Safety of vaginal birth after cesarean delivery.

OBJECTIVE: To compare the outcomes of labor induction in women with a history of 1 cesarean section (CS) who undergo trial of labor. METHODS: A prospective observational study of 702 pregnant women who had 1 previous CS was conducted at Women's Hospital, Hamad Medical Corporation, Doha, Qatar, between April 2003 and April 2004. Those with no history of vaginal delivery were assigned to one group and those with a history of vaginal delivery were assigned to another group, and the latter group was then divided into 2 subgroups according to the results of trial of labor. RESULTS: Of these 702 women with a history of 1 CS, 62.4% also had a history of vaginal delivery. After trial of labor, vaginal delivery occurred more often among women with no history of vaginal delivery (64.8%). Moreover, trial of labor resulted in a vaginal delivery more often in women who were delivered only once and by CS (87.7%) than in women who also had a history of vaginal delivery (79.2%). CONCLUSION: These findings indicate that women who have had a CS should strongly consider natural delivery for subsequent pregnancies.     

Ethnic disparity in the success of vaginal birth after cesarean delivery

Objective.?To estimate whether maternal race/ethnicity is independently associated with successful vaginal birth after cesarean delivery (VBAC).

Study design.?A retrospective cohort study from January 1, 1997 to July 30, 2002 of women with singleton pregnancies and a previous cesarean delivery. The odds ratio (OR) for successful VBAC as a function of ethnicity was corrected for age >35 years, parity, weight gain, diabetes mellitus, hospital site, prenatal care provider, gestational age, induction, labor augmentation, epidural analgesia, and birth weight >4000 g.

Results.?Among 54 146 births, 8030 (14.8%) occurred in women with previous cesarean deliveries. The trials of labor rates were similar among Caucasian (46.6%), Hispanic (45.4%), and African American (46.0%) women. However, there was a significant difference among ethnic groups for VBAC success rates (79.3% vs. 79.3% vs. 70.0%, respectively). When compared to Caucasian women, the adjusted OR for VBAC success was 0.37 (95% confidence interval (CI) 0.27–0.50) for African American women and 0.63 (95% CI 0.51–0.79) for Hispanic women.

Conclusion.?African American and Hispanic women are significantly less likely than Caucasian women to achieve successful VBAC.     

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.     

Ethnic disparity in the success of vaginal birth after cesarean delivery.

OBJECTIVE: To estimate whether maternal race/ethnicity is independently associated with successful vaginal birth after cesarean delivery (VBAC). STUDY DESIGN: A retrospective cohort study from January 1, 1997 to July 30, 2002 of women with singleton pregnancies and a previous cesarean delivery. The odds ratio (OR) for successful VBAC as a function of ethnicity was corrected for age >35 years, parity, weight gain, diabetes mellitus, hospital site, prenatal care provider, gestational age, induction, labor augmentation, epidural analgesia, and birth weight >4000 g. RESULTS: Among 54 146 births, 8030 (14.8%) occurred in women with previous cesarean deliveries. The trials of labor rates were similar among Caucasian (46.6%), Hispanic (45.4%), and African American (46.0%) women. However, there was a significant difference among ethnic groups for VBAC success rates (79.3% vs. 79.3% vs. 70.0%, respectively). When compared to Caucasian women, the adjusted OR for VBAC success was 0.37 (95% confidence interval (CI) 0.27-0.50) for African American women and 0.63 (95% CI 0.51-0.79) for Hispanic women. CONCLUSION: African American and Hispanic women are significantly less likely than Caucasian women to achieve successful VBAC.     

Interdelivery interval and the success of vaginal birth after cesarean delivery.

