Disruption of prior uterine incision following misoprostol for labor induction in women with previous cesarean delivery

Misoprostol for Second-Trimester Pregnancy Termination in Women With a Prior Cesarean Delivery

OBJECTIVE

To evaluate the use of misoprostol in second-trimester abortion in women with prior cesarean deliveries.

METHODS

A review of women with prior cesarean deliveries undergoing abortion at 14-28 weeks of gestation for a fetal anomaly over a 7.5-year period. Outcome data were compared with a contemporaneous cohort of women with unscarred uteri undergoing the same procedure. Misoprostol was used to induce abortion in all cases, and a variety of dosage regimens were used, the most frequent being 400 mug vaginally every 6 hours (71.3%).

RESULTS

During the study period, 720 consecutive women underwent a second-trimester abortion for a fetal anomaly using misoprostol. One hundred one women (14%) had at least 1 prior cesarean delivery: 78 women had 1, 19 women had 2, and 4 women had 3 prior cesarean deliveries. Women with a prior cesarean birth were significantly older (30 years [interquartile range 26-35] versus 33 years [29-37], no cesarean delivery versus cesarean delivery, P = < .001) and of increased parity. The median gestational age at delivery was 19.4 weeks (interquartile range 18-20.7) versus 19.3 weeks (17.7-21), no cesarean delivery versus cesarean delivery, P = .48. The presence of a prior uterine scar did not impact upon abortion duration (16.6 hours [12.1-23.8] versus 14.5 hours [11.4-21.4], no cesarean delivery versus cesarean delivery, P = .07). No differences in blood loss, major hemorrhage, or blood transfusion occurred. There was no case of uterine rupture or hysterectomy.

CONCLUSION

In second-trimester abortion, the use of misoprostol in women with prior cesarean delivery was not associated with an excess of complications compared with women with unscarred uteri.

LEVEL OF EVIDENCE

II-2.

Do maternity care provider groups have different attitudes towards birth?

OBJECTIVE

To compare family physicians', obstetricians' and midwives' self-reported practices, attitudes and beliefs about central issues in childbirth.

DESIGN

Mail-out questionnaire. SETTING/POPULATION; All registered midwives in the province, and a sample of family physicians and obstetricians in a maternity care teaching hospital. Response rates: 91% (n = 50), 69% (n = 97) and 89% (n = 34), respectively.

METHODS

A postal survey.

MAIN OUTCOME MEASURES

Twenty-three five-point Likert scale items (strongly agree to strongly disagree) addressing attitudes toward routine electronic fetal monitoring, induction of labour, epidural analgesia, episiotomy, doulas, vaginal birth after caesarean section (VBACs), birth centres, provision educational material, birth plans and caesarean section.

RESULTS

Cluster analysis identified three distinct clusters based on similar response to the questions. The 'MW' cluster consisted of 100% of midwives and 26% of the family physicians. The 'OB' cluster was composed of 79% of the obstetricians and 16% of the family physicians. The 'FP' cluster was composed of 58% the family physicians and 21% the obstetricians. Members of the 'OB' cluster more strongly believed that women had the right to request a caesarean section without maternal/fetal indications (P < 0.001), that epidurals early in labour were not associated with development of fetal malpositions (P < 0.001) and that increasing caesarean rates were a sign of improvement in obstetrics (P < 0.001). The 'OB' cluster members were more likely to say they would induce women as soon as possible after 41 3/7 weeks of gestation (P < 0.001) and were least likely to encourage the use of birth plans (P < 0.001). The 'MW' cluster's views were the opposite of the 'OBs' while the 'FP' cluster's views fell between the 'MW' and 'OB' clusters.

CONCLUSIONS

In our environment, obstetricians were the most attached to technology and interventions including caesarean section and inductions, midwives the least, while family physicians fell in the middle. While generalisations can be problematic, obstetricians and midwives generally follow a defined and different approach to maternity care. Family physicians are heterogeneous, sometimes practising more like midwives and sometimes more like obstetricians.

