Misoprostol induction of labor among women with a history of cesarean delivery

OBJECTIVE: Several reports have appeared of uterine rupture among women with a history of cesarean delivery who received misoprostol for induction of labor. A recent review suggested a uterine rupture rate of almost 6%, but the experience at our institution did not seem to reflect this high complication rate. This study was undertaken to compare complications of labor induction with misoprostol between women with a history of cesarean delivery and women without uterine scarring. STUDY DESIGN: A computerized database was used to select women with a viable fetus who underwent induction of labor with misoprostol during the period from January 1996 through December 1998. Patients were given 50 microg misoprostol every 4 hours. Women with a history of cesarean delivery were retrospectively compared with those without uterine scarring. RESULTS: A total of 425 women were given misoprostol for induction of labor: 48 had a history of cesarean delivery and 377 did not. Women with a history of cesarean delivery were more likely to be delivered abdominally (56% vs 28%; P <.04). Among women with a history of cesarean delivery, women who had a history of vaginal birth after cesarean were more likely to be delivered vaginally (92% vs 42%; P =.003). There was no difference in the overall rate of complications (2% with scarring vs 3% without scarring). There were no uterine ruptures. However, the previous cesarean group was more likely than the unscarred group to have blood loss >500 mL (38% vs 22%; P <.03). Although the incidences of fetal distress were similar, neonates born to women in the previous cesarean group were more likely to have an Apgar score <7 at 5 minutes (13% vs 5%; P <.04). CONCLUSION: Misoprostol induction of labor in women with a history of cesarean resulted in a higher rate of cesarean delivery than was seen among women without uterine scarring but was not associated with a higher incidence of complications. There were no uterine ruptures in either group.     

Uterine rupture and dehiscence associated with intravaginal misoprostol cervical ripening

OBJECTIVE: To evaluate if the prostaglandin E1 analogue misoprostol, when used as an agent for cervical ripening, is associated with uterine rupture. STUDY DESIGN: We performed a two-year retrospective chart review to determine the incidence of uterine rupture in patients with a previous cesarean delivery undergoing cervical ripening or the induction of labor. RESULTS: Uterine dehiscence occurred in 1 and uterine rupture occurred in 3 of 48 women with a prior cesarean delivery treated with 50 micrograms doses of intravaginal misoprostol for cervical ripening. Uterine rupture was found in 1 of 89 women who had an oxytocin infusion for induction of labor and none of the 24 patients who received intravaginal prostaglandin E2 placed for cervical ripening. CONCLUSION: Intravaginal misoprostol appears to be associated with an increased incidence of uterine rupture when used in patients undergoing a trial of labor after cesarean.     

Uterine rupture associated with the use of misoprostol in the gravid patient with a previous cesarean section

Objective: Our purpose is to report our experience with uterine rupture in patients undergoing a trial of labor after previous cesarean delivery in which labor was induced with misoprostol. The literature on the use of misoprostol in the setting of previous cesarean section is reviewed. Study Design: This report was based on case reports, a computerized search of medical records, and literature review. Results: Uterine rupture occurred in 5 of 89 patients with previous cesarean delivery who had labor induced with misoprostol. The uterine rupture rate for patients attempting vaginal birth after cesarean section was significantly higher in those who received misoprostol, 5.6%, than in those who did not, 0.2% (1/423, P = .0001). Review of the literature reveals insufficient data to support the use of misoprostol in the patient with a previous cesarean delivery. Conclusion: Misoprostol may increase the risk of uterine rupture in the patient with a scarred uterus. Carefully controlled studies of the risks and benefits of misoprostol are necessary before its widespread use in this setting. (Am J Obstet Gynecol 1999;180:1535-42.)     

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.     

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.     

Comparison of the safety and efficacy of intravaginal misoprostol (prostaglandin E1 ) with those of dinoprostone (prostaglandin E2 ) for cervical ripening and induction of labor in a community hospital

