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.     

Mechanical Methods for the Induction of Labour After Previous Caesarean Section – An Updated,Evidence-based Review

There are currently no up-to-date evidence-based recommendations on the preferred method to induce labour after previous Caesarean section, especially for patients with unripe cervix, as randomised controlled studies are lacking. Intravenous oxytocin and misoprostol are contraindicated in these women because of the high risk of uterine rupture. In women with ripe cervix (Bishop Score > 6), intravenous administration of oxytocin is an effective procedure with comparable rates of uterine rupture to those with spontaneous onset of labour. Vaginal prostaglandin E ₂ (PGE ₂ ) and mechanical methods (balloon catheters, hygroscopic cervical dilators) are effective methods to induce labour in pregnant women with unripe cervix and previous Caesarean section. According to current guidelines, the administration of PGE ₂ is associated with a higher rate of uterine rupture compared to balloon catheters. Balloon catheters are therefore a suitable alternative to PGE ₂ to induce labour after previous Caesarean section, even though this is an off-label use. In addition to two meta-analyses published in 2016, 12 mostly retrospective cohort/observational studies with low to moderate levels of evidence have been published on mechanical methods of cervical ripening after previous Caesarean section. But because of the significant heterogeneity of the studies, substantial differences in study design, and insufficient numbers of pregnant women included in the studies, it is not possible to make any evidence-based recommendations based on these studies. According to a recent meta-analysis, the average rate using balloon catheters is approximately 53% and the average rate after spontaneous onset of labour is 72%. The uterine rupture rate was 0.2–0.9% for vaginal PGE ₂ and 0.56–0.94% for balloon catheters and is therefore comparable to the uterine rupture rate associated with spontaneous onset of labour. According to the product informations, hygroscopic cervical dilators (Dilapan-S) are currently the only method which is not contraindicated for cervical ripening/induction of labour in women with previous Caesarean section, although data are insufficient. Well-designed, randomised, controlled studies with sufficient case numbers comparing balloon catheters and hygroscopic cervical dilators with mechanical methods and vaginal prostaglandin E ₂ /oral misoprostol are therefore necessary to allow proper decision-making.     

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.     

Induction of labor: Comparison of a cohort with uterine scar from previous cesarean section vs. a cohort with intact uterus

Objective. To compare the risk of uterine rupture between a cohort of women with previous low-transverse cesarean section (CS) and a cohort with intact uterus.

Methods. All women with a singleton pregnancy and previous low-transverse CS requiring induction of labor from January 1, 1992 to December 30, 2001 (n = 310) were compared with a cohort of women with intact uterus undergoing induction of labor during the same study period (n = 5420). Protocols of induction using prostaglandin E₂ gel and oxytocin infusion were consistent within groups, but differed between the previous CS and the intact uterus group.

Results. Uterine rupture occurred in 0.3% in the previous CS group vs. 0.03% in the intact uterus group (p = 0.37). Logistic regression analysis showed no significant difference in rate of uterine rupture between the previous CS vs. intact uterus group (p = 0.16) after controlling for maternal age, parity, gestational age at delivery, Bishop score on admission, use of prostaglandin and oxytocin, and birth weight. Our study had adequate power to detect a 0.38% difference in rate of uterine rupture between the two groups (α = 0.05, β = 0.80).

Conclusion. Induction of labor is not associated with significantly higher rates of uterine rupture among women with previous low-transverse CS compared with women with intact uterus provided a consistent protocol with strict intervention criteria is adopted.     

Induction of labor with an unfavorable cervix: how does BMI affect success?‡

Objective: Obesity places women and their babies at risk for obstetric and perinatal morbidity including induction of labor and cesarean delivery. We sought to evaluate the impact of body mass index (BMI) on successful induction of labor using misoprostol at our institution. The primary outcome was time to delivery. Secondary outcomes were number of doses of misoprostol, duration of oxytocin and cesarean delivery.

Methods: A retrospective cohort over two years found 329 patients who were >?37 weeks of gestational age and had a Bishop score <?5 prior to beginning induction. Patients were divided into three categories based on their BMI: Group 1: BMI?≤?30 kg/m², Group 2: BMI 30 to 39.9 kg/m² and Group 3: BMI?≥?40 kg/m². Statistical analysis included the use of multivariate analysis, contingency tables and Chi-square tests for categorical data and Pearson’s correlation coefficient for numerical data.

Results: There were no significant differences among the groups when analyzed for gestational age, bishop score, median parity or race. Time to delivery increased significantly with increasing BMI (p?<?0.01). Furthermore, women with higher BMIs required more doses of misoprostol (p?<?0.01), longer duration of oxytocin administration prior to delivery (p?<?0.02) and increased risk of cesarean section (p?<?0.0006).

Conclusion: As BMI increases, obese patients undergoing induction with misoprostol have a longer time to delivery, require more doses of misoprostol, require a longer duration of oxytocin and have higher cesarean delivery rate.     

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.     

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.     

A comparison of obstetrical outcomes with labor induction agents used at term

Abstract

Objective: To compare the obstetrical outcomes of term pregnancies induced with one of four commonly used labor induction agents.

