Induction of labor vs expectant management among low-risk patients with 1 prior cesarean delivery.

BACKGROUND: Studies that have compared induction of labor in individuals with 1 prior cesarean delivery to expectant management have shown conflicting results. OBJECTIVE: To determine the association between clinical outcomes and induction of labor at 39 weeks in a national sample of otherwise low-risk patients with 1 prior cesarean delivery. STUDY DESIGN: This cross-sectional study analyzed 2016 to 2021 US Vital Statistics birth certificate data. Individuals with vertex, singleton pregnancies, and 1 prior cesarean delivery were included. Patients with prior vaginal deliveries, delivery before 39 weeks 0 days or after 42 weeks 6 days of gestation, and medical comorbidities were excluded. The primary exposure of interest was induction of labor at 39 weeks 0 days to 39 weeks 6 days compared to expectant management with delivery from 40 weeks 0 days to 42 weeks 6 days. The primary outcome was vaginal delivery. The main secondary outcomes were separate maternal and neonatal morbidity composites. The maternal morbidity composite included uterine rupture, operative vaginal delivery, peripartum hysterectomy, intensive care unit admission, and transfusion. The neonatal morbidity composite included neonatal intensive care unit admission, Apgar score less than 5 at 5 minutes, immediate ventilation, prolonged ventilation, and seizure or serious neurological dysfunction. Unadjusted and adjusted log binomial regression models accounting for demographic variables and the exposure of interest (induction vs expectant management) were performed. Results are presented as unadjusted and adjusted risk ratios with 95% confidence intervals. RESULTS: From 2016 to 2021, a total of 198,797 individuals with vertex, singleton pregnancies, and 1 prior cesarean were included in the primary analysis. Of these individuals, 25,915 (13.0%) underwent induction of labor from 39 weeks 0 days to 39 weeks 6 days and 172,882 (87.0%) were expectantly managed with deliveries between 40 weeks 0 days and 42 weeks 6 days. In adjusted analyses, patients induced at 39 weeks were more likely to have a vaginal delivery when compared to those expectantly managed (38.0% vs 31.8%; adjusted risk ratio 1.32, 95% confidence interval 1.28, 1.36). Among those who had vaginal deliveries, induction of labor was associated with increased likelihood of operative vaginal delivery (11.1% vs 10.0; adjusted risk ratio 1.15, 95% confidence interval 1.07, 1.24). The maternal morbidity composite occurred in 0.9% of individuals in both the induction and expectant management groups (adjusted risk ratio 0.92, 95% confidence interval 0.79, 1.06). The rates of uterine rupture (0.3%), peripartum hysterectomy (0.04% vs 0.05%), and intensive care unit admission (0.1% vs 0.2%) were all relatively low and did not differ significantly between groups. There was also no significant difference in the neonatal morbidity composite between the induction and expectant management groups (7.3% vs 6.7%; adjusted risk ratio 1.04, 95% confidence interval 0.98, 1.09). CONCLUSION: When compared to expectant management, elective induction of labor at 39 weeks in low-risk patients with 1 prior cesarean delivery was associated with a significantly higher likelihood of vaginal delivery with no difference in composite maternal and neonatal morbidity outcomes. Prospective studies are needed to better elucidate the risks and benefits of induction of labor in this patient population.

Trial of labor after cesarean, vaginal birth after cesarean, and the risk of uterine rupture: an expert review.

The decision to pursue a trial of labor after cesarean delivery is complex and depends on patient preference, the likelihood of successful vaginal birth after cesarean delivery, assessment of the risks vs benefits of trial of labor after cesarean delivery, and available resources to support safe trial of labor after cesarean delivery at the planned birthing center. The most feared complication of trial of labor after cesarean delivery is uterine rupture, which can have catastrophic consequences, including substantial maternal and perinatal morbidity and mortality. Although the absolute risk of uterine rupture is low, several clinical, historical, obstetrical, and intrapartum factors have been associated with increased risk. It is therefore critical for clinicians managing patients during trial of labor after cesarean delivery to be aware of these risk factors to appropriately select candidates for trial of labor after cesarean delivery and maximize the safety and benefits while minimizing the risks. Caution is advised when considering labor augmentation and induction in patients with a previous cesarean delivery. With established hospital safety protocols that dictate close maternal and fetal monitoring, avoidance of prostaglandins, and careful titration of oxytocin infusion when induction agents are needed, spontaneous and induced trial of labor after cesarean delivery are safe and should be offered to most patients with 1 previous low transverse, low vertical, or unknown uterine incision after appropriate evaluation, counseling, planning, and shared decision-making. Future research should focus on clarifying true risk factors and identifying the optimal approach to intrapartum and induction management, tools for antenatal prediction, and strategies for prevention of uterine rupture during trial of labor after cesarean delivery. A better understanding will facilitate patient counseling, support efforts to improve trial of labor after cesarean delivery and vaginal birth after cesarean delivery rates, and reduce the morbidity and mortality associated with uterine rupture during trial of labor after cesarean delivery.

Induction of labor in twin pregnancy in patients with a previous cesarean delivery.

