Complicated primary cesarean delivery increases the risk for uterine rupture at subsequent trial of labor after cesarean

Purpose

To evaluate whether cesarean delivery (CD) indication, labor status, and other primary CD characteristics affect the risk for uterine rupture in subsequent deliveries.

Methods

A case–control study of women attempting trial of labor after cesarean (TOLAC) in a single, tertiary, university-affiliated medical center (2007–2016). Deliveries complicated by uterine rupture were matched to successful vaginal birth after cesarean (VBAC) deliveries in a 1:3 ratio. Indication, labor status and post-partum complications (postpartum hemorrhage and postpartum infection) at primary CD were compared between study and control group.

Results

During study period, there were 75,682 deliveries, of them, 3937 (5.2%) were TOLAC. Study group included 53 cases of uterine rupture at TOLAC and 159 women with successful VBAC. Women in study group had significantly lower rates of previous VBAC (15.1 vs. 28.9%, p?=?0.047). Rate of postpartum complications at primary CD was significantly higher in women with TOLAC complicated by uterine rupture (7.5 vs. 1.9%, respectively, p?=?0.042). Utilizing the multivariate logistic regression analysis, postpartum complications remained an independent risk factor for uterine rupture in the following TOLAC (aOR 4.07, 95% CI 1.14–14.58, p?=?0.031).

Conclusion

Postpartum hemorrhage and infection, in primary CD, seem to be associated with increased risk for uterine rupture during subsequent TOLAC.

     

Risk factors for uterine rupture during a trial of labor after cesarean.

The rate of vaginal birth among women with a previous cesarean increased from 18.9% in 1989 to 28.3% in 1996. By 1998, the rate had decreased to 26.3% and preliminary data from 1999 suggest that the rate for that year would be even lower (23.4%). It is not known whether that decrease represents a trend related to increasing concern by providers and women about the risk of uterine rupture. Whereas the overall risk of rupture is 1%, our review demonstrates that there is considerable variation of that risk. More than one previous scar, induction of labor, a short interdelivery interval, or a history of postpartum fever during a previous cesarean may increase the risk of a uterine rupture during a trial of labor. However, there does not appear to be an increase in risk associated with low-vertical scars, and a previous vaginal delivery may be somewhat protective. Further delineation of the factors that increase the risk of uterine rupture will permit better prediction of individualized risk and identification of women for whom attempting a vaginal delivery after cesarean represents a safe option.     

Vaginal birth after cesarean section: risk of uterine rupture with labor induction

We assessed the rate of uterine rupture in patients undergoing labor induction for attempted vaginal birth after cesarean (VBAC). A retrospective study was performed of data from a computerized database. Deliveries from January 1, 1998, to June 30, 2001, in the Southern California Kaiser Permanente system were reviewed and various perinatal characteristics analyzed. A total of 16,218 patients had a prior low transverse cesarean section. Of these, 6832 (42.1%) had a trial of labor. Successful VBAC occurred in 86% of patients with spontaneous onset of labor and 66% of patients with labor induction ( p < 0.001). The uterine rupture rate was not different between patients with spontaneous or induced labor (1.0% versus 1.2%, p = 0.51). Similarly, there was no significant difference between oxytocin or prostaglandin E2 induction (1.4% versus 1.0%, p = 0.59). In our study, labor induction did not appear to increase the risk of uterine rupture in women attempting VBAC.     

The association of maternal age and symptomatic uterine rupture during a trial of labor after prior cesarean delivery

OBJECTIVE: To estimate whether maternal age is associated with a symptomatic uterine rupture during a trial of labor after prior cesarean delivery. METHODS: We retrospectively reviewed the medical records of all patients undergoing a trial of labor after prior cesarean delivery over a 12-year period. We analyzed the labors of women with one prior cesarean and no prior vaginal deliveries. The uterine rupture rate was determined with respect to maternal age. Multiple logistic regression was used to control for potential confounding variables. RESULTS: Overall, 32 (1.1%) uterine ruptures occurred among 3015 women. For women younger than 30 years, the risk of uterine rupture was 0.5%, and for those women aged at least 30 years, the risk of uterine rupture was 1.4% (P =.02). Controlling for birth weight, induction, augmentation, and interdelivery interval, the odds ratio for symptomatic uterine rupture for women aged at least 30 years compared with those less than 30 years was 3.2 (95% confidence interval 1.2, 8.4). CONCLUSION: Women aged 30 years or older have a greater risk of uterine rupture as compared with women younger than 30 years.     