Objective: This clinical trial evaluated the efficacy of intravaginal misoprostol (prostaglandin E₁ ) and compared it with that of dinoprostone (prostaglandin E₂ ) for cervical ripening and induction of labor in a community hospital. Study Design: This study involved a retrospective analysis of 81 patients undergoing cervical ripening and induction of labor with prostaglandin E₂ from May 1, 1996, to May 1, 1997. A comparison prospective analysis of 145 patients undergoing the same procedure with prostaglandin E₁ from May 1, 1997 to May 1, 1998, was performed. Results: The mean time to delivery was significantly shorter with misoprostol (19.8 ± 10.4 hours) than with prostaglandin E₂ (31.3 ± 13.0 hours, P < .001). Delivery within 24 hours of induction was significantly more frequent with misoprostol (71.9% of subjects vs 31.3%, P < .001). There was no difference in the cesarean delivery rate with misoprostol (25.6% vs 22.2%, P < .67). The incidence of uterine hyperstimulation was higher with prostaglandin E₂ (7.4% vs 0.7%, P < .007). There were no uterine ruptures with prostaglandin E₂ . There were 2 uterine ruptures and 1 dehiscence with prostaglandin E₁ in 3 patients with previous cesarean deliveries and 1 rupture in a patient without a history of uterine scarring. There was no difference in neonatal outcome, with the exception of a fetal death related to uterine rupture in the misoprostol group. Conclusions: Compared with prostaglandin E₂ , misoprostol is more effective in cervical ripening and induction of labor, is as safe for patients who do not have a history of cesarean birth, may carry a higher incidence of uterine rupture, and should not be used for patients attempting vaginal birth after previous cesarean delivery. (Am J Obstet Gynecol 1999;180:1551-9.)     

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.     

Induction of labor in women with a uterine scar

Objective: To evaluate the frequency of uterine rupture following induction of labor in women with a previous cesarean section. Misoprostol was compared to other methods of induction.

Methods: A retrospective cohort study of 208 women attempting induction of labor after one previous cesarean section. Delivery data were collected retrospectively and compared. Group 1(2009–2010) was compared with Group 2 (2012–2013). In Group 1, the main method of induction was vaginal PGE₂ (prostaglandin-E₂), amniotomy, oxytocin or a balloon catheter. In Group 2, the dominant method of induction was an oral solution of misoprostol. Main outcome measures: frequency of uterine rupture in the two groups.

Results: Nine cases (4.3%) of uterine rupture occurred. There was no significant difference in the frequency of uterine rupture following the change of method of induction from PGE₂, amniotomy, oxytocin or mechanical dilatation with a balloon catheter to orally administered misoprostol (4.1 versus 4.6%, p?=?0.9). All ruptures occurred in women with no prior vaginal delivery.

Conclusion: The shift to oral misoprostol as the primary method of induction in women with a previous cesarean section did not increase the frequency of uterine rupture in the cohort studied.     

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.     

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.     

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.     

Risk of uterine rupture and adverse perinatal outcome at term after cesarean delivery

OBJECTIVE: Current information on the risk of uterine rupture after cesarean delivery has generally compared the risk after trial of labor to that occurring with an elective cesarean delivery without labor. Because antepartum counseling cannot account for whether a woman will develop an indication requiring a repeat cesarean delivery or whether labor will occur before scheduled cesarean delivery, the purpose of this analysis was to provide clinically useful information regarding the risks of uterine rupture and adverse perinatal outcome for women at term with a history of prior cesarean delivery. METHODS: Women with a term singleton gestation and prior cesarean delivery were studied over 4 years at 19 centers. For this analysis, outcomes from five groups were studied: trial of labor, elective repeat with no labor, elective repeat with labor (women presenting in early labor who subsequently underwent cesarean delivery), indicated repeat with labor, and indicated repeat without labor. All cases of uterine rupture were reviewed centrally to assure accuracy of diagnosis. RESULTS: A total of 39,117 women were studied. In term pregnant women with a prior cesarean delivery, the overall risk for uterine rupture was 0.32% (125 of 39,117), and the overall risk for serious adverse perinatal outcome (stillbirth, hypoxic ischemic encephalopathy, neonatal death) was 106 of 39,049 (0.27%). The uterine rupture risk for indicated repeat cesarean delivery (labor or without labor) was 7 of 6,080 (0.12%); the risk for elective (no indication) repeat cesarean delivery (labor or without labor) was 4 of 17,714 (0.02%). Indicated repeat cesarean delivery increased the risk of uterine rupture by a factor of 5 (odds ratio 5.1, 95% confidence interval 1.49-17.44). In the absence of an indication, the presence of labor also increased the risk of uterine rupture (4 of 2,721 [0.15%] compared with 0 of 14,993, P<.01). The highest rate of uterine rupture occurred in women undergoing trial of labor (0.74%, 114 of 15,323). CONCLUSION: At term, the risk of uterine rupture and adverse perinatal outcome for women with a singleton and prior cesarean delivery is low regardless of mode of delivery, occurring in 3 per 1,000 women. Maternal complications occurred in 3-8% of women within the five delivery groups.     

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.     

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.     

A trial of labor after cesarean section in patients with or without a prior vaginal delivery.