BACKGROUND: Trial of labor after cesarean delivery (TOLAC) in twin gestations has been associated with decreased rates of successful vaginal delivery compared to singleton pregnancies, with mixed results regarding maternal and neonatal morbidity. However, induction of labor (IOL) in this unique population has not yet been fully evaluated. OBJECTIVE: To assess success rates and maternal and neonatal outcomes in women with a twin gestation and a previous cesarean delivery undergoing IOL. METHODS: A retrospective cohort study including women with a twin gestation and one previous cesarean delivery undergoing a trial of labor between the years 2009-2020. Patients requiring IOL were compared to those with a spontaneous onset of labor. RESULTS: There were 53 patients who met the inclusion criteria: 31 had a spontaneous onset of labor (58%) and 22 required an IOL. Baseline characteristics were comparable between the groups apart from a history of labor arrest which was more common in the IOL group (40.9% vs. 9.6%, P = 0.006). A successful vaginal delivery occurred in all (100%) women with a spontaneous labor compared to 81% in the IOL group (p = 0.02). Secondary outcomes were comparable. A history of no previous vaginal delivery, maternal obesity, and IOL were associated with TOLAC failure. CONCLUSIONS: IOL after cesarean delivery in twin gestation is associated with an increased risk of TOLAC failure compared to spontaneous onset of labor. However, no adverse neonatal or maternal outcomes were found. IOL in this high-risk population is feasible but patients should be counseled about the lower rate of success.

Is there an optimal inter-delivery interval in women who underwent trial of labor after cesarean delivery (TOLAC)?

BACKGROUND: Inter-delivery interval (IDI) has been proven to be a factor associated with adverse maternal and neonatal outcomes. However, the optimal IDI in trial of labor after cesarean delivery (TOLAC) remains unclear. We aimed to investigate the association between IDI and major maternal and neonatal outcomes in women who underwent TOLAC. METHODS: A multicenter, retrospective cohort study including five hospitals was conducted between January 2018 and December 2019 in Foshan, China. This study included 1080 pregnant women with one or two cesarean deliveries who attempted a TOLAC. Data on maternal and neonatal outcomes were collected from the electronic record system. Maternal and neonatal outcomes in different groups of IDI were compared by univariate and multivariable analyses. RESULTS: A short IDI of < 24 months did not show a statistically significant association with uterine rupture in the univariate analysis (P = 0.668). In multivariable analysis, the incidences of postpartum hemorrhage (OR 19.6, 95% CI:4.4-90.9, P < 0.05), preterm birth (OR 5.5, 95% CI:1.5-21.3, P < 0.05), and low birth weight (OR 3.5, 95% CI:1.2-10.3, P < 0.05) were significantly increased in women with an IDI of < 24 months than in those with a normal interval (24-59 months). Infection morbidity (OR 1.8, 95% CI:1.4-7.9, P < 0.05), transfusion (OR 7.4, 95% CI:1.4-40.0, P < 0.05), and neonatal unit admission (OR 2.6, 95% CI:1.4-5.0, P < 0.05) were significantly increased in women with an IDI of 120 months or more than in those with a normal interval. Postpartum hemorrhage (P = 0.062) had a trend similar to that of a significant IDI of 120 months or more. We found no statistically significant difference in maternal and neonatal outcomes between 24-59 months and 60-119 months. CONCLUSIONS: An IDI of less than 24 months or 120 months or more increased the risk of major maternal and neonatal outcomes. We recommend that the optimal interval for women who underwent TOLAC should be 24 to 119 months.

An inter-delivery interval (IDI) that is too short or too long increases the risk of adverse maternal and neonatal outcomes. However, the optimal IDI for trial of labor after cesarean delivery (TOLAC) remains unclear. We performed a multicenter, electronic medical record-based, retrospective cohort study that included 1080 pregnant women who had one or two cesarean deliveries and underwent TOLAC. Data on maternal and neonatal outcomes were collected from the electronic record system. In multivariable analysis, the incidences of postpartum hemorrhage, preterm birth, and low birth weight were significantly increased in women with an IDI of < 24 months than in those with a normal interval (24­59 months). Infections, transfusion, and neonatal unit admission were significantly increased in women with an IDI of ≥ 120 months than in those with a normal interval. In conclusion, we found that an IDI < 24 months or ≥ 120 months increased the risk of major maternal and neonatal outcomes. We recommend that the optimal interval for women who underwent TOLAC should be 24 to 119 months.

Sonographic fetal head circumference is associated with trial of labor after cesarean section success.

PURPOSE: The purpose is to study the association of the fetal sonographic head circumference (SHC) with trial of labor after cesarean (TOLAC) success rate, among women with no prior vaginal deliveries. METHODS: A retrospective case-control study including all women with no prior vaginal delivery undergoing TOLAC during 3/2011-6/2020 with a sonographic estimated fetal weight within one week from delivery. TOLAC success and failure groups were compared. RESULTS: Of 1232 included women, 948 (76.9%) delivered vaginally. The mean fetal SHC was smaller in the TOLAC success group (330 ± 10 vs. 333 ± 11 mm, p < 0.001). In a multivariate regression analysis, predelivery BMI, hypertensive disorders, gestational age at prior CD, SHC and epidural analgesia administration were independently associated with TOLAC success. A ROC analysis of the multivariable model composed of the factors found independently associated with TOLAC success, excluding SHC, yielded an area under curve of 0.659 (95% CI 0.622-0.697) compared with 0.668 (95% CI 0.630-0.705) with SHC included. CONCLUSION: Smaller SHC is independently associated with TOLAC success among women that did not deliver vaginally before, and has additive clinical value for the prediction of TOLAC success when combined with non-sonographic factors.