Methods: This is a retrospective cohort study of induced deliveries between 1 August 1995 and 31 December 2007 occurring at the Los Angeles County?+?University of Southern California Medical Center. Viable, singleton, term pregnancies undergoing induction were identified. Exclusion criteria included gestational age less than 37 weeks, previous cesarean delivery, breech presentation, stillbirth, premature rupture of membranes, and fetal anomaly. Induction methods studied were oxytocin, misoprostol, dinoprostone and Foley catheter. Our primary outcome was cesarean delivery rate among the four induction agents. Secondary outcomes included rate of failed induction, obstetrical complications, and immediate neonatal complications.

Results: A total of 3707 women were included in the study (1486 nulliparous; 2221 multiparous). Outcomes were compared across induction methods using Chi-square Tests (Pearson or Fisher’s, as appropriate). Among the nulliparous patients, there was no statistical difference among the four induction agents with regards to cesarean delivery rate (p?=?0.51), frequency of failed inductions (p?=?0.49), the cesarean delivery frequency for “fetal distress” (p?=?0.82) and five minute Apgar score <7 (p?=?0.24). Among parous patients, the cesarean delivery rate varied significantly by induction method (p?<?0.001), being lowest among those receiving misoprostol (10%). Those receiving oxytocin and transcervical Foley catheter had cesarean rates of 22%, followed by dinoprostone at 18%. The rate of failed inductions was 2% among those receiving misoprostol, compared to 7–8% among those in the other groups (p?<?0.01). Although cases of “fetal distress” between the four induction agents was not significantly different amongst multipara women, the cesarean delivery indication for “fetal distress” was higher among multipara receiving misoprostol (p?=?0.004). There was no difference among the different induction agents with regards to five minute Apgar <7 (p?=?0.34).

Conclusion: Among nulliparous women, all induction methods have similar rate of cesarean delivery. The use of misoprostol appears to be associated with a lower risk of cesarean birth among parous women induced at our institution.     

Sublingual misoprostol is as effective as intravenous oxytocin to reduce intra-operative blood loss during cesarean delivery in women living at high altitude

Objective: To assess the effect of sublingual misoprostol compared to intravenous oxytocin for blood loss during cesarean delivery in women living at high altitude.

Study design: In a randomized trial, conducted in Quito, Ecuador (2800?m above sea level), 100 women received either sublingual misoprostol (400?µg) or intravenous oxytocin (10?IU).

Results: Bleeding in the misoprostol was no different than in the oxytocin group. Shivering was reported in 66% of women in the misoprostol group.

Conclusion: Sublingual misoprostol might be a valid alternative to oxytocin reduce intra-operative blood loss during cesarean section in women living at high altitude.     

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.     

Disruption of Prior Uterine Incision following Misoprostol for Labor Induction in Women with Previous Cesarean Delivery

Background: Although induction of labor in women with prior cesareans is controversial, we compared misoprostol to oxytocin in such women in a randomized trial. The investigation was terminated prematurely because of safety concerns.Cases: Disruption of the prior uterine incision was found in two of 17 misoprostol-treated women. The first woman underwent repeat cesarean delivery at 42 weeks because of fetal tachycardia and repetitive late decelerations. A 10-cm vertical rent in the anterior myometrium was discovered. The second woman underwent induction for fetal growth restriction. Loss of fetal heart tones and abnormal abdominal contour prompted emergent cesarean for suspected uterine rupture. An 8-cm longitudinal uterine defect was found.Conclusion: When misoprostol is used in women with previous cesareans, there is a high frequency of disruption of prior uterine incisions.     

A randomized comparison between intravaginal misoprostol and prostaglandin E<Subscript>2</Subscript> for labor induction

Objective The aim of this randomized study was to compare the effectiveness, safety, and side effects of 6 h vaginal misoprostol versus vaginal prostaglandin E₂ (PGE₂) for labor induction. Study design Fifty microgram of misoprostol was given intravaginally in the misoprostol group (204 women), and 3 mg PGE₂ was given intravaginally in the PGE₂ group (211 women). In both groups, the dose was repeated every 6 h for a maximum of three doses, until active labor was achieved. Artificial rupture of membranes and oxytocin infusion was used during labor in both groups where it was indicated. Results The mean interval from the institution of labor induction to delivery was 11.3 ± 8.6 h for the misoprostol group, and 15.7 ± 9.3 h for PGE₂ group (P < 0.05). In the misoprostol group, oxytocin was used less frequently, but there was a higher prevalence of tachysystole. No statistically significant differences were observed between the two groups as regard abnormal patterns of fetal heart rate, the mode of delivery, and the need for neonatal intervention. Conclusion In conclusion, the intravaginal administration of 50 μg misoprostol at 6 h interval (maximum three doses) is comparable in safety, but more effective for induction of labor than 3 mg intravaginal PGE₂.     