Induction of labour for women with a previous Caesarean birth: A systematic review of the literature

AIMS

To compare the benefits and harms of planned elective repeat Caesarean section with induction of labour and to assess different methods of cervical ripening and induction of labour for women with a previous Caesarean birth who require induction of labour in a subsequent pregnancy.

METHODS

The Cochrane controlled trials register and MEDLINE (1966-current) were searched using the following terms: vaginal birth after C(a)esare(i)an, trial of labo(u)r, elective C(a)esare(i)an, C(a)esare(i)an repeat, induction of labo(u)r, prostaglandins, prostaglandin E(2), misoprostol, prostaglandin E(1) analogs, mifepristone, oxytocin, Syntocinon, randomis(z)ed controlled trial, randomis(z)ed trial and clinical trial, to identify all published randomised controlled trials with reported data comparing outcomes for women and infants who have a planned elective repeat Caesarean section with induction of labour; and different methods of induction of labour, where a prior birth was by Caesarean section.

RESULTS

There were no randomised controlled trials identified where women with a prior Caesarean birth, whose labour required induction in a subsequent pregnancy, compared elective repeat Caesarean section with induction of labour. There were three randomised controlled trials identified in which women with a prior Caesarean section were allocated to different methods of induction of labour - vaginal prostaglandin E(2) versus intravenous oxytocin; mifepristone versus placebo; and vaginal misoprostol versus intravenous oxytocin. These studies varied considerably in the methods used and meta-analysis was not appropriate.

CONCLUSIONS

There is a paucity of safety information for induction of labour agents in the women with a scarred uterus, and caution should be exercised in their use.

Medical management for termination of second and third trimester pregnancies: a comparison of strategies

OBJECTIVE

Misoprostol and sulprostone are prostaglandins that can be used for the termination of second and third trimester pregnancy. The aim of the present study was to compare the effectiveness of both agents for the termination of second and third trimester pregnancy in cases of congenital or genetic abnormalities, and for the induction of labour in cases of intra-uterine foetal death.

STUDY DESIGN

We collected data from all women who had been treated with misoprostol in the second or third trimester of pregnancy between January 2001 and July 2002 in cases of congenital or genetic abnormalities, and for the induction of labour in cases of intra-uterine foetal death. In cases where the foetus was alive, misoprostol was usually (77%) combined with mifepristone. Women were matched to women who had been treated with sulprostone for termination of second and third trimester pregnancy before 2001. We matched for hospital, previous vaginal delivery, intra-uterine death and duration of pregnancy. The primary outcome measure was time to delivery.

RESULTS

Since the treatment effect was different in patients in whom labour was induced for intra-uterine death and patients in whom labour was induced while the foetus was alive, the analysis was stratified for this parameter. In 94 patients with intra-uterine death, there was no significant difference in time to delivery, blood loss, operative removal of the placenta and need for pain relief between misoprostol and sulprostone. In vital pregnancy (n = 96), time to delivery was significantly shorter in the misoprostol group. The relative risk for haemorrhage exceeding 1000 ml in this group was 0.40 (95% confidence interval, CI, 0.13-1.2). We observed no significant differences with respect to operative removal of the placenta or need for pain relief.

CONCLUSION

In cases of intra-uterine death, the effectiveness of misoprostol for termination of pregnancy is comparable to that of sulprostone. In vital pregnancy, combination of mifepristone and misoprostol is more effective than sulprostone alone.

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.

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.

