Can a prediction model for vaginal birth after cesarean also predict the probability of morbidity related to a trial of labor?

Reexamining the use of race in medical algorithms: the maternal health calculator debate

The concept of race is prevalent in medical, nursing, and public health literature. Clinicians often incorporate race into diagnostics, prognostic tools, and treatment guidelines. An example is the recently heavily debated use of race and ethnicity in the Vaginal Birth After Cesarean (VBAC) calculator. In this case, the critics argued that the use of race in this calculator implied that race confers immutable characteristics that affect the ability of women to give birth vaginally after a c-section. This debate is co-occurring as research continues to highlight the racial disparities in health outcomes, such as high maternal mortality among Black women compared to other racial groups in the United States. As the healthcare system contemplates the necessity of utilizing race-a social and political construct, to monitor health outcomes, it has sparked more questions about incorporating race into clinical algorithms, including pulmonary tests, kidney function tests, pharmacotherapies, and genetic testing. This paper critically examines the argument against the race-based Vaginal Birth After Cesarean (VBAC) calculator, shedding light on its implications. Moreover, it delves into the detrimental effects of normalizing race as a biological variable, which hinders progress in improving health outcomes and equity.

The association between obesity and the success of trial of labor after cesarean delivery (TOLAC) in women with past vaginal delivery

OBJECTIVES

To evaluate the effect of overweight (body mass index; BMI 25.0-29.9 kg/m2), and obesity (BMI>30 kg/m2), on the success of trial of labor after cesarean delivery (TOLAC), with consideration of successful past vaginal birth.

METHODS

This retrospective cohort study was performed using electronic database of obstetrics department at a university-affiliated tertiary medical center. All women admitted for TOLAC at 37-42 weeks of gestational age, carrying a singleton live fetus at cephalic presentation, with a single previous low segment transverse cesarean delivery between 1/2015 and 5/2021 were included. Primary outcome was the rate of cesarean delivery during labor, and subgroup analysis was performed for the presence of past vaginal birth.

RESULTS

Of the 1200 TOLAC deliveries meeting the inclusion criteria, 61.9 % had BMI in the normal range, 24.6 % were overweight (BMI 25.0-29.9 kg/m2), and 13.4 % were obese (BMI of 30 kg/m2 and over). Using a multivariate analysis, BMI≥30 kg/m2 was associated with increased risk of cesarean delivery compared to normal weight. However, in the subgroup of 292 women with a history of successful vaginal birth BMI did not affect TOLAC success.

CONCLUSIONS

BMI does not affect the success of TOLAC in women with previous vaginal birth. This information should be considered during patients counselling, in order to achieve a better selection of mode of delivery and higher patients' satisfaction.

Epistemic Silences and Experiential Knowledge in Decisions After a First Cesarean: The case of a vaginal birth after cesarean calculator

Evidence-based obstetrics can employ statistical models to justify greater use of cesareans, sometimes excluding experiential elements from informed decision making. Over the past decade, prenatal providers adopted a vaginal birth after cesarean (VBAC) calculator designed to support patients in making informed decisions about their births by estimating their probability for a VBAC. Among other factors, the calculator used race and ethnicity to make its estimate, assigning lower probabilities for a successful VBAC to Black and Hispanic patients. I analyze how a diverse group of women and their providers engaged with the VBAC calculator. Some providers used low calculator scores to remove a shared decision-making model by prescriptively counseling Black and Hispanic women who desired a VBAC into undergoing repeat cesareans. Consequently, women racialized by the calculator as Black or Hispanic used experiential knowledge to challenge the calculator's assessment of their supposed lesser ability to give birth vaginally.

Prediction of Emergency Cesarean Section Using Detectable Maternal and Fetal Characteristics Among Saudi Women

Background

The worldwide rate of cesarean section (CS) is increasing. Development of prediction models for a specific population may improve the unmet need for CS as well as reduce the overuse of CS.

Objective

To explore risk factors associated with emergency CS, and to determine the accuracy of predicting it.

Methods

A retrospective analysis of the medical records of women who delivered between January 1, 2021-December 2022 was conducted, relevant maternal and neonatal data were retrieved.

Results

Out of 1793 deliveries, 447 (25.0%) had emergency CS. Compared to control, the risk of emergency CS was higher in primiparous women (OR 2.13, 95% CI 1.48 to 3.06), in women with higher Body mass index (BMI) (OR 1.77, 95% CI 1.27 to 2.47), in association with history of previous CS (OR 4.81, 95% CI 3.24 to 7.15) and in women with abnormal amniotic fluid (OR 2.30, 95% CI 1.55 to 3.41). Additionally, women with hypertensive disorders had a 176% increased risk of emergency CS (OR 2.76, 95% CI 1.35-5.63). Of note, the risk of emergency CS was more than three times higher in women who delivered a small for gestational age infant (OR 3.29, 95% CI 1.93-5.59). Based on the number of risk factors, a prediction model was developed, about 80% of pregnant women in the emergency CS group scored higher grades compared to control group. The area under the curve was 0.72, indicating a good discriminant ability of the model.

Conclusion

This study identified several risk factors associated with emergency CS in pregnant Saudi women. A prediction model showed 72% accuracy in predicting the likelihood of emergency CS. This information can be useful to individualize the risk of emergency CS, and to implement appropriate measures to prevent unnecessary CS.

Comparing Cesarean Birth Utilization Between US Hospitals: A Demonstration of the Robson Ten-Group Classification System for Use in Quality Improvement and Benchmarking

BACKGROUND

The World Health Organization-endorsed Robson Ten-Group Classification System (TGCS) is a standard reporting mechanism for cesarean birth, yet this approach is not widely adopted in the United States.

OBJECTIVE

To describe the application and utility of the TGCS to compare hospital-level cesarean births rates, for use in quality improvement and benchmarking.

METHODS

We conducted a descriptive, secondary data analysis of the Consortium on Safe Labor dataset using data from 228 438 women's births, from 2002 to 2008, in 12 sites across the United States. We stratified births into 10 mutually exclusive groups and calculated within-group proportions of group size and cesarean birth rates for between-hospital comparisons of cesarean birth, trial of labor after cesarean (TOLAC), and labor induction utilization.

RESULTS

There is variation in use of cesarean birth, labor induction, and TOLAC across the 12 sites.

CONCLUSION

The TGCS provides a method for between-hospital comparisons, particularly for revealing usage patterns of labor induction, TOLAC, and cesarean birth. Adoption of the TGCS in the United States would provide organizations and quality improvement leaders with an effective benchmarking tool to assist in reducing the use of cesarean birth and increasing the support of TOLAC.

Quality Initiative to Reduce Failed Trial of Labor after Cesarean Using Calculated VBAC Success Likelihood

OBJECTIVE

 Vaginal birth after cesarean can reduce morbidity associated with multiple cesarean deliveries. Failed vaginal birth after cesarean is associated with increased maternal and neonatal morbidity. The Maternal-Fetal Medicine Units Vaginal Birth After Cesarean calculator is a validated tool to predict the likelihood of successful trial of labor after cesarean. Predicted likelihood < 60% has been associated with increased maternal and neonatal morbidity. We sought to determine if formal incorporation of calculated vaginal birth after cesarean likelihood into patient-centered counseling would reduce failed vaginal birth after cesarean.

STUDY DESIGN

 This is a quality improvement intervention at a single tertiary-care academic medical center, in which standardized patient counseling was implemented, facilitated by an electronic medical record template featuring patient-specific likelihood of vaginal birth after cesarean success. Term singleton pregnancies with history of one to two cesareans were included; those with contraindication to labor were excluded. Historical controls (January 2016-December 2018, n = 693) were compared with a postimplementation cohort (January 2019-April 2020, n = 328). Primary outcome was failed vaginal birth after cesarean.