Early versus late amniotomy for labour induction: a randomized controlled trial

Objective: To evaluate the impact of early vs. late amniotomy on delivery mode in women undergoing induction of labor. Study design: 143 women admitted for induction were randomized to early amniotomy (EA, concomitant with the beginning of oxytocin infusion; n = 71) or to late amniotomy (LA, four hours after the beginning of oxytocin; n = 72). Randomization was stratified by parity. The primary outcome was the rate of cesarean. Secondary outcomes were duration of labor and intrapartum fever. Results: The cesarean rate was similar between groups (18% vs. 17% among nulliparous; and 3% vs. 0% among parous women, in EA and LA group, respectively). However, EA was associated with shorter oxytocin-to-delivery interval (12 vs. 15?h) and a non-significant decrease in intrapartum fever (3% vs. 25%) than LA in nulliparous women (p = 0.05). Conclusion: For women undergoing oxytocin induction, early amniotomy is associated with shorter labor in nulliparous women with no effect on the risk of cesarean section in both nulliparous and multiparous women.     

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.)     

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.)     

Early versus delayed amniotomy during labor induction with oxytocin in women with Bishop’s score of ≥6: a randomized trial

Objective: To study the effect of “early amniotomy” {initiating induction of labor (IOL) with amniotomy followed by oxytocin} versus “late amniotomy” (initiating IOL with oxytocin followed by amniotomy 4–8?h later) in induced labor.

Methods and Materials: One hundred and fifty women with Bishop’s score of ≥6 undergoing IOL were randomized into “early amniotomy” and “delayed amniotomy”.

Results: Early amniotomy resulted in a reduced induction-delivery interval (IDI) (7.35 versus 11.66?h with delayed amniotomy, p?=?.000) but higher the caesarean section (CS) rate was observed (10.7 versus 2.7% with delayed amniotomy, p?=?.049). With early amniotomy, the proportion of women delivering within 12?h was higher (86.7 versus 60%, p?=?.000) and the maximum oxytocin concentration used was lower (30.05 versus 39.68?mU/min, p?=?.001) as compared to delayed amniotomy. The neonatal outcomes were similar in the two groups. Early amniotomy detected meconium prior to initiating uterine contractions with oxytocin in three women who underwent CS for meconium.

Conclusion: Initiating IOL with amniotomy in women with a favorable cervix was efficacious in expediting delivery, but it resulted in a higher CS rate. The higher CS rate was partly due to CS for meconium detected as a result of early amniotomy.

Clinical Trials Registry (CTRI), India: Registration number CTRI/2015/01/005418     

Comparison of two misoprostol regimens for mid-trimester pregnancy terminations after FIGO’s misoprostol dosage recommendation in 2012

Objective: To compare the safety and efficacy of two misoprostol regimens for mid-trimester pregnancy terminations.

Methods: Retrospective analysis of 263 cases of pregnancy terminations with misoprostol between 12 and 24 weeks was performed. Group 1 (total 129 patients) consisted of patients who were given 200?mcg vaginal misoprostol every 4?h until the abortion, whereas Group 2 patients (total 134 patients) were given misoprostol as in International Federation of Gynecology and Obstetrics’s (FIGO) 2012 recommendation. In case of a previous cesarean section doses were halved in both groups. Primary outcomes of the study were the time to abortion and the total drug dose used. Secondary outcome was the rate of complications.

Results: Total dose and time to abortion did not differ between the groups. As for complications, one patient (%0.8) in group 1 developed HELLP syndrome and had hysterotomy. One patient (%0.8) in group 2 had uterine rupture and had total hysterectomy. Two patients in both groups considered failure of induction and terminated with surgery (hysterotomy). Groups did not show difference in induction failure rates.

Conclusions: We respect the presence of dose recommendation stated by the FIGO and found similar results with our recent protocol. Other misoprostol regimens used worldwide should also be compared with this guideline in order to improve its efficacy.     

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.     

Induction of Labour With Prostaglandin Gel in Grand Multipara with a Previous Caesarean Delivery

ObjectiveThis study sought to evaluate the safety of induction of labour with prostaglandin E₂ (PGE₂) gel in grand multiparous (GMP) women and to compare the labour outcome of GMP women who have undergone one previous Caesarean section (CS) with that of GMP women who never had a previous CS.MethodsThis prospective cohort study (Canadian Task Force Classification II-2) evaluated induction of labour with 1 mg of PGE₂ gel in 96 GMP women with one previous CS (study group) and in 104 GMP women without previous CS (control group).ResultsOne uterine rupture occurred in the study group (1%), and another occurred in the control group (0.9%). Additional oxytocin was used in seven patients (7.3%) in the study group and in 28 others (26.9%) in the control group (P = 0.002). Both uterine ruptures occurred with oxytocin augmentation. One case of uterine scar dehiscence was found in the study group. There was no significant difference between the study group and the control group regarding the rate of vaginal delivery (74 [77.1%] vs. 78 [75%]) or the rate of CS (21 [21.9%] vs. 24 [23.1%]), respectively. There was no significant difference between the groups in 5-minute Apgar scores ≤7. There was no neonatal death in either group.ConclusionA low dose (1.0 mg) of PGE₂ gel for induction of labour in GMP women with one previous CS is appropriate and appears to be safe for both mother and baby. Augmentation by oxytocin should be used judiciously.