Induction of labour with an unfavourable cervix

Labour induction is undertaken when the advantages for the mother and/or the baby are considered to outweigh the disadvantages. When the uterine cervix is unfavourable, oxytocin, with or without amniotomy, is frequently ineffective. Vaginal prostaglandin E(2) is most commonly used if it is affordable. Evidence regarding many alternative methods is discussed in this chapter. Of particular interest are misoprostol and extra-amniotic saline infusion.Misoprostol, an orally active prostaglandin E(1) analogue, has been used widely by the vaginal and oral routes for labour induction at or near term. Several recent trials have confirmed that it is highly effective. Overall Caesarean section rates appear to be reduced, despite a relative increase in Caesarean sections for fetal heart rate abnormalities. Concern remains regarding increased rates of uterine hyperstimulation and meconium-stained amniotic fluid, although data on perinatal outcome have been reassuring. Postpartum haemorrhage may be increased following labour induction with misoprostol, and isolated reports of uterine rupture, with or without previous Caesarean section, have appeared. Using small dosages appears to reduce adverse outcomes. Very large trials are needed to evaluate rare adverse outcomes.Extra-amniotic saline infusion is an effective method which appears to reduce the risk of uterine hyperstimulation that occurs with the use of exogenous uterotonics.

Induction of labor: the misoprostol controversy

Misoprostol (Cytotec) is safe and effective for induction of labor, although it is not approved by the Food and Drug Administration (FDA) for use in pregnancy. In August 2000, the manufacturer of misoprostol warned against its use in pregnancy because of its abortifacient properties and cited reports of maternal and fetal deaths when misoprostol was used to induce labor, fueling the misoprostol controversy. More than 45 randomized trials including more than 5400 women have found vaginal misoprostol to be more effective than oxytocin or vaginal prostaglandin E2 at effecting vaginal delivery within 24 hours. Cesarean delivery rates with vaginal misoprostol are lower than with oxytocin alone, but similar to prostaglandin E2. There have been no significant differences in the frequency of serious adverse maternal or neonatal outcomes with low-dose misoprostol compared with oxytocin or prostaglandin E2; however, the relative risk of rare adverse outcomes with misoprostol is unknown. The data suggest that absolute risks are low when misoprostol is used appropriately. We recommend 25 mcg vaginally every 4 to 6 hours for carefully selected patients in closely monitored settings. Whether misoprostol will prove to be the most cost-effective agent for inducing labor in women with an unfavorable cervix remains to be determined.

Uterine rupture during VBAC trial of labor: risk factors and fetal response

For the woman with a prior uterine scar, neither repeat elective cesarean birth nor vaginal birth after cesarean birth (VBAC) trial of labor (TOL) is risk-free. When VBAC-TOL is successful, it is associated with less morbidity than repeat cesarean birth. However, when VBAC-TOL fails due to uterine rupture, severe consequences often ensue. The challenge for clinicians today is to provide women who desire TOL after cesarean birth, a more individualized risk assessment of uterine rupture, thereby enhancing success and optimizing outcome. This article examines major risk factors for uterine rupture during VBAC-TOL. In addition, fetal response to uterine rupture and neonatal outcomes are reviewed.

VBAC--is it worth the risk?

Enthusiasm for vaginal birth after cesarean section has waned. As a result, the cesarean birth rate is again on the rise. As a medical community and society we must decide whether the most appropriate question is "What is safest for my baby?" or "Is the risk associated with vaginal birth after cesarean acceptable?" There are risks associated with vaginal birth after cesarean, but in a hospital setting with appropriate resources these risks are low and would still seem to be acceptable.

Vaginal misoprostol for cervical ripening and induction of labour

BACKGROUND

Misoprostol (Cytotec, Searle) is a prostaglandin E1 analogue marketed for use in the prevention and treatment of peptic ulcer disease. It is inexpensive, easily stored at room temperature and has few systemic side effects. It is rapidly absorbed orally and vaginally. Although not registered for such use, misoprostol has been widely used for obstetric and gynaecological indications, such as induction of abortion and of labour. This is one of a series of reviews of methods of cervical ripening and labour induction using standardised methodology.

OBJECTIVES

To determine the effects of vaginal misoprostol for third trimester cervical ripening or induction of labour.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register (October 2002), the Cochrane Controlled Trials Register (The Cochrane Library, Issue 3, 2002) and bibliographies of relevant papers.