OBJECTIVE: To determine whether a short interdelivery interval is associated with decreased rate of successful vaginal birth after cesarean (VBAC). METHODS: A retrospective cohort study from January 1, 1997, to December 31, 2000, was conducted. Patients with previous cesarean delivery who attempted VBAC were identified. The analysis was limited to patients at term with one prior cesarean. The interdelivery interval was calculated in months between the index pregnancy and prior cesarean delivery. RESULTS: A total of 1516 subjects who attempted VBAC were identified among 24,162 deliveries, with complete data available in 1185 cases. The VBAC success rate was 79.0% for patients with an interdelivery interval less than 19 months compared with 85.5% for patients with an interval delivery greater than or equal to 19 months (P =.12). For patients whose labors were induced, interdelivery intervals of less than 19 months were associated with a decreased rate of VBAC success when compared with longer intervals (P <.01). Sufficient power (beta =.95) existed to detect a 64% difference between the groups (alpha =.05). No significant difference was detected in women who underwent spontaneous labor (P =.98). There was no difference in the rate of symptomatic uterine rupture (P = 1.00). CONCLUSION: Interdelivery intervals of less than 19 months were associated with a decreased rate of VBAC success in patients who underwent induction, a difference not found in those with spontaneous labor.     

Racial disparity in the success and complications of vaginal birth after cesarean delivery

OBJECTIVE: To determine if race is associated with election to attempt vaginal birth after cesarean delivery (VBAC), VBAC success, and maternal morbidities associated with VBAC. METHODS: A retrospective, multi-center cohort study was conducted of women with a history of at least one prior cesarean delivery. Data were obtained on maternal demographics, medical history, antepartum and intrapartum course, delivery mode, and maternal outcomes. This analysis examines the association between race and the choice to have VBAC and compares the rates of VBAC success and maternal morbidity, including uterine rupture, and a composite morbidity outcome (uterine rupture, bladder and bowel injury, and artery laceration) across race groups. Race was determined by patient self-report. Univariable and multivariable analyses were performed to assess the independent association of race and clinical outcomes. RESULTS: The cohort included 25,005 patients with at least one prior cesarean delivery. In unadjusted and multivariable analysis, black patients were more likely to undertake a trial of labor than patients of other races, and slightly more likely to experience a failure of VBAC attempt. However, black women who attempt VBAC are 40% less likely to sustain a uterine rupture (0.6% compared with 1.1%) than other racial groups, even after adjusting for relevant potentially confounding variables. CONCLUSION: Despite increased rates of VBAC attempt and VBAC failure among black women as compared with other racial groups, black women are significantly less likely to experience a uterine rupture. It is unclear whether this discrepancy in magnitudes of risks and benefits across race associated with VBAC trials is attributable to selection bias or inherent racial differences.     

Current concepts regarding vaginal birth after cesarean delivery

PURPOSE OF REVIEW: To review the current literature on vaginal birth after cesarean delivery efficacy and safety. RECENT FINDINGS: There are two major themes in current vaginal birth after cesarean delivery research. The first is continued work on the short-term safety, including maternal events such as uterine rupture and perinatal death. The second theme focuses on identifying predictors for success and failure. SUMMARY: Current information suggests that the rate of major maternal and neonatal complications with vaginal birth after cesarean delivery is low, and this option should be offered to women with a single prior low transverse cesarean. Future research should focus on an evaluation of both short-term and long-term consequences of vaginal birth after cesarean delivery compared with elective repeat cesarean section.     

The effect of prematurity on vaginal birth after cesarean delivery: success and maternal morbidity

OBJECTIVE: We sought to compare vaginal birth after cesarean (VBAC) success and uterine rupture rates between preterm and term gestations in women with a history of one prior cesarean delivery. Our hypothesis was that preterm women undergoing VBAC were more likely to be successful and have a lower rate of complications than term women undergoing VBAC. METHODS: We reviewed medical records of women with a history of a cesarean delivery who either attempted a VBAC or underwent a repeat cesarean delivery from 1995 through 2000 in 17 community and university hospitals. We collected information on demographics, medical and obstetric history, complications, and outcome of the index pregnancy. The primary analysis was limited to women with singleton gestations and one prior cesarean delivery. Statistical analysis consisted of bivariate and multivariable techniques. RESULTS: Among the 20,156 patients with one prior cesarean delivery, 12,463 (61%) attempted a VBAC. Mean gestational ages for the term and preterm women were 39.2 weeks and 33.9 weeks of gestation, respectively. The VBAC success rates for the term and preterm groups were 74% and 82%, respectively (P < .001). Multivariable analysis showed that the VBAC success was higher (adjusted odds ratio 1.54, 95% confidence interval 1.27-1.86) in preterm gestations. A decreased risk of rupture among preterm gestations was suggested in these results (adjusted odds ratio 0.28, 95% confidence interval 0.07-1.17; P = .08). CONCLUSION: Preterm patients undergoing a VBAC have higher success rates when compared with term patients undergoing a VBAC. Preterm patients undergoing VBAC may have lower uterine rupture rates.     