OBJECTIVE: To determine the outcome of labor in women with a previous cesarean section, with or without prior vaginal delivery. METHOD: Records were reviewed for 1065 women with a previous cesarean section at 'Virgen Macarena' Hospital who were attended for a subsequent labor. RESULTS: Chi-squared tests demonstrated that women with previous vaginal delivery (n = 346) had a significantly higher rate of vaginal delivery after a trial of labor (95.24%) than those without previous vaginal delivery (n = 719) (82.95%). All the ruptures of uterine scar (n = 4) were found in women without previous vaginal delivery. CONCLUSION: It appears that a cesarean section in a multiparous woman is not a determinant fact in her reproductive history and the risk of rupture of uterine scar did not appear to be present.     

Comparison of oral and vaginal misoprostol for induction of labor at term: a randomized controlled trial

OBJECTIVE: To compare the efficacy of oral with vaginal misoprostol for induction of labor at term. METHODS: One hundred and fifty-three pregnant women at term with indications for induction of labor and Bishop score < or = 6 were randomly assigned to receive misoprostol either 100 microg orally or 50 microg vaginally every 6 h for 48 h. Repeated doses were given until Bishop score > or = 8 was achieved or spontaneous rupture of membranes occurred. Those who were not in labor after 48 h had labor induced with amniotomy and oxytocin. The main outcome measure was induction to delivery time. RESULTS: The median induction to vaginal delivery time in the oral group (14.3 h) was not significantly different from that of the vaginal group (15.8 h). The median number of doses was also not significantly different in the oral group compared with the vaginal group. There was a significant higher incidence of uterine tachysystole in the vaginal group compared to the oral group (17.1% vs 5.3%, P = 0.032). There was no hyperstimulation in either group. There were no significant differences between the groups with respect to oxytocin augmentation, cesarean section rate, analgesic requirement, and neonatal outcomes. CONCLUSION: Oral administration of 100 microg misoprostol has similar efficacy to intravaginal administration of 50 microg misoprostol for labor induction with less frequent abnormal uterine contractility. 100 microg of misoprostol orally can be used as an alternative to the vaginal route for labor induction.     

A prospective randomized study comparing misoprostol and oxytocin for premature rupture of membranes at term.

OBJECTIVE: The aim of this randomized trial was to compare the efficacy and safety of vaginal misoprostol and oxytocin for cervical ripening and labor induction in patients with premature rupture of membrane (PROM) at term. METHODS: Ninety-seven women with PROM at term were assigned randomly to receive intravaginal misoprostol or oxytocin. The primary outcome measure was the induction-delivery interval. Secondary outcomes included the number of women who delivered vaginally within 12 hours of the start of the induction in the two groups, the cesarean, hyperstimulation, and failed induction rates, the mode of delivery, and the neonatal outcome. RESULTS: Forty-eight women were assigned to intravaginal misoprostol and 49 to oxytocin administration. The mean interval from induction to delivery was 10.61 +/- 2.45 hours in the misoprostol group and 11.57 +/- 1.91 hours in the oxytocin group (p = 0.063). The rates of vaginal delivery were 83.3% and 87.7% and cesarean delivery were 16.7% and 8.2% in the misoprostol and oxytocin groups, respectively. Neonatal outcomes were not significantly different. Of the cases, 8.3% in the misoprostol group and 8.2% in the oxytocin group revealed uterine contraction abnormalities. CONCLUSION: Our study demonstrates that, intravaginally, misoprostol results in a similar interval from induction of labor to delivery when compared to oxytocin.     

Interdelivery interval and risk of symptomatic uterine rupture

OBJECTIVE: To relate interdelivery interval to risk of uterine rupture during a trial of labor after prior cesarean delivery. METHODS: We reviewed the medical records of all women who had a trial of labor after cesarean delivery over 12 years (July 1984 to June 1996). Analysis was limited to women with only one prior cesarean delivery and no prior vaginal deliveries who delivered term singletons and whose medical records included the month and year of the prior delivery. The time in months between the prior cesarean delivery and the index trial of labor was calculated, and the women were divided accordingly to permit comparison with respect to symptomatic uterine rupture. RESULTS: Two thousand four hundred nine women had trials of labor after one prior cesarean delivery and had complete data from the medical records. There were 29 uterine ruptures (1.2%) in the population. For interdelivery intervals up to 18 months, the uterine rupture rate was 2.25% (seven of 311) compared with 1.05% (22 of 2098) with intervals of 19 months or longer (P =.07). Multiple logistic regression was used to assess the risk of uterine rupture according to interdelivery interval while controlling for maternal age, public assistance, length of labor, gestational age at least 41 weeks, and oxytocin use. Women with interdelivery intervals of up to 18 months were three times as likely (95% confidence interval, 1.2, 7.2) to have symptomatic uterine rupture. CONCLUSION: Interdelivery intervals of up to 18 months were associated with increased risk of symptomatic uterine rupture during a trial of labor after cesarean delivery compared with that for longer interdelivery intervals.     

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.