RESULTS

 Fewer patients in the postintervention cohort had a history of an arrest disorder (PRE: 48%, 330/693 vs. POST: 40%, 130/326, p = 0.03); demographics were otherwise similar, including the proportion of patients with <60% likelihood of success (PRE: 39%, 267/693, vs. POST: 38%, 125/326). Following implementation, induction of labor in patients with a <60% likelihood of successful vaginal birth after cesarean decreased from 17% (45/267) to 5% (6/125, p < 0.01). The proportion of failed vaginal birth after cesarean decreased from 33% (107/329) to 22% (32/143, p = 0.04). Overall vaginal birth after cesarean rate did not change (PRE: 32%, 222/693, vs. POST: 34%, 111/326, p = 0.52).

CONCLUSION

 An intervention targeting provider counseling that included a validated vaginal birth after cesarean success likelihood was associated with decreased risk of failed trial of labor after cesarean without affecting overall vaginal birth after cesarean rate.

KEY POINTS

· Labored cesarean increases maternal morbidity.. · Application of the Maternal-Fetal Medicine Units (MFMU) calculator to antenatal counseling decreased labored cesarean.. · Application of the MFMU calculator to antenatal counseling did not decrease overall vaginal birth after cesarean rate..

Maternal and neonatal outcomes of trial of labor compared with elective cesarean delivery according to predicted likelihood of vaginal delivery

OBJECTIVE

The vaginal birth after cesarean (VBAC) calculator developed by the Maternal-Fetal Medicine Units Network (MFMU) helps to identify the likelihood of VBAC. We sought to compare adverse maternal and neonatal outcomes of trial of labor after cesarean (TOLAC) to those of elective cesarean delivery after stratifying by VBAC likelihood.

STUDY DESIGN

This was a retrospective cohort study of all women whose primary low transverse segment cesarean delivery and subsequent singleton term delivery with vertex presentation occurred at an academic center from January 2009 to June 2018. Only data from the second pregnancy were analyzed. The final analysis included 835 women. The MFMU VBAC calculator was used to assess the likelihood of VBAC. The two primary outcomes were composite adverse maternal (death or severe maternal complications) and neonatal outcomes (perinatal death or severe neonatal complications). The analyses were stratified based on the VBAC likelihood (less than 60% and 60-100%). Multivariable logistic regression was used to calculate adjusted odds ratio (OR) and 95% confidence interval (CI), controlling for predefined covariates.

RESULTS

Among women with VBAC likelihood less than 60%, TOLAC compared with elective cesarean was associated with increased odds of the primary adverse maternal outcome (16.4% vs. 4.2%; adjusted OR 4.60 [95%CI 1.48-14.35]) and the primary adverse neonatal outcome (17.8% vs. 6.3%; adjusted OR 3.93 [95%CI 1.31-11.75]). Among women with VBAC likelihood of 60-100%, TOLAC compared with elective cesarean was associated with decreased odds of the primary adverse maternal outcome (6.4% vs. 11%; adjusted OR 0.47 [95%CI 0.25-0.89]) and similar odds of the primary adverse neonatal outcome (6.7% vs. 8.3%; adjusted OR 0.98 [95%CI 0.52-1.84]).

CONCLUSIONS

Among women with a history of a primary low transverse cesarean delivery, those who underwent TOLAC compared to those who had elective cesarean had increased odds of adverse maternal and neonatal outcomes when VBAC likelihood was less than 60%.

Prediction of odds for emergency cesarean section: A secondary analysis of the CHILD term birth cohort study

INTRODUCTION

Previously developed cesarean section (CS) and emergency CS prediction tools use antenatal and intrapartum risk factors. We aimed to develop a predictive model for the risk of emergency CS before the onset of labour utilizing antenatal obstetric and non-obstetric factors.

METHODS

We completed a secondary analysis of data collected from the CHILD Cohort Study. The analysis was limited to term (≥37 weeks), singleton pregnant women with cephalic presentation. The sample was divided into a training and validation dataset. The emergency CS prediction model was developed in the training dataset and the performance accuracy was assessed by the area under the receiver operating characteristic curve(AUC) of the receiver operating characteristic analysis (ROC). Our final model was subsequently evaluated in the validation dataset.

RESULTS

The participant sample consisted of 2,836 pregnant women. Mean age of participants was 32 years, mean BMI of 25.4 kg/m2 and 39% were nulliparous. 14% had emergency CS delivery. Each year of increasing maternal age increased the odds of emergency CS by 6% (adjusted Odds Ratio (aOR 1.06,1.02-1.08). Likewise, there was a 4% increase odds of emergency CS for each unit increase in BMI (aOR 1.04,1.02-1.06). In contrast, increase in maternal height has a negative association with emergency CS. The final emergency CS delivery predictive model included six variables (hypertensive disorders of pregnancy, antenatal depression, previous vaginal delivery, age, height, BMI). The AUC for our final prediction model was 0.74 (0.72-0.77) in the training set with a similar AUC in the validation dataset (0.77; 0.71-0.82).

CONCLUSION

The developed and validated emergency CS delivery prediction model can be used in counselling prospective parents around their CS risk and healthcare resource planning. Further validation of the tool is suggested.

Defining a Cesarean Delivery Rate for Optimizing Maternal and Neonatal Outcomes

After the global cesarean delivery rate nearly doubled between 2000 and 2015, cesarean deliveries now account for nearly one third of births in the United States. Although rates have plateaued, the high national cesarean delivery rate has garnered criticism from both lay and academic communities because it has not been associated with improvements in maternal or neonatal outcomes. Efforts are underway to lower the cesarean delivery rate through implementation of hospital-level and national guidelines. However, the cesarean delivery rate that optimizes maternal and neonatal outcomes is not known. Defining a cesarean delivery rate that optimizes perinatal outcomes and reduces morbidity seems simple. However, there are a host of challenges to such a task, including determining the outcomes that are most meaningful to use, deciding the population that should define the rate, and incorporating person-centered decision making, given that people place different value on different outcomes. Rather than a "call" for cesarean delivery rate reductions of a specific and arbitrary magnitude, we need further attention to defining an evidence-based optimal target. This commentary summarizes current national and international cesarean delivery rate targets, discusses the challenges of identifying an evidence-based national cesarean delivery rate target, and explores future considerations for best defining a cesarean delivery rate target.

Racial and Ethnic Disparities Among Women Undergoing a Trial of Labor After Cesarean Delivery: Performance of the VBAC Calculator with and without Patients' Race/Ethnicity

The Maternal Fetal Medicine Units Network (MFMU) vaginal birth after cesarean (VBAC) calculator is a clinical tool designed to predict trial of labor after cesarean delivery (TOLAC) success. The calculator has come under scrutiny for its inclusion of race and ethnicity, which systematically predicts a lower likelihood of success for patients who identify as African American or Hispanic. We hypothesized that the calculator would predict VBAC more accurately without the use of race or ethnicity. A retrospective chart review including all patients undergoing TOLAC from 2016 to 2019 was conducted. A multivariate logistic regression was used to compare one model that utilizes the original variables in predicting VBAC (model 1) and another that uses the same variables except for race and ethnicity (model 2). In model 1, race and ethnicity were the only variables not associated with the probability of successful TOLAC (p = 0.065). The area under the curve (AUC) for models 1 and 2 were 0.77 and 0.78, respectively. There was not a statistically significant difference between the predictive abilities of the two models (p = 0.40). Rates of PPH (p = 0.001), abruption (p = 0.04), intra-amniotic infection (p < 0.0001), and other postpartum complications (p = 0.005) differed significantly by race and ethnicity. The use of race and ethnicity did not contribute to the accuracy of VBAC prediction. The use of race and ethnicity in this predictive model should be omitted to prevent inherent bias and discrimination. There were also significant racial and ethnic differences in overall postpartum complication rates.

Is there an Association between Vaginal Birth after Cesarean Prediction and Obstetric Anal Sphincter Injury?

OBJECTIVE

This study aimed to estimate whether there is an association between the predicted probability of vaginal birth after cesarean delivery (VBAC) and the occurrence of obstetric anal sphincter injuries (OASIS).