Prediction of vaginal birth after cesarean delivery in term gestations: a calculator without race and ethnicity.

BACKGROUND: Investigators have attempted to derive tools that could provide clinicians with an easily obtainable estimate of the chance of vaginal birth after cesarean delivery for those who undertake trial of labor after cesarean delivery. One tool that has been validated externally was derived from data from the Maternal-Fetal Medicine Units Cesarean Registry. However, concern has been raised that this tool includes the socially constructed variables of race and ethnicity. OBJECTIVE: This study aimed to develop an accurate tool to predict vaginal birth after cesarean delivery, using data easily obtainable early in pregnancy, without the inclusion of race and ethnicity. STUDY DESIGN: This was a secondary analysis of the Cesarean Registry of the Maternal-Fetal Medicine Units Network. The approach to the current analysis is similar to that of the analysis in which the previous vaginal birth after cesarean delivery prediction tool was derived. Specifically, individuals were included in this analysis if they were delivered on or after 37 0/7 weeks' gestation with a live singleton cephalic fetus at the time of labor and delivery admission, had a trial of labor after cesarean delivery, and had a history of 1 previous low-transverse cesarean delivery. Information was only considered for inclusion in the model if it was ascertainable at an initial prenatal visit. Model selection and internal validation were performed using a cross-validation procedure, with the dataset randomly and equally divided into a training set and a test set. The training set was used to identify factors associated with vaginal birth after cesarean delivery and build the logistic regression predictive model using stepwise backward elimination. A final model was generated that included all variables found to be significant (P<.05). The accuracy of the model to predict vaginal birth after cesarean delivery was assessed using the concordance index. The independent test set was used to estimate classification errors and validate the model that had been developed from the training set, and calibration was assessed. The final model was then applied to the overall analytical population. RESULTS: Of the 11,687 individuals who met the inclusion criteria for this secondary analysis, 8636 (74%) experienced vaginal birth after cesarean delivery. The backward elimination variable selection yielded a model from the training set that included maternal age, prepregnancy weight, height, indication for previous cesarean delivery, obstetrical history, and chronic hypertension. Vaginal birth after cesarean delivery was significantly more likely for women who were taller and had a previous vaginal birth, particularly if that vaginal birth had occurred after a previous cesarean delivery. Conversely, vaginal birth after cesarean delivery was significantly less likely for women whose age was older, whose weight was heavier, whose indication for previous cesarean delivery was arrest of dilation or descent, and who had a history of medication-treated chronic hypertension. The model had excellent calibration between predicted and empirical probabilities and, when applied to the overall analytical population, an area under the receiver operating characteristic curve of 0.75 (95% confidence interval, 0.74-0.77), which is similar to the area under the receiver operating characteristic curve of the previous model (0.75) that included race and ethnicity. CONCLUSION: We successfully derived an accurate model (available at https://mfmunetwork.bsc.gwu.edu/web/mfmunetwork/vaginal-birth-after-cesarean-calculator), which did not include race or ethnicity, for the estimation of the probability of vaginal birth after cesarean delivery.

Predicting obstetrical anal sphincter injuries in patients who undergo vaginal birth after cesarean delivery.

BACKGROUND: Women with a history of previous cesarean delivery must weigh the numerous potential risks and benefits of elective repeat cesarean delivery or trial of labor after cesarean delivery. Notably, 1 important risk of vaginal delivery is obstetrical anal sphincter injuries. Furthermore, the rate of obstetrical anal sphincter injuries is high among women undergoing vaginal birth after cesarean delivery. However, the risk of obstetrical anal sphincter injuries is not routinely included in the trial of labor after cesarean delivery counseling, and there is no tool available to risk stratify obstetrical anal sphincter injuries among women undergoing vaginal birth after cesarean delivery. OBJECTIVE: This study aimed to develop and validate a predictive model to estimate the risk of obstetrical anal sphincter injuries in the setting of vaginal birth after cesarean delivery population to improve antenatal counseling of patients regarding risks of trial of labor after cesarean delivery. STUDY DESIGN: This study was a secondary subgroup analysis of the Maternal-Fetal Medicine Units Network Trial of Labor After Cesarean Delivery prospective cohort (1999-2002). We identified women within the Maternal-Fetal Medicine Units Network cohort with 1 previous cesarean delivery followed by a term vaginal birth after cesarean delivery. This Maternal-Fetal Medicine Units Network Vaginal Birth After Cesarean Delivery cohort was stratified into 2 groups based on the presence of obstetrical anal sphincter injuries, and baseline characteristics were compared with bivariate analysis. Significant covariates in bivariate testing were included in a backward stepwise logistic regression model to identify independent risk factors for obstetrical anal sphincter injuries and generate a predictive model for obstetrical anal sphincter injuries in the setting of vaginal birth after cesarean delivery. Internal validation was performed using bootstrapped bias-corrected estimates of model concordance indices, Brier scores, Hosmer-Lemeshow chi-squared values, and calibration plots. External validation was performed using data from a single-site retrospective cohort of women with a singleton vaginal birth after cesarean delivery from January 2011 to December 2016. RESULTS: In this study, 10,697 women in the Maternal-Fetal Medicine Units Network Trial of Labor After Cesarean Delivery cohort met the inclusion criteria, and 669 women (6.3%) experienced obstetrical anal sphincter injuries. In the model, factors independently associated with obstetrical anal sphincter injuries included use of forceps (adjusted odds ratio, 5.08; 95% confidence interval, 4.10-6.31) and vacuum assistance (adjusted odds ratio, 2.64; 95% confidence interval, 2.02-3.44), along with increasing maternal age (adjusted odds ratio, 1.05; 95% confidence interval, 1.04-1.07 per year), body mass index (adjusted odds ratio, 0.99; 95% confidence interval, 0.97-1.00 per unit kg/m2), previous vaginal delivery (adjusted odds ratio, 0.19; 95% confidence interval, 0.15-0.23), and tobacco use during pregnancy (adjusted odds ratio, 0.59; 95% confidence interval, 0.43-0.82). Internal validation demonstrated appropriate discrimination (concordance index, 0.790; 95% confidence interval, 0.771-0.808) and calibration (Brier score, 0.047). External validation used data from 1266 women who delivered at a tertiary healthcare system, with appropriate model discrimination (concordance index, 0.791; 95% confidence interval, 0.735-0.846) and calibration (Brier score, 0.046). The model can be accessed at oasisriskscore.xyz. CONCLUSION: Our model provided a robust, validated estimate of the probability of obstetrical anal sphincter injuries during vaginal birth after cesarean delivery using known antenatal risk factors and 1 modifiable intrapartum risk factor and can be used to counsel patients regarding risks of trial of labor after cesarean delivery compared with risks of elective repeat cesarean delivery.

