAC cohort, 1,806 women had a reliably documented indication for the previous cesarean delivery. Uterine rupture occurred in 91 women (1.2%). Maternal and obstetrical characteristics are detailed in Table 1. Women who experienced uterine rupture delivered at an earlier gestational age (38.5 vs. 39.4, p<0.001) and had lower median neonatal birthweight (3120 gr. vs. 3260 gr., p=0.013). The median inter-delivery interval did not differ significantly between groups (2.7 vs. 2.6 years, p = 0.31). Induction of labor and oxytocin usage rates were comparable between groups (p = 0.38 and p = 0.51, respectively). \RL A history of previous VBAC was less frequent among women who experienced rupture (27% vs. 2%, p <0.001), whereas non-reassuring fetal heart rate (NRFHR) patterns during labor were more common in this group (7.5% vs. 13.2%, p <0.046). Among the uterine ruptures cases, 59/91 cases (0.8% \RL of the total TOLAC cohort) were diagnosed following maternal or fetal clinical signs suggestive of uterine rupture including non-reassuring fetal heart rate patterns, acute abdominal pain, or abnormal uterine bleeding, \RL whereas 32 cases (0.4%) were identified only at the time of cesarean delivery performed for other medical indications. The distribution of uterine rupture cases according to the four predefined prior cesarean indication groups was 52.7% antepartum indications, 30.8% suspected fetal distress, 4.4% first-stage dystocia, and 12.1% second-stage dystocia (table 2). Women with uterine rupture were significantly more likely to have a previous cesarean section performed for second-stage dystocia (12.1% vs. 3.2%, p < 0.001), whereas the distribution of other indications did not differ significantly between groups (p = 0.27 for antepartum indications, p = 0.65 for suspected fetal distress, and p = 1.0 for first-stage dystocia). In a multivariable logistic regression analysis adjusting for relevant confounders, second-stage dystocia as the indication for the previous cesarean delivery remained independently associated with uterine rupture (adjusted OR 3.9, 95% CI 1.14–13.37, p = 0.03, table 3 and figure 1). No other indications for previous cesarean section were associated with rupture risk. First-stage dystocia was excluded from the model due to the limited number of cases (n = 4). Epidural analgesia was independently associated with a reduced risk of uterine rupture (adjusted OR 0.44, 95% CI 0.27–0.71, p < 0.001).

In this large tertiary-center cohort of 7,340 women attempting TOLAC, uterine rupture occurred in 91 cases (1.2%). Among the subset of women with complete documentation enabling stratification by prior cesarean indication, those whose previous cesarean was performed for second-stage dystocia had a substantially higher rupture rate compared with all other indication groups. After adjustment for gestational age, epidural use, prior vaginal birth and neonatal birthweight, second-stage dystocia remained an independent predictor of rupture (adjusted OR 3.9, 95% CI 1.14–13.37). No other prior cesarean indications were independently associated with an increased risk of rupture. Epidural analgesia was found to be inversely associated with rupture, whereas other maternal and obstetric characteristics were broadly comparable between groups. Our findings in the context of other observations Among the 91 women who experienced uterine rupture in our cohort, 59 cases (0.8%) were diagnosed following maternal or fetal clinical signs. This finding is consistent with large cohort studies such as the NICHD MFMU Network analysis by Landon et al. (\RL9), which reported symptomatic rupture rates of approximately 0.7%. Existing literature has consistently demonstrated an association between markers of labor dysfunction and the risk of uterine rupture. Jastrow et al. (\RL13) notably reported significantly higher rupture rates among women whose index cesarean was performed at full dilation, a finding corroborated by additional observational studies linking prolonged second-stage labor to increased rupture risk (\RL12, 7). However, a specific gap remains in current predictive tools. While dystocia-related variables have been