STUDY DESIGN

This was a single-site retrospective cohort study of all women with a singleton vaginal birth after a previous cesarean section between January 2011 and December 2016. Women were divided into four ordinal groupings by the predicted probability of achieving vaginal birth after cesarean using the Maternal-Fetal Medicine Units Network VBAC calculator (less than 41%, 40.1-60%, 60.1-80%, and greater than 80%). The primary outcome was OASIS, defined as a 3rd or 4th degree perineal laceration. Bivariable and multivariable analyses were used to examine the association between predicted VBAC probability and OASIS.

RESULTS

In total, 1,411 women met inclusion criteria and 73 (5.2%) sustained OASIS. The median predicted probability of VBAC was lower in women with OASIS compared with those without OASIS (60% [interquartile range {IQR}: 48-70%] vs. 66% (IQR: 52-80%), p = 0.02]. On bivariable and multivariable logistic regression, predicted probability of VBAC was associated with increased odds of OASIS (less than 41% probability: adjusted odds ratio [aOR]: 3.18, 95% confidence interval [CI]: 0.90-11.21; 41-60% probability: aOR: 3.76, 95% CI: 1.34-10.57; 61-80% probability aOR: 3.47, 95% CI: 1.25-9.69) relative to women with a predicted probability of VBAC of greater than 80%.

CONCLUSION

Having a lower predicted probability of VBAC is associated with an increased risk of OASIS at the time of a VBAC relative to those with greater than 80% predicted probability. Incorporation of this aspect of maternal morbidity may inform risk-stratification at the time of trial of labor after cesarean, as well as the choice of performing an operative vaginal delivery.

KEY POINTS

· Predicted probability of VBAC is associated with OASIS.. · Low predicted probability of VBAC is associated with increased odds of OASIS.. · Forceps delivery was associated with the highest odds of OASIS..

A Model to Predict Vaginal Delivery and Maternal and Neonatal Morbidity in Low-Risk Nulliparous Patients at Term

OBJECTIVE

This study aimed to develop and validate a model to predict the probability of vaginal delivery (VD) in low-risk term nulliparous patients, and to determine whether it can predict the risk of severe maternal and neonatal morbidity.

METHODS

Secondary analysis of an obstetric cohort of patients and their neonates born in 25 hospitals across the United States (n = 115,502). Trained and certified research personnel abstracted the maternal and neonatal records. Nulliparous patients with singleton, nonanomalous vertex fetuses, admitted with an intent for VD ≥ 37 weeks were included in this analysis. Patients in active labor (cervical exam > 5 cm), those with prior cesarean and other comorbidities were excluded. Eligible patients were randomly divided into a training and test sets. Based on the training set, and using factors available at the time of admission for delivery, we developed and validated a logistic regression model to predict the probability of VD, and then estimated the prevalences of severe morbidity according to the predicted probability of VD.

RESULTS

A total of 19,611 patients were included. Based on the training set (n = 9,739), a logistic regression model was developed that included maternal age, body mass index (BMI), cervical dilatation, and gestational age on admission. The model was internally validated on the test set (n = 9,872 patients) and yielded a receiver operating characteristic-area under the curve (ROC-AUC) of 0.71 (95% confidence interval [CI]: 0.70-0.72). Based on a subset of 18,803 patients with calculated predicted probabilities, we demonstrated that the prevalences of severe morbidity decreased as the predicted probability of VD increased (p < 0.01).

CONCLUSION

In a large cohort of low-risk nulliparous patients in early labor or undergoing induction of labor, at term with singleton gestations, we developed and validated a model to calculate the probability of VD, and maternal and neonatal morbidity. If externally validated, this calculator may be clinically useful in helping to direct level of care, staffing, and adjustment for case-mix among various systems.

KEY POINTS

· A model to predict the probability of vaginal delivery in low-risk nulliparous patients at term.. · The model also predicts the risk of severe maternal and neonatal morbidity.. · The prevalences of severe morbidity decrease as the probability of vaginal delivery increases..

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.

Risk management of vaginal birth after cesarean section (Review)

The increasing number of patients who desire to experience vaginal birth after cesarean (VBAC) and the optimized protocols for trial of labor after cesarean (TOLAC) has led to a shift of old obstetrical paradigms. The VBAC trend is accompanied with numerous challenges for healthcare professionals, from establishing suitability of each pregnant patient profile for TOLAC to active labor management, and ethical or legal issues, which occasionally are not included in specific guidelines. That is why an individualized risk assessment and management can serve obstetricians as a useful tool for improving outcomes of patients, satisfaction, and also for avoiding legal or moral liabilities. The risk management concept aims to reduce foreseen risks and to emulate strategies for prediction and prevention of unwanted events. In obstetrics, and particularly for the VBAC topic, this concept is relatively new and undefined, and thus its features are disparate between guideline recommendations and clinical studies. This narrative review intends to offer a new and organic perspective over clinical aspects of TOLAC and VBAC risk management.

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.

The prediction of morbidity related to vaginal delivery in nulliparous women - A secondary analysis from the genesis multicenter trial

OBJECTIVE

In the prospective multicenter Genesis study, we developed a prediction model for Cesarean delivery (CD) in term nulliparous women. The objective of this secondary analysis was to determine whether the Genesis model has the potential to predict maternal and neonatal morbidity associated with vaginal delivery.

STUDY DESIGN

The national prospective Genesis trial recruited 2,336 nulliparous women with a vertex presentation between 39 + 0- and 40 + 6-weeks' gestation from seven tertiary centers. The prediction model used five parameters to assess the risk of CD: maternal age, maternal height, body mass index, fetal head circumference and fetal abdominal circumference. Simple and multiple logistic regression analyses were used to develop the Genesis model. The risk score calculated using this model were correlated with maternal and neonatal morbidity in women who delivered vaginally: postpartum hemorrhage (PPH), obstetric anal sphincter injury (OASI), shoulder dystocia, one- and five-minute Apgar score ≤ 7, neonatal intensive care (NICU) admission, cephalohematoma, fetal laceration, nerve palsy and fractures. The morbidities associated with spontaneous vaginal delivery were compared with those associated with operative vaginal delivery (OVD). The likelihood ratios for composite morbidity and the morbidity associated with OVD based on the Genesis risk scores were also calculated.

RESULTS

A total of 1,845 (79%) nulliparous women had a vaginal delivery. A trend of increasing intervention and morbidity was observed with increasing Genesis risk score, including OVD (p < 0.001), PPH (p < 0.008), NICU admission (p < 0.001), low Apgar score at one-minute (p < 0.001) and OASI (p = 0.009). The morbidity associated with OVD was significantly higher compared to spontaneous vaginal delivery, including NICU admission (p < 0.001), PPH (p = 0.022), birth injury (p < 0.001), shoulder dystocia (p = 0.002) and Apgar score of<7 at one-minute (p < 0.001). The positive likelihood ratios for composite outcomes (where the OVD was excluded) increases with increasing risk score from 1.005 at risk score of 5% to 2.507 for risk score of>50%.

CONCLUSION

In women who ultimately achieved a vaginal birth, we have shown more maternal and neonatal morbidity in the setting of a Genesis nomogram-determined high-risk score for intrapartum CD. Therefore, the Genesis prediction tool also has the potential to predict a more morbid vaginal delivery.

External validation of a prediction model on vaginal birth after caesarean in a The Netherlands: a prospective cohort study

OBJECTIVES

Discussing the individual probability of a successful vaginal birth after caesarean (VBAC) can support decision making. The aim of this study is to externally validate a prediction model for the probability of a VBAC in a Dutch population.

METHODS

In this prospective cohort study in 12 Dutch hospitals, 586 women intending VBAC were included. Inclusion criteria were singleton pregnancies with a cephalic foetal presentation, delivery after 37 weeks and one previous caesarean section (CS) and preference for intending VBAC. The studied prediction model included six predictors: pre-pregnancy body mass index, previous vaginal delivery, previous CS because of non-progressive labour, Caucasian ethnicity, induction of current labour, and estimated foetal weight ≥90th percentile. The discriminative and predictive performance of the model was assessed using receiver operating characteristic curve analysis and calibration plots.

