Trial of labor after cesarean delivery: the effect of previous vaginal delivery

Frequency of Maternal Anemia in Patients Presenting With Preterm Premature Rupture of Membranes

BACKGROUND

Preterm premature rupture of membranes (PPROM) is the rupture of fetal membranes before 38 weeks of gestation. The etiology is multifactorial. Maternal anemia is one of the factors leading to PPROM. This study aims to determine the frequency of maternal anemia in patients presenting with PPROM.

MATERIALS AND METHODS

This cross-sectional study was carried out at the Department of Obstetrics and Gynecology, Lady Reading Hospital, Peshawar. This study was conducted from July 1 to December 31, 2021. One hundred and twenty two patients with PPROM presenting to the Department of Obstetrics and Gynecology were included. The diagnosis of PPROM was made based on the history of the PV leak, followed by confirmation with the nitrazine litmus test, microscopic fern test, and ultrasonographic amniotic fluid index measurement. Anemia was determined by examination of hemoglobin levels in the maternal blood samples. Hb <11gm/dl was labeled as anemia. IBM Corp. Released 2011. IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp. was used for statistical analysis.

RESULTS

 The age of the patients ranged from 20 to 40 years. The mean age was 29.14 ± 6.194 years. 63 patients (51.6%) were multiparous (parity 2 to 4). Maternal anemia was observed in 39 patients (32.0%). A significant association (p = 0.005) was observed between maternal anemia and grand multiparity (parity 2 to 4).

CONCLUSION

 Maternal anemia significantly contributes to PPROM, especially in multiple pregnancies. Meticulous family planning and consistent obstetrical monitoring throughout pregnancy are key to addressing this, potentially reducing both maternal anemia risk and PPROM complications.

VBAC calculator 2.0: Recent evidence

Following criticism for the use of race as a biological predictor of vaginal birth after cesarean (VBAC), an updated version of the Society for Maternal-Fetal Medicine (SMFM) VBAC calculator has been published. The variable "African American" or "Hispanic" (yes/no), which produced systematically lower chances of VBAC for nonwhites has been replaced with "chronic hypertension requiring treatment" (yes/no). Although there are no published external validation studies to date, developers report accuracy (area under the curve and calibration) nearly identical to the original calculator and it is published online for immediate use. This review examines the history of the calculator, measures of its validity, and recent studies measuring its performance among Hispanics, Blacks, Asians, and others with lower range scores. Underprediction of successful VBAC is evident in the original calculator, especially as predicted VBAC decreases. These studies raise a concern about the use of calculator scores in clinical management, that is, discouraging or restricting access to labor after cesarean (LAC) for parents with lower calculator scores. This raises special concern for minority populations who experience increased cesarean-related morbidity, face obstacles accessing LAC care, and who may benefit disproportionately from increased LAC uptake. Although calculator developers have discouraged using calculator scores to restrict access to LAC, such uses are documented. It is not clear what effect the removal of race will have on calculator performance, and further study is required before calculator scores are used in counseling. This includes studies that include large numbers of low scoring and minority patients.

Neonatal and maternal outcomes with trial of labor after two prior cesarean births: stratified by history of vaginal birth

INTRODUCTION

To determine the impact of prior vaginal birth on neonatal and maternal outcomes among individuals undergoing a trial of labor after two cesarean births.

MATERIALS AND METHODS

This was a cross-sectional study using the U.S. National Vital Statistics 2014-2018 period linked birth and infant death data. Inclusion criteria were term, cephalic, singleton pregnancies with two prior cesarean births. The primary exposure variable was a trial of labor after cesarean vs prelabor repeat cesarean birth. Cohorts were defined by the presence or absence of a prior vaginal birth. The primary outcome was a composite of adverse neonatal outcomes (Apgar score <5 at 5 min, assisted ventilation >6 h, neonatal seizures, or neonatal death within 27 days). Secondary outcomes included a maternal composite and the cesarean birth rate. Propensity score matching was used to account for baseline differences in treatment allocation within each cohort, and conditional logistic regression assessed the association between the exposure and outcomes.

RESULTS

The composite neonatal adverse outcome was significantly higher in those undergoing a trial of labor after cesarean compared to prelabor repeat cesarean birth in both individuals without a prior vaginal birth (8.2 vs 11.6 per 1000 live births, OR 1.41; 95% CI 1.12-1.70) and with a prior vaginal birth (9.6 vs 12.4 per 1000 live births, OR 1.30; 95% CI 1.08-1.57). The composite maternal adverse outcome was significantly higher among individuals without a prior vaginal birth undergoing trial of labor after cesarean (6.0 vs 9.5 per 1000 live births, OR 1.59; 95% CI 1.26-2.09), but was similar in those with a prior vaginal birth (7.9 vs 9.3 per 1000 live births, OR 1.18; 95% CI 0.97-1.46).

CONCLUSION

In individuals with two prior cesarean births, trial of labor after cesarean was associated with increased neonatal adverse outcomes when compared to prelabor repeat cesarean birth, irrespective of a history of vaginal birth. In individuals with a prior vaginal birth, the composite maternal adverse outcome was not elevated in the trial of labor cohort.