Uterine rupture during a trial of labor after previous cesarean delivery

Uterine rupture, which involves complete separation of the uterine wall, occurs in about 1% of those attempting vaginal birth after cesarean. Because uterine rupture is one of the most significant complications of a trial of labor (TOL) after previous cesarean, identifying those at increased risk of uterine rupture is paramount to the safety of a TOL after previous cesarean birth. It seems that both antepartum demographic characteristics and intrapartum factors modify the risk of uterine rupture. The ability to reliably predict an individual's a priori risk for intrapartum uterine rupture remains a major area of investigation.     

Toward a new modality for detecting a uterine rupture: electrohysterogram propagation analysis during trial of labor after cesarean

Objective: Observational cohort study which aimed to explore the potential of electrohysterogram (EHG) analysis for detecting a uterine rupture during trial of labor after cesarean. The EHG propagation characteristics surrounding the uterine scar of six patients with a previous cesarean section were compared to a control group of five patients without a scarred uterus.

Methods: The EHG was recorded during the first stage of labor using a high-resolution 64-channel electrode grid positioned on the maternal abdomen across the cesarean scar. Based on simulations, the inter-channel correlation and propagation direction were adopted as EHG parameters for evaluating possible disruption of electrical propagation by the uterine scar.

Results: No significant differences in inter-channel correlation or propagation direction were observed between the group of patients with an intact uterine scar and the control group. A strong predominance of vertical propagation was observed in one case, in which scar rupture occurred.

Conclusions: The results support unaffected propagation of electrical activity through the intact uterine scar tissue suggesting that changes in the EHG might only occur in case of rupture.     

Risk of uterine rupture with a trial of labor in women with multiple and single prior cesarean delivery

OBJECTIVE: To determine whether the risk for uterine rupture is increased in women attempting vaginal birth after multiple cesarean deliveries. METHODS: We conducted a prospective multicenter observational study of women with prior cesarean delivery undergoing trial of labor and elective repeat operation. Maternal and perinatal outcomes were compared among women attempting vaginal birth after multiple cesarean deliveries and those with a single prior cesarean delivery. We also compared outcomes for women with multiple prior cesarean deliveries undergoing trial of labor with those electing repeat cesarean delivery. RESULTS: Uterine rupture occurred in 9 of 975 (0.9%) women with multiple prior cesarean compared with 115 of 16,915 (0.7%) women with a single prior operation (P = .37). Multivariable analysis confirmed that multiple prior cesarean delivery was not associated with an increased risk for uterine rupture. The rates of hysterectomy (0.6% versus 0.2%, P = .023) and transfusion (3.2% versus 1.6%, P < .001) were increased in women with multiple prior cesarean deliveries compared with women with a single prior cesarean delivery attempting trial of labor. Similarly, a composite of maternal morbidity was increased in women with multiple prior cesarean deliveries undergoing trial of labor compared with those having elective repeat cesarean delivery (odds ratio 1.41, 95% confidence interval 1.02-1.93). CONCLUSION: A history of multiple cesarean deliveries is not associated with an increased rate of uterine rupture in women attempting vaginal birth compared with those with a single prior operation. Maternal morbidity is increased with trial of labor after multiple cesarean deliveries, compared with elective repeat cesarean delivery, but the absolute risk for complications is small. Vaginal birth after multiple cesarean deliveries should remain an option for eligible women. LEVEL OF EVIDENCE: II-2.     