RESULTS

The area under the curve was 0.73 (CI 0.69-0.78). The average predicted probability of a VBAC according to the prediction model was 70.3% (range 33-92%). The actual VBAC rate was 71.7%. The calibration plot shows some overestimation for low probabilities of VBAC and an underestimation of high probabilities.

CONCLUSIONS

The prediction model showed good performance and was externally validated in a Dutch population. Hence it can be implemented as part of counselling for mode of delivery in women choosing between intended VBAC or planned CS after previous CS.

Counselling Patients for Trial of Labour after Cesarean (TOLAC) and Invasive Placentation: Are We Missing the Mark? The Importance of Local Data and Informed Choice

OBJECTIVE

Rates of cesarean delivery are increasing, and these procedures carry potential complications, like the risk of invasive placentation, which increases with each cesarean. A trial of labour after cesarean (TOLAC) is a viable option for patients; however, it has been associated with uterine rupture, a complication with maternal and fetal risks. To better counsel patients considering TOLAC, we aimed to determine local uterine rupture rates and maternal and neonatal outcomes with TOLAC and compare these with outcomes related to invasive placentation.

METHODS

A 4-year retrospective chart review was conducted at our tertiary centre of all patients with a history of a previous cesarean delivery. We assessed rates of TOLAC, vaginal delivery after cesarean (VBAC), and uterine rupture, as well as maternal and neonatal outcomes associated with invasive placentation. Cases of uterine rupture from 1988 to the present were also reviewed, and their outcomes were compared with those of invasive placentation.

RESULTS

Our uterine rupture rate was 0.44% and VBAC rate was 73.8%. We identified 8 cases of uterine rupture since 1988 and 67 invasive placentas during the 4-year chart review. Invasive placentation was associated with a significantly increased risk of neonatal respiratory morbidity, hysterectomy, maternal complications, and longer length of maternal hospital stay when compared with uterine rupture.

CONCLUSION

While uterine rupture remains a potential complication of TOLAC, it is rare with overall excellent maternal and neonatal outcomes. Invasive placentation, the risk of which increases with cesarean delivery, carries potentially higher complication rates than uterine rupture. Local complication data is important for individual sites offering TOLAC. The implications of invasive placentation cannot be overlooked when counselling patients considering TOLAC.

Prediction of vaginal birth after cesarean deliveries using machine learning

BACKGROUND

Efforts to reduce cesarean delivery rates to 12-15% have been undertaken worldwide. Special focus has been directed towards parturients who undergo a trial of labor after cesarean delivery to reduce the burden of repeated cesarean deliveries. Complication rates are lowest when a vaginal birth is achieved and highest when an unplanned cesarean delivery is performed, which emphasizes the need to assess, in advance, the likelihood of a successful vaginal birth after cesarean delivery. Vaginal birth after cesarean delivery calculators have been developed in different populations; however, some limitations to their implementation into clinical practice have been described. Machine-learning methods enable investigation of large-scale datasets with input combinations that traditional statistical analysis tools have difficulty processing.

OBJECTIVE

The aim of this study was to evaluate the feasibility of using machine-learning methods to predict a successful vaginal birth after cesarean delivery.

STUDY DESIGN

The electronic medical records of singleton, term labors during a 12-year period in a tertiary referral center were analyzed. With the use of gradient boosting, models that incorporated multiple maternal and fetal features were created to predict successful vaginal birth in parturients who undergo a trial of labor after cesarean delivery. One model was created to provide a personalized risk score for vaginal birth after cesarean delivery with the use of features that are available as early as the first antenatal visit; a second model was created that reassesses this score after features are added that are available only in proximity to delivery.

RESULTS

A cohort of 9888 parturients with 1 previous cesarean delivery was identified, of which 75.6% of parturients (n=7473) attempted a trial of labor, with a success rate of 88%. A machine-learning-based model to predict when vaginal delivery would be successful was developed. When features that are available at the first antenatal visit are used, the model showed a receiver operating characteristic curve with area under the curve of 0.745 (95% confidence interval, 0.728-0.762) that increased to 0.793 (95% confidence interval, 0.778-0.808) when features that are available in proximity to the delivery process were added. Additionally, for the later model, a risk stratification tool was built to allocate parturients into low-, medium-, and high-risk groups for failed trial of labor after cesarean delivery. The low- and medium-risk groups (42.4% and 25.6% of parturients, respectively) showed a success rate of 97.3% and 90.9%, respectively. The high-risk group (32.1%) had a vaginal delivery success rate of 73.3%. Application of the model to a cohort of parturients who elected a repeat cesarean delivery (n=2145) demonstrated that 31% of these parturients would have been allocated to the low- and medium-risk groups had a trial of labor been attempted.

CONCLUSION

Trial of labor after cesarean delivery is safe for most parturients. Success rates are high, even in a population with high rates of trial of labor after cesarean delivery. Application of a machine-learning algorithm to assign a personalized risk score for a successful vaginal birth after cesarean delivery may help in decision-making and contribute to a reduction in cesarean delivery rates. Parturient allocation to risk groups may help delivery process management.

Third-trimester prediction of successful vaginal birth after one cesarean delivery-A Swedish model

INTRODUCTION

The objective was to create a clinically useful prediction model for vaginal birth in trial of labor after one cesarean section, appropriate for a third trimester consultation.

MATERIAL AND METHODS

Women with one cesarean section and at least one following delivery (N = 38 686) in the Swedish Medical Birth Register, 1998-2013, were studied. The women were randomly divided into one development and one validation data set. From the development data set, variables associated with vaginal birth after cesarean (VBAC) were identified by univariable logistic regression. Stepwise backward selection was performed until all variables were statistically significant. From the final fitted multivariable logistic model, likelihood ratios were calculated, in order to transpose odds ratios into clinically useful measurements. A constant, based on the delivery ward VBAC in trial of labor rate, was used. By applying the likelihood ratios on the validation data set, the VBAC chance for each woman was estimated with the Bayesian theorem, and the ability of the model to predict VBAC was explored using receiver operating characteristics (ROC) curves.

RESULTS

A previous VBAC, and a previous cesarean section for non-cephalic presentation, were the strongest VBAC predictors. The lowest chances were found for a previous cesarean section due to dystocia, and among women with <18 months since the last cesarean section. The area under the ROC curve was 0.67.

CONCLUSIONS

The new model was satisfactory in predicting VBAC in trial of labor. Developed as a software application, it would become a clinically useful decision-aid.

Risk score for failed trial of vaginal birth after a previous cesarean section including data of labor course

AIM

There is much discussion about the advantages and disadvantages of a trial of labor after cesarean (TOLAC). Some data suggest the greater the likelihood of success, the lower the risks of TOLAC. Our goal was to identify clinical and demographic variables associated with a failed TOLAC, available at admission for spontaneous labor and until 3 h later, with the aim of building two scores for risk of failed TOLAC.

METHODS

This is a nested case-control study with live births to women with one previous cesarean, in a public Brazilian teaching hospital. Preterm, induction, noncephalic presentations, twins, fetal malformations were excluded. Cases were failed TOLAC, and controls, the successful TOLAC. It was accessed the association of the cases with 20 variables (P < 0.05). Associated variables were tested in multivariate analysis to build the scores, which were internally validated.

RESULTS

We included 260 TOLAC, 42 cases and 218 controls. We found 11 variables associated with failed TOLAC. In the score to be applied at admission, we included hypertension, fundal height, previous vaginal birth and dilatation at admission. In the second score hypertension, fundal height at admission, membrane status and difference in dilatation 3 h after admission. Both scores presented good performance in the receiver-operator curve (areas under curve: 0.73 and 0.84, respectively). Both scores were translated into nomograms for clinical use.

CONCLUSION

Two scores were built for risk of failed TOLAC, to be applied at admission and 3 h later. We believe that choosing the more favorable cases makes risks of TOLAC lower.