Increased success of trial of labor after previous vaginal birth after cesarean

OBJECTIVE: To estimate whether a history of a previous successful vaginal birth after cesarean delivery (VBAC) has an effect on a subsequent VBAC attempt. METHODS: A chart review of cases identified from the International Classification of Diseases, 9th Revision (ICD-9) codes and cases identified in the logbooks on Labor and Delivery yielded 1,216 cases of attempted VBAC from 1996 to 2000. Data gathered from these cases included history of previous successful VBAC. Variables of interest included previous successful normal spontaneous vaginal delivery, history of diabetes, labor induction, and recurrent indication for cesarean delivery. RESULTS: Of the 336 patients with a history of one or more previous successful VBAC attempts, 94.6% had a subsequent successful VBAC, whereas 70.5% of the remaining 880 patients were successful (P <.001). For those patients with one or more previous successful normal spontaneous vaginal deliveries, 87.8% had a successful VBAC, whereas 75.6% were successful without this history (P =.001). The presence of diabetes and a recurrent indication for cesarean delivery both decreased VBAC success and were independently associated with poor outcome (P <.001). Patients with a history of previous VBAC were 7 times more likely to have a subsequent VBAC success (odds ratio 7.40, 95% confidence interval 4.51-12.16; P <.001). Those with a history of previous normal spontaneous vaginal delivery were not more likely to have a successful VBAC when the other variables were controlled. Induction did not affect VBAC outcome. CONCLUSION: A history of a previous successful VBAC increases the likelihood for success with future attempts. Maternal diabetes and history of a recurrent indication for cesarean delivery are poor prognosticators for successful trial of labor. LEVEL OF EVIDENCE: II-2     

Predicting failure of a vaginal birth attempt after cesarean delivery

OBJECTIVE: To identify a group of clinical factors that could be used to accurately predict failure in women attempting vaginal birth after cesarean (VBAC). METHODS: We conducted a planned secondary analysis of a retrospective cohort study of women who were offered VBAC from 1996 to 2000 in 17 community and university hospitals. We collected information about maternal history and outcomes of the index pregnancy. We used univariable and multivariable statistical methods to develop a multivariable prediction model for the outcome of VBAC failure. RESULTS: A total of 13,706 patients attempted VBAC, with a failure rate of 24.5%. Six variables were significantly associated with VBAC failure in our final logistic regression model: gestational age at delivery, maternal age, maternal race, labor type (spontaneous, augmented, or induced), history of vaginal delivery, and cephalopelvic disproportion or failed induction (combined variable) as prior cesarean indication. The area under the receiver operating characteristics curve is 0.717. To achieve a sensitivity of approximately 75%, a false-positive rate of approximately 40% would result. CONCLUSION: Our results indicate that significant clinical variables (prelabor and labor) cannot reliably predict VBAC failure. LEVEL OF EVIDENCE: II.     

Cervical length measured before delivery and the success rate of vaginal birth after cesarean (VBAC)

Objective: To test the hypothesis that measuring cervical length (CL) close to the time of delivery is a predictor of successful vaginal birth following a cesarean.

Methods: A prospective longitudinal study included women with singleton pregnancies at 38–41 weeks, who previously underwent a cesarean, and who were interested in trial of labor. Patients who did not have a spontaneous onset of labor were induced at 41 weeks’ gestation. CL measurements were performed prior to labor by transvaginal ultrasound, recorded, and blinded from the caring physicians.