Maternal and Neonatal Outcomes Following Trial of Labor After Two Previous Cesareans: a Retrospective Cohort Study

The objective of this study is to evaluate the maternal and neonatal outcomes of parturients attempting trial of labor (TOL) after two previous CD versus those who had an elective third repeat CD. A retrospective computerized database cohort study was conducted at a single tertiary center between 2005 and 2019. Various maternal and neonatal outcomes were compared between parturients attempting TOL after two CD versus parturients opting for elective third repeat CD. TOL after two CD was allowed only for those who met all the criteria of our departments' protocol. Parturients with identified contraindication to vaginal delivery were excluded from the analysis. A univariate analysis was conducted and was followed by a multivariate analysis. A total of 2719 eligible births following two CD were identified, of which 485 (17.8%) had attempted TOL. Successful vaginal delivery rate following two CDs was 86.2%. Uterine rupture rates were higher among those attempting TOL (0.6% vs 0.1% p = 0.04). However, rates of hysterectomy, re-laparotomy, blood product infusion, and intensive care unit admission did not differ significantly between the groups. Neonatal outcomes following elective repeat CD were less favorable (specifically, neonatal intensive care unit admission and composite adverse neonatal outcome). Nonetheless, when controlling for potential confounders, an independent association between composite adverse neonatal outcome and an elective repeat CD was not demonstrated. In a subgroup analysis, diabetes mellitus and hypertensive disorders of pregnancy were found independently associated with failed TOLAC. When following a strict protocol, TOL after two CD is a reasonable alternative and associated with favorable outcomes.

Predicting vaginal birth after previous cesarean: Using machine-learning models and a population-based cohort in Sweden

Introduction

Predicting a woman’s probability of vaginal birth after cesarean could facilitate the antenatal decision‐making process. Having a previous vaginal birth strongly predicts vaginal birth after cesarean. Delivery outcome in women with only a cesarean delivery is more unpredictable. Therefore, to better predict vaginal birth in women with only one prior cesarean delivery and no vaginal deliveries would greatly benefit clinical practice and fill a key evidence gap in research. Our aim was to predict vaginal birth in women with one prior cesarean and no vaginal deliveries using machine‐learning methods, and compare with a US prediction model and its further developed model for a Swedish setting.

Material and methods

A population‐based cohort study with a cohort of 3116 women with only one prior birth, a cesarean, and a subsequent trial of labor during 2008‐2014 in the Stockholm‐Gotland region, Sweden. Three machine‐learning methods (conditional inference tree, conditional random forest and lasso binary regression) were used to predict vaginal birth after cesarean among women with one previous birth. Performance of the new models was compared with two existing models developed by Grobman et al (USA) and Fagerberg et al (Sweden). Our main outcome measures were area under the receiver‐operating curve (AUROC), overall accuracy, sensitivity and specificity of prediction of vaginal birth after previous cesarean delivery.

Results

The AUROC ranged from 0.61 to 0.69 for all models, sensitivity was above 91% and specificity below 22%. The majority of women with an unplanned repeat cesarean had a predicted probability of vaginal birth after cesarean >60%.

Conclusions

Both classical regression models and machine‐learning models had a high sensitivity in predicting vaginal birth after cesarean in women without a previous vaginal delivery. The majority of women with an unplanned repeat cesarean delivery were predicted to succeed with a vaginal birth (ie specificity was low). Additional covariates combined with machine‐learning techniques did not outperform classical regression models in this study.

The effect of polyhydramnios on the success of trial of labor after cesarean delivery (TOLAC): A retrospective cohort

OBJECTIVE

Prediction of success of trial of labor after cesarean delivery (TOLAC) is of major importance. We investigated the impact of polyhydramnios on the success rate of TOLAC.

STUDY DESIGN

A retrospective cohort study of all women with singleton pregnancies ≥ 34th weeks of gestation who underwent TOLAC after one previous cesarean delivery, between 2011 and 2016 in a single tertiary care center. Polyhydramnios was defined as amniotic fluid index ≥ 240 mm. Primary outcome was defined as the rate of successful TOLAC.

RESULTS

31,245 women gave birth during the study period, of them 1637 (5.3 %) women underwent TOLAC and met inclusion criteria. 39 (2.4 %) women with polyhydramnios were compared to a control group of 1598 (97.6 %) women with amniotic fluid index < 240 mm. Polyhydramnios significantly reduced the rate of successful TOLAC: 69.2 % (27/39) in the study group compared to 85.8 % (1371/1598) in the control group (P = 0.009). In a subgroup analysis based on amniotic fluid index, women with AFI > 270 mm had substantially lower TOLAC success rate [9/19 (47.4 %) vs 18/20 (90 %); P = 0.006]. There was no difference in the rate of uterine rupture between the groups (0/39 (o%) vs 9/1598 (0.56 %); P = 0.64). Logistic regression analysis revealed that polyhydramnios remained significantly associated with higher rates of cesarean delivery [OR 3.09 (95 % CI, 1.37-6.98)] after adjustment for confounding factors.

CONCLUSION

Polyhydramnios was associated with significantly reduced TOLAC success rate with no statistical difference in the rate of uterine rupture. This information should be considered in physician counseling.

Maternal and neonatal outcomes associated with induction of labor after one previous cesarean delivery: A French retrospective study

Background

The safety of methods of labor induction in women with previous cesarean deliveries is still debated. We investigated perinatal outcomes associated with labor induction among women with a trial of labor after one cesarean delivery.

Methods

This retrospective study included 339 women with a trial of labor after one prior cesarean and a singleton term fetus in cephalic presentation in 2013–2016 in a French maternity unit. Labor induction was performed with oxytocin, artificial rupture of membranes and/or prostaglandin E2, according to the Bishop score. The primary outcome was a composite of uterine rupture, low Apgar score, neonatal resuscitation or admission to a neonatal unit. The secondary outcomes included cesarean delivery after onset of labor, postpartum hemorrhage and maternal hospital stay after delivery. We used logistic regression to estimate odds ratios adjusted (aOR) for potential confounders.