ACOG Practice Bulletin No. 205: Vaginal Birth After Cesarean Delivery

Trial of labor after cesarean delivery (TOLAC) refers to a planned attempt to deliver vaginally by a woman who has had a previous cesarean delivery, regardless of the outcome. This method provides women who desire a vaginal delivery the possibility of achieving that goal-a vaginal birth after cesarean delivery (VBAC). In addition to fulfilling a patient's preference for vaginal delivery, at an individual level, VBAC is associated with decreased maternal morbidity and a decreased risk of complications in future pregnancies as well as a decrease in the overall cesarean delivery rate at the population level (). However, although TOLAC is appropriate for many women, several factors increase the likelihood of a failed trial of labor, which in turn is associated with increased maternal and perinatal morbidity when compared with a successful trial of labor (ie, VBAC) and elective repeat cesarean delivery (). Therefore, assessing the likelihood of VBAC as well as the individual risks is important when determining who is an appropriate candidate for TOLAC. Thus, the purpose of this document is to review the risks and benefits of TOLAC in various clinical situations and to provide practical guidelines for counseling and management of patients who will attempt to give birth vaginally after a previous cesarean delivery.

The association of patient preferences and attitudes with trial of labor after cesarean

OBJECTIVE

To evaluate the association of patient preferences and attitudes with TOLAC.

STUDY DESIGN

Prospective observational study of TOLAC-eligible women at 26-34 weeks gestation. Preferences (utilities) were elicited using the time trade-off and standard gamble metrics. Logistic regression was used to identify preference- and attitude-based factors associated with TOLAC.

RESULTS

Of the 231 participants, most (n = 197, 85%) preferred vaginal delivery, but only 40% (n = 93) underwent TOLAC. Utilities for uterine rupture outcomes did not differ based on delivery approach. In multivariable analysis, strength of preference for vaginal delivery, value for the experience of labor, and the opinion of the person whom the participant thought of as most important to this decision were associated with TOLAC.

CONCLUSIONS

Future decision support interventions incorporating individualized information regarding the likelihood of vaginal birth and empowering patients to express their preferences and engage their families in the decision-making process may improve decision quality and increase TOLAC rates.

Effect of a two-stage intervention package on the cesarean section rate in Guangzhou, China: A before-and-after study

BACKGROUND

The cesarean section (CS) rate has risen globally during the last two decades. Effective and feasible strategies are needed to reduce it. The aim of this study was to assess the CS rate change after a two-stage intervention package that was designed to reduce the overall CS rate in Guangzhou, China.

METHODS AND FINDINGS

This intervention package was implemented by the Health Commission of Guangzhou Municipality in 2 stages (October 2010-September 2014 and October 2014-December 2016) and included programs for population health education, skills training for healthcare professionals, equipment and technical support for local healthcare facilities, and capacity building for the maternal near-miss care system. A retrospective repeated cross-sectional study was conducted to evaluate influences of the intervention on CS rates. A pre-intervention period from January 2008 to September 2010 served as the baseline. The primary outcome was the CS rate, and the secondary outcomes included maternal mortality ratio (MMR) and perinatal mortality rate (PMR), all obtained from the Guangzhou Perinatal Health Care and Delivery Surveillance System (GPHCDSS). The Cochran-Armitage test was used to examine the trends of the overall CS rate, MMR, and PMR across different stages. Segmented linear regression analysis was used to assess the change of the CS rate over the intervention period. A total of 1,921,932 records of births and 108 monthly CS rates from 2008 to 2016 were analyzed. The monthly CS rate declined across the intervention stages (Z = 75.067, p < 0.001), with an average rate of 42.4% at baseline, 39.8% at Stage 1, and 35.0% at Stage 2. The CS rate declined substantially among nulliparous women who delivered term singletons, with an accelerating decreasing trend observed across Stage 1 and Stage 2 (the difference in slopes: -0.09 [95% CI -0.16 to -0.02] between Stage 1 and baseline, p = 0.014; -0.11 [95% CI -0.20 to -0.02] between Stage 1 and Stage 2, p = 0.017). The CS rate in the remaining population increased during baseline and Stage 1 and subsequently decreased during Stage 2. The sensitivity analysis suggested no immediate impact of the universal two-child policy on the trend of the CS rate. The MMR (Z = -4.368, p < 0.001) and PMR (Z = -13.142, p < 0.001) declined by stage over the intervention period. One of the main limitations of the study is the lack of a parallel control group. Moreover, the influence of temporal changes in the study population on the CS rate was unknown. Given the observational nature of the present study, causality cannot be confirmed.

CONCLUSIONS

Apparent decline in the overall CS rate was observed in Guangzhou, China, after the implementation of a two-stage intervention package. The decline was most evident among nulliparous women who delivered term singletons. Despite some limitations for causal inference, Guangzhou's experience in controlling the CS rate by implementing composite interventions with public health education and perinatal healthcare service improvement could have implications for other similar areas with high rates of CS.

[Induction of labor in women with previous caesarean delivery with balloon catheter: Is it worth it?]

OBJECTIF

Balloon catheters for labor induction at term after previous cesarean section is an alternative option to iterative cesarean section. The aim of this study was to analyze the maternal and neonatal outcomes of the trial of labor after cesarean (TOLAC) in women with unfavorable cervix and balloon catheter induction, 2 years after introduction of this process.

METHODS

Unicentric observational study of women with term cephalic singleton, unfavorable cervix (simplified Bishop score<5) after TOLAC using double-balloon catheter. Were analyzed the mode of delivery and severe maternal (uterine rupture, post-partum hemorrhage, severe perineal tears) and neonatal (neonatal unit admission, APGAR<7 at 5minutes, pH<7.1) outcomes. Predictive factors for failed TOLAC were analyzed by using multivariate logistic regression.

RESULTS

Between 2016-2017, 455 (75.4%) women had TOLAC, whose 59 (13%) women with balloon catheter. The overall vaginal delivery (VD) was 73.9%. After Balloon catheter, the VD rate was 50.8%, versus 79.1% after spontaneous labor, and 68.2% after alone oxytocin/artificial membrane rupture induction (P<0.05). Previous VD (aOR 0.176 CI-95% [0.048-0.651]) and prior sweeping membrane (aOR 0.161 CI-95% [0.034-0.761]) was protective for cesarean section after TOLAC. Severe maternal and neonatal morbidities were observed in 10 (17%) and 8 (13.6%) cases, respectively.

CONCLUSION

Double-Balloon catheter is an option for unfavorable cervix and term induction after previous cesarean section. However, the TOLAC in women whose unfavorable cervix is not without maternal and neonatal risk, especially due to its failure.

Trial of labor after cesarean (TOLAC) in women with premature rupture of membranes. J Matern Fetal Neonatal Med 2019;33:2976-2982. [PMID: 30652525 DOI: 10.1080/14767058.2019.1566312]

Introduction: The aim of this study was to assess the success rate of a trial of labor after a previous cesarean section (TOLAC) in the settings of premature rupture of membranes (PROM) and to compare conservative management with spontaneous labor and induction of labor.Methods: This was a retrospective cohort study conducted in a single tertiary care center between January 2011 and March 2017. Women with singleton pregnancy and a previous cesarean section (CS) who presented with PROM and underwent TOLAC were included. Outcomes and rate of successful vaginal delivery after induction of labor were compared to conservative treatment and spontaneous labor.Results: Among 830 women who met the inclusion criteria, 723 (87.1%) had a spontaneous onset of labor following PROM and 107 (12.9%) had an induction of labor. The rate of successful TOLAC was similar between the groups (75.7 vs. 81.6%, respectively, p = .22). However, induction of labor was associated with an increased risk for uterine rupture (1.87 vs. 0.96%, p < .001), operative complications (6.7 vs. 2.3%, p < .001), and composite maternal postpartum complications (21.4 vs. 10.7%, respectively, p = .014) compared to conservative management with spontaneous initiation of labor. There was no difference in neonatal outcome between the groups.Conclusion: Induction of labor following PROM in women with a previous CS is associated with high successful vaginal delivery rate. However, the risk for uterine rupture and operative and maternal complications is significantly increased compared to spontaneous initiation of labor.