Examination of the association of physical activity during pregnancy after cesarean delivery and vaginal birth among Chinese women.

BACKGROUND: The goal was to study whether higher physical activity can increase the success rate of Vaginal Birth after Cesarean Delivery (VBAC). METHODS: We enrolled 823 patients with previous cesarean section delivery history (between January 2015 and December 2017) and measured their physical activity during pregnancy. A final number of 519 patients were included for the trial of labor after cesarean delivery (TOLAC). All patients signed informed consent forms. RESULTS: We conducted bivariate analyses and identified that several variables were associated with successful VBAC: Prior history of vaginal birth (odds ratio [OR] 2.4, 95% CI 1.8-3.9); previous indication for primary cesarean delivery (OR 2.2, 95% CI 1.5-3.0); age younger than 40 years (OR 2.1, 95% CI 1.3-3.4); Weight gain less than 20 kg (OR 1.5, 95% CI 1.3-2.4); high pelvic/birth weight score (OR 1.4, 95% CI 1.1-2.0); no induction of labor (OR 1.9, 95% CI 1.4-2.8); and estimated prenatal fetal weight (OR 1.4, 95% CI 1.2-1.5). We also found that the bivariate association between physical activity and VBAC was significant (p = 0.002). In addition, there was higher odds of VBAC in women who had active physical activity of more than 150 min/week (adjusted OR 1.86, 95% CI 1.69-2.07). Lower odds of VBAC was associated with older age, weight gain during pregnancy, induction of labor, and having estimated prenatal fetal weight more than 3500 g. CONCLUSION: Physical activity during pregnancy may influence the success rate of VBAC in Chinese women. Future studies will be needed to prove the robustness of this association using more detailed exposure and outcome definitions.

Trial of labor following one previous cesarean delivery: the effect of gestational age.

PURPOSE: To stratify maternal and neonatal outcomes of trials of labor after previous cesarean delivery (TOLAC) by gestational age. METHODS: Retrospective cohort study of all singleton pregnancies with one previous cesarean delivery in TOLAC at term between 2007 and 2014. We compared outcomes of delivery at an index gestational week, with outcomes of women who remained undelivered at this index gestational week (ongoing pregnancy). Odds ratios and 95% confidence intervals were adjusted for maternal age, previous vaginal delivery, induction of labor, epidural use, presence of meconium, and birth weight > 4000 g. RESULTS: Overall, 2849 women were eligible for analysis. Of those, 2584 (90.7%) had a successful TOLAC and 16 women (0.56%) had uterine rupture. Those rates did not differ significantly for any gestational age (GA) group. Following adjustment for possible confounders, GA was not found to be independently associated with adverse maternal or neonatal outcomes. CONCLUSION: Among women at term with a single previous cesarean delivery, GA at delivery was not found to be an independent risk factor for TOLAC success or uterine rupture. We suggest that GA by itself will not serve as an argument for or against TOLAC.

Attempted operative vaginal delivery vs repeat cesarean in the second stage among women undergoing a trial of labor after cesarean delivery.