Results

In our sample, 67.3% of women had spontaneous labor and 32.7% were induced. More than half of the women received oxytocin during labor regardless of the mode of labor. The proportions of the composite outcome and of cesarean after onset of labor were higher in the induced group compared to the spontaneous group (26.1% vs 15.8%, p = 0.02 and 45.0% vs 27.6%, p<0.01, respectively). There were 9 uterine ruptures (2.6%) and this proportion was higher in the induced group compared to the spontaneous group, although this difference was not statistically significant (3.6% vs 2.2%, p = 0.48). After adjustment, labor induction was associated with higher risks of the composite outcome (aOR = 2.45, 95% CI: 1.29–4.65), cesarean after onset of labor (aOR = 2.06, 95% CI: 1.15–3.68) and maternal hospital stay after delivery ≥6 days (aOR = 6.20, 95% CI: 3.25–11.81). No association was found with postpartum hemorrhage.

Conclusion

Labor induction after one prior cesarean was associated with a higher risk of adverse perinatal outcome. Nevertheless, the higher proportion of uterine rupture did not differ significantly from that in the spontaneous labor group.

Is Early Amniotomy Associated with Higher Likelihood of Vaginal Birth after Cesarean?

Objective  The study aims to reduce cesarean rates, eligible women are being offered an option of vaginal birth after cesarean (VBAC). However, little data exist regarding efficacy of amniotomy as a tool in this population. We sought to evaluate the impact of early amniotomy on VBAC success. Study Design  This is a secondary analysis case-control study using the MFMU (Maternal-Fetal Medicine Units Network) Cesarean Registry. Women were included if they had a singleton pregnancy, were attempting VBAC, and underwent induction with artificial rupture of membranes. Cases were defined as subjects with successful VBAC; controls were defined as subjects with failed trial of labor after cesarean (TOLAC). Early amniotomy was defined as amniotomy at <4 cm. Demographic and obstetric characteristics were compared and multivariate logistic regression was performed. Results  A total of 1,490 women were included. Early amniotomy occurred in 59.5% with VBAC versus 63.2% with failed TOLAC ( p  = 0.24). After controlling for body mass index, prior vaginal delivery, African-American race, labor length, gestational age, birthweight, epidural use, Foley catheter balloon ripening, induction method and oxytocin use, early amniotomy was associated with a 34% decrease in VBAC success ( p  < 0.01). Women who had early amniotomy did not have higher rates of chorioamnionitis (2.8 vs. 2.9%, p  > 0.99). Conclusion  Unlike data from nulliparous women, our data suggest that induction with early amniotomy does not increase the likelihood of VBAC.

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.

Factors associated with successful vaginal birth after a cesarean section: a systematic review and meta-analysis

Background

Evidence for the relationship between maternal and perinatal factors and the success of vaginal birth after cesarean section (VBAC) is conflicting. We aimed to systematically analyze published data on maternal and fetal factors for successful VBAC.

Methods

A comprehensive search of Medline, Embase, and the Cumulative Index to Nursing and Allied Health Literature, from each database’s inception to March 16, 2018. Observational studies, identifying women with a trial of labor after one previous low-transverse cesarean section were included. Two reviewers independently abstracted the data. Meta-analysis was performed using the random-effects model. Risk of bias was assessed by the Newcastle-Ottawa Scale.

Results

We included 94 eligible observational studies (239,006 pregnant women with 163,502 VBAC). Factors were associated with successful VBAC with the following odds ratios (OR;95%CI): age (0.92;0.86–0.98), obesity (0.50;0.39–0.64), diabetes (0.50;0.42–0.60), hypertensive disorders complicating pregnancy (HDCP) (0.54;0.44–0.67), Bishop score (3.77;2.17–6.53), labor induction (0.58;0.50–0.67), macrosomia (0.56;0.50–0.64), white race (1.39;1.26–1.54), previous vaginal birth before cesarean section (3.14;2.62–3.77), previous VBAC (4.71;4.33–5.12), the indications for the previous cesarean section (cephalopelvic disproportion (0.54;0.36–0.80), dystocia or failure to progress (0.54;0.41–0.70), failed induction (0.56;0.37–0.85), and fetal malpresentation (1.66;1.38–2.01)). Adjusted ORs were similar.

Conclusions

Diabetes, HDCP, Bishop score, labor induction, macrosomia, age, obesity, previous vaginal birth, and the indications for the previous CS should be considered as the factors affecting the success of VBAC.

Practice Bulletin No. 184: 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 (1-3). 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 (4-6). 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.

Association between prior vaginal birth after cesarean and subsequent labor outcome

OBJECTIVE

To estimate the effect of prior successful vaginal birth after cesarean (VBAC) on the rate of uterine rupture and delivery outcome in women undergoing labor after cesarean.

METHODS

A retrospective cohort study of all women attempting labor after cesarean delivery in a university-affiliated tertiary-hospital (2007-2014) was conducted. Study group included women attempting vaginal delivery with a history of cesarean delivery and at least one prior VBAC. Control group included women attempting first vaginal delivery following cesarean delivery. Primary outcome was defined as the rate of uterine rupture. Secondary outcomes were delivery and maternal outcomes.

RESULTS

Of 62,463 deliveries during the study period, 3256 met inclusion criteria. One thousand two hundred and eleven women had VBAC prior to the index labor and 2045 underwent their first labor after cesarean. Women in the study group had a significantly lower rate of uterine rupture 9 (0.7%) in respect to control 33 (1.6%), p = .036, and had a higher rate of successful vaginal birth (96 vs. 84.9%, p < .001). In multivariate analysis, previous VBAC was associated with decreased risk of uterine rupture (OR = 0.46, 95% CI 0.21-0.97, p = .04).