Maternal and neonatal outcomes after uterine rupture in labor

OBJECTIVE: There is significant controversy about the risks related to attempted vaginal birth after cesarean and the implications for informed consent of the patient. Recent data suggest that women who deliver in hospitals with high attempted vaginal birth after cesarean rates are more likely to experience successful vaginal birth after cesarean, as well as uterine ruptures. We conducted a study to evaluate maternal and neonatal morbidity and mortality after uterine rupture at a tertiary care center. STUDY DESIGN: We performed a retrospective chart review of cases of uterine rupture from 1976 to 1998. All women who had a history of uterine rupture were identified with International Classification of Diseases, Ninth Revision, identifiers with hospital discharge data cross-referenced with a separate obstetric database. We abstracted demographic information, fetal heart rate patterns, maternal pain and bleeding patterns, umbilical cord gas values, and Apgar scores from the medical record. Outcome variables were uterine rupture events and major and minor maternal and neonatal complications. RESULTS: During the study period there were 38,027 deliveries. The attempted vaginal birth after cesarean rate was 61.3%, of which 65.3% were successful. We identified 21 cases of uterine rupture or scar dehiscence. Seventeen women had prior cesarean deliveries (10 with primary low transverse cesarean delivery, 3 with unknown scars, 1 with classic cesarean delivery, 2 with two prior cesarean deliveries, and 1 with four prior cesarean deliveries). Of the 4 women who had no history of previous uterine surgery, one had a bicornuate uterus whereas the others had no factors increasing the risk for uterine rupture. We confirmed uterine rupture and scar dehiscence in 19 women. Specific details were not available for 2 patients. Uterine rupture or scar dehiscence was clinically suspected in 16 women with 3 cases identified at delivery or after delivery. Sixteen women had symptoms of increased abdominal pain, vaginal bleeding, or altered hemodynamic status. There were 2 patients who required hysterectomies and 3 women who received blood transfusions; there were no maternal deaths related to uterine rupture. The fetal heart rate pattern in 13 cases showed bradycardia and repetitive variable or late decelerations. Thirteen neonates had umbilical artery pH >7.0. Two cases of fetal or neonatal death occurred, one in a 23-week-old fetus whose mother had presented to an outlying hospital and the second in a 25-week-old fetus with Potter's syndrome. All live-born infants were without evidence of neurologic abnormalities at the time of discharge. CONCLUSION: Our data confirm the relatively small risk of uterine rupture during vaginal birth after cesarean that has been demonstrated in previous studies. In an institution that has in-house obstetric, anesthesia, and surgical staff in which close monitoring of fetal and maternal well-being is available, uterine rupture does not result in major maternal morbidity and mortality or in neonatal mortality.     

Oxytocin use during a trial of labor in patients with previous cesarean section

In patients who have had a previous cesarean section (C/S), the use of oxytocin during a trial of labor (TOL) remains controversial. In order to better delineate the risks associated with oxytocin usage in patients with prior C/S undergoing a TOL, a retrospective investigation was undertaken. During the study period, January 1 to December 31, 1980, 308 previous-C/S patients underwent a TOL. Oxytocin was used on 58 (18.8%) for either labor induction (12) or augmentation (46). Vaginal delivery was accomplished in 31 (53.4%) of the patients who received oxytocin. Vaginal delivery was accomplished in 196 (83.8%) of the 292 patients who labored spontaneously. Patients who had no vaginal deliveries after previous C/S and required oxytocin were at a significantly increased risk of undergoing C/S. There was no statistically significant difference between the oxytocin vs. nonoxytocin groups with regard to instruments used in vaginal delivery, uterine scar dehiscence, transfusions, birth trauma or neonatal outcome. In patients with a previous C/S who undergo a TOL, the use of oxytocin in a judicious manner appears to be safe. However, additional studies are required to corroborate this conclusion.     