Efficacy of the NICHD vaginal birth after cesarean delivery calculator: a single center experience

Objective: As the cesarean delivery rate has risen future pregnancy outcomes are impacted including the decision to undergo a repeat cesarean or a vaginal birth after cesarean (VBAC) in the subsequent pregnancy. A calculator was developed by the maternal fetal medicine units (MFMUs) network in 2007 to estimate the chance of successful VBAC and is used widely. The purpose of this study was to investigate the calculator's validity on our obstetric patient population.Study design: This was a retrospective study of patients attempting a VBAC delivery at a single center from January 2012 to June 2014. Chances for success were estimated using the MFMU network VBAC calculator in 201 evaluable patients. We then compared the calculator's results with the outcomes observed. In order to determine if the MFMU VBAC calculator was accurately predicting successful vaginal deliveries, we discretized our dataset by binning into MFMU score deciles. Each decile was then tested for significant deviations from the predicted success rate using an exact binomial test. Significance was determined at 0.05 levels.Results: Two hundred and one patients were included. Our results demonstrated higher actual VBAC success than anticipated by using the MFMU network calculator for patients with scores in the 40-80% decile range. When stratified by race, we found the calculator to be a better predictor of success in African-American patients, as the calculator appears to underestimate success in white and Hispanic patients.Conclusion: Calculators are helpful to facilitate patient counseling and shared decision-making regarding the patient's choice for VBAC. When providing such counseling, the potential for reduced predicted VBAC success in the mid-decile range with the MFMU calculator should be recognized.

Estimating success of vaginal birth after caesarean section in a regional Australian population: Validation of a prediction model

BACKGROUND

Following a primary caesarean section (CS), women must decide between attempted vaginal birth after caesarean (VBAC) and elective repeat caesarean section (ERCS) in subsequent pregnancies. Both options carry potential morbidity and mortality for mother and child, with the most feared being uterine rupture and its consequences. In attempts to reduce morbidity, several predictive nomograms have been developed to assist in delivery mode decisions.

AIM

To assess the validity of the predictive nomogram developed by Grobman et al. in our regional Australian population.

MATERIALS AND METHODS

In our retrospective analysis, patients at term, with one previous CS who had a trial of labour were assigned a 'Grobman score' based on antenatal details. Outcomes were noted and patient groups analysed according to percentage deciles of estimated VBAC success, compared with actual VBAC success rates.

RESULTS

A total of 395 women underwent trial of labour after a single prior CS, with a VBAC success rate of 83%. The Grobman model displayed adequate calibration and the re-calibrated model good calibration with the slope coefficient of 0.87 (95% CI 0.54-1.19) and intercept 0.19 (95% CI -0.34-0.72). Discrimination was moderate with receiver operating characteristic area of 0.71 (95% CI 0.67-0.76).

CONCLUSION

This analysis supports further validation studies in larger Australian settings, and suggests that use of the original Grobman predictive nomogram may be appropriate in Australia.

Limitations of Vaginal Birth After Cesarean Success Prediction

The Society for Maternal-Fetal Medicine endorses an algorithm for estimating the probability of successful vaginal birth for women undergoing trial of labor after cesarean (TOLAC). The algorithm is available online in the form of an easy-to-use calculator. This calculator has significant limitations that are easily overlooked by women and providers alike. The calculator has much greater positive than negative predictive power, and it cannot predict unsuccessful TOLAC or uterine rupture. Furthermore, the calculator cannot predict rare catastrophes, such as unplanned hysterectomy, permanent injury, or death. Predictions are heavily influenced by race and ethnicity, which are social and not biological constructs. Relevant variables, such as provider attitudes and institutional differences, are not accounted for. Providers should be mindful and transparent about calculator limitations when counseling women, particularly Latina and African American women. It may be appropriate to use the calculator to inform but not restrict women's options.

French validation and adaptation of the Grobman nomogram for prediction of vaginal birth after cesarean delivery

OBJECTIVE

To validate Grobman nomogram for predicting vaginal birth after cesarean delivery (VBAC) in a French population and adapt it.

STUDY DESIGN

Multicenter retrospective study of maternal and obstetric factors associated with VBAC between May 2012 and May 2013 in 6 maternity units. External validation and adaptation of the prenatal and intrapartum Grobman nomograms for vaginal birth prediction after cesarean delivery in a French cohort.

RESULTS

The study included 523 women with previous cesarean deliveries; 70% underwent a trial of labor for a subsequent delivery (n=367) with a success rate of 65% (n=240). In the univariate analysis, 5 factors were associated with successful VBAC: previous vaginal delivery before the cesarean (P<0.001), the number of previous vaginal deliveries (P<0.001), and a favorable cervix at delivery room admission, cervical effacement (P=0.035), or cervical dilatation at least 3cm (P<0.001), or a Bishop score >6 (P=0.03). A potentially recurrent indication (defined as arrest of dilation or descent as the indication for the previous cesarean) (P=0.039), a hypertensive disorder during pregnancy (P=0.05), and labor induction (P=0.017) were each associated with failed VBAC. External validation of the prenatal and intrapartum Grobman nomograms showed an area under the ROC curve of 69% (95% CI: 0.638, 0.736) and 65% (95% CI: 0.599, 0.700) respectively. Adaptation of the nomogram to the French cohort resulted in the inclusion of the following factors: maternal age, body mass index at last prenatal visit, hypertensive disorder, gestational age at delivery, recurring indication, cervical dilatation, and induction of labor. Its area under the curve to predict successful VBAC was 78% (95% CI: 0.738, 0.825).

CONCLUSION

The nomogram to predict VBAC developed by Grobman et al. is validated in the French population. Adaptation to the French population, by excluding ethnicity, appeared to improve its performance. Impact of the nomogram use on the caesarean section rate has to be validated in a randomized control trial.

A cluster-randomized trial to reduce major perinatal morbidity among women with one prior cesarean delivery in Québec (PRISMA trial): study protocol for a randomized controlled trial

Background

Rates of cesarean delivery are continuously increasing in industrialized countries, with repeated cesarean accounting for about a third of all cesareans. Women who have undergone a first cesarean are facing a difficult choice for their next pregnancy, i.e.: (1) to plan for a second cesarean delivery, associated with higher risk of maternal complications than vaginal delivery; or (b) to have a trial of labor (TOL) with the aim to achieve a vaginal birth after cesarean (VBAC) and to accept a significant, but rare, risk of uterine rupture and its related maternal and neonatal complications. The objective of this trial is to assess whether a multifaceted intervention would reduce the rate of major perinatal morbidity among women with one prior cesarean.

Methods/design

The study is a stratified, non-blinded, cluster-randomized, parallel-group trial of a multifaceted intervention. Hospitals in Quebec are the units of randomization and women are the units of analysis. As depicted in Figure 1, the study includes a 1-year pre-intervention period (baseline), a 5-month implementation period, and a 2-year intervention period. At the end of the baseline period, 20 hospitals will be allocated to the intervention group and 20 to the control group, using a randomization stratified by level of care. Medical records will be used to collect data before and during the intervention period. Primary outcome is the rate of a composite of major perinatal morbidities measured during the intervention period. Secondary outcomes include major and minor maternal morbidity; minor perinatal morbidity; and TOL and VBAC rate. The effect of the intervention will be assessed using the multivariable generalized-estimating-equations extension of logistic regression. The evaluation will include subgroup analyses for preterm and term birth, and a cost-effectiveness analysis.

Discussion

The intervention is designed to facilitate: (1) women’s decision-making process, using a decision analysis tool (DAT), (2) an estimate of uterine rupture risk during TOL using ultrasound evaluation of low-uterine segment thickness, (3) an estimate of chance of TOL success, using a validated prediction tool, and (4) the implementation of best practices for intrapartum management.

Trial registration

Current Controlled Trials, ID: ISRCTN15346559. Registered on 20 August 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2150-x) contains supplementary material, which is available to authorized users.