CONCLUSIONS

In women attempting labor after cesarean, prior VBAC appears to be associated with lower rate of uterine rupture and higher rate of successful vaginal birth.

Elective repeat cesarean delivery compared with trial of labor after a prior cesarean delivery: a propensity score analysis

OBJECTIVE

To determine neonatal and short term maternal outcomes according to intentional mode of delivery following a cesarean delivery (CD).

STUDY DESIGN

Women pregnant after CD between January 2000 and December 2007 were categorized according to whether they had an elective repeat CD (ERCD) or a Trial of Labor (TOL). Prognostically equal ERCD and TOL groups were created using the propensity score matching technique. Conditional logistic regression was performed to assess differences in neonatal and maternal outcomes.

POPULATION

Women in their second ongoing pregnancy with a history of CD.

RESULTS

After ERCD the rates of low 5min Apgar score (OR 0.3, 95%CI 0.2-0.5, p<0.001), meconium aspiration (OR 0.0, 95%CI 0-0.7, p=0.02) and birth trauma (OR 0.08, 95%CI 0.002-0.5, p<0.001) were lower compared to TOL. The rate of transient tachypnoea of the newborn (TTN) appears higher in the ERCD group (OR 1.7, 95%CI 1.0-2.8, p=0.04). Uterine rupture (OR 0.1, 95%CI 0.003-0.8, p=0.02) and hemorrhage (OR 0.6, 95%CI 0.5-0.8, p<0.001) occurred less in the ERCD group.

CONCLUSION

Neonatal and short term maternal morbidity appears to be lower after ERCD than after TOL. Only TTN was seen more often after ERCD.

Factors associated with successful vaginal birth after cesarean section and outcomes in rural area of Anatolia

Successful vaginal birth after cesarean section is more comfortable than repeat emergency or elective cesarean section. Antenatal examinations are important in selection for trial of labor, while birth management can be difficult when the patients present at emergency condition. But there is an increased chance of vaginal birth with advanced cervical dilation. This study attempts to evaluate factors associated with success of vaginal birth after cesarean section and to compare the maternal and perinatal outcomes between vaginal birth after cesarean section and intrapartum cesarean section in patients who were admitted to hospital during the active or second stage of labor. A retrospective evaluation was made from the results of 127 patients. Cesarean section was performed in 57 patients; 70 attempted trial of labor. The factors associated with success of vaginal birth after cesarean section were investigated. Maternal and neonatal outcomes were compared between the groups. Vaginal birth after cesarean section was successful in 55% of cases. Advanced cervical opening, effacement, gravidity, parity, and prior vaginal delivery were factors associated with successful vaginal birth. The vaginal birth group had more complications (P<0.01), but these were minor. The rate of blood transfusion and prevalence of changes in hemoglobin level were similar in both groups (P>0.05). In this study, cervical opening, effacement, gravidity, parity, and prior vaginal delivery were important factors for successful vaginal birth after cesarean section. The patients' requests influenced outcome. Trial of labor should take into consideration the patient's preference, together with the proper setting.

Pregnancy outcome in women with previous one cesarean section

OBJECTIVE

The purpose of this study was to determine the outcome of pregnancy in women with previous one cesarean section in relation to vaginal delivery and maternal and perinatal complications. It also aimed at identifying the factors, which can influence the outcome of trial of scar (TOS).

MATERIALS AND METHODS

A retrospective analysis of medical records of 151 women with previous one cesarean section who delivered at the Mafraq Hospital, Abu Dhabi between January-August 2011was carried out. Those women with previous classical cesarean section and those with extreme prematurity were excluded. The collected data were analyzed using SPSS software version 20. Continuous and categorical data were presented in the form of mean, standard deviation and percentage, while proportions were analyzed using the chi-square test. A p-value ≤0.05 was considered statistically significant.

RESULTS

Of the 151 women, 115 were candidates for TOS. Of them, 96 (83.47%) had vaginal birth after cesarean (VBAC) and 19 (16.5%) had a repeat cesarean section. There were four cases of primary postpartum hemorrhage (PPH) and two cases of scar dehiscence in the study group. No significant perinatal morbidity was observed. VBAC rate was significantly more in women who had prior vaginal deliveries, especially in those with previous VBAC.

CONCLUSION

In carefully selected cases, trial of labour (TOL) after a prior cesarean is safe and often successful. A prior vaginal delivery, particularly, a prior VBAC are associated with a higher rate of successful TOL.

Vaginal birth after cesarean and trial of labor after cesarean: what should we be recommending relative to maternal risk:benefit?

Trial of labor after cesarean (TOLAC) delivery is currently a hot obstetrical topic owing to the acute rise in the rate of cesarean deliveries, both primary and repeat. When the physician and patient are considering TOLAC, several factors should be considered: risk of uterine rupture, contraindications, minimizing risk and morbidity, choosing the appropriate candidate and whether or not to induce. Each patient has her own set of individual risk factors that may decrease her chance of successful vaginal birth after cesarean delivery or increase her risks with TOLAC. Once all things are considered, the risk:benefit of TOLAC should be weighed up before a decision is reached. Each of these factors is discussed in respect to maternal risk:benefit, with the focus on evidence presented in the current literature.

[Management of pregnancies with a previous cesarean]

The cesarean rate in France has reached 21% in 2010. With a maintained fertility rate, management of a pregnant woman with a previous caesarean scar is becoming a daily situation for most obstetrical teams. Considering the small rate of vaginal birth after cesarean (VBAC), we will try to establish an up-to-date review of the benefits and risks of encouraging trial of VBAC. This information can help professionals provide adequate counselling women or couples.

