External cephalic version after previous cesarean section: a series of 38 cases

External cephalic version following prior cesarean delivery: A comparative cohort analysis

OBJECTIVE

To analyze the success rate of external cephalic version (ECV) in pregnant women with a history of previous cesarean section, as well as to describe the rate of complications associated with the procedure.

METHODS

A retrospective cohort study of women who were offered an ECV at "Virgen de la Arrixaca" Clinic University Hospital (Murcia, Spain) between January 2014 and December 2023. We collected data for previous cesarean delivery, obstetric history, fetal presentation, amniotic fluid volume, ECV success rate, complications related to ECV, mode of delivery, and neonatal outcomes. The study confidently performed ECV under sedation with propofol and tocolysis with ritodrine. Univariate and multivariate analyses were conducted to compare the success rate of ECV, ECV complications, and mode of delivery between women with and without previous cesarean sections.

RESULTS

Of 1116 pregnant women who were offered ECV, 911 were included in the study, with 42 having a previous cesarean section. The success rate of ECV in pregnant women with a previous cesarean section was 78.6% (adjusted odds ratio 1.18; 95% confidence interval 0.49-2.86; P = 0.708), with a low complication rate of 9.5%, such as non-reassuring fetal heart rate (7.1%) or major vaginal bleeding (2.4%). Of the women who attempted a vaginal delivery after ECV, 80.8% were successful.

CONCLUSIONS

These findings support that ECV is a safe and effective option for women with a previous cesarean section, with success rates comparable to those in women without a previous cesarean section.

Safety and efficacy of external cephalic version after a previous caesarean delivery: A systematic review

BACKGROUND

External cephalic version (ECV) is a common procedure and has been shown to be safe and effective in turning a baby from a breech to cephalic presentation. However, whether ECV is safe and effective in women with a scarred uterus from a previous caesarean section remains contentious.

AIM

To evaluate the safety and efficacy of external cephalic version in women with a singleton breech pregnancy and at least one previous caesarean delivery.

MATERIAL AND METHODS

Literature searches were conducted on MEDLINE, PUBMED, EMBASE, CINAHL and SCOPUS up to June 2020. The search strategy included the following keywords: ('external cephalic version OR ECV') AND ('previous OR prior OR past' AND 'caesarean OR caesarean OR uterine scar'). Studies were included if they evaluated the efficacy and/or safety of external cephalic version in women after 36 weeks' gestation with a singleton breech pregnancy and at least one previous caesarean delivery.

RESULTS

Nine studies were included in the review. ECV success rates and subsequent vaginal delivery rates ranged from 50 to 100% and from 50 to 74.9%, respectively. ECV complications reported included abnormal fetal heart rate, abnormal cardiotocography and transient vaginal bleeding. No studies reported cases of uterine rupture.

CONCLUSIONS

ECV in women with a previous caesarean delivery is a relatively successful and low-risk procedure compared to women without a previous caesarean delivery. The results from this systematic review provide useful information for professional bodies in updating clinical guidelines such that ECV may be offered to women with one previous caesarean delivery.

Vaginal Delivery After External Cephalic Version in Patients With a Previous Cesarean Delivery: A Systematic Review and Meta-analysis

OBJECTIVE

To estimate the rate of vaginal delivery after successful external cephalic version for breech presentation in women with compared with without a previous cesarean birth.

DATA SOURCES

We searched MEDLINE, Scopus, EMBASE, CINAHL, ClinicalTrials.gov, and Cochrane Central Register of Controlled Trials for studies comparing the mode of delivery after successful external cephalic version in women with and without a previous cesarean birth.

METHODS OF STUDY SELECTION

Two reviewers independently identified studies, extracted data, and evaluated study quality. The rate of vaginal delivery after successful external cephalic version in women with and without a previous cesarean birth was compared, and odds ratios (ORs) with 95% CIs were estimated.

TABULATION, INTEGRATION, AND RESULTS

Six cohort studies and two case-control studies, reporting on 14,515 women were identified. The median point prevalence of a successful external cephalic version was 74% (interquartile range 63-81%) in women with a previous cesarean birth compared with 69% (interquartile range 64-83%) in women without a previous cesarean birth. The overall success rate of external cephalic version in women with a previous cesarean birth was similar compared with women without a previous cesarean birth (pooled OR 0.84, 95% CI 0.61-1.15). The median point prevalence of a vaginal delivery was 75% (interquartile range 61-84%) in women with a previous cesarean birth compared with 92% (interquartile range 85-95%) in women without a previous cesarean birth after a successful external cephalic version. The overall success rate of a vaginal delivery in women with a previous cesarean birth was less compared with women without a previous cesarean birth (pooled OR 0.26, 95% CI 0.14-0.50). A planned subgroup analysis on studies that included only multiparous women in the control group (parity one or greater) noted the overall success rate of external cephalic version in women with a previous cesarean birth 76% (853/1,123) was lower compared with multiparous women without a previous cesarean birth 84% (9,911/11,855) (pooled OR 0.70, 95% CI 0.54-0.89, I 37%). The overall success rate of a vaginal delivery in women with a previous cesarean birth 83% (666/806) was less compared with women without a previous cesarean birth 97% (9,449/9,746) (pooled OR 0.21, 95% CI 0.12-0.39, I 73%).