Results: Vaginal birth was achieved in 63/105 (60%) of patients participating in the study. The mode of delivery significantly correlated with CL, Bishop score, and previous obstetrical history. When multivariate analysis was performed, only CL and previous obstetrical history correlated significantly with mode of delivery. In the subgroup of patients with no previous vaginal delivery, only CL had a significant correlation with mode of delivery. The ROC curve demonstrated a high prediction of vaginal delivery by CL for the entire study group and for the subgroup of patients with no previous vaginal delivery (AUC?=?0.8, p?Conclusions: CL measurement after 36 weeks has a high predictive accuracy for a successful vaginal birth after cesarean.     

Safety and efficacy of attempted vaginal birth after cesarean beyond the estimated date of delivery.

OBJECTIVE: To provide data regarding safety and efficacy for women attempting a trial of labor following earlier cesarean birth who have reached their due date. STUDY DESIGN: A computerized data base was analyzed to identify women who were at or beyond 40 weeks of gestation between January 1, 1995, and March 31, 1996. Ninety women attempted vaginal birth after cesarean (VBAC) during the study period; 90 controls were matched for age, race and parity. Delivery route and complications were outcome variables identified. RESULTS: The rate of successful VBAC was 65.6% as compared to the 94.4% vaginal delivery rate among women who had not had a prior cesarean (P < .0001). Among women attempting VBAC, 62% of those who had no prior vaginal births successfully delivered vaginally, while 82% of women with one prior vaginal birth delivered vaginally (P < .0001). Women of greater parity were more successful at a trial of labor. Infectious morbidity was more common among women attempting VBAC than among those with no prior cesarean. CONCLUSION: The patient and her family can be reassured that passing her due date does not alter the efficacy or safety of a trial of labor. No change in counseling is warranted simply due to the completion of 40 weeks' gestation.     

Diet-controlled gestational diabetes mellitus does not influence the success rates for vaginal birth after cesarean delivery

OBJECTIVE: We sought to determine whether women with diet-controlled gestational diabetes mellitus who attempt vaginal birth after cesarean delivery are at increased risk of failure, when compared with their non-diabetic counterparts. STUDY DESIGN: We identified 13,396 women who attempted vaginal birth after cesarean delivery among 25,079 pregnant women with a previous cesarean delivery who were delivered between 1995 and 1999 at 16 community and university hospitals. Analysis was limited to 9437 women without diabetes mellitus and 423 women with diet-controlled diabetes mellitus who attempted vaginal birth after cesarean delivery with a singleton gestation and 1 previous low-flap cesarean delivery. Data that were collected by trained abstractors, included demographics, medical history, and both pregnancy and neonatal outcomes. Multivariable logistic regression analysis was performed to determine an adjusted odds ratio for vaginal birth after cesarean delivery success among women with diet-controlled gestational diabetes compared with women with no diabetes mellitus. We controlled for birth weight, maternal age, race, tobacco, chronic hypertension, hospital settings, labor management, and obstetric history. RESULTS: Forty-nine percent of the women with gestational diabetes mellitus and 67% of the women with no diabetes mellitus attempted vaginal birth after cesarean delivery. The success rate for attempted vaginal birth after cesarean delivery among gestational diabetic women was 70%, compared with 74% for non-diabetic women. We found that gestational diabetes mellitus is not an independent risk factor for vaginal birth after cesarean delivery failure. The relative risk for vaginal birth after cesarean delivery success in women with gestational diabetes mellitus compared with women without gestational diabetes mellitus was 0.94 (95% CI, 0.87-1.00). After an adjustment was made for confounding, the odds ratio for success with gestational diabetes mellitus was 0.87 (95% CI, 0.68-1.10). CONCLUSION: Women with diet-controlled gestational diabetes mellitus who were carrying singleton fetuses who had no more than 1 previous low flap cesarean delivery should be counseled that their disease does not decrease their chances for a successful vaginal birth after cesarean delivery. Among diet-controlled diabetic women, the overall success rate for vaginal birth after cesarean delivery remains acceptable, and attempted vaginal birth after cesarean delivery should not be discouraged solely on the basis of gestational diabetes mellitus.