New insights on vaginal birth after cesarean: can it be predicted?

OBJECTIVE

To evaluate existing vaginal birth after cesarean (VBAC) screening tools and to identify additional factors that may predict VBAC or failed trial of labor.

DATA SOURCES

Relevant studies were identified through MEDLINE, Database of Abstracts of Reviews of Effectiveness, and the Cochrane databases (1980-September 2009), and from recent systematic reviews, reference lists, reviews, editorials, web sites, and experts.

METHODS OF STUDY SELECTION

Inclusion criteria limited studies to those of humans, written in English, studies conducted in the United States and developed countries, and those rated good or fair quality by the U.S. Preventive Services Task Force criteria. Studies of individual predictors were combined using a random effects model when the estimated odds ratios were comparable across included studies.

TABULATION, INTEGRATION, AND RESULTS

We identified 3,134 citations and reviewed 963 papers, of which 203 met inclusion criteria and were quality-rated. Twenty-eight provided evidence on predictors of VBAC and 16 presented information on scored models for predicting VBAC (or failed trial of labor). Six of the 11 scored models for predicting VBAC (or failed trial of labor) were validated by separated dataset, cross-validation, or both. Whereas accuracy remained high across all models for predicting VBAC, with predictive values ranging from 88% to 95%, accuracy for predicting failed trial of labor was low, ranging from 33% to 58%. Individual predictors including Hispanic ethnicity, African-American race, advanced maternal age, no previous vaginal birth history, birth weight heavier than 4 kg, and use of either augmentation or induction were all associated with reduced likelihood of VBAC.

CONCLUSION

Current scored models provide reasonable predictability for VBAC, but none provides consistent ability to identify women at risk for failed trial of labor. A scoring model is needed that incorporates known antepartum factors and can be adjusted for current obstetric factors and labor patterns if induction or augmentation is needed. This would allow women and clinicians to better determine individuals most likely to require repeat cesarean delivery.

Birth after previous cesarean delivery: short-term maternal outcomes

An estimated 40% of the 1.3 million cesarean deliveries performed each year in the United States are repeat procedures. The appropriate clinical management approach for women with previous cesarean delivery remains challenging because options are limited. The risks and benefits of clinical management choices in the woman's health need to be quantified. Thus, we discuss the available published scientific data on (1) the short-term maternal outcomes of trial of labor after cesarean and elective repeat cesarean delivery, (2) the differences between outcomes for both, (3) the important factors that influence these outcomes, and (4) successful vs. unsuccessful vaginal birth after cesarean. For women with a previous cesarean delivery, a successful trial of labor offers several distinct, consistently reproducible advantages compared with elective repeat cesarean delivery, including fewer hysterectomies, fewer thromboembolic events, lower blood transfusion rates, and shorter hospital stay. However, when trial of labor after cesarean fails, emergency cesarean is associated with increased uterine rupture, hysterectomy, operative injury, blood transfusion, endometritis, and longer hospital stay. Care of women with a history of previous cesarean delivery involves a confluence of interactions between medical and nonmedical factors; however, the most important determinants of the short-term outcomes among these women are likely individualized counseling, accurate clinical diagnoses, and careful management during a trial of labor. We recommend a randomized controlled trial among women undergoing a TOLAC and a longitudinal cohort study among women with previous cesarean to evaluate adverse outcomes, with focused attention on both mother and the infant.

Rates and prediction of successful vaginal birth after cesarean

There have been multiple observational studies that have assessed the probability that a woman who undertakes a trial of labor after a previous cesarean delivery will have a vaginal birth. These studies have demonstrated a population-level probability of a successful vaginal birth after cesarean (VBAC) that ranges between 60% and 80%. However, within a population the chances for success of a given individual may vary to a significant degree on the basis of particular demographic characteristics and obstetric history. This review summarizes the different characteristics that have been prominently associated with successful VBAC as well as the different attempts that have been made to develop accurate prediction models for successful VBAC.

Trial of labor after one cesarean: role of the order and number of prior vaginal births on the risk of emergency cesarean delivery and neonatal admission

OBJECTIVE

To evaluate the influences of mode of immediate preceding delivery and number of prior vaginal births on the risk of repeat cesarean and neonatal admission at attempted vaginal birth after cesarean.

MATERIALS AND METHODS

We performed a retrospective study of the risk factors for emergency repeat cesarean delivery and neonatal admission in a trial of labor after prior cesarean section. The study comprised 342 women at term with at least one prior vaginal delivery in addition to one previous lower transverse cesarean. Clinical variables with crude p < 0.2 on Fisher's exact test for the defined primary outcomes of repeat cesarean and neonatal admission were included in the model for multivariable logistic regression analysis.

RESULTS

Cesarean as the immediate preceding mode of delivery (adjusted odds ratio, 5.3; 95% confidence interval, 2.5-10.8) was an independent predictor of emergency repeat cesarean delivery but not of neonatal admission. Higher parity of two or more previous vaginal deliveries compared with only one prior vaginal delivery was not associated with repeat cesarean or neonatal admission.

CONCLUSION

In women who have had prior vaginal birth attempting a trial of labor after cesarean, a vaginal delivery before cesarean delivery is an independent risk factor for repeat cesarean. Women with two or more prior vaginal births have a similar risk for repeat cesarean and neonatal admission to women with only one prior vaginal birth.

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

OBJECTIVE

The objective of the study was to determine whether a model for predicting vaginal birth after cesarean (VBAC) can also predict the probabilty of morbidity associated with a trial of labor (TOL).