BACKGROUND: It is not well-characterized whether attempting operative vaginal delivery is a safe and effective alternative among women who undergo a trial of labor after cesarean delivery who are unable to complete second-stage labor with a spontaneous vaginal delivery. OBJECTIVE: The purpose of this study was to compare maternal and neonatal outcomes that are associated with attempted operative vaginal delivery with those that are associated with second-stage repeat cesarean delivery without an operative vaginal delivery attempt among women who undergo a trial of labor after cesarean delivery. STUDY DESIGN: This is a retrospective secondary analysis of data from Cesarean Registry of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. Women who underwent a trial of labor after cesarean delivery who were at least 36 weeks gestation were eligible for analysis if they had a live, singleton, nonanomalous gestation in cephalic presentation and reached second-stage labor (defined as complete cervical dilation) with a fetal station of at least +2. The data for women who had an attempted operative vaginal delivery with either forceps or vacuum were compared with those of women who underwent second stage repeat cesarean delivery without operative vaginal delivery attempt. Outcomes of maternal and neonatal complications were compared between groups with bivariable and multivariable analyses. RESULTS: Of 1230 women whose cases were eligible for analysis, 945 women (76.8%) had an attempted operative vaginal delivery. Of those who underwent attempted operative vaginal delivery, 914 women (96.7%) achieved a vaginal delivery. Women who attempted operative vaginal delivery had a lower mean body mass index (30.4±6.0 vs 31.8±5.9 kg/m2; P=.001) and gestational age (39.5±1.3 vs 39.8±1.2 weeks; P=.012) at delivery and were more likely to be of non-Hispanic black race (30.0% vs 22.1%; P=.002), to have had a previous vaginal delivery (34.9% vs 20.4%; P<.001), and to have fetal descent greater than +2 station at complete dilation (55.6% vs 16.8%; P<.001) and were less likely to have chorioamnionitis (6.8% vs 19.3%; P<.001). The frequency of endometritis was significantly lower among women who had an attempted operative vaginal delivery compared with those who had repeat cesarean delivery (2.5% vs 9.1%; P<.001). However, other serious maternal or neonatal adverse outcomes were not statistically different between the groups. These findings persisted after adjustment for potential confounders. CONCLUSION: In the setting of a trial of labor after cesarean delivery in the second stage with a fetal station of at least +2, attempted operative vaginal delivery resulted in a vaginal birth after cesarean delivery in most women and was not associated with increased adverse maternal and neonatal outcomes but was associated with a reduced frequency of endometritis compared with repeat cesarean delivery without operative vaginal delivery attempt.

A prediction model of vaginal birth after cesarean in the preterm period.

BACKGROUND: A validated model exists that predicts the probability of vaginal birth after cesarean delivery in patients at term who are undergoing a trial of labor after cesarean delivery. However, a model that predicts the success of a vaginal birth after cesarean delivery in the preterm period has not been developed. OBJECTIVE: We sought to develop and validate a predictive model for vaginal birth after cesarean delivery for women undergoing a trial of labor after cesarean delivery during the preterm period. STUDY DESIGN: We performed a secondary analysis of a prospective cohort study designed to evaluate perinatal outcomes in women with a prior cesarean scar. We included women with 1 prior low transverse cesarean delivery undergoing a trial of labor after cesarean delivery with a vertex singleton pregnancy in the preterm period (26-36 weeks). Using multivariable logistic regression modeling, we constructed a predictive model for vaginal birth after cesarean delivery with information known at admission for preterm delivery. Using a 70% to 30% random split of the data, the model was developed in the training data and subsequently confirmed in the validation data. Predictions and area under the curve were based on a 10-fold cross-validated jackknife estimation and based on 1000 bootstrap resampling methods. The adequacy of all models was evaluated based on the Hosmer-Lemeshow goodness-of-fit test. RESULTS: One thousand two hundred ninety-five women met our criteria for analysis. The significant predictors of vaginal birth after cesarean delivery success were chronic hypertension, hypertensive disease of pregnancy (gestational hypertension or preeclampsia), prior vaginal delivery, dilation on cervical examination at admission, prior vaginal birth after cesarean delivery, a recurring indication in a prior cesarean delivery, and induction of labor as well as a 2-way interactions between dilation and hypertensive disease of pregnancy, dilation and diabetes mellitus (pregestational or gestational), and induction of labor and hypertensive disease of pregnancy. The area under the curve from the prediction model was 0.80 (95% confidence interval, 0.77-0.83) and the model fit the data well (Hosmer-Lemeshow P = .367). The bootstrap and 10-fold cross-validated jackknife estimates of the corrected area under the curve of the model were 0.78 (95% confidence interval, 0.74-0.82) and 0.77 (95% confidence interval, 0.73-0.82), respectively, following incorporation of regression shrinkage. CONCLUSION: A cross-validated predictive model was created for patients undergoing a trial of labor after cesarean delivery in the preterm period using 8 variables known on admission. These factors were notably different from factors used in the model for term patients. This new model can be used to counsel patients in the preterm period who want to undergo a trial of labor after cesarean delivery on their predicted vaginal birth after cesarean delivery success.

Does midtrimester cervical length aid in predicting vaginal birth after cesarean?