The importance of clinically and ethically fine-tuning decision-making about cesarean delivery

In obstetric practice, each pregnant woman presents with a composite of maternal and fetal characteristics that can alter the risk of significant harm without cesarean intervention. The hospital's availability of resources and the obstetrician's training, experience, and skill level can also alter the risk of significant harm without cesarean intervention. This paper proposes a clinical ethical framework that takes these clinical and organizational factors into account, to promote a deliberative rather than simplistic approach to decision-making and counseling about cesarean delivery. The result is a clinical ethical framework that should guide the obstetrician in fine-tuning his or her evidence-based, beneficence-based analysis of specific clinical and organizational factors that can affect the strength of the beneficence-based clinical judgment about cesarean delivery. We illustrate the clinical application of this framework for three common obstetric conditions: Category II fetal heart rate tracing, prior non-classical cesarean delivery, and breech presentation.

Validation of a Prediction Model for Vaginal Birth after Cesarean Delivery Reveals Unexpected Success in a Diverse American Population

Objective To investigate the validity of a prediction model for success of vaginal birth after cesarean delivery (VBAC) in an ethnically diverse population. Methods We performed a retrospective cohort study of women admitted at a single academic institution for a trial of labor after cesarean from May 2007 to January 2015. Individual predicted success rates were calculated using the Maternal-Fetal Medicine Units Network prediction model. Participants were stratified into three probability-of-success groups: low (<35%), moderate (35-65%), and high (>65%). The actual versus predicted success rates were compared. Results In total, 568 women met inclusion criteria. Successful VBAC occurred in 402 (71%), compared with a predicted success rate of 66% (p = 0.016). Actual VBAC success rates were higher than predicted by the model in the low (57 vs. 29%; p < 0.001) and moderate (61 vs. 52%; p = 0.003) groups. In the high probability group, the observed and predicted VBAC rates were the same (79%). Conclusion When the predicted success rate was above 65%, the model was highly accurate. In contrast, for women with predicted success rates <35%, actual VBAC rates were nearly twofold higher in our population, suggesting that they should not be discouraged by a low prediction score.

Effect of Entonox on reducing the need for Pethidine and the Relevant Fetal and Maternal Complications for Painless Labor

Background

Pain relief during labour is one of the major concerns in obstetrics; severe labor pain causes fear of the next pregnancy, and interferes with the mother’s family relationship.

Objective

The aim of this study was to evaluate the analgesic effects of Entonox during labor on reducing the need for pethidine (Meperidine) and fetal-maternal complications.

Methods

This double-blind randomized clinical trial was conducted on pregnant women who were candidates for vaginal delivery in Educational Hospitals of Mashhad University of Medical Sciences, Iran between January 2014 and November 2015. After entering into the inactive phase of labor, participants were randomly allocated to receive inhaled Entonox gas (n=200) or inhale Oxygen (n=200) as a control group. Mothers inhaled the gas at commencement of pain, and ceased as soon as the pain diminished, up to the end of the second stage of labor which was the neonate’s birth. Main outcomes were pain score based on NRS (numerical rating scale), duration of delivery, required pethidine, maternal complications and satisfaction during labour. Chi-square and Independent T-test were used via SPSS for data analysis and P-value less than 0.05 was considered statistically significant.

Results

Four-hundred pregnant women with a mean age of 26.4±5.9 years were studied. Complications such as nausea, vomiting, dizziness, and drowsiness were reported in 25% of the Entonox group and 23% in the control group (p=0.640). Mean of pain severity score during labor in the Entonox and control groups was 4.5±1.2 and 5.2±1.4, respectively (p<0.001). Pethidine requirement, significantly was lower in the Entonox group (31.6±11.8 versus 35.7±12.4; p<0.001).

Conclusion

In our study, Entonox significantly reduced pain during delivery without significant increase in maternal and neonatal complications.

Trial registration

The trial is registered at the Iranian Clinical Trial Registry (IRCT.ir) with the IRCT identification number IRCT2015102713159N6.

Funding

This research has been financially supported by Research Council of Mashhad University of Medical Sciences.

Evaluation of Maternal-Neonatal Outcomes in Vaginal Birth After Cesarean Delivery Referred to Maternity of Academic Hospitals

Objective: To evaluate the maternal and neonatal complications of vaginal birth after cesarean section (VBAC). Materials and methods: This cross sectional study was conducted in Mashhad University of medical sciences. Eighty women with previous cesarean section who were candidate for VBAC were enrolled the study. Patients were followed up for 6 weeks after delivery. The complication of VBAC was compared between successful or unsuccessful VBAC cases. Data was analyzed by SPSS version 16. Results: VBAC success rate was 91%. Post-partumhemorrhage occurred in 2.7% of woman with successful VBAC and 1.3% of CS cases. Maternal and neonatal death did not happen during our study, and none of our cases experienced uterine rupture, dystocia and neonatal tachypnea. Neonatal complications include NICU admission and neonatal resuscitation frequency in VBAC and CS were 6.8% and 57.1%, respectively (p = 0.002). Birth weight of neonates in successful VBAC was 2940 ± 768 grams and 3764 ± 254 grams in unsuccessful VBAC and this difference was significant (p = 0.007). Mean maternal admission duration in VBAC and CS were 1 ± 0.1 days and 2 ± 0.4 days (p < 0.001). Successful breastfeeding rate were higher in VBAC patients (95.8%) in comparison with CS (42.9%) and this difference was statistically significant (p = 0.002). Conclusion: Our results revealed that VBAC can be considered as a safe maternal and neonatal delivery method in patients with past CS women.

Evaluation of outcomes associated with trial of labor after cesarean delivery after a change in clinical practice guidelines in an academic hospital

OBJECTIVE

To evaluate maternal-neonatal morbidity for women undergoing trial of labor after cesarean (TOLAC) following clinical practice changes based upon ACOG's 2010 VBAC guideline.

STUDY DESIGN

Four-year retrospective cohort analysis around implementation of a hospital guideline in women undergoing TOLAC with a live, cephalic, singleton without lethal anomaly ≥24 weeks and ≥1 prior cesarean. Maternal-neonatal outcomes pre- and post-guideline implementation were compared. Primary outcome was composite maternal morbidity (uterine rupture or dehiscence, hysterectomy, transfusion, thromboembolism, operative/delivery injury, chorioamnionitis/endometritis, shoulder dystocia, death). Secondary outcomes included neonatal morbidity.

RESULTS

Four hundred and fifty women underwent TOLAC before and 781 after guideline implementation. Post-guideline, there was a significant increase in age, body mass index, labor length, women with >1 cesarean, comorbid condition and induced labor. Composite maternal morbidity was significantly higher after the guideline (13.78% versus 18.82%, p = 0.02), possibly due to an increased rate of chorioamnionitis/endometritis, which was no longer significant after control for potential confounders in multivariable analysis. There were no differences in neonatal outcomes. Vaginal birth after cesarean (VBAC) success rates were unchanged (78.9% before versus 78.1% after, p = 0.75), however hospital VBAC rates increased after the guideline (26% versus 33%, p < 0.0001).

CONCLUSIONS

Adoption of ACOG's TOLAC practice changes can increase VBAC rates without increasing maternal-neonatal morbidity from TOLAC.

Validation of the close-to-delivery prediction model for vaginal birth after cesarean delivery in a Middle Eastern cohort

OBJECTIVE

To validate a prediction model for vaginal birth after cesarean (VBAC) that incorporates variables available at admission for delivery among Middle Eastern women.

METHODS

The present prospective cohort study enrolled women at 37weeks of pregnancy or more with cephalic presentation who were willing to attempt a trial of labor (TOL) after a single prior low transverse cesarean delivery at Al-Jahra Hospital, Kuwait, between June 2013 and June 2014. The predicted success rate of VBAC determined via the close-to-delivery prediction model of Grobman et al. was compared between participants whose TOL was and was not successful.

