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.     

Cervical ripening with transcervical foley catheter and the risk of uterine rupture

OBJECTIVE: To estimate whether the rate of uterine rupture in patients with a previous cesarean delivery is related to labor induction and/or cervical ripening using transcervical Foley catheter. METHODS: Charts of all patients who had a trial of labor after a previous cesarean delivery in our institution between 1988 and 2002 were reviewed. The rates of successful vaginal birth after cesarean delivery and uterine rupture in patients with spontaneous labor (control group) were compared with those of patients who underwent a labor induction by means of amniotomy with or without oxytocin and patients who underwent a labor induction/cervical ripening using a transcervical Foley catheter. Logistic regression analysis was performed to adjust for confounding variables. RESULTS: Of 2479 patients, 1807 had a spontaneous labor, 417 had labor induced by amniotomy with or without oxytocin, and 255 had labor induced by using transcervical Foley catheter. The rate of successful vaginal birth after cesarean delivery was significantly different among the groups (78.0% versus 77.9% versus 55.7%, P <.001), but not the rate of uterine rupture (1.1% versus 1.2% versus 1.6%, P =.81). After adjusting for confounding variables, the odds ratio (OR) for successful vaginal birth after cesarean delivery was 0.68 (95% confidence interval [CI] 0.41, 1.15), and the OR for uterine rupture was 0.47 (95% CI 0.06, 3.59) in patients who underwent an induction of labor using a transcervical Foley catheter when compared with patients with spontaneous labor. CONCLUSION: Labor induction using a transcervical Foley catheter was not associated with an increased risk of uterine rupture.     

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.     

Single- versus double-layer uterine incision closure and uterine rupture.

OBJECTIVE: To evaluate whether closure of the uterine incision with one or two layers changes uterine rupture or vaginal birth after cesarean section (VBAC) success rates. METHODS: Subjects with one previous cesarean section by documented transverse uterine incision that attempted VBAC were identified. Exclusion criteria included lack of documentation of the type of closure of the previous uterine incision, multiple gestation, more than one previous cesarean section, and previous scar other than low transverse.Uterine rupture and VBAC success rates were compared between those with single-layer and double-layer uterine closure. Time interval between deliveries, birth weight, body mass index (BMI), and history of previous VBAC were evaluated as possible confounders. RESULTS: Of 948 subjects identified, 913 had double-layer closure and 35 had single-layer closure. The uterine rupture rate was significantly higher in the single-layer closure group (8.6% vs. 1.3%, p = 0.015). This finding persisted when controlling for previous VBAC, induction, birth weight >4000 g, delivery interval >19 months, and BMI >29 (OR 8.01, 95% CI 1.96-32.79). There was no difference in VBAC success rate (74.3% vs. 77%, p = 0.685). CONCLUSION: Single-layer uterine closure may be more likely to result in uterine rupture.     

Spontaneous versus induced labor after a previous cesarean delivery

OBJECTIVE: To compare maternal and neonatal outcomes in spontaneous versus induced labor after one previous cesarean delivery. METHODS: Women with one previous cesarean delivery who had spontaneous labor between January 1992 and January 2000 were compared with those whose labor was induced. RESULTS: Three thousand seven hundred forty-six patients had a trial of labor (2943 spontaneous, 803 induced). Those induced had more frequent early postpartum hemorrhage (7.3% versus 5.0%; odds ratio [OR] 1.66; 95% confidence interval [CI] 1.18, 2.32), cesarean delivery (37.5% versus 24.2%; OR 1.84; 95% CI 1.51, 2.25), and neonatal intensive care unit (NICU) admission (13.3% versus 9.4%; OR 1.69; 95% CI 1.25, 2.29). There was a trend toward higher uterine rupture rates in those with induced versus spontaneous labor (0.7% versus 0.3%, P =.128) and for patients undergoing dinoprostone (prostaglandin E(2)) induction versus other methods (1.1% versus 0.6%, P =.62), although neither difference achieved statistical significance. CONCLUSION: Induced labor is associated with an increased rate of early postpartum hemorrhage, cesarean delivery, and neonatal ICU admission. The higher rate of uterine rupture in those who had labor induced was not statistically significant.     