OBJECTIVE: A longer midtrimester cervical length (CL) is associated with an increased chance of cesarean delivery, but CL has not been used to predict the chance of successful trial of labor after cesarean delivery (TOLAC). The objective of this study was to identify whether midtrimester CL improves the prediction of vaginal birth after cesarean delivery (VBAC) among women undergoing a TOLAC. STUDY DESIGN: Women with 1 prior cesarean and a singleton gestation in the vertex position who had a routine CL assessment between 18 and 24 weeks and chose to undergo a TOLAC were identified. Midtrimester CL and characteristics identifiable in early prenatal care that have been used in a validated predictive model for VBAC (ie, age, body mass index, race/ethnicity, prior vaginal delivery, prior VBAC, and indication for prior cesarean delivery) were abstracted from the medical record. Multivariable regressions with VBAC as the dependent variable, with and without CL, were created and their predictive capacity compared using receiver-operating characteristic curves and reclassification tables. RESULTS: Of the 678 women who met inclusion criteria, 517 (76.3%) experienced a VBAC. Mean midtrimester CL was lower in women who achieved a VBAC compared with those who required a cesarean delivery in labor (4.3 ± 0.8 cm vs 4.7 ± 0.8 cm, P < .001). In a multivariable logistic regression, midtrimester CL (centimeters) was significantly associated with a reduced chance of VBAC (adjusted odds ratio [aOR], 0.60; 95% confidence interval [CI], 0.47-0.76). Although the addition of CL improved the area under the receiver-operating characteristic curve (aOR, 0.695 [95% CI, 0.648-0.743] vs aOR, 0.727 [95% CI, 0.681-0.773]; P = .03), it did not significantly enhance the clinical value of the model, as quantified by net reclassification improvement (P = .11). CONCLUSION: Shorter midtrimester CL is associated with a greater chance of vaginal birth after a TOLAC. However, midtrimester CL does not significantly improve the clinical value of a previously developed VBAC prediction model.

Surgical speed and risk for maternal operative morbidity in emergent repeat cesarean delivery.

OBJECTIVE: The purpose of this study was to determine whether surgical speed is associated with maternal outcomes in women who have a history of previous cesarean delivery (CD) and who require emergent delivery. STUDY DESIGN: This is a secondary analysis of a multicenter, prospective observational study of women with a history of previous CD. Women who attempted a vaginal birth after CD and required emergent CD were dichotomized into those with a skin incision-to-fetal delivery time of ≤2 min (I-D ≤2) or >2 min (I-D >2), based on the mode I-D. Rates of composite maternal complications and specific surgical complications were compared. RESULTS: Seven hundred ninety-three women had an emergency repeat CD: 108 women (13.6%) had I-D ≤2, and 685 women (86.4%) had I-D >2. The composite of maternal morbidity occurred in 36% of women with I-D≤2 and 23% with I-D>2 (P < .01). Women with I-D ≤2 had higher odds of intraoperative transfusion, uterine artery ligation, and broad ligament hematoma. In a multivariable regression model, the only variable that remained associated with maternal outcome was I-D (relative risk, 1.66; 95% confidence interval, 1.23-2.23). There was no difference in the incidence of neonatal acidemia between groups. CONCLUSION: Among women who underwent emergent repeat cesarean delivery, surgical speed was associated with an increased risk for maternal complications.

The cost-effectiveness of a trial of labor accrues with multiple subsequent vaginal deliveries.

OBJECTIVE: The purpose of this study was to estimate costs and outcomes of subsequent trials of labor after cesarean delivery (TOLAC) compared with elective repeat cesarean deliveries (ERCD). STUDY DESIGN: To compare TOLAC and ERCD, maternal and neonatal decision analytic models were built for each hypothetic subsequent delivery. We assumed that only women without previa would undergo TOLAC for their second delivery, that women with successful TOLAC would desire future TOLAC, and that women who chose ERCD would undergo subsequent ERCD. Main outcome measures were maternal and neonatal mortality and morbidity rates, direct costs, and quality-adjusted life years. Values were derived from the literature. One-way and Monte-Carlo sensitivity analyses were performed. RESULTS: TOLAC was less costly and more effective for most models. A progression of decreasing incremental cost and increasing incremental effectiveness of TOLAC was found for maternal outcomes with increasing numbers of subsequent deliveries. This progression was also displayed among neonatal outcomes and was most prominent when neonatal and maternal outcomes were combined, with an incremental cost and effectiveness of -$4700.00 and .073, respectively, for the sixth delivery. Net-benefit analysis showed an increase in the benefit of TOLAC with successive deliveries for all outcomes. The maternal model of the second delivery was sensitive to cost of delivery and emergent cesarean delivery. Successive maternal models became more robust, with the models of the third-sixth deliveries sensitive only to cost of delivery. Neonatal models were not sensitive to any variables. CONCLUSION: Although nearly equally effective relative to ERCD for the second delivery, TOLAC becomes less costly and more effective with subsequent deliveries.

Perinatal outcomes following uterine rupture during a trial of labor after cesarean: A 12-year single-center experience.

OBJECTIVE: To determine perinatal outcomes following uterine rupture during a trial of labor after one previous cesarean delivery (CD) at term. METHODS: A retrospective single-center study examining perinatal outcomes in women with term singleton pregnancies with one prior CD, who underwent a trial of labor after cesarean (TOLAC) and were diagnosed with uterine rupture, between 2011 and 2022. The primary outcome was a composite maternal outcome, and the secondary outcome was a composite neonatal outcome. Additionally, we compared perinatal outcomes between patients receiving oxytocin during labor with those who did not. RESULTS: Overall, 6873 women attempted a TOLAC, and 116 were diagnosed with uterine rupture. Among them, 63 (54.3%) met the inclusion criteria, and 18 (28%) had the maternal composite outcome, with no cases of maternal death. Sixteen cases (25.4%) had the composite neonatal outcome, with one case (1.6%) of perinatal death. No differences were noted between women receiving oxytocin and those not receiving oxytocin in the rates of maternal composite (35.7% vs 26.5%, P = 0.502, respectively) or neonatal composite outcomes (21.4% vs 26.5%, P = 0.699). CONCLUSION: Uterine rupture during a TOLAC entails increased risk for myriad adverse outcomes for the mother and neonate, though possibly more favorable than previously described. Oxytocin use does not affect these risks.