STUDY DESIGN

Using a previously published prediction model, we categorized women with 1 prior cesarean by chance of VBAC. Prevalence of maternal and neonatal morbidity was stratfied by probability of VBAC success and delivery approach.

RESULTS

Morbidity became less frequent as the predicted chance of VBAC increased among women who underwent TOL (P < .001) but not elective repeat cesarean section (ERCS) (P > .05). When the predicted chance of VBAC was less than 70%, women undergoing a TOL were more likely to have maternal morbidity (relative risk [RR], 2.2; 95% confidence interval [CI], 1.5-3.1) than those who underwent an ERCS; when the predicted chance of VBAC was at least 70%, total maternal morbidity was not different between the 2 groups (RR, 0.8; 95% CI, 0.5-1.2). The results were similar for neonatal morbidity.

CONCLUSION

A prediction model for VBAC provides information regarding the chance of TOL-related morbidity and suggests that maternal morbidity is not greater for those women who undergo TOL than those who undergo ERCS if the chance of VBAC is at least 70%.

Vaginal birth after cesarean delivery

By 2004, only 9.2% of women in the United States with prior cesareans underwent a term of labor (TOL), although nearly two thirds of these women are actually candidates for a TOL. In this article, the author notes that the principal risk associated with vaginal birth after cesarean delivery (VBAC)-TOL is uterine rupture, which can lead to perinatal death, fetal hypoxic brain injury, and hysterectomy. Risk factors for uterine rupture include number of prior cesareans, prior vaginal delivery, interdelivery interval, and uterine closure technique. The author concludes by noting that a pregnant woman with prior cesarean delivery is at risk for maternal and perinatal complications, whether undergoing TOL or choosing elective repeat operation. Complications of both procedures should be discussed and an attempt made to individualize the risk for uterine rupture and the likelihood of successful VBAC.

Prior Cesarean: A Contraindication to Labor Induction?

In 2004, cesarean rates were the highest ever in the United States. Simultaneously, the vaginal birth after cesarean (VBAC) rate fell, largely a result of reports of uterine rupture associated with VBAC attempts. This chapter reviews the efficacy and safety of VBAC associated with labor induction. Mechanical and pharmacologic methods of labor induction (notably misoprostol) are associated with increased maternal and perinatal morbidity compared with spontaneous VBAC attempts. However, the absolute risks remain low. Labor induction is not contraindicated in women with a prior cesarean but sound judgment, clinical precautions and specific consent are required.

Essai de travail en cas de césarienne antérieure

OBJECTIVE

The aim of this review was to relate the evolution of obstetrical management of delivery in women who had previously undergone cesarean delivery and to search the studies supporting the choice of the mode of delivery.

MATERIAL AND METHOD

We identified relevant studies through a computer search in the Medline database.

RESULTS

After a period from 1980 to 2000 when the vaginal delivery had been increasingly recommended, a growth in the use of the planned cesarean delivery was observed. Recent studies report more evidence that uterine rupture is the result of trial of labor and that adverse perinatal outcomes are associated with uterine rupture. The risk of uterine rupture is increased with labor induction. The use of prostaglandins appears to be implicated in a significant increase of uterine rupture, and subsequently might be contraindicated in this situation. The use of oxytocin induced labor appears to increase the risk of uterine rupture. However, the level of adverse perinatal outcomes is low. The choice of the mode of delivery should take into account the likelihood of a further pregnancy, due to the increased risk of placental pathologic conditions depending on the number of repeated cesarean sections.

CONCLUSION

An optimal decision for the mode of delivery should be shared with the pregnant women and all these factors should be taken into consideration.

General obstetrics: Vaginal birth after caesarean section versus elective repeat caesarean section: assessment of maternal downstream health outcomes

OBJECTIVE

To compare the maternal implications of strategies of vaginal birth after caesarean section (VBAC) attempt versus elective repeat caesarean section in women with one previous lower segment caesarean section.

DESIGN

Decision model.

POPULATION

Women with one prior low transverse caesarean section who are eligible for trial of labour.

METHODS

Two decision models were built: the first one applying to women planning only one more pregnancy, the second one applying to women planning two more pregnancies. Probability estimates for VBAC success rate and risks of uterine rupture, placenta praevia, placenta accreta and hysterectomy were extracted from the available literature.

MAIN OUTCOME MEASURES

Hysterectomy for uterine rupture, placenta accreta or other indications.

RESULTS

In the first model VBAC attempt led to a higher hysterectomy rate (267/100,000) compared with repeat caesarean section (187/100,000). However, in the second model a policy of elective repeat caesarean section led to higher cumulative hysterectomy rate: 1465/100,000 versus 907/100,000 for VBAC. The first model was robust to all but one variable in sensitivity analyses. The second model was robust to all variables in sensitivity analyses.

CONCLUSIONS

These results indicate that long term reproductive consequences of multiple caesarean sections should be considered when making policy decisions regarding the risk-benefit ratio of VBAC.

Comment informer sur la voie d'accouchement une patiente ayant un antécédent de césarienne ?