Risk of uterine rupture in labor induction of patients with prior cesarean section: an inner city hospital experience

OBJECTIVE: This study was undertaken to determine the risk of uterine rupture in patients induced with oxytocin or misoprostol after 1 or more previous cesarean sections. STUDY DESIGN: Patients with 1 or more previous cesarean sections who delivered after 28 weeks' gestation between 1996 and 2002 were identified by database. Among 3533 total patients, rates of uterine rupture were compared among 4 groups: oxytocin induction (n = 430), misoprostol induction (n = 142), spontaneous labor (n = 2523), and repeat cesarean section without labor (n = 438). Statistical analysis included chi(2) test, Fisher exact test, unpaired t test, and Mantel-Haenszel test. RESULTS: Rate of rupture was increased in all inductions compared with that of the spontaneous labor group. Among patients with 1 prior cesarean, rupture rates with misoprostol and oxytocin induction were 0.8% and 1.1%, respectively. CONCLUSION: Induction of labor with oxytocin or misoprostol is associated with a higher rate of uterine rupture compared with those who deliver after spontaneous labor. After 1 prior cesarean, rupture rate with misoprostol induction is not increased compared with oxytocin induction.     

Modified Bishop's score and induction of labor in patients with a previous cesarean delivery

OBJECTIVES: The purpose of this study was to evaluate the association between preinduction modified Bishop's score and obstetric outcome, including successful vaginal birth after prior cesarean (VBAC) and uterine rupture in patients with a previous cesarean undergoing induction of labor. STUDY DESIGN: Medical records of all patients who had an induction of labor after a previous cesarean in our institution between 1988 and 2002 were reviewed. Patients were divided into 4 groups according to the modified Bishop's score (0 to 2, 3 to 5, 6 to 8, and 9 to 12). The rates of successful VBAC, symptomatic uterine rupture, and other obstetric outcomes were evaluated in each group. Multivariate regression analyses were performed to adjust for confounding factors. RESULTS: Out of 685 women included in the study, 187 (27.3%) had a modified Bishop's score <2, 276 (40.3%) of 3 to 5, 189 (27.6%) of 6 to 8, and 33 (4.8%) of 9 to 12. The rate of successful VBAC significantly correlated with the modified Bishop's score (57.5%, 64.5%, 82.5%, and 97.0%, respectively, P < .001). However, the rate of uterine rupture was not statistically significant between the groups (2.1%, 1.8%, 0.5%, 0.0%, P=.48). After adjusting for confounding variables, a modified Bishop's score >/=6 remained associated with successful VBAC (odds ratio [OR] 2.07, 95% CI 1.28-3.35, P < .001). CONCLUSION: The modified Bishop's score before induction of labor is an independent factor associated with successful VBAC.     

Uterine rupture associated with misoprostol labor induction in women with previous cesarean delivery

OBJECTIVE: To review our experience with uterine rupture in patients undergoing a trial of labor with a history of previous cesarean delivery in which labor was induced with misoprostol. STUDY DESIGN: A retrospective chart review was used to select patients who underwent induction of labor with misoprostol during the period from February 1999 to June 2002. Women with a history of cesarean delivery were retrospectively compared with those without uterine scarring. RESULTS: Uterine rupture occurred in 4 of 41 patients with previous cesarean delivery who had labor induced with misoprostol. The rate of uterine rupture (9.7%) was significantly higher in patients with a previous cesarean delivery (P<0.001). No uterine rupture occurred in 50 patients without uterine scarring. Women with a history of cesarean delivery were more likely to have oxytocin augmentation than those without uterine scarring (41% versus 20%; P=0.037). CONCLUSION: Misoprostol induction of labor increases the risk of uterine rupture in women with a history of cesarean delivery.     

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.     

Uterine rupture during induced trial of labor among women with previous cesarean delivery

OBJECTIVE: This study was undertaken to compare the rates of uterine rupture during induced trials of labor after previous cesarean delivery with the rates during a spontaneous trial of labor. STUDY DESIGN: All deliveries between 1992 and 1998 among women with previous cesarean delivery were evaluated. Rates of uterine rupture were determined for spontaneous labor and different methods of induction. RESULTS: Of 2119 trials of labor, 575 (27%) were induced. The overall rate of uterine rupture was 0.71% (15/2119). The uterine rupture rate with induced trial of labor (8/575; 1.4%) was significantly higher than with a spontaneous trial of labor (7/1544; 0.45%; P =.0004). Uterine rupture rates associated with different methods of induction were compared with the rate seen with spontaneous labor and were as follows: prostaglandin E(2) gel, 2.9% (5/172; P =.004); intracervical Foley catheter, 0.76% (1/129; P =.47); and labor induction not requiring cervical ripening, 0.74% (2/274; P =.63). The uterine rupture rate associated with inductions other than with prostaglandin E(2) was 0.74% (3/474; P =.38). The relative risk of uterine rupture with prostaglandin E(2) use versus spontaneous trial of labor was 6.41 (95% confidence interval, 2. 06-19.98). CONCLUSION: Induction of labor was associated with an increased risk of uterine rupture among women with a previous cesarean delivery, and this association was highest when prostaglandin E(2) gel was used.     