Previous preterm cesarean delivery and risk of subsequent uterine rupture

OBJECTIVE: To determine if women with a history of a previous preterm cesarean delivery experienced an increased risk of subsequent uterine rupture compared with women who had a previous nonclassic term cesarean delivery. METHODS: A prospective observational study was performed in singleton gestations that had a previous nonclassic cesarean delivery from 1999 to 2002. Women with a history of a previous preterm cesarean delivery were compared with women who had a previous term cesarean delivery. Women who had both a preterm and term cesarean delivery were included in the preterm group. RESULTS: A prior preterm cesarean delivery was significantly associated with an increased risk of subsequent uterine rupture (0.58% compared with 0.28%, P<.001). When women who had a subsequent elective cesarean delivery were removed (remaining n=26,454) women with a previous preterm cesarean delivery were still significantly more likely to sustain a uterine rupture (0.79% compared with 0.46%, P=.001). However, when only women who had a subsequent trial of labor were included, there was still an absolute increased risk of uterine rupture, but it was not statistically significant (1.00% compared with 0.68%, P=.081). In a multivariable analysis controlling for confounding variables (oxytocin use, two or more previous cesarean deliveries, a cesarean delivery within the past 2 years, and preterm delivery in the current pregnancy), patients with a previous preterm cesarean delivery remained at an increased risk of subsequent uterine rupture (P=.043, odds ratio 1.6, 95% confidence interval 1.01-2.50) compared with women with previous term cesarean delivery. CONCLUSION: Women who have had a previous preterm cesarean delivery are at a minimally increased risk for uterine rupture in a subsequent pregnancy when compared with women who have had previous term cesarean deliveries.     

Vaginal birth after cesarean and uterine rupture rates in California

OBJECTIVE: To describe attempted and successful vaginal birth after cesarean (VBAC) rates and uterine rupture rates for women with and without prior cesareans, and compare delivery outcomes in hospitals with different attempted VBAC rates. METHODS: We used California hospital discharge summary data for 1995 to calculate attempted and successful VBAC rates and uterine rupture rates. We used multivariate logistic regression models to evaluate and adjust for age, ethnicity, and payment source. We report the relative risk (RR), attributable fraction, and 95% confidence intervals (CIs) for uterine rupture. RESULTS: There were 536,785 delivery discharges during 1995. The cesarean rate was 20.8%, and 12.5% of women had histories of cesareans. Of women with histories of cesareans, 61.4% attempted VBAC and 34.8% were successful. There were 392 uterine ruptures (0.07%). Women with prior cesareans were 16.98 (95% CI 13.51, 21.43) times more likely to experience uterine rupture, attributable fraction 66% (95% CI 60%, 73%). Among women with prior cesareans, those who attempted VBAC were 1.88 (95% CI 1.45, 2.44) times as likely to have uterine rupture, attributable fraction 34% (95% CI 21%, 46%). Women who delivered in hospitals with high attempted VBAC rates were less likely to have cesarean deliveries, more likely to have successful VBACs, and more likely to experience uterine ruptures. CONCLUSION: Uterine rupture occurs at a low rate in women with and without prior cesarean delivery. Risk of rupture is increased among women with prior cesarean delivery and among those who attempt VBAC.     

Rate of uterine rupture during a trial of labor in women with one or two prior cesarean deliveries.

OBJECTIVE: We sought to determine whether there is a difference in the rate of symptomatic uterine rupture after a trial of labor in women who have had 1 versus 2 prior cesarean deliveries. STUDY DESIGN: The medical records of all women with a history of either 1 or 2 prior cesarean deliveries who elected to undergo a trial of labor during a 12-year period (July 1984-June 1996) at the Brigham and Women's Hospital were reviewed. Rates of uterine rupture were compared for these 2 groups. Potential confounding variables were controlled by using logistic regression analyses. RESULTS: Women with 1 prior cesarean delivery (n = 3757) had a rate of uterine rupture of 0.8%, whereas women with 2 prior cesarean deliveries (n = 134) had a rate of uterine rupture of 3.7% (P =.001). In a logistic regression analysis that was controlled for maternal age, use of epidural analgesia, oxytocin induction, oxytocin augmentation, the use of prostaglandin E(2) gel, birth weight, gestational age, type of prior hysterotomy, year of trial of labor, and prior vaginal delivery, the odds ratio for uterine rupture in those patients with 2 prior cesarean deliveries was 4.8 (95% confidence interval, 1.8-13. 2) CONCLUSIONS: Women with a history of 2 prior cesarean deliveries have an almost 5-fold greater risk of uterine rupture than those with only 1 prior cesarean delivery.     