RESULTS

Among 203 enrolled women, 140 (69.0%) had successful VBAC. The predicted VBAC success rate was higher among women with successful TOL (82.4%±13.1%) than among those with failed TOL (67.7%±18.3%; P<0.001). There was a high positive correlation between actual and predicted success rates. For deciles of predicted success rate increasing from >30%-40% to >90%-100%, the actual success rate was 20%, 30.7%, 38.5%, 59.1%, 71.4%, 76%, and 84.5%, respectively (r=0.98, P=0.013).

CONCLUSION

The close-to-delivery prediction model was found to be applicable to Middle Eastern women and might predict VBAC success rates, thereby decreasing morbidities associated with failed TOL.

Misoprostol for Labour Induction after Previous Caesarean Section - Forever a "No Go"?

Misoprostol in oral or vaginal form is an established method of labour induction worldwide. Its use after previous caesarean section is associated with a high rate of uterine rupture; according to international guidelines it is therefore contraindicated in this setting. However the evidence base for this recommendation comprises case reports, one randomised trial that was discontinued prematurely, and numerous low quality retrospective data analyses published between 1997 and 2004. New insights into e.g. resorption kinetics, dosage and application intervals, dose dependant uterine hyperstimulation rates, as well as increasing clinical experience with misoprostol have lead to a critical reappraisal of these "historical" studies. Accordingly the evidence supporting a ban on vaginal and particularly oral misoprostol for labour induction in the context of a scarred uterus is currently insufficient for a convincing guideline recommendation. In view of the clear advantages of misoprostol over prostaglandin E₂ (cheaper, more effective) a retrospective review of registry data should be conducted to determine the incidence of uterine rupture following misoprostol and the circumstances in which it occurs. A prospective, randomised trial could then be conducted on the basis of these findings (e.g. oral misoprostol vs. vaginal prostaglandin E₂); known risk factors for uterine rupture including the type of uterine scar would need to be taken into account when selecting patients for vaginal delivery. Until new data from well-designed studies are available, misoprostol will continue to be contraindicated in clinical guidelines for use in labour induction after previous caesarean section.

Obstetric outcomes associated with induction of labor after 2 prior cesarean deliveries

OBJECTIVE

We sought to determine whether, in the setting of induction, obstetric outcomes differ based on the number of prior cesarean deliveries (CD) and to determine whether women with 2 cesareans undergoing induction face increased risks of adverse outcomes compared to women undergoing a repeat CD.

STUDY DESIGN

This is a secondary analysis of a 4-year multicenter prospective cohort. Women with 1 or 2 CD were included. Frequencies of vaginal birth after cesarean as well as maternal and neonatal complications were compared among women with 1 CD undergoing induction, women with 2 CD undergoing induction, and women undergoing repeat CD with 2 cesareans.

RESULTS

Of the 10,262 women included in this study, 4100 (40.0%) underwent an induction after 1 CD, 152 (1.5%) underwent an induction after 2 CD, and 6010 (58.6%) had a repeat CD after 2 CD. In women undergoing induction, the chance of vaginal birth after cesarean was no different in women with 2 compared to 1 prior CD (65% vs 69%, P = .28). Similarly, composite maternal (adjusted odds ratio [aOR], 1.2; 95% confidence interval [CI], 0.6-2.3) and neonatal (aOR, 1.1; 95% CI, 0.7-1.7) outcomes were not different between the 2 groups. In women who had 2 prior CD, undergoing an induction carried similar composite adverse maternal and neonatal outcomes compared to having a repeat CD (aOR, 0.7; 95% CI, 0.3-2.0; aOR, 1.1; 95% CI, 0.6-2.2).

CONCLUSION

Labor induction outcomes are similar regardless of whether women have had 1 or 2 CD. After 2 CD, undergoing an induction carries similar maternal and neonatal risks as having a repeat CD.

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.

Does the interval since vaginal delivery influence the chance of vaginal birth after cesarean?

OBJECTIVE

To examine the association between interval since vaginal delivery and vaginal birth after cesarean (VBAC).

METHODS

Women with one prior low transverse cesarean and a prior vaginal delivery undergoing a trial of labor after cesarean at term were included in this cohort study. Multivariable analyses were performed to determine whether length of time since prior vaginal delivery was independently associated with VBAC and, if so, whether its inclusion enhanced the predictive capacity of previously published models.

RESULTS

Of the 5628 women included, 4901 (87%) achieved a VBAC. Each additional year since vaginal delivery decreased the odds of VBAC by 11% (95% CI: 10-13%). When added to an existing predictive model that included only factors available at early prenatal care, interval since vaginal delivery marginally improved the model's predictive ability (area under the curve [AUC] 0.73 versus 0.71, p < 0.01). When added to a model that included factors available proximate to the time of delivery, the addition of interval since vaginal delivery did not change the AUC (0.76 versus 0.75, p = 0.08).

CONCLUSIONS

A longer interval since vaginal delivery is associated with a decreased odd of VBAC. However, the addition of this interval to VBAC prediction models does not substantively improve their predictive ability.

A modified prediction model for VBAC, in a European population

OBJECTIVE

The first aim of the study is to validate the Grobman's Nomogram on Italian population, and then to include other variables with the purpose to increase the accuracy of the Nomogram.

METHODS

This is a multicenter study in which eligible subjects were pregnant women reaching term having one prior cesarean section (CS) and then choosing for a trial of labor. Multivariate logistic regression model have been performed, and then the predicted percentages of vaginal delivery (VD) success were divided into 10 groups and compared with the observed ones.

RESULTS

Among 1161 women, 1100 were enrolled, of which 857 (77.9%) delivered vaginally. At the multivariate logistic regression, the variables predicting vaginal birth after cesarean (VBAC) in the validation were maternal age (p < 0.001), maternal body mass index (p = 0.007), having had a VD (p = 0.008) and recurring indication for CS (p < 0.001). By adding the two new variables in the proposed model, was reached the significance of "African ethnicity" (p = 0.037) and especially "years of education" (p = 0.032).

CONCLUSIONS

The Grobman's Nomogram seems to be applicable to Italian population too, even if with less accuracy than in the US population. The addition of the level of maternal education increases the accuracy of the model, underlining the importance of the social context in the choice of VBAC.

Validation of a prediction model for predicting the probability of morbidity related to a trial of labour in Quebec

BACKGROUND

Pregnant women with a history of previous Caesarean section face the decision either to undergo an elective repeat Caesarean section (ERCS) or to attempt a trial of labour with the goal of achieving a vaginal birth after Caesarean (VBAC). Both choices are associated with their own risks of maternal and neonatal morbidity. We aimed to determine the external validity of a prediction model for the success of trial of labour after Caesarean section (TOLAC) that could help these women in their decision-making.

METHODS

We used a perinatal database including 185,437 deliveries from 32 obstetrical centres in Quebec between 2007 and 2011 and selected women with one previous Caesarean section who were eligible for a TOLAC. We compared the frequency of maternal and neonatal morbidity between women who underwent TOLAC and those who underwent an ERCS according to the probability of success of TOLAC calculated from a published model of prediction.

RESULTS

Of 8508 eligible women, including 3113 who underwent TOLAC, both maternal and neonatal morbidities became less frequent as the predicted chance of VBAC increased (P < 0.05). Women undergoing a TOLAC were more likely to have maternal morbidity than those who underwent an ERCS when the predicted probability of VBAC was less than 60% (relative risk [RR] 2.3; 95% CI 1.4 to 4.0); conversely, maternal morbidity was not different between the two groups when the predicted probability of VBAC was at least 60% (RR 0.8; 95% CI 0.6 to 1.1). Neonatal morbidity was similar between groups when the probability of VBAC success was 70% or greater (RR 1.2; 95% CI 0.9 to 1.5).

CONCLUSION

The use of a prediction model for TOLAC success could be useful in the prediction of TOLAC success and perinatal morbidity in a Canadian population. Neither maternal nor neonatal morbidity are increased with a TOLAC when the probability of VBAC success is at least 70%.