incorporated into predictive models, including those proposed by Grobman et al. (\RL14), second-stage arrest has not been separately quantified as a distinct predictor for uterine rupture. To our knowledge, the present study is one of the first to isolate second-stage arrest from the broader category of dystocia, thereby clarifying its independent contribution to the risk of uterine rupture. Potential Mechanisms The biological mechanisms underlying the increased rupture risk associated with second-stage dystocia likely reflect a combination of anatomical, mechanical, and iatrogenic factors. Prolonged second-stage labor exposes the lower uterine segment to sustained mechanical stress as the fetal head remains deeply engaged, potentially contributing to microtrauma, impaired healing, or altered collagen remodeling at the hysterotomy site (\RL9,15). Second-stage cesarean sections also pose unique surgical challenges. Because the fetal head can be difficult to disengage at full dilation, surgeons may need to place the hysterotomy slightly higher than in a routine low transverse incision to gain adequate access. Although still classified as low transverse, such incisions may involve a thicker, less distensible myometrium, an anatomic location associated with a greater risk of rupture (3,\RL9). Together, these physiological and surgical factors likely contribute to the substantially elevated rupture risk observed in women with prior second-stage dystocia. Clinical Implications These findings have important implications for both counseling and intrapartum management. First, a history of second-stage dystocia should be recognized as a distinct risk factor and integrated into individualized TOLAC counseling sessions. Women with nonrecurring prior indications can be counseled that their risk of rupture approximates the population average (0.5–1%), whereas those with prior second-stage dystocia may face a substantially higher risk and may benefit from a more tailored discussion of TOLAC versus elective repeat cesarean delivery. Second, intrapartum care for these patients should include increased vigilance. If labor abnormalities resembling those of the previous delivery recur, especially a prolonged second stage, clinicians may consider an earlier operative intervention to avoid excessive mechanical loading of the scar. Finally, although TOLAC remains safe for most women with a prior low transverse incision, our findings demonstrate that incorporating prior cesarean indications enhances risk stratification beyond conventional predictors. Strengths and Limitations A key limitation is that indication‐specific analyses could only be performed for women whose prior cesarean delivery was documented at our institution (1,806 of 7,340 TOLACs). Because uterine rupture is rare, all rupture cases underwent manual chart review, ensuring complete documentation of the prior indication, whereas many women without rupture lacked full operative details if their previous cesarean had been performed elsewhere. However, within this internally consistent cohort, the relative differences between indication groups – particularly the markedly higher rate among women with prior second-stage dystocia – are likely to reflect true clinical variation rather than data artefact. By contrast, the overall rupture rate of 1.2% in the entire TOLAC cohort, which includes both symptomatic and incidentally detected (“asymptomatic”) ruptures, provides the most robust population-level estimate. The strengths of this study include its large sample size, detailed verification of all rupture cases, and comprehensive adjustment for relevant clinical confounders, factors that together enhance the robustness and clinical applicability of the findings.

Among women undergoing TOLAC, prior second-stage dystocia was independently associated with a significantly increased risk of uterine rupture compared to all other prior cesarean section indications. The magnitude of this association (adjusted OR 3.9) underscores the importance of incorporating prior cesarean indication into individualized risk assessment and shared decision-making for women considering TOLAC.