Post-cesarean delivery fever and uterine rupture in a subsequent trial of labor

OBJECTIVE: To evaluate the association of uterine rupture during a trial of labor after cesarean with postpartum fever after the prior cesarean delivery. METHODS: We conducted a nested, case-control study in a cohort of all women undergoing a trial of labor after cesarean over a 12-year period in a single tertiary care institution. The current study was limited to all women undergoing a trial of labor after cesarean at term with a symptomatic uterine rupture and who also had their prior cesarean at the same institution. Four controls, who all had their prior cesarean at the same institution, were matched to each case by year of delivery, number of prior cesareans, prior vaginal delivery, and induction in the index pregnancy. Medical records were reviewed for maximum postpartum temperature for the previous cesarean. Fever was defined as a temperature above 38C. Conditional logistic regression analysis was performed taking into account potential confounding factors. RESULTS: There were 21 cases of uterine rupture included in the analysis. The rate of fever following the prior cesarean was 38% (8/21) among the cases, and 15% (13/84) in the controls, P =.03. Multiple logistic regression analysis examining the association of uterine rupture and postpartum fever adjusting for confounders revealed an odds ratio of 4.0, 95% confidence interval 1.0, 15.5. CONCLUSION: Postpartum fever after cesarean delivery is associated with an increased risk of uterine rupture during a subsequent trial of labor.     

Effect of previous vaginal delivery on the risk of uterine rupture during a subsequent trial of labor

OBJECTIVE: We examined the effect of prior vaginal delivery on the risk of uterine rupture in pregnant women undergoing a trial of labor after prior cesarean delivery. STUDY DESIGN: The medical records of all pregnant women with a history of cesarean delivery who attempted a trial of labor during a 12-year period at a single center were reviewed. For the current analysis, the study population was limited to term pregnancies. The effect of previous vaginal delivery on the risk of uterine rupture during a subsequent trial of labor was evaluated. Separate analyses were performed for women with a single previous cesarean delivery and for those with >1 prior cesarean delivery. For each of these subgroups, the rate of uterine rupture among women who had > or =1 prior vaginal delivery was compared with the rate among women with no prior vaginal delivery. Logistic regression analysis was used to examine the associations with control for confounding factors. RESULTS: Of 3783 women with 1 prior scar, 1021 (27.0%) also had > or =1 prior vaginal delivery. During a subsequent trial of labor, the rate of uterine rupture was 1.1% among pregnant women without prior vaginal delivery and 0.2% among pregnant women with prior vaginal delivery (P =.01). Logistic regression analysis controlling for duration of labor, induction, birth weight, maternal age, year of birth, epidural analgesia, and oxytocin augmentation indicated that, among women with a single scar, those with a prior vaginal delivery had a risk of uterine rupture that was one fifth that of women without a previous vaginal delivery (odds ratio, 0.2; 95% confidence interval, 0.04-0.8). In the group of 143 pregnant women with >1 previous cesarean delivery, women with a prior vaginal delivery had a somewhat lower risk of uterine rupture (3.9% vs 2.5%; adjusted odds ratio, 0.6; 95% confidence interval, 0.01-6.7). This difference was not statistically significant. CONCLUSION: Among women with 1 prior cesarean delivery undergoing a subsequent trial of labor, those with a prior vaginal delivery were at substantially lower risk of uterine rupture than women without a previous vaginal delivery.