Prediction of cesarean delivery using the fetal-pelvic index.

OBJECTIVE: The purpose of this study was to estimate the usefulness of the fetal-pelvic index (FPI) in the prediction of cesarean delivery among nulliparous and women who undergo a trial of labor after cesarean delivery (TOLAC). STUDY DESIGN: This prospective cohort study included subjects at 2 hospitals from the University of Pennsylvania Health system. The study sample included nulliparous women and women who attempted TOLAC, with nonanomalous pregnancies at ≥37 weeks of gestation in vertex presentation (n = 221 and 207, respectively). FPI score was calculated with the ultrasound-based fetal biometric measures that were performed within 2 weeks of delivery and x-ray pelvimetry that was performed within 48 hours of delivery. Multivariable logistic regression was used to develop a clinical predictive index for cesarean delivery, which included FPI and clinical factors, in nulliparous women or women who attempted TOLAC. The prediction models were tested for accuracy with the area under the receiver operating characteristics curve. RESULTS: Higher FPI scores were associated with greater odds of cesarean delivery. A unit increase in FPI score increased the odds of cesarean delivery by 15% (adjusted odds ratio, 1.15; 95% confidence interval, 1.09-1.21) for nulliparous women and 15% for women who attempted TOLAC (adjusted odds ratio, 1.15; 95% confidence interval, 1.10-1.20) after adjustment for maternal age, race, medical risk factors, and labor method. Among nulliparous women, the receiver operating characteristics analysis estimated an area under the curve of 0.88, with positive and negative predictive values of 76% and 87%, respectively. Similar findings were observed in the subgroup of women who attempted TOLAC. CONCLUSION: The FPI when combined with clinical risk factors can identify accurately women who are at a high risk for cesarean delivery.

Prediction of vaginal birth after cesarean in China.

OBJECTIVE: This study aimed to develop and validate a prediction model of vaginal birth after cesarean delivery (VBAC) in China. METHODS: A nomogram for effective prediction of VBAC of singleton, cephalic and one previous low-transverse cesarean section deliveries was created by comparing the combinations of ultrasonographic and non-ultrasonographic factors from five hospitals between 2018 and 2019. RESULTS: A total of 1066 women were included. Of the women who underwent trial of labor after cesarean (TOLAC), 854 (80.1%) had a VBAC. Ultrasound factors included reached a higher area under the curve (AUC) combined with non-ultrasonographic factors. Of the three ultrasonographic factors analyzed, the best predictive factor for successful TOLAC was fetal abdominal circumference. A nomogram was generated with eight validated factors, including maternal age, gestational week, height, previous vaginal delivery, Bishop score, dilatation of the cervix at the time of admission, body mass index at delivery, and fetal abdominal circumference by ultrasound. The trained and validated AUC were 0.719 (95% confident interval 0.674-0.764) and 0.774 (95% confident interval 0.712-0.837), respectively. CONCLUSION: Our VBAC nomogram based on obstetric factors and fetal abdominal circumference obtained by ultrasound could be used to counsel women who are considering TOLAC.

Assessing the predictive accuracy of the new vaginal birth after cesarean delivery calculator.

BACKGROUND: The vaginal birth after cesarean delivery calculator by the Maternal-Fetal Medicine Units Network was created to help providers counsel patients on predicted success of trial of labor after cesarean delivery using individualized risk assessment. The inclusion of race and ethnicity as predictors of vaginal birth after cesarean delivery in the 2007 calculator was problematic and potentially exacerbated racial disparities in obstetrics. Thus, a modified calculator without race and ethnicity was published in June 2021. OBJECTIVE: This study aimed to assess the accuracy of the 2007 and 2021 Maternal-Fetal Medicine Units vaginal birth after cesarean delivery calculators in predicting vaginal birth after cesarean delivery success among racial/ethnic minority patients receiving obstetrical care at a single urban tertiary medical center. STUDY DESIGN: All patients with 1 previous low transverse cesarean delivery who underwent a trial of labor at term with a vertex singleton gestation at an urban tertiary medical center from May 2015 to December 2018 were reviewed. Demographic and clinical data were collected retrospectively. Associations between maternal characteristics and success of vaginal birth after cesarean delivery were assessed using univariate and multivariable logistic regression. Predicted vaginal birth after cesarean delivery success rates using the Maternal-Fetal Medicine Units calculator were compared with actual outcomes (ie, successful trial of labor after cesarean delivery/vaginal birth after cesarean delivery vs repeated cesarean delivery) across each racial and ethnic group. RESULTS: A total of 910 patients met eligibility criteria and attempted trial of labor after cesarean delivery; 662 (73%) achieved vaginal birth after cesarean delivery. The rate of vaginal birth after cesarean delivery was highest among Asian women (81%) and lowest among Black women (61%). Univariate analyses demonstrated that success of vaginal birth after cesarean delivery was associated with maternal body mass index <30 kg/m2, history of vaginal delivery, and absence of indication of arrest of dilation or descent for previous cesarean delivery. Multivariate analyses evaluating predictors of vaginal birth after cesarean delivery reported in the 2021 calculator showed that maternal age, history of arrest disorder for previous cesarean delivery, and treated chronic hypertension were not significant in our patient population. Most patients who were of White, Asian, or "Other" race with a vaginal birth after cesarean delivery had a 2007 calculator-predicted probability of vaginal birth after cesarean delivery of >65%, whereas most Black and Hispanic patients with a vaginal birth after cesarean delivery were more likely to have a predicted probability of vaginal birth after cesarean delivery between 35% and 65% (P<.001). Most White, Asian, and Other-race patients with a repeated cesarean delivery had a 2007 calculator-predicted probability of vaginal birth after cesarean delivery of >65%, whereas most Black and Hispanic patients with a repeated cesarean delivery had a predicted probability of vaginal birth after cesarean delivery between 35% and 65%. Across all racial and ethnic groups, most patients with a vaginal birth after cesarean delivery had a 2021 calculator-predicted probability of vaginal birth after cesarean delivery of >65%. CONCLUSION: The inclusion of race/ethnicity in the 2007 Maternal-Fetal Medicine Units vaginal birth after cesarean delivery calculator underestimated predicted vaginal birth after cesarean delivery success rates among Black and Hispanic patients receiving obstetrical care at an urban tertiary medical center. Thus, we support the use of the 2021 vaginal birth after cesarean delivery calculator without race/ethnicity. Excluding race and ethnicity from vaginal birth after cesarean delivery counseling may be one way in which providers can ultimately contribute toward the reduction of racial and ethnic disparity in maternal morbidity in the United States. Further research is needed to understand the implications of treated chronic hypertension for the success of vaginal birth after cesarean delivery.