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Table 1: Baseline and intrapartum characteristics of women with and without uterine rupture | Maternal age (Mean, SD) | 34.5 (3.9) | 34.4 (4.5) | 0.067 | | Birth weight (median, IQR) | 3260 (2980, 3535) | 3120 (2740, 3550) | 0.013 | | Gestational age (median, IQR) | 39.4 (38.5, 40.2) | 38.5 (37.1, 40.2) | <0.001 | | Pre-pregnancy BMI (median, IQR) | 22.04 (19.9, 24.9) | 21.9 (20.2, 24.8) | 0.613 | | Interval from previous cesarean to current TOLAC (years) (median, IQR) | 2.7 (2.0- 4.2) | 2.6 (2.0-3.4) | 0.31 | | Intrapartum fever (n, %) | 34 (3.0) | - | - | | Epidural (n, %) | 1251 (69.3) | 36 (39.6) | <0.001 | | Previous VBAC (n, %) | 487 (27.0) | 2 (2.2) | <0.001 | | Induction of labor (n, %) | 1\RL63 (\RL9) | \RL6 (\RL6.\RL6) | \RL0.38 | | Oxytocin during delivery (n, %) | 545 (30.2) | 27 (29.7) | 0.511 | | Gestational Diabetes (n, %) | 150 (8.3) | 3 (3.3) | 0.054 | | Preeclampsia (n, %) | 22 (1.2) | 1 (1.1) | 0.69 | | Antibiotic during delivery (n, %) | 589 (32.6) | 71 (78.0) | <0.001 | | Macrosomia (n, %) actual birthweight | 21 (1.2) | 1 (1.1) | 0.71 | | Small for Gestational Age (n, %) \RL | 35 (1.9) | - | - | | GBS (n, %) | 142 (17.0) | 3 (3.3) | <0.001 | | NRFHR (n, %) | 136 (7.5) | 12 (13.2) | 0.046 | | Prolonged second stage (n, %) | 143 (7.9) | 3 (3.3) | 0.069 | | Grand Multiparty (n, %) | 20 (1.1) | 2 (2.2) | 0.29 | Bold values denote statistical significance at the p < 0.05 level. \(\ {}^{a}\) Calculated as the number of years between the previous cesarean and the current TOLAC attempt. VBAC, vaginal birth after cesarean; GBS, group B streptococcus; NRFHR, non-reassuring fetal hearth rate Table 2. Previous Cesarean Section Indications Among Women with and Without Uterine Rupture | Antepartum Indications\(\ {}^{a}\) (n, %) | 1065 (59) | 48 (52.7) | 0.27 | | Intrapartum – Fetal distress\(\ {}^{b}\) (n, %) | 603 (33.4) | 28 (30.8) | 0.65 | | First stage dystocia\(\ {}^{c}\) (n, %) | (4.4) | 4 (4.4) | 1 | | Second stage dystocia\(\ {}^{d}\) (n, %) | 58 (3.2) | 11 (12.1) | <0.001 | Bold values denote statistical significance at the p < 0.05 level.\(\ {}^{a}\ \)previous CD, patient request, malpresentation, multiple pregnancy, past shoulder dystocia, placenta previa, vasa previa, IUGR, previous anal sphincter laceration;\(\ {}^{b}\)non reassuring fetal heart rate, cord prolapse \(\displaystyle;\ ^{c}\)dysfunctional labor, failed induction;\(\ {}^{d}\)arrest Table 3. Multivariable conditional logistic regression analysis for predictors of uterine rupture | Epidural during labor | 0.42 (0.26–0.66) | <0.001 | | VBAC | 0.072 (0.018–0.29) | <0.001 | | Gestational age | 0.77 (0.67-0.9) | <0.001 | | Newborn weight | 1.0 (1.0-1.001) | 0.45 | | Antepartum Indications\(\ {}^{a}\) | 0.94 (0.32–2.73) | 0.91 | | Intrapartum – Fetal distress\(\ {}^{b}\) | 1.24 (0.42–3.7) | 0.7 | | Second stage dystocia\(\ {}^{d}\) | 3.9 (1.14–13.37) | 0.03 | Bold values denote statistical significance at the p < 0.05 level. VBAC, vaginal birth after cesarean;\(\ {}^{a}\)patient request, malpresentation, multiple pregnancy, past shoulder dystocia, placenta previa, IUGR, previous anal sphincter laceration;\(\ {}^{b}\)non reassuring fetal heart rate, cord prolapse\(;\ ^{c}\)dysfunctional labor, failed induction; \(\ {}^{d}\)arrest, failed vacuum Information & Authors Information Version history Copyright This work is licensed under a Non Exclusive No Reuse License.

Authors Metrics & Citations Metrics Article Usage 237views 66downloads Citations Download citation Einat Tako, Itamar GILBOA, Daniel Gabbai, et al. The Association between the Indication for Previous Cesarean Delivery and the risk for Uterine Rupture in TOLAC: A Retrospective Cohort Study. Authorea. 02 February 2026. DOI: https://doi.org/10.22541/au.177003207.76445536/v1 DOI: https://doi.org/10.22541/au.177003207.76445536/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu.