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

Validation of updated antenatal vaginal birth after caesarean section prediction model without race and ethnicity in Australia

BACKGROUND

The Grobman antenatal nomogram to predict likelihood of successful vaginal birth after caesarean section (VBAC) has been validated in multiple institutions. However, due to concerns regarding inclusion of ethnicity, a new nomogram has been developed.

AIM

The aim was to evaluate the efficacy of the updated Grobman nomogram without ethnicity in a regional hospital in Australia.

MATERIALS AND METHODS

This was a retrospective cohort study of women electing to have a VBAC at a regional hospital over a nine-year period. Maternal demographics and obstetric outcomes were collected. Women were assigned a predicted likelihood of successful VBAC using the updated Grobman nomogram, with variables such as age, pre-pregnancy weight, height and arrest disorder as indications for previous caesarean birth, previous vaginal birth, previous VBAC and treated chronic hypertension. The predicted likelihood of successful VBAC was compared with actual successful VBAC rates.

RESULTS

A total of 541 women attempted VBAC with a VBAC success rate of 74.3% (402/541). The nomogram demonstrated good fit, with a receiver operating curve area under the curve of 0.707 (95% confidence interval 0.659-0.755). Using a cut-off value of 0.5, the success rate of classification with this model was 74.3%. On comparing each predicted decile, the nomogram performed poorly in those predicted to have a <40% chance of successful VBAC.

CONCLUSIONS

This study confirms the use of the updated Grobman nomogram without ethnicity, alongside usual counselling, to provide individualised advice for informed decision-making. However, clinicians should be mindful of the limitation of poor accuracy in women with a low predicted probability of VBAC.

Trial of labor of vertex-nonvertex twins following a previous cesarean delivery

BACKGROUND

Maternal and neonatal outcomes of trial of labor after cesarean delivery of twins are similar to those of singleton trials of labor after cesarean delivery. However, previous studies did not stratify outcomes by second-twin presentation on admission to labor.

OBJECTIVE

To examine maternal and neonatal outcomes following trial of labor after cesarean delivery in twins with vertex-nonvertex presentation.

STUDY DESIGN

A retrospective multicenter study was conducted including data on deliveries occurring between the years 2005 and 2020. We included trials of labor after a previous cesarean delivery (at ≥32^0/7 weeks' gestation) of twin gestations with a vertex-presenting first twin on admission to labor. The exposed group was defined as deliveries with a nonvertex second twin at admission to labor, whereas the comparison group included deliveries with a vertex second twin at admission. Only parturients who attempted vaginal delivery were included. Cases of prelabor fetal death of either twin or major fetal anomalies were excluded. The primary outcome was uterine rupture.

RESULTS

A total of 236 twin trials of labor after cesarean delivery were included, of which 128 involved nonvertex second twins and 108 a second vertex twin. Uterine rupture rates were comparable between the groups (1/128 [0.9%] vs 1/108 [0.8%]; P=1.000). Successful trial of labor after cesarean delivery of both twins occurred in 76.6% of the exposed group vs 81.5% of the comparison group, whereas cesarean delivery of both twins was performed in 21.9% of the exposed group vs 17.6% of the comparison group (P=.418; odds ratio, 1.32; confidence interval, 0.7-2.5). Two cases of cesarean delivery of the second twin occurred in the exposed group and 1 in the comparison group (1.6% vs 0.9%, respectively, P=1.000). There was no difference between the groups in maternal outcomes, including rates of postpartum hemorrhage, blood transfusion, placental abruption, thromboembolic events, and maternal fever. Neonatal outcomes were also comparable between the groups, including rates of intensive care admission and low (≤7) 5-minute Apgar scores.

CONCLUSION

Our data show that trial of labor after cesarean delivery of noncephalic second twins holds favorable maternal and neonatal outcomes, comparable with those of vertex-vertex trials of labor after cesarean delivery. Second-twin noncephalic presentation should not discourage parturients and caregivers from considering trial of labor after cesarean delivery if desired.

Number of prior vaginal deliveries and trial of labor after cesarean success

OBJECTIVE

Prior vaginal delivery (VD), including vaginal birth after cesarean (VBAC), is one of the greatest predictors of successful trial of labor after cesarean (TOLAC) and uterine rupture. We aimed to evaluate VBAC and uterine rupture rates associated with TOLAC in women with VD prior to cesarean delivery (CD) or with prior VBAC, and the cumulative effect of the number of prior VD's.

STUDY DESIGN

This retrospective study included women having TOLAC between 2005-2019. The study compared the caesarean and uterine rupture rates of TOLAC in women with only prior VD as compared to women with only prior VBAC. Comparison analysis was performed by univariate analysis and followed by adjusted multiple logistic regression models. Receiver operating characteristic (ROC) and decision tree analyses (chi-square automatic interaction detection algorithm) was conducted to evaluate the influence of the number of prior VD's on the likelihood of successful TOLAC.

RESULTS

Overall, 9,038 women met the inclusion criteria. Women with prior VBAC and prior VD showed significantly higher rates of successful VBAC compared to those with no prior VD or prior VBAC (96 % and 86 % vs 76 %; p < 0.01). However, women with prior VBAC but not women with prior VD showed significantly lower rates of uterine rupture compare to women with no prior VD or VBAC (0.1 % vs 0.6 % and 0.6 %; p < 0.01). The prevented fraction of TOLAC success was significantly higher in women with prior VBAC than that of women with VD prior to CD (83 % vs. 42 %, p < 0.01). ROC curve showed that the number of prior VBACs was a better predictor of TOLAC success and uterine rupture than the number of prior VD's. However, each single variable was found to have low positive predictive value (PPV) and requires other variables to improve the prediction. Finally, decision tree analysis demonstrated significant association between TOLAC success rate and prior VBAC, prior VD, and CD indications, without any association with the number of prior deliveries.

CONCLUSION

Prior VBAC has some prediction value for TOLAC success and uterine rupture. However, it has low PPV as a single variable and requires other variables to improve the prediction. The number of prior VDs is not improving prediction.

Induction of labor after one previous Cesarean section in women with an unfavorable cervix: A retrospective cohort study

Objective

Uterine rupture is a well-known but unusual complication in vaginal deliveries with a Cesarean section in the history. The risk of uterine rupture is at least two-fold when labor is induced. In Sweden, women are allowed to deliver vaginally after one previous Cesarean section, regardless if labor starts spontaneously or is induced. The aim of the study is to compare the proportion of uterine ruptures between the three methods (balloon catheter, Minprostin® and Cytotec®) for induction of labor in women with an unfavorable cervix and one previous Cesarean section.

Material and methods

Retrospective cohort study of all women with one previous Cesarean section and induction of labor with an unfavorable cervix at the four largest clinics in Stockholm during 2012–2015. Inclusion criteria: Women with a previous Cesarean section and induction of labor with a viable fetus, cephalic presentation, singleton, at ≥34 w, (n = 910).

Results

3.0% (27/910) of the women with induction of labor had a uterine rupture, 91% of them had no previous vaginal delivery. The proportion of uterine ruptures was 2.0% (6/295) with orally administrated Cytotec®, 2.1% (7/335) with balloon catheter and 5.0% (14/ 281) when Minprostin® was used.

Conclusions

No difference in the proportion of uterine ruptures was shown when orally administrated Cytotec® and balloon catheter were compared (p = 0.64). Orally administrated Cytotec® and balloon catheter give a high success rate of vaginal deliveries (almost 70%) despite an unfavorable cervix.

Maternal and newborn outcomes after a prior cesarean birth by planned mode of delivery and history of prior vaginal birth in British Columbia: a retrospective cohort study

BACKGROUND

As rates for cesarean births continue to rise, more women are faced with the choice to plan a vaginal or a repeat cesarean birth after a previous cesarean. The objective of this population-based retrospective cohort study was to compare the safety of planned vaginal birth with cesarean birth after 1-2 previous cesarean sections.

METHODS

We identified singleton term births in British Columbia from 2000 to 2008 using data from the British Columbia Perinatal Data Registry. Women carrying a singleton fetus in cephalic presentation at term (37-41 weeks of gestation completed) with 1-2 prior cesarean births were included. Those with gestational hypertension, pre-existing diabetes and cardiac disease were excluded. Maternal and neonatal outcomes were classified as either life-threatening or non-life threatening. We compared outcomes among women with none versus at least 1 previous vaginal birth, by planned method of delivery. We estimated relative risks (RR) and 95% confidence intervals (CI) for composite outcomes using Poisson regression.

RESULTS

Of the 33 812 women in the sample, 5406 had a history of vaginal delivery and 28 406 did not. The composite risk for life-threatening maternal outcomes was elevated among women planning vaginal compared with cesarean birth both with and without a prior vaginal birth (RR 2.06, 95% CI 1.20-3.52) and (2.52, 95% CI 2.04-3.11). Absolute differences (attributable risk [AR]) were 1.01% and 1.31% respectively. Non-life threatening maternal outcomes were decreased among women planning a vaginal birth if they had had at least 1 prior vaginal delivery (RR 0.51, 95% CI 0.33-0.77; AR 1.17%). The composite risk of intrapartum stillbirth, neonatal death or life-threatening neonatal outcomes did not differ among women planning vaginal or cesarean birth with a prior vaginal delivery and non-life threatening neonatal outcomes were decreased, (RR 0.67, 95% CI 0.52-0.86); AR 1.92%).

INTERPRETATION

After 1 or 2 previous cesarean births, risks for adverse outcomes between planned vaginal and cesarean birth are reduced among women with a prior vaginal birth. Our data offer women and their health care providers the opportunity to consider risk profiles separately for women who have and have not had a prior vaginal delivery.

The risk of uterine rupture is not increased with single- compared with double-layer closure: a Swedish cohort study

OBJECTIVE

To compare single- with double-layer closure of the uterus for the risk of uterine rupture in women attempting vaginal birth after one prior caesarean delivery.

DESIGN

Cohort study.

SETTING

Sweden.

POPULATION

From a total of 19 604 nulliparous women delivered by caesarean section in the years 2001-2007, 7683 women attempting vaginal birth in their second delivery were analysed.

METHODS

Data from population-based registers were linked to hospital-based registers that held data from maternity and delivery records. Logistic regression was used to estimate the risk of uterine rupture after single- or double-layer closure of the uterus. Results are presented as odds ratios (ORs) with 95% confidence intervals (95% CIs).

MAIN OUTCOME MEASURE

Uterine rupture.

RESULTS

Uterine rupture during labour occurred in 103 (1.3%) women. There was no increased risk of uterine rupture when single- was compared with double-layer closure of the uterus (OR 1.17; 95% CI 0.78-1.76). Maternal factors associated with uterine rupture were: age ≥35 years and height ≤160 cm. Factors from the first delivery associated with uterine rupture in a subsequent delivery were: infection and giving birth to an infant large for gestational age. Risk factors from the second delivery were induction of labour, use of epidural analgesia, and a birthweight of ≥4500 g.

CONCLUSIONS

There was no significant difference in the rate of uterine rupture when single-layer closure was compared with double -layer closure of the uterus.

Prediction of scar integrity and vaginal birth after caesarean delivery

A statistically significant association with uterine rupture during a trial of labour after caesarean delivery was found in at least two studies for the following variables: inter-delivery interval (higher risk with short interval), birth weight (higher risk if 4000 g or over), induction of labour (higher risk), oxytocin dose (higher risk with higher doses), and previous vaginal delivery (lower risk). However, no clinically useful risk estimation model that includes clinical variables has been published. A thin lower uterine segment at 35-40 weeks, as measured by ultrasound in women with a caesarean hysterotomy scar, increases the risk of uterine rupture or dehiscence. No cut-off for lower uterine segment thickness, however, can be suggested because of study heterogeneity, and because prospective validation is lacking. Large caesarean hysterotomy scar defects in non-pregnant women seen at ultrasound examination increase the risk of uterine rupture or dehiscence in subsequent pregnancy, but the strength of the association is unknown. To sum up, we currently lack a method that can provide a reliable estimate of the risk of uterine rupture or dehiscence during a trial of labour in women with caesarean hysterotomy scar(s).

Trends, risk factors and pregnancy outcome in women with uterine rupture

OBJECTIVE

This study aimed at determining trends, risk factors and pregnancy outcome in women with uterine rupture.

METHODS

A population-based study, comparing all singleton deliveries with and without uterine rupture between 1988 and 2009 was conducted. Statistical analysis was performed using a multiple logistic regression analysis.

RESULTS

Uterine rupture occurred in 0.06% (n = 138) of all deliveries included in the study (n = 240,189); 59% in women with a previous cesarean delivery (CD). A gradual increase in the rate of uterine rupture from 1988 (0.01%) to 2009 (0.05%) was noted. Independent risk factors for uterine rupture in a multivariable analysis were: previous CD (OR = 7.4, 95% CI 5.2-10.6), preterm delivery (<37 weeks, OR = 2.5, 95% CI 1.5-4.1), malpresentation (OR = 3.0, 95% CI 1.9-4.5), parity (OR = 1.2, 95% CI 1.1-1.3 for each birth), and dystocia during the first and second stages of labor (OR = 4.1, 95% CI 2.3-7.4 and OR = 11.2, 95% CI 6.7-18.7, respectively). Uterine rupture led to significant maternal morbidity and perinatal mortality. In another multivariable analysis, with perinatal mortality as the outcome variable uterine rupture was noted as an independent risk factor for perinatal mortality (adjusted OR = 17.7; 95% CI 10.0-31.4, P < .01).

CONCLUSIONS

Uterine rupture, associated with previous cesarean delivery, malpresentation, and labor dystocia, is an independent risk factor for perinatal mortality.

Risk of uterine rupture in women undergoing trial of labour with a history of both a caesarean section and a vaginal delivery

PURPOSE

To determine the risk of uterine rupture for women undergoing trial of labour (TOL) with both a prior caesarean section (CS) and a vaginal delivery.

METHODS

A systematic literature search was performed using keywords for CS and uterine rupture. The results were critically appraised and the data from relevant and valid articles were extracted. Odds ratios were calculated and a pooled estimate was determined using the Mantel-Haenszel method.

RESULTS

Five studies were used for final analysis. Three studies showed a significant risk reduction for women with both a previous CS and a prior vaginal delivery (PVD) compared to women with a previous CS only, and two studies showed a trend towards risk reduction. The absolute risk of uterine rupture with a prior vaginal delivery varied from 0.17 to 0.46%. The overall odds ratio for PVD was 0.39 (95% CI 0.29-0.52, P < 0.00001).

CONCLUSION

Women with a history of both a CS and vaginal delivery are at decreased risk of uterine rupture when undergoing TOL compared with women who have only had a CS.

Uterine rupture during a trial of labor after previous cesarean delivery

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

Birth after previous cesarean delivery: short-term maternal outcomes

An estimated 40% of the 1.3 million cesarean deliveries performed each year in the United States are repeat procedures. The appropriate clinical management approach for women with previous cesarean delivery remains challenging because options are limited. The risks and benefits of clinical management choices in the woman's health need to be quantified. Thus, we discuss the available published scientific data on (1) the short-term maternal outcomes of trial of labor after cesarean and elective repeat cesarean delivery, (2) the differences between outcomes for both, (3) the important factors that influence these outcomes, and (4) successful vs. unsuccessful vaginal birth after cesarean. For women with a previous cesarean delivery, a successful trial of labor offers several distinct, consistently reproducible advantages compared with elective repeat cesarean delivery, including fewer hysterectomies, fewer thromboembolic events, lower blood transfusion rates, and shorter hospital stay. However, when trial of labor after cesarean fails, emergency cesarean is associated with increased uterine rupture, hysterectomy, operative injury, blood transfusion, endometritis, and longer hospital stay. Care of women with a history of previous cesarean delivery involves a confluence of interactions between medical and nonmedical factors; however, the most important determinants of the short-term outcomes among these women are likely individualized counseling, accurate clinical diagnoses, and careful management during a trial of labor. We recommend a randomized controlled trial among women undergoing a TOLAC and a longitudinal cohort study among women with previous cesarean to evaluate adverse outcomes, with focused attention on both mother and the infant.

[Frequency of uterine rupture at delivery and accompanying risks for the mother and the newborn]

BACKGROUND/AIM

Uterine rupture at delivery is a severe lifethreatening complication for both mather and the newborn. The aim of the study was to determine the frequency of total number uterine rupture within the deliveries, to perceive circumstances and causes that lead to rupture, to establish perinatal and maternal mortality and to present our therapeutic procedure.

METHODS

In the group of 37 ruptures at 59 660 deliveries from the period 1991-2000 included in this retrospective study we analyzed age, level of education, gestational age, parity, previous caesarian section and other operations on uterus, time of diagnosing rupture, grade and place of rupture, use of Syntocinon and Prostaglandin at delivery, perinatal and maternal mortality, as well as therapeutic procedures at rupture that occurred.

RESULTS

The highest influence on uterine rupture in our group had been exerted by previous caesarian section and myomectomy in relation 33 : 4. Incomplete uterine ruptures were more frequent, 26 (70.27%), in relation to complete ones, 11 (29.75%). The most frequent place of uterine rupture was the front wall, 34 (91.89%), two ruptures occurred on the fundus and one on the back wall. The most frequently applied therapeutic procedures were rupture suture in 31 (83.78%) cases, and in six (16.22%) cases hysterectomy. Perinatal mortality was three times higher than average (17.78%) in that period and was 51.28%.

CONCLUSION

We emphasize that rupture frequency in the total number of deliveries was one rupture at 1 612 deliveries, whereas rupture frequency on the intact uterus was 1 : 17 269, and frequency of uterine rupture after caesarian section was one rupture at 245 deliveries. Our research as well as researches of other authors, showed that a previous caesarian section is the most frequent cause for the occurrence of uterine rupture. Therefore, caesarian section should be avoided whenever possible, not just because of a potential rupture, but also because of more frequent hysterectomy that interrupts woman's reproductive ability.

Vaginal prostaglandin gel to induce labour in women with one previous caesarean section

This retrospective study reviewed the mode of delivery when vaginal prostaglandins were used to induce labour in women with a single previous lower segment caesarean section. Over a 4-year period, PGE 2 gel was used cautiously in low doses in 54 women. Induction with PGE 2 gel was associated with an overall vaginal birth after caesarean section (VBAC) rate of 74%, which compared favourably with the 74% VBAC rate in women who went into spontaneous labour (n = 1969). There were no adverse outcomes recorded after the prostaglandin inductions but the number reported are too small to draw any conclusions about the risks, such as uterine rupture. We report our results because they may be helpful in assessing the chances of a successful VBAC in the uncommon clinical circumstances where prostaglandin induction is being considered.

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.

Maternal morbidity following a trial of labor after cesarean section vs elective repeat cesarean delivery: a systematic review with metaanalysis

This study reviewed maternal morbidity following trial of labor (TOL) after cesarean section, compared with elective repeat cesarean delivery (ERCS). Articles were pooled to compare women planning vaginal birth after cesarean (VBAC) with those undergoing ERCS with regard to maternal morbidity (MM), uterine rupture/dehiscence (UR/D), blood transfusion (BT), and hysterectomy. The former group was subdivided into successful VBAC (S-VBAC) and failed TOL (F-TOL). VBAC was successful in 17,905 of 24,349 patients (73%). MM, BT, and hysterectomy were similar in women planning VBAC or ERCS, whereas UR/D was different (1.3%; 0,4%). MM, UR/D, BT and hysterectomy were more common after F-TOL (17%, 4.4%, 3%; 0.5%) than after S-VBAC (3.1%, 0.2%, 1.1%; 0.1%) or ERCS (4.3%, 0.4%, 1%; 0.3%). Outcomes were more favorable in S-VBAC than ERCS. These findings show that a higher risk of UR/D in women planning VBAC than ERCS is counterbalanced by reduction of MM, UR/D. and hysterectomy when VBAC is successful.

Prediction of uterine rupture associated with attempted vaginal birth after cesarean delivery

OBJECTIVE

The purpose of this study was to develop a model that predicts individual-specific risk of uterine rupture during an attempted vaginal birth after cesarean delivery.

STUDY DESIGN

Women with 1 previous low-transverse cesarean delivery who underwent a trial of labor with a term singleton were identified in a concurrently collected database of deliveries that occurred at 19 academic centers during a 4-year period. We analyzed different classification techniques in an effort to develop an accurate prediction model for uterine rupture.

RESULTS

Of the 11,855 women who were available for analysis, 83 women (0.7%) had had a uterine rupture. The optimal final prediction model, which was based on a logistic regression, included 2 variables: any previous vaginal delivery (odds ratio, 0.44; 95% CI, 0.27-0.71) and induction of labor (odds ratio, 1.73; 95% CI, 1.11-2.69). This model, with a c-statistic of 0.627, had poor discriminating ability and did not allow the determination of a clinically useful estimate of the probability of uterine rupture for an individual patient.

CONCLUSION

Factors that were available before or at admission for delivery cannot be used to predict accurately the relatively small proportion of women at term who will experience a uterine rupture during an attempted vaginal birth after cesarean delivery.

Identifying risk factors for uterine rupture

Uterine rupture, whether in the setting of a prior uterine incision or in an unscarred uterus, is an obstetric emergency with potentially catastrophic consequences for both mother and child. Numerous studies have been published regarding various risk factors associated with uterine rupture. Despite the mounting data regarding both antepartum and intrapartum factors, it currently is impossible to predict in whom a uterine rupture will occur. This article reviews the data regarding these antepartum and intrapartum predictors for uterine rupture. The author hopes that the information presented in this article will help clinicians assess an individual's risk for uterine rupture.

Is vaginal birth after cesarean (VBAC) or elective repeat cesarean safer in women with a prior vaginal delivery?

OBJECTIVE

This study was undertaken to determine whether vaginal birth after cesarean (VBAC) or elective repeat cesarean delivery is safer overall for a woman with a prior vaginal delivery.

STUDY DESIGN

This retrospective cohort study of pregnant women from 1996 to 2000 who had a prior cesarean delivery, was conducted in 17 centers. Trained nurses extracted historical and maternal outcome data on subjects by using standardized tools. This planned secondary analysis examined the subcohort that had also previously undergone a vaginal delivery, comparing those who underwent a VBAC trial with those who elected to have a repeat cesarean delivery. Outcomes included uterine rupture, bladder injury, fever, transfusion and a composite (uterine rupture, bladder injury, and artery laceration). We performed bivariate and multivariable analyses.

RESULTS

Of 6619 patients with a prior cesarean delivery who had also had a prior vaginal delivery, 5041 patients attempted a VBAC delivery and 1578 had an elective cesarean delivery. Although there was no significant difference in uterine rupture or bladder injury between the two groups, women who underwent a VBAC attempt were less likely to experience the composite adverse maternal outcome, have a fever, or require a transfusion.

CONCLUSION

Among VBAC candidates who have had a prior vaginal delivery, those who attempt a VBAC trial have decreased risk for overall major maternal morbidities, as well as maternal fever and transfusion requirement compared with women who elect repeat cesarean delivery. Physicians should make this more favorable benefit-risk ratio explicit when counseling this patient subpopulation on a trial of labor.

Can uterine rupture in patients attempting vaginal birth after cesarean delivery be predicted?

OBJECTIVE

This study was undertaken to use multivariable methods to develop clinical predictive models for the occurrence of uterine rupture by using both antepartum and early intrapartum factors.

STUDY DESIGN

This was a planned secondary analysis from a multicenter case-control study of uterine rupture among women attempting vaginal birth after cesarean (VBAC) delivery. Multivariable methods were used to develop 2 separate clinical predictive indices--one that used only prelabor factors and the other that used both prelabor and early labor factors. These indices were also assessed with the use of Receiver operating characteristic curves.

RESULTS

We identified 134 cases of uterine rupture and 665 noncases. No single individual factor is sufficiently sensitive or specific for clinical prediction of uterine rupture. Likewise, the 2 clinical predictive indices were neither sufficiently sensitive nor specific for clinical use (receiver operating characteristic curve [area under the curve] 0.67 and 0.70, respectively).

CONCLUSION

Uterine rupture cannot be predicted with either individual or combinations of clinical factors. This has important clinical and medical-legal implications.

Is gestational age an independent variable affecting uterine scar rupture rates?

OBJECTIVE

To evaluate the influence of gestational age on uterine scar rupture.

METHODS

This was a population-based study of data from Cardiff Births Survey over a 10-year (1990-1999) period. Women with only one previous lower segment caesarean section with singleton uncomplicated pregnancy of 37 or more week's gestation, undergoing trial of vaginal delivery were included. SPSS version 10 was used for statistical analysis. Mann-Whitney, Fisher's exact test and Chi-square tests were used wherever appropriate. Odds ratio (OR) with confidence intervals (CI) was used to quantify the risk. Potential confounding by other factors was controlled using logistic regression and corrected odds ratios with 95% confidence intervals were calculated. The data was analysed separately for induced and spontaneous labours. Primary outcome measure assessed was uterine scar rupture rate. Secondary outcome measures were repeat caesarean section rates, maternal and perinatal mortality and morbidity.

RESULTS

Total sample number was 1620. Eighty percent (n = 1301) of the population went into spontaneous labour and 20% (n = 319) were induced. Successful trial of vaginal birth was accomplished in 60% and trial of scar after estimated date of delivery did not alter this outcome significantly (39.1% versus 43.6%, p > 0.05). We noted an overall scar rupture rate of 0.9% (n = 14) and caesarean section rate of 40.4% (n = 654). Scar rupture rates significantly increased in women who underwent trial of labour after estimated date of delivery (p < 0.001, OR 6.3, CI 1.9-20.2) without a corresponding increase in caesarean section, maternal and perinatal morbidity figures. The influence of gestational age on scar rupture persisted even after controlling for other confounding factors such as birth weight, induction of labour and BMI (corrected OR 1.9, CI 1.1-3.5).

CONCLUSIONS

The overall incidence of scar rupture and success of trial of scar after previous caesarean section in our population was similar to that quoted in the literature. Previous evidence has suggested that it is safe for these women to exceed 40 weeks gestation but our data do not support this.

Comment informer sur la voie d'accouchement une patiente ayant un antécédent de césarienne ?

A trial of labor after prior cesarean delivery is associated with a greater perinatal risk than is elective repeated cesarean delivery without labor, although absolute risks are low. Information and counselling aim to estimate specific risks and to balance these risks according to individual factors. Therefore, the physician has to answer two questions: (i) which would be the probability of successful vaginal delivery? (ii) which would be the risk of uterine rupture with a trial of labor? The risk factors for failure of trial of labor are: increased maternal age, obesity, and fetal macrosomia. The risk factors for uterine rupture are: increased maternal age, postpartum fever after the previous cesarean delivery, short interdelivery interval, history of at least two previous cesarean deliveries, and a history of classical incision. Conversely, other factors are of good prognosis: a prior vaginal delivery and, particularly, a prior VBAC (Vaginal Birth After Caesarean) are associated with a higher rate of successful trial of labor compared with patients with no prior vaginal delivery; ultrasonographic measurement of the lower uterine segment thickness>3.5 mm has an excellent negative predictive value for the risk of uterine defect. Finally, the wish for additional pregnancies following a cesarean section must be considered as an argument in favour of a trial of labor after accounting for the increasing risks correlated with repeated elective cesarean deliveries.

Maternal complications with vaginal birth after cesarean delivery: a multicenter study

OBJECTIVE

This study was undertaken to determine incidence and risk factors for uterine rupture in women attempting vaginal birth after cesarean delivery (VBAC) in a wide range of hospital settings.

STUDY DESIGN

We performed a case-control study nested within a cohort of women who have had a prior cesarean to determine the incidence and risk factors for uterine rupture in women attempting VBAC.

RESULTS

The incidence rate of uterine rupture in those who attempt VBAC was 9.8 per 1000. A prior vaginal delivery was associated with a lower risk of uterine rupture (adjusted odds ratio [OR] = 0.40, 95% CI 0.20-0.81). Although prostaglandins alone were not associated with uterine rupture, sequential use of prostaglandin and pitocin was associated with uterine rupture (adjusted OR = 3.07, 95% CI 0.98-9.88).

CONCLUSION

Women with a prior cesarean should be offered VBAC, and women with a prior cesarean and prior vaginal delivery should be encouraged to VBAC. Although other studies have suggested that prostaglandins should be avoided, we suggest that inductions requiring sequential agents be avoided.

WHO systematic review of maternal mortality and morbidity: the prevalence of uterine rupture

OBJECTIVE

To determine the prevalence of uterine rupture worldwide.

DESIGN

Systematic review of all available data since 1990.

SETTING

Community-based and facility-based reports from urban and rural studies worldwide. Sample Eighty-three reports of uterine rupture rates are included in the systematic review. Most are facility based using cross-sectional study designs.

METHODS

Following a pre-defined protocol an extensive search was conducted of 10 electronic databases as well as other sources. Articles were evaluated according to specified inclusion criteria. Uterine rupture data were collected along with information on the quality of reporting including definitions and identification of cases. Data were entered into a database and tabulated using SAS software.

MAIN OUTCOME MEASURES

Prevalence of uterine rupture by country, period, study design, setting, participants, facility type and data source.

RESULTS

Prevalence figures for uterine rupture were available for 86 groups of women. For unselected pregnant women, the prevalence of uterine rupture reported was considerably lower for community-based (median 0.053, range 0.016-0.30%) than for facility-based studies (0.31, 0.012-2.9%). The prevalence tended to be lower for countries defined by the United Nations as developed than the less or least developed countries. For women with previous caesarean section, the prevalence of uterine rupture reported was in the region of 1%. Only one report gave a prevalence for women without previous caesarean section, from a developed country, and this was extremely low (0.006%).

CONCLUSION

In less and least developed countries, uterine rupture is more prevalent than in developed countries. In developed countries most uterine ruptures follow caesarean section. Future research on the prevalence of uterine rupture should differentiate between uterine rupture with and without previous caesarean section.

Factors predisposing to perinatal death related to uterine rupture during attempted vaginal birth after caesarean section: retrospective cohort study

OBJECTIVE

To determine the factors associated with an increased risk of perinatal death related to uterine rupture during attempted vaginal birth after caesarean section.

DESIGN

Population based retrospective cohort study.

SETTING

Data from the linked Scottish Morbidity Record and Stillbirth and Infant Death Survey of births in Scotland, 1985-98.

PARTICIPANTS

All women with one previous caesarean delivery who gave birth to a singleton infant at term by a means other than planned repeat caesarean section (n = 35 854).

MAIN OUTCOME MEASURES

All intrapartum uterine rupture and uterine rupture resulting in perinatal death (that is, death of the fetus or neonate).

RESULTS

The overall proportion of vaginal births was 74.2% and of uterine rupture was 0.35%. The risk of intrapartum uterine rupture was higher among women who had not previously given birth vaginally (adjusted odds ratio 2.5, 95% confidence interval 1.6 to 3.9, P < 0.001) and those whose labour was induced with prostaglandin (2.9, 2.0 to 4.3, P < 0.001). Both factors were also associated with an increased risk of perinatal death due to uterine rupture. Delivery in a hospital with < 3000 births a year did not increase the overall risk of uterine rupture (1.1, 0.8 to 1.5, P = 0.67). However, the risk of perinatal death due to uterine rupture was significantly higher in hospitals with < 3000 births a year (one per 1300 births) than in hospitals with >or= 3000 births a year (one per 4700; 3.4, 1.0 to 14.3, P = 0.04).

CONCLUSION

Women who have not previously given birth vaginally and those whose labour is induced with prostaglandin are at increased risk of uterine rupture when attempting vaginal birth after caesarean section. The risk of consequent death of the infant is higher in units with lower annual numbers of births.

Effect of Prior Vaginal Delivery or Prior Vaginal Birth After Cesarean Delivery on Obstetric Outcomes in Women Undergoing Trial of Labor

OBJECTIVE

We sought to study the effects of prior vaginal delivery or prior vaginal birth after cesarean delivery (VBAC) on the success of a trial of labor after a cesarean delivery.

METHODS

An observational study of patients who underwent a trial of labor after a single low-transverse cesarean delivery. Patients with a previous cesarean delivery and no vaginal birth were compared with patients with a single vaginal delivery before or after the previous cesarean delivery. The rates of successful VBAC, uterine rupture, and scar dehiscence were analyzed. Multivariable regression was performed to adjust for confounding variables.

RESULTS

Of 2,204 patients, 1,685 (76.4%) had a previous cesarean delivery and no vaginal delivery, 198 (9.0%) had a vaginal delivery before the cesarean delivery, and 321 (14.6%) had a prior VBAC. The rate of successful trial of labor was 70.1%, 81.8%, and 93.1%, respectively (P <.001). A prior VBAC was associated with fewer third- and fourth-degree lacerations (8.5% versus 2.5% versus 3.7%, P <.001) and fewer operative vaginal deliveries (14.7% versus 5.6% versus 1.9%, P <.001) but not with uterine rupture (1.5% versus 0.5% versus 0.3%, P =.12). Patients with a prior VBAC had, in addition, a higher rate of uterine scar dehiscence (21.8%) compared with patients with a previous cesarean delivery and no vaginal delivery (5.3%; P =.001).

CONCLUSION

A prior vaginal delivery and, particularly, a prior VBAC are associated with a higher rate of successful trial of labor compared with patients with no prior vaginal delivery. In addition, prior VBAC is associated with an increased rate of uterine scar dehiscence.

Induction of labor after one prior cesarean: predictors of vaginal delivery

OBJECTIVE

To estimate the characteristics most associated with vaginal birth in patients undergoing induction of labor after 1 prior cesarean delivery.

METHODS

All patients who presented for induction of labor from 1996 to 2001 with a history of 1 prior cesarean delivery were identified. Relevant demographic and obstetric data were abstracted from the charts. Univariate analysis was used to identify predictive factors associated with vaginal birth after cesarean. Binary logistic regression was further used to identify which factors were independently associated with the outcome measure.

RESULTS

Of the 429 women included in the study, 334 (77.9%) had a successful trial of labor. In the final binary logistic regression equation, prior vaginal delivery (odds ratio [OR] 3.75; 95% confidence interval [CI] 1.96, 7.18) remained independently associated with an increased chance of a vaginal delivery after a trial of labor. Conversely, prior cesarean delivery for dystocia (OR 0.46; 95% CI 0.27, 0.79), induction on or past the estimated date of delivery (OR 0.46; 95% CI 0.27, 0.78), need for cervical ripening (OR 0.35; 95% CI 0.20, 0.61), and maternal gestational or preexisting diabetes (OR 0.16; 95% CI 0.06, 0.40) were all factors associated with a decreased likelihood of achieving a successful trial of labor.

CONCLUSION

Several factors are available which may assist in identifying patients with the best chance of vaginal delivery after an induction of labor in the presence of a prior low-transverse cesarean scar.

LEVEL OF EVIDENCE

II-2

Trial of labor in patients with a previous cesarean section: does maternal age influence the outcome?

OBJECTIVE

This study was undertaken to evaluate the effect of maternal age on the rate of vaginal delivery and the rate of uterine rupture in patients undergoing a trial of labor (TOL) after a prior cesarean delivery.

STUDY DESIGN

A cohort study of all women with a live singleton fetus undergoing a TOL after a previous low-transverse cesarean delivery was performed between 1988 and 2002 in a tertiary care center. Patients were divided into 3 groups according to maternal age: less than 30 years old, 30 to 34 years old, and 35 years or older. Women with no prior vaginal delivery and with at least 1 prior vaginal delivery were analyzed separately. The rate of vaginal delivery and the rate of symptomatic uterine rupture were calculated. Multivariate logistic regression analyses were performed to adjust for potential confounding variables.

RESULTS

Of the 2493 patients who met the study criteria, there were 1750 women without a prior vaginal delivery (659, 721, and 370, respectively) and 743 women with a prior vaginal delivery (199, 327, and 217, respectively). The rate of uterine rupture was comparable between the groups (2.0%, 1.1%, 1.4%, P=.404 and 0%, 0.3%, 0.9%, P=.312). Successful vaginal delivery was inversely related to maternal age (71.9%, 70.7%, 65.1%, P=.063, and 91.5%, 91.1%, 82.9%, P=.005). After adjusting for confounding variables, maternal age equal to or greater than 35 years old was associated with a lower rate of successful vaginal delivery in patients without prior vaginal delivery (odds ratio [OR] 0.73, 95% CI: 0.56-0.94), and in patients with a prior vaginal delivery (OR: 0.47, 95% CI: 0.29-0.74).