A trial of labor after prior cesarean delivery is associated with a greater perinatal risk than is elective repeated cesarean delivery without labor, although absolute risks are low. Information and counselling aim to estimate specific risks and to balance these risks according to individual factors. Therefore, the physician has to answer two questions: (i) which would be the probability of successful vaginal delivery? (ii) which would be the risk of uterine rupture with a trial of labor? The risk factors for failure of trial of labor are: increased maternal age, obesity, and fetal macrosomia. The risk factors for uterine rupture are: increased maternal age, postpartum fever after the previous cesarean delivery, short interdelivery interval, history of at least two previous cesarean deliveries, and a history of classical incision. Conversely, other factors are of good prognosis: a prior vaginal delivery and, particularly, a prior VBAC (Vaginal Birth After Caesarean) are associated with a higher rate of successful trial of labor compared with patients with no prior vaginal delivery; ultrasonographic measurement of the lower uterine segment thickness>3.5 mm has an excellent negative predictive value for the risk of uterine defect. Finally, the wish for additional pregnancies following a cesarean section must be considered as an argument in favour of a trial of labor after accounting for the increasing risks correlated with repeated elective cesarean deliveries.

Maternal complications with vaginal birth after cesarean delivery: a multicenter study

OBJECTIVE

This study was undertaken to determine incidence and risk factors for uterine rupture in women attempting vaginal birth after cesarean delivery (VBAC) in a wide range of hospital settings.

STUDY DESIGN

We performed a case-control study nested within a cohort of women who have had a prior cesarean to determine the incidence and risk factors for uterine rupture in women attempting VBAC.

RESULTS

The incidence rate of uterine rupture in those who attempt VBAC was 9.8 per 1000. A prior vaginal delivery was associated with a lower risk of uterine rupture (adjusted odds ratio [OR] = 0.40, 95% CI 0.20-0.81). Although prostaglandins alone were not associated with uterine rupture, sequential use of prostaglandin and pitocin was associated with uterine rupture (adjusted OR = 3.07, 95% CI 0.98-9.88).

CONCLUSION

Women with a prior cesarean should be offered VBAC, and women with a prior cesarean and prior vaginal delivery should be encouraged to VBAC. Although other studies have suggested that prostaglandins should be avoided, we suggest that inductions requiring sequential agents be avoided.

Effect of Prior Vaginal Delivery or Prior Vaginal Birth After Cesarean Delivery on Obstetric Outcomes in Women Undergoing Trial of Labor

OBJECTIVE

We sought to study the effects of prior vaginal delivery or prior vaginal birth after cesarean delivery (VBAC) on the success of a trial of labor after a cesarean delivery.

METHODS

An observational study of patients who underwent a trial of labor after a single low-transverse cesarean delivery. Patients with a previous cesarean delivery and no vaginal birth were compared with patients with a single vaginal delivery before or after the previous cesarean delivery. The rates of successful VBAC, uterine rupture, and scar dehiscence were analyzed. Multivariable regression was performed to adjust for confounding variables.

RESULTS

Of 2,204 patients, 1,685 (76.4%) had a previous cesarean delivery and no vaginal delivery, 198 (9.0%) had a vaginal delivery before the cesarean delivery, and 321 (14.6%) had a prior VBAC. The rate of successful trial of labor was 70.1%, 81.8%, and 93.1%, respectively (P <.001). A prior VBAC was associated with fewer third- and fourth-degree lacerations (8.5% versus 2.5% versus 3.7%, P <.001) and fewer operative vaginal deliveries (14.7% versus 5.6% versus 1.9%, P <.001) but not with uterine rupture (1.5% versus 0.5% versus 0.3%, P =.12). Patients with a prior VBAC had, in addition, a higher rate of uterine scar dehiscence (21.8%) compared with patients with a previous cesarean delivery and no vaginal delivery (5.3%; P =.001).

CONCLUSION

A prior vaginal delivery and, particularly, a prior VBAC are associated with a higher rate of successful trial of labor compared with patients with no prior vaginal delivery. In addition, prior VBAC is associated with an increased rate of uterine scar dehiscence.

Predicting vaginal birth after cesarean delivery: a review of prognostic factors and screening tools

OBJECTIVE

Our purpose was to identify the factors associated with vaginal delivery after trial of labor in patients with a prior cesarean and to evaluate the effectiveness of existing screening tools.

STUDY DESIGN

Studies were identified through MEDLINE and HealthSTAR (1980-2002), reference list reviews, and suggestions of national experts.

RESULTS

Thirteen of the 100 eligible studies provided fair to good quality evidence for the predictive nature of 12 factors. Two of the six screening tools were considered promising and demonstrated reproducibility through validation studies.

CONCLUSIONS

There is little high-quality data to guide clinical decisions regarding which women are likely to have a successful trial of labor. Although we identified two validated screening tools that may be reasonable for practitioners to use, further development is needed to deliver them in a user-friendly manner and further research is needed to determine the clinical setting in which they are most useful. Conducting high-quality research on the factors that delineate women who are at higher likelihood of vaginal delivery without complications and developing accurate user-friendly screening tools to integrate these data should be a national research priority.

Vaginal birth after Caesarean section: review of antenatal predictors of success

OBJECTIVE

To determine antenatal factors that may predict successful vaginal birth after Caesarean (VBAC).

DATA SOURCES

The MEDLINE database was searched for all English-language articles describing the impact of various factors on outcomes when VBAC is attempted. Articles reviewed included published abstracts, retrospective and prospective studies, and meta-analyses. CRITERIA FOR STUDY SELECTION: Studies were included if they reported both a control group of pregnant women without the factor under evaluation and a study group with this factor, both undergoing a trial of labour (TOL). Other criteria included accountability for all individuals enrolled at study outset, and vaginal delivery rates in both study and control groups stated or easily calculated.