CONCLUSION

Women with previous cesarean birth have similar rates of successful external cephalic version when compared with women without a cesarean birth. Although the rate of vaginal delivery is lower, the majority of patients have a successful vaginal birth after cesarean.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42020160145.

No. 382-Trial of Labour After Caesarean

OBJECTIVE

To provide evidence-based guidelines for the provision of a trial of labour after Caesarean section.

OUTCOMES

Fetal and maternal morbidity and mortality associated with vaginal birth after Caesarean and repeat Caesarean section.

EVIDENCE

MEDLINE database was searched for articles published from January 1, 1995, to October 31, 2017 using the key words "vaginal birth after Caesarean (Cesarean) section." The quality of evidence is described using the Evaluation of Evidence criteria outlined in the Report of the Canadian Task Force on the Periodic Health Exam.

VALIDATION

These guidelines were approved by the Clinical Practice Obstetrics Committee and the Board of the Society of Obstetricians and Gynaecologists of Canada.

RECOMMENDATIONS

Correlation of Obesity with External Cephalic Version Success among Women with One Previous Cesarean Delivery

Objective  Our aim was to assess the correlation of body mass index (BMI) with the success rate of external cephalic version (ECV) among women with one prior cesarean delivery. Study Design  A cross-sectional study of pregnant women with one previous cesarean delivery who underwent ECV. The relationship between BMI and success rate of ECV was assessed. Adverse outcomes were also compared between women with an ECV attempt, and women who had a repeat cesarean delivery. Data were extracted from the U.S. Natality Database from 2014 to 2017. Pearson's correlation coefficient was performed to assess the relationship between BMI and success rate of ECV. Results  There were 2,329 women with prior cesarean delivery underwent an ECV attempt. The success rate of ECV among the entire cohort was 68.3%. There was no correlation between BMI and success rate of ECV ( r  = 0.024, p  = 0.239). Risks of adverse maternal and neonatal outcomes were similar between the ECV attempt group and the repeat cesarean delivery group. Conclusion  There was no correlation of BMI with the rate of successful ECV among women with one prior cesarean delivery. Given the similar success rates of ECV and adverse outcomes, obese women with one prior cesarean delivery should be offered ECV.

No. 155-Guidelines for Vaginal Birth After Previous Caesarean Birth

OBJECTIVE

To provide evidence-based guidelines for the provision of a trial of labour (TOL) after Caesarean section.

OUTCOME

Fetal and maternal morbidity and mortality associated with vaginal birth after Caesarean (VBAC) and repeat Caesarean section.

EVIDENCE

MEDLINE database was searched for articles published from January 1, 1995, to February 28, 2004, using the key words "vaginal birth after Caesarean (Cesarean) section." The quality of evidence is described using the Evaluation of Evidence criteria outlined in the Report of the Canadian Task Force on the Periodic Health Exam.

RECOMMENDATIONS

VALIDATION: These guidelines were approved by the Clinical Practice Obstetrics and Executive Committees of the Society of Obstetricians and Gynaecologists of Canada.

External cephalic version after previous cesarean section: A cohort study of 100 consecutive attempts

OBJECTIVE

External cephalic version is commonly not performed in women with a previous cesarean section. Fear of uterine rupture and cesarean section in labor are prominent. The risks, however, of these are unclear. This study aims to document the safety and efficacy of external cephalic version in women with a prior cesarean section in a series of 100 consecutive attempts, and to perform a literature of the existing literature.

STUDY DESIGN

This is a retrospective cohort study of prospectively collected data of external cephalic version attempts in women at term with a previous cesarean section, and a literature review of previously published series. External cephalic version was performed by one of 3 experienced operators, with salbutamol tocolysis if appropriate, using ultrasound to visualize the fetal heart and place of fetal parts.

RESULTS

100 women with a prior cesarean section underwent external cephalic version over a 16-year period in one institution. 68% had no previous vaginal delivery. The external cephalic version success rate was 50%, and 30 (63.8%) of these subsequently delivered vaginally. There were no cases of uterine rupture or other complications. A literature review of series containing a total of 549 cases revealed no cases of uterine rupture or perinatal death.

CONCLUSIONS

External cephalic version in women with a prior cesarean section is safe but enables a vaginal birth in only about a third of women.

Maternal and Neonatal Outcomes after Attempted External Cephalic Version among Women with One Previous Cesarean Delivery

Objective  This study was aimed to evaluate success rates of (1) external cephalic version (ECV) among women with one prior cesarean delivery (CD) and (2) maternal and neonatal outcomes after ECV among women with prior CD. Study Design  Two linked studies using U.S. Natality Database were performed. First we performed a retrospective cohort comparing ECV success rates of women with prior CD and women without prior CD. Then we compared the outcomes of TOLACs (trial of labor after cesarean delivery) that occurred after ECV with those that occurred without ECV. Multivariable logistic regression analysis was used to estimate adverse outcomes. Results  A total of 715 women had ECV after 36 weeks with prior CD and 9,976 had ECV without prior scar. ECV success rate with scar was 80.6% and without scar was 86.4% ( p  < 0.001). Seven hundred and sixteen women underwent TOLAC after ECV attempt and 234,617 underwent TOLAC without a preceding attempt. Women with preceding version had increased risks of maternal transfusion (1 vs. 0.4%, adjusted OR [odds ratio]: 2.48 [95% CI (confidence interval): 1.17-5.23]), unplanned hysterectomy (0.4 vs. 0.06%, adjusted OR: 6.90