CONCLUSION

Patients who are 35 years or older are more prone to have a failed TOL after a prior cesarean delivery.

Maternal and perinatal complications with uterine rupture in 142,075 patients who attempted vaginal birth after cesarean delivery: A review of the literature

OBJECTIVE

The purpose of this study was to determine the rate of uterine rupture and its complications as the result of trial of labor after previous cesarean delivery.

STUDY DESIGN

PubMed was searched from 1989 to 2001, with the terms "VBAC, uterine rupture," "trial of labor, uterine rupture," "cesarean delivery, uterine rupture," and "scarred uterus, rupture." For inclusion, reports had to contain data from at least 100 patients with trials of labor that included a description of adverse outcomes. Duplicate reporting from a single institution was excluded. Odds ratios and 95% CIs were calculated.

RESULTS

Seventy-two of the 361 articles (20%) that were identified met the inclusion criteria. A 6.2 per 1000 trial of labor rate of uterine rupture (total=880 uterine ruptures in 142,075 trials of labor) was determined. For every 1000 trials of labor the uterine rupture-related complication rate was 1.8 for packed red blood cell transfusion, 1.5 for pathologic fetal acidosis (cord pH<7.00), 0.9 for hysterectomy, 0.8 for genitourinary injury, 0.4 for perinatal death, and 0.02 for maternal death. The perinatal mortality rate was significantly lower among studies from the United States versus other countries (0.3 vs 0.6; odds ratio, 0.50; 95% CI, 0.26-0.94) and in series that exceeded 1000 patients (0.2 vs 1.7; odds ratio, 7.34; 95% CI, 3.94-13.69).

CONCLUSION

Although relatively uncommon, uterine rupture is associated with several adverse outcomes, depending on the time of the publication and the site and size of the population that was studied.

Extrusion of fetus into the abdominal cavity following complete rupture of uterus: a case report

A gravida 10 para 9, after one Cesarean section (CS) followed by four vaginal deliveries was admitted at term without uterine contractions complaining of abdominal pain. The type of uterine scar was unknown. Severe bradycardia was observed at admission and an emergency Cesarean section was performed. A complete uterine rupture was revealed, the fetus in intact membranes and placenta were found in the abdominal cavity.

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.

Management of vaginal birth after cesarean

OBJECTIVE

To raise the success rate of vaginal birth after cesarean (VBAC) without increasing maternal or perinatal morbidity and mortality rates.

METHODS

Of 468 women with a prior scar, 365 gave valid informed consent for our management of VBAC at Akashi Municipal Hospital during 1986-1999. Trials of labor (TOL) were attempted in 322 cases principally by waiting for spontaneous labor onset and teaching the patients a breathing method to avoid straining until expulsion by vacuum extraction become possible, controlling the intrauterine pressure. Our selection criteria for TOL changed during the trial; from 1991-1999 patients with a prior scar extending into fundus were excluded.

RESULTS

Of the 322 TOL, 88.2% were successful, and VBAC was successful in 77.8% (284 of the 365 patients). Uterine rupture was observed in 2 cases (0.62%). Fetal death occurred in 1 case. Three women gave birth to neonates with a 1-minute Apgar score < or = 6.

CONCLUSION

The rate of VBAC was 77.8% in all women with a prior scar. During our management of VBAC, maternal or perinatal morbidity and mortality rates did not increase significantly.

The impact of a single-layer or double-layer closure on uterine rupture

OBJECTIVE

Our purpose was to measure the impact of a single-layer or double-layer closure on uterine rupture at subsequent delivery.

STUDY DESIGN

This is an observational cohort study of all women undergoing a trial of labor from 1988 to 2000 in a tertiary care center, after a single low transverse cesarean delivery. Factors most highly associated with uterine rupture were identified by using univariate regression analysis. Multivariate logistic regression analysis was used to adjust for selected confounding variables.

RESULTS

Of the 2142 women who met the study criteria, 1980 (92.4%) had maternal records and original operative reports reviewed. After adjustments were made for confounding variables, the odds ratio for uterine rupture in women with a single-layer closure was 3.95 (95% CI, 1.35-11.49).

CONCLUSION

A single-layer closure of the previous lower segment incision was the most influential factor and was associated with a 4-fold increase in the risk of uterine rupture compared with a double-layer closure.

Uterine rupture

Uterine rupture is an uncommon obstetric event. It is important because it continues to be associated with maternal mortality, especially in developing countries, and with major maternal morbidity, particularly peripartum hysterectomy. It is also associated with a high incidence of perinatal mortality and morbidity worldwide. This chapter examines the incidence, aetiology, clinical presentation, complications and prevention of uterine rupture. The key factor in the cause of rupture is whether or not the uterus is scarred. Rupture of an unscarred uterus is rare, usually traumatic, and its incidence decreases with improvement in obstetric practice. Rupture of the scarred uterus is more common, and usually occurs after a trial of labour in a patient with a previous Caesarean section. This chapter also explores how the incidence and complications of uterine rupture may be minimized, and yet the incidence of vaginal birth after Caesarean section (VBAC) optimized, in clinical practice.