External validation of vaginal birth after cesarean delivery calculator in Israeli cohort of parturients and construction of an improved model.

OBJECTIVE: To validate the Maternal Fetal Medicine Unit's (MFMU) vaginal birth after cesarean delivery (VBAC) calculator in an Israeli cohort, and to detect other variables associated with VBAC and construct an improved VBAC calculator. METHODS: A retrospective cohort study was performed at a single university-affiliated medical center. Women carrying a singleton, term, cephalic-presenting fetus, with previous one low transverse cesarean delivery who opted for trial of VBAC were included. Demographic and obstetric characteristics were incorporated into the MFMU's calculator, to predict probabilities of VBAC and compare prediction performance with the original publication utilizing receiver operating characteristic (ROC) statistics. Logistic regression analysis was used to investigate other variables and construct an improved model for success of VBAC. RESULTS: Of 490 parturients, 396 (80.8%) had a successful vaginal delivery. Compared to the original publication, the MFMU's calculator underperformed: area under the ROC curve (AUC) was 0.709 (95% confidence interval [CI] 0.652-0.766, P < 0.001). Sensitivity, specificity, positive and negative predictive values, and overall accuracy were 67.42%, 65.96%, 89.30%, 32.46%, and 32.46%, respectively. An improved model that included previous VBAC, prior vaginal delivery, spontaneous onset of delivery, and maternal diabetes resulted in improved prediction performance with an AUC of 0.771 (95% CI 0.723-0.82, P < 0.001). CONCLUSION: MFMU's VBAC calculator needs to be validated in different populations before implementation.

Foley catheter compared with controlled release dinoprostone vaginal insert for labor induction after one previous cesarean delivery: A randomized trial.

OBJECTIVE: To compare Foley catheter and controlled-release dinoprostone vaginal insert on induction-to-delivery interval and maternal satisfaction in women with one previous cesarean delivery. METHODS: This randomized controlled trial was conducted at the University Malaya Medical Center, Kuala Lumpur, Malaysia, from December 12, 2018, to May 28, 2019. A total of 78 term women scheduled for labor induction with one previous cesarean delivery who had ripe cervixes, singleton gestation, cephalic presentation, intact membranes, and reassuring cardiotocogram were randomized to Foley catheter or dinoprostone insert. The primary outcome was induction-to-delivery interval (in hours) and the secondary outcomes included maternal satisfaction on birth experience (assessed by 100-mm visual analog scale). RESULTS: Induction-to-delivery intervals were as follows: median 33.5 h (interquartile range [IQR], 26.1-36.2 h) versus 23.5 h (IQR, 12.7-34.5 h) (P = 0.004), and maternal satisfaction on birth process 100-mm visual analog scale was 80 mm (IQR, 64-88 mm) versus 82 mm (IQR, 67-88 mm) (P = 0.919) for the Foley and controlled-release dinoprostone arms, respectively. Cesarean delivery rates were 23 of 39 (59%) versus 20 of 39 (51%) (relative risk, 1.15 [95% confidence interval, 0.77-1.72]) (P = 0.496) and trial device insertion to removal time mean ± standard deviation was 20.1 ± 7.1 h versus 14.2 ± 7.3 h (P = 0.001) for Foley versus controlled-release dinoprostone, respectively. CONCLUSION: In term women after one previous cesarean delivery with unripe cervixes, controlled-release dinoprostone vaginal insert compared with Foley catheter shortens the induction-to-delivery interval but maternal satisfaction was not significantly increased. CLINICAL TRIAL REGISTRATION: This study was registered with ISRCTN on November 30, 2018, with trial identification number: ISRCTN16957529 (https://doi.org/10.1186/ISRCTN16957529). The first participant was recruited on December 12, 2018.