SELECTION CRITERIA

The criteria for inclusion included the following: (1) clinical trials comparing vaginal misoprostol used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed above it on a predefined list of labour induction methods; (2) random allocation to the treatment or control group; (3) adequate allocation concealment; (4) violations of allocated management not sufficient to materially affect conclusions; (5) clinically meaningful outcome measures reported; (6) data available for analysis according to the random allocation; (7) missing data insufficient to materially affect the conclusions.

DATA COLLECTION AND ANALYSIS

A strategy was developed to deal with the large volume and complexity of trial data relating to labour induction. This involved a two-stage method of data extraction. The initial data extraction was done centrally, and incorporated into a series of primary reviews arranged by methods of induction of labour, following a standardised methodology. The data will be extracted from the primary reviews into a series of secondary reviews, arranged by category of woman. To avoid duplication of data in the primary reviews, the labour induction methods have been listed in a specific order, from one to 25. Each primary review includes comparisons between one of the methods (from two to 25) with only those methods above it on the list.

MAIN RESULTS

Sixty-two trials have been included. Compared to placebo, misoprostol was associated with increased cervical ripening (relative risk of unfavourable or unchanged cervix after 12 to 24 hours with misoprostol 0.09, 95% confidence interval (CI) 0.03 to 0.24). It was also associated with reduced failure to achieve vaginal delivery within 24 hours (relative risk (RR) 0.36, 95% CI 0.19 to 0.68). Uterine hyperstimulation, without fetal heart rate changes, was increased (RR 11.7 95% CI 2.78 to 49). Compared with vaginal prostaglandin E2, intracervical prostaglandin E2 and oxytocin, vaginal misoprostol labour induction was associated with less epidural analgesia use, fewer failures to achieve vaginal delivery within 24 hours and more uterine hyperstimulation. Compared with vaginal or intracervical prostaglandin E2, oxytocin augmentation was less common, with misoprostol and meconium-stained liquor more common. Compared with intracervical prostaglandin E2, unchanged or unfavourable cervix after 12 to 24 hours was less common with misoprostol. Lower doses of misoprostol compared to higher doses were associated with more need for oxytocin augmentation, less uterine hyperstimulation, with and without fetal heart rate changes, and a non-significant trend to fewer admissions to neonatal intensive care unit. Use of a gel preparation of misoprostol versus tablet was associated with less hyperstimulation and more use of oxytocin and epidural analgesia. Information on women's views is conspicuously lacking.

REVIEWER'S CONCLUSIONS

Vaginal misoprostol appears to be more effective than conventional methods of cervical ripening and labour induction. The apparent increase in uterine hyperstimulation is of concern. Doses not exceeding 25 mcg four-hourly of concern. Doses not exceeding 25 mcg four-hourly appeared to have similar effectiveness and risk of uterine hyperstimulation to conventional labour inducing methods. The studies reviewed were not large enough to exclude the possibility of rare but serious adverse events, particularly uterine rupture, which has been reported anecdotally following misoprostol use in women with and without previous caesarean section. The authors request information on cases of uterine rupture known to readers. Further research is needed to establish the ideal route of administration and dosage, and safety. Professional and governmental bodies should agree guidelines for the use of misoprostol, based on the best available evidence and local circumstances.

Preinduction cervical ripening: basis and methods of current practice

The rate of women undergoing labor induction is increasing, primarily because of patient-physician preferences. The widespread availability of preinduction cervical ripening agents has contributed to this rising trend. Approximately half of all women undergoing an induction of labor will have an unfavorable cervix that will require some ripening agent. Pharmacologic and mechanical dilator techniques have been proven to ripen the unfavorable cervix. A topically applied prostaglandin product, containing either dinoprostone or misoprostol, is the most popular means to soften and dilate the cervix. Any uterine hyperstimulation may be reversed by administering a tocolytic drug and, if possible, by removal of the ripening agent. A minimum trial of adequate labor is necessary before considering the induction to be a failure. Cesarean delivery rates may be higher and the length of hospital stay more prolonged. Careful consideration about the need for labor induction is recommended until prospective clinical trials can better validate marginal reasons for cervical ripening.