Committee opinion. Induction of labor for vaginal birth after cesarean delivery

A recent population-based study of vaginal birth after cesarean delivery (VBAC) attempts observed uterine rupture rates of 24.5 per 1,000 with prostaglandin-induced labor, while the uterine rupture rates with spontaneous labor and labor induced without prostaglandins were lower (5.2/1,000 and 7.71/1,000 respectively). The authors did not confirm the diagnoses by examining individual medical records, so the actual incidence of uterine rupture may have been overstated. Despite this limitation, the Committee on Obstetric Practice concludes that the risk of uterine rupture during VBAC attempts is substantially increased with the use of various prostaglandin cervical ripening agents for the induction of labor, and their use for this purpose is discouraged.     

ACOG committee opinion Induction of labor for vaginal birth after cesarean delivery

A recent population-based study of vaginal birth after cesarean delivery (VBAC) attempts observed uterine rupture rates of 24.5 per 1,000 with prostaglandin-induced labor, while the uterine rupture rates with spontaneous labor and labor induced without prostaglandins were lower (5.2/1,000 and 7.7/1,000 respectively). The authors did not confirm the diagnoses by examining individual medical records, so the actual incidence of uterine rupture may have been overstated. Despite this limitation, the Committee on Obstetric Practice concludes that the risk of uterine rupture during VBAC attempts is substantially increased with the use of various prostaglandin cervical ripening agents for the induction of labor, and their use for this purpose is discouraged.     

Induction of labor with prostaglandin E2 in women with previous cesarean section and unfavorable cervix

OBJECTIVE: To study the pregnancy outcome of induction of labor with prostaglandin E2 (PGE2) in women with one previous lower segment cesarean section. METHODS: A retrospective cohort design was used. The study sample included 1028 consecutive women with one previous cesarean section, of whom 97 underwent induction of labor (study group) and 931 were admitted with spontaneous onset of labor (control group). Vaginal tablets of PGE2 were used for cervical ripening in the study group. Mode of delivery, neonatal outcome, indications for cesarean section, and rate of uterine rupture were compared between the groups. RESULTS: There were no significant differences between the study and control groups in mean (+/-S.D.) maternal age (30.9 +/- 4.7 years versus 31.2 +/- 4.8 years, P = 0.6), gestational age at delivery (39.2 +/- 1.8 weeks versus 39.3 +/- 1.6 weeks, P = 0.36), overall rate of cesarean section (36% versus 37.3%, P = 0.8), rates of low 5-min Apgar score < or =7 (3.1% versus 3.7%, P = 0.67) or cesarean section performed for nonreassuring fetal heart rate (6.1% versus 3.1%, P = 0.1). There were four cases of uterine rupture, all in the control group compared to none in the study group (nonsignificant). CONCLUSION: The findings suggest that induction of labor in women with one previous cesarean section does not increase the risk of cesarean section rate and does not adversely affect immediate neonatal outcome. We cautiously suggest that when there is no absolute indication for repeated cesarean section, induction of labor may be considered.     

Uterine rupture with the use of PGE2 vaginal inserts for labor induction in women with previous cesarean sections

OBJECTIVE: To analyze the rate of uterine rupture in women with previous cesarean sections undergoing a trial of labor in which a prostaglandin E2 (PGE2) vaginal insert was used. STUDY DESIGN: The study was based on a computerized search and review of pharmacy records, medical records and the pertinent literature. Pharmacy records were correlated with the medical records of all women undergoing a trial of labor after cesarean section over a 33-month period. RESULTS: Between January 1998 and September 2000, 13,544 patients delivered. Of these cases, 790 were vaginal trials of labor after previous cesarean section. A PGE2 vaginal insert was used in 58 of the patients. A total of 6 of these 58 patients (10.3%) experienced uterine rupture. This compares to a rupture rate of 1.1% (8/732) in deliveries not using PGE2 vaginal inserts. CONCLUSION: The risk of uterine rupture was significantly increased in patients undergoing a trial of labor after previous cesarean section when a PGE2 vaginal insert was used. Physicians need to be aware that using a PGE2 vaginal inserts for cervical ripening and/or induction of labor in women with a previous cesarean section might increase the risk of uterine rupture above the standard risk for vaginal birth after cesarean (VBAC) candidates. We recommend that all VBAC patients using a PGE2 vaginal insert be closely monitored for evidence of uterine rupture.     

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?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.     