RESULTS

A nonrecurrent indication for previous Caesarean section (CS), such as breech presentation or fetal distress, is associated with a much higher successful VBAC rate than recurrent indications, such as cephalopelvic disproportion (CPD). Even with a history of CPD, two-thirds of women will have successful VBAC, though rates decrease with increasing numbers of prior CS. Prior vaginal deliveries are excellent prognostic indicators of successful VBAC, especially if the vaginal delivery follows the prior CS. A low vertical uterine incision does not seem to adversely affect VBAC success rates as compared to a low transverse incision. Maternal obesity and diabetes mellitus adversely affect VBAC outcomes. Fetal macrosomia does not appear to be a contraindication to VBAC, as success rates exceeding 50% are achieved and uterine rupture rates are not increased. Twin gestation does not preclude VBAC. Post-dates pregnancies may deliver successfully by VBAC in greater than two-thirds of cases.

CONCLUSION

There are few absolute contraindications to attempted VBAC. Attempted VBAC will be successful in the majority of attempted cases.

The effect of birth weight on vaginal birth after cesarean delivery success rates

OBJECTIVE

The purpose of this study was to evaluate the effect of increasing birth weight on the success rates for a trial of labor in women with one previous cesarean delivery.

STUDY DESIGN

To evaluate the effect of increasing birth weight for women who undergo a trial of labor, the medical records of women who had attempted a vaginal birth after cesarean delivery (VBAC) from 1995 through 1999 in 16 community and university hospitals were reviewed retrospectively by trained abstractors. Information was collected about demographics, medical history, obstetric history, neonatal birth weight, complications, treatment, and outcome of the index pregnancy. The analysis was limited to women with singleton gestations with a history of 1 previous cesarean delivery. Because women with previous vaginal deliveries have higher vaginal birth after cesarean delivery success rates, the women were divided into four risk groups on the basis of their birth history. Groups were defined as women with no previous vaginal deliveries (group 1), women with a history of a previous vaginal birth after cesarean delivery (group 2), women with a history of a vaginal delivery before their cesarean delivery (group 3), and a group of women with a vaginal delivery both before and after the previous cesarean delivery (group 4).

RESULTS

There were 9960 women with a singleton gestation and a history of one previous cesarean delivery. The overall vaginal birth after cesarean delivery success rate for the cohort was 74%. The overall vaginal birth after cesarean delivery success rates for groups 1, 2, 3, and 4 were 65%, 94%, 83%, and 93%, respectively. An analysis of neonatal birth weights of <4000 g, 4000 to 4249 g, 4250 to 4500 g, and >4500 g in group 1 showed a reduction in vaginal birth after cesarean delivery success rates from 68%, 52%, 45%, and 38%, respectively. In the remaining groups, there was no success rate below 63% for any of the birth weight strata. For group 1, vaginal birth after cesarean delivery success rates were decreased when the indication for the previous cesarean delivery was cephalopelvic disproportion or failure to progress or when the treatment was either an induction or augmentation of labor. The uterine rupture rate was higher in women for group 1 with birth weights of > or =4000 g (relative risk, 2.3; P <.001).

CONCLUSION

Women with macrosomic fetuses and a history of a previous vaginal delivery should be informed of the favorable vaginal birth after cesarean delivery success rates. Given the risks of vaginal birth after cesarean delivery, those women with no history of a vaginal delivery should be counseled that the success rates may be <50% when the neonatal birth weight exceeds 4000 g and that the success rates may be even lower if the indication for the previous cesarean delivery was cephalopelvic disproportion or failure to progress or if the treatment requires either induction or augmentation of labor. The uterine rupture rate was 3.6% in women for group 1 with a birth weight > or =4000 g.

Outcomes of trial of labor following previous cesarean delivery among women with fetuses weighing >4000 g

OBJECTIVE

To compare outcomes at term of a trial of labor in women with previous cesarean delivery who delivered neonates weighing > 4000 g versus women with those weighing < or = 4000 g.

STUDY DESIGN

We reviewed medical records for all women undergoing a trial of labor after prior cesarean delivery during a 12-year period. The current analysis was limited to women at term with one prior cesarean and no other deliveries. The rates of cesarean delivery and symptomatic uterine rupture for women with infants weighing > 4000 g were compared to the rates for women with infants weighing < or = 4000 g. Logistic regression was used to control for the potential confounding by use of epidural, maternal age, labor induction, labor augmentation, indication for previous cesarean, type of uterine hysterotomy, year of delivery, receiving public assistance, and maternal race. Adjusted odds ratios and 95% confidence intervals were calculated.

RESULTS

Of 2749 women, 13% (365) had infants with birth weights > 4000 g. Cesarean delivery rate associated with birth weights < or = 4000 g was 29% versus 40% for those with birth weights > 4000 g (P = .001). With use of logistic regression, we found that birth weight > 4000 g was associated with a 1.7-fold increase in risk of cesarean delivery (95% CI, 1.3-2.2). The rate of uterine rupture for women with infants weighing < or = 4000 g was 1.0% versus a 1.6% rate for those with infants weighing > 4000 g (P = .24). Although the logistic regression analysis revealed a somewhat higher rate of uterine rupture associated with birth weights of > 4000 g (adjusted OR, 1.6; 95% CI, 0.7-4.1), this difference was not statistically significant. The rate of uterine rupture was 2.4% for women with infants weighing > 4250 g, but this rate did not differ significantly from the rate of uterine rupture associated with birth weights < or = 4250 g (P = .1).

CONCLUSION

A trial of labor after previous cesarean delivery may be a reasonable clinical option for pregnant women with suspected birth weights of > 4000 g, given that the rate of uterine rupture associated with these weights does not appear to be substantially increased when compared to lower birth weights. However, some caution may apply when considering a trial of labor in women with infants weighing > 4250 g. In these women with infants weighing > 4000 g, the likelihood of successful vaginal delivery, although lower than for neonates weighing < or = 4000 g, is still 60%.