A randomized controlled trial comparing two protocols for the use of misoprostol in midtrimester pregnancy termination

OBJECTIVE

Our purpose was to compare the efficacy of oral misoprostol with that of vaginal misoprostol for midtrimester termination of pregnancy.

STUDY DESIGN

Women seen for midtrimester pregnancy termination were randomly assigned to receive either misoprostol orally in a dose of 200 microg every hour for 3 hours followed by 400 microg every 4 hours or vaginally in a dose of 400 microg every 4 hours. The protocol was followed for 24 hours, after which time further management was at the discretion of the attending physician. The primary outcome measure was the induction-to-delivery interval. Sample size was calculated a priori. Statistical analysis was performed with the t test for continuous variables and the chi(2) test for categorical variables. P <.05 was considered significant.

RESULTS

One hundred fourteen women were randomized, with 49 receiving vaginal misoprostol and 65 receiving oral misoprostol. The two groups were comparable with respect to maternal age, parity, indication for pregnancy termination, gestational age, and maternal weight. The mean induction-to-delivery interval was significantly shorter for the vaginal group (19.6 +/- 17.5 hours vs 34.5 +/- 28.2 hours, P <.01). Length of stay was also shorter in the vaginal group (32.3 +/- 17.3 hours vs 50.9 +/- 27.9 hours, P <.01). Significantly more patients in the vaginal group were delivered within 24 hours (85.1% vs 39.5%, P <.01), and more patients in the oral group required changes in the method of induction when they were undelivered after 24 hours (38.2% vs 7%, P <.01). The only complication was an increase in febrile morbidity in the vaginal group (25% vs 6.7%, P =.046). This did not result in an increased use of antibiotics, and all the fevers resolved post partum without further complications.

CONCLUSIONS

Vaginal administration of misoprostol resulted in a shorter induction-to-delivery interval. The shorter length of stay should result in improved patient care.

Comparison of 25 and 50 microg vaginally administered misoprostol for preinduction of cervical ripening and labor induction

Our purpose was to compare the efficacy of 25 microg and 50 microg intravaginally administered misoprostol tablets for cervical ripening and labor induction. Either 25-microg (n: 58) or 50-microg (n: 56) misoprostol tablets were randomly administered intravaginally to 114 subjects with an unripe cervix for labor induction. The physician was blinded to the medication. Intravaginal misoprostol was given every 4 h until the onset of labor. The mean Bishop score before misoprostol administration was 2.1 +/- 1.6 in the 25-microg group and 2.0 +/- 1.4 in the 50-microg group (p > 0.05). With the 25-microg dose the time until delivery was significantly longer (991.2 +/- 514.4 min vs. 703.12 +/- 432.6 min in the 50-microg group). The use of oxytocin augmentation was significantly higher in the 25-microg group (63.8%) than the 50-microg group (32.1%; p < 0.05). The proportions of patients with tachysystoles and hypersystoles were not significantly different between the two groups (19 and 6.9%, respectively, in the 25-microg group and 25 and 17.8%, respectively, in 50-microg group; p > 0.05). Overall, in the 25-microg group more women achieved vaginal delivery (79.3 vs. 60.7%; p < 0.05). The rate of cesarean sections due to non-reassuring fetal status was higher in the 50-microg misoprostol group (28.6 vs. 10.3%; p < 0.05). The number of neonates with a low 1-min Apgar score (<7) was significantly higher in the 50-microg misoprostol group (26.8 vs. 8.6%; p < 0.05), but 5-min Apgar scores and umbilical artery blood gas values at the time of delivery were not significantly different between the groups (p > 0.05). One patient in the 25-microg group suffered a ruptured uterus. Intravaginal administration of 25 microg of misoprostol is a clinically effective labor induction regimen and has the least adverse effects and complications.