Safety and success of vaginal birth after cesarean delivery in patients with preeclampsia

The objective of this study was to determine if preeclampsia (PRE) or gestational hypertension (GH) affects the rate of success of vaginal birth after cesarean delivery (VBAC), VBAC-related complications, or patient election to attempt VBAC. We performed a retrospective cohort study of all women who were offered VBAC from 1996 to 2000 in 17 community and university hospitals. Demographic, medical, and obstetric history, complications, treatment, and index pregnancy outcome information was collected on all patients in the database. Bivariate analysis and multivariable logistic regression were used to assess the independent association between GH and PRE and the rate of success of VBAC, VBAC-related complications, or patient election to attempt VBAC. A total of 25,005 patients were registered in the database. 13,706 (54.81%) attempted VBAC and 11,299 (45.19%) elected repeat cesarean delivery. After adjusting for confounding variables using multivariable logistic regression, patients with PRE were more likely to fail VBAC (relative risk [RR], 1.56; 95% CI, 1.22 to 2.00). Patients with GH were less likely to attempt VBAC (RR, 0.39; 95% CI, 0.34 to 0.46). A total of 304 (1.46%) patients had a uterine rupture. The VBAC group had a rupture rate of 0.93% and the elective cesarean group had a rupture rate of 0.04%. There was no difference in uterine rupture rates between the cohorts. Patients with gestational hypertension were less likely to attempt a VBAC. Patients with PRE, if they attempted a VBAC trial, had a higher VBAC failure rate. Patients with PRE or GH do not have increased uterine rupture rates. These findings can be used to improve mode of delivery counseling for VBAC candidate patients with preeclampsia.     

Previous preterm cesarean delivery: identification of a new risk factor for uterine rupture in VBAC candidates.

OBJECTIVE: A major risk of trials of labor in patients with prior cesarean delivery is uterine rupture. We evaluated the question of whether a previous cesarean delivery at an early gestational age predisposes the patient to subsequent uterine rupture. METHODS: This was a retrospective chart review of patients delivering at North Shore University Hospital with a trial of labor after previous cesarean delivery to ascertain all cases of uterine rupture. Patients who had had a previous cesarean delivery at our institution who did not suffer uterine rupture during a trial of labor served as controls. RESULTS: Twenty-five patients suffered a uterine rupture. The incidence of prior preterm cesarean delivery (PPCD) in this group was 40%, compared to 10.9% of 691 laboring vaginal birth after cesarean (VBAC) patients without rupture (p < 0.001). Patients in the rupture group with a PPCD were less likely to have experienced labor in the index pregnancy and more likely to have had an interdelivery interval of less than two years. CONCLUSIONS: An undeveloped lower segment in the preterm uterus represents a risk for later rupture, even if the incision is transverse.     

Uterine rupture during induced or augmented labor in gravid women with one prior cesarean delivery.

OBJECTIVE: Our purpose was to examine the risk of uterine rupture during induction or augmentation of labor in gravid women with 1 prior cesarean delivery. STUDY DESIGN: The medical records of all gravid women with history of cesarean delivery who attempted a trial of labor during a 12-year period at a single center were reviewed. The current analysis was limited to women at term with 1 prior cesarean delivery and no other deliveries. The rate of uterine rupture in gravid women within that group undergoing induction was compared with that in spontaneously laboring women. The association of oxytocin induction, oxytocin augmentation, and use of prostaglandin E(2) gel with uterine rupture was determined. Logistic regression analysis was used to examine these associations, with control for confounding factors. RESULTS: Of 2774 women in the analysis, 2214 had spontaneous onset of labor and 560 women had labor induced with oxytocin or prostaglandin E(2) gel. The overall rate of rupture among all patients with induction of labor was 2.3%, in comparison with 0.7% among women with spontaneous labor (P =.001). Among 1072 patients receiving oxytocin augmentation, the rate of uterine rupture was 1.0%, in comparison with 0.4% in nonaugmented, spontaneously laboring patients (P =.1). In a logistic regression model with control for birth weight, use of epidural, duration of labor, maternal age, year of delivery, and years since last birth, induction with oxytocin was associated with a 4.6-fold increased risk of uterine rupture compared with no oxytocin use (95% confidence interval, 1.5-14.1). In that model, augmentation with oxytocin was associated with an odds ratio of 2.3 (95% confidence interval, 0.8-7.0), and use of prostaglandin E(2) gel was associated with an odds ratio of 3.2 (95% confidence interval, 0.9-10.9). These differences were not statistically significant. CONCLUSION: Induction of labor with oxytocin is associated with an increased rate of uterine rupture in gravid women with 1 prior uterine scar in comparison with the rate in spontaneously laboring women. Although the rate of uterine rupture was not statistically increased during oxytocin augmentation, use of oxytocin in such cases should proceed with caution.