Induction of labour with misoprostol

Misoprostol, an orally active prostaglandin E1 analogue, has been used widely by the vaginal and oral routes for labour induction at or near term. Several recent trials have confirmed that it is highly effective. Overall caesarean section rates appear to be reduced, despite a relative increase in caesarean sections for fetal heart rate abnormalities. Concern remains regarding increased rates of uterine hyperstimulation and meconium-stained amniotic fluid, although data on perinatal outcomes have been reassuring. Recent reports reviewed here have raised the possibility that postpartum haemorrhage may be increased after the induction of labour with misoprostol, and isolated reports of uterine rupture with or without previous caesarean section, continue to appear. Using small dosages appears to reduce adverse outcomes. Very large trials are needed to evaluate rare adverse outcomes.

Titrated oral misoprostol solution for induction of labour: a multi-centre, randomised trial

OBJECTIVES

To determine the effects of titrated oral misoprostol solution, compared with vaginal dinoprostone.

STUDY DESIGN

Open, randomised clinical trial.

SETTING

Academic hospitals in South Africa and Liverpool, UK.

METHODS

Women undergoing induction of labour after 34 weeks of pregnancy were allocated by randomised, sealed opaque envelopes, to induction of labour with titrated oral misoprostol solution, or two doses of vaginal dinoprostone (2mg) administered six hours apart. Failure to deliver within 24 hours of randomisation was the primary outcome on which the sample size was based. The data were analysed by intention-to-treat.

RESULTS

Six hundred and ninety-five women were randomly allocated: 346 to oral misoprostol and 349 to vaginal dinoprostone. There were no significant differences in substantive outcomes. Vaginal delivery within 24 hours was not achieved in 38% of women in the oral misoprostol group and 36% in the vaginal dinoprostone group (RR 1.08; 95% CI 0.89-1.31). The caesarean section rates were 16% and 20%, respectively (RR 0.80; 95% CI 0.58-1.11). Hyperstimulation with fetal heart rate changes occurred in 4% of women in the oral misoprostol group and 3% after vaginal dinoprostone (RR 1.32, 95% CI 0.59-2.98). The response to induction of labour in women with unfavourable cervices was somewhat slower with misoprostol when membranes were intact, and with dinoprostone when membranes were ruptured. There were no differences in neonatal outcome between the two groups.

CONCLUSIONS

This new approach to oral misoprostol administration was successful in minimising the risk of uterine hyperstimulation, which has been a feature of misoprostol use for induction of labour, at the expense of a somewhat slower response in women with intact membranes and unfavourable cervices. Misoprostol is not registered for use in pregnant women, and further research is needed to confirm optimal and safe dosages.

Risk of uterine rupture during labor among women with a prior cesarean delivery

BACKGROUND

Each year in the United States, approximately 60 percent of women with a prior cesarean delivery who become pregnant again attempt labor. Concern persists that a trial of labor may increase the risk of uterine rupture, an uncommon but serious obstetrical complication.

METHODS

We conducted a population-based, retrospective cohort analysis using data from all primiparous women who gave birth to live singleton infants by cesarean section in civilian hospitals in Washington State from 1987 through 1996 and who delivered a second singleton child during the same period (a total of 20,095 women). We assessed the risk of uterine rupture for deliveries with spontaneous onset of labor, those with labor induced by prostaglandins, and those in which labor was induced by other means; these three groups of deliveries were compared with repeated cesarean delivery without labor.

RESULTS

Uterine rupture occurred at a rate of 1.6 per 1000 among women with repeated cesarean delivery without labor (11 women), 5.2 per 1000 among women with spontaneous onset of labor (56 women), 7.7 per 1000 among women whose labor was induced without prostaglandins (15 women), and 24.5 per 1000 among women with prostaglandin-induced labor (9 women). As compared with the risk in women with repeated cesarean delivery without labor, uterine rupture was more likely among women with spontaneous onset of labor (relative risk, 3.3; 95 percent confidence interval, 1.8 to 6.0), induction of labor without prostaglandins (relative risk, 4.9; 95 percent confidence interval, 2.4 to 9.7), and induction with prostaglandins (relative risk, 15.6; 95 percent confidence interval, 8.1 to 30.0).

CONCLUSIONS

For women with one prior cesarean delivery, the risk of uterine rupture is higher among those whose labor is induced than among those with repeated cesarean delivery without labor. Labor induced with a prostaglandin confers the highest risk.

Uterine rupture associated with vaginal birth after cesarean section: a complication of intravaginal misoprostol?

Intravaginal misoprostol has become increasingly employed for labor induction among patients with an unfavorable Bishop's score. Almost all of the reported studies have specifically excluded patients with prior uterine surgery. There has been, therefore, very little information concerning its usage among patients attempting vaginal birth after cesarean section. We report a patient with two prior low transverse uterine incisions who experienced uterine rupture after having received a single 25-microg intravaginal dose of misoprostol.

Vaginal birth after caesarean (VBAC)

This review of vaginal birth after caesarean (VBAC) focuses on practical issues that will be useful for the physician in training and the obstetrician in clinical practice. Although VBAC has long been a common practice in many European nations, the same has not been true in North America. As recently as 1970 essentially all hospitals in the United States maintained a policy that women with a history of previous caesarean delivery would undergo repeat caesarean operations for any and all subsequent births. Although VBAC rates in many nations increased dramatically in the 1980s and 1990s, many aspects of trial of labour (also known as trial of scar) remain controversial at the dawn of the 21st century.

Labor induction

Labor induction has become commonplace in modern obstetrics. The increasing rate of labor induction has probably played a role in the increased rate of cesarean delivery observed in the United States during the past few decades. Clearly, the favorability of the cervix has a substantial impact on the potential success of any labor induction. Induction in the setting of an unfavorable cervix can result in prolonged induction, prolonged hospitalization, failed induction, and an increased cesarean delivery rate. In this modern era of healthcare reform and cost containment, the identification of therapeutic strategies to enhance the success and cost-effectiveness of labor induction are of great interest. Ongoing research is needed to advance our knowledge of the mechanisms of parturition and cervical ripening in order to direct interventions for labor induction more effectively.

Uterine emergencies. Atony, inversion, and rupture

Uterine atony, inversion, and rupture are potentially fatal events that may occur in pregnancy. They are obstetric emergencies that require immediate attention. Although all women may experience these complications, identification or known risk factors allow the obstetric team to prepare for rapid diagnosis and intervention. This article includes management options to help prepare for these uncommon events.

Labor induction with misoprostol

Misoprostol, a prostaglandin E(1 ) analog, is widely used in the United States for cervical ripening and labor induction. Its use for these indications is not approved by the US Food and Drug Administration. The only Food and Drug Administration-approved indication in the product labeling is the treatment and prevention of intestinal ulcer disease resulting from nonsteroidal anti-inflammatory use. Multiple trials have proved that misoprostol is an effective agent for cervical ripening and labor induction in term pregnancy; however, investigations continue regarding the optimal dose, dosing regimen, and route of administration. Uterine contraction abnormalities are often found in association with higher misoprostol doses. Some trials also indicate increased frequencies of meconium passage, neonatal acidemia, and cesarean delivery for fetal distress in women receiving higher doses of misoprostol. Overall, most trials fail to demonstrate a significant change in the cesarean delivery rate with the use of this agent. Misoprostol is an effective agent for cervical ripening and labor induction when used in a judicious and cautious fashion.

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.

Cervical ripening

Induction of labor is indicated when the benefits to either the mother or the fetus outweigh the benefits of continuing the pregnancy. The state of the cervix is clearly related to the success of labor induction and the duration of labor. In cases of unfavorable cervices, physicians usually use a ripening agent before inducing labor. Unfortunately, as reviewed in this article, the ideal ripening agent is not found yet. No method of cervical ripening has shown a consistent and significant reduction in CS rate. In fact, women with the most unfavorable cervices (Bishop score, < or = 2) still face high rates of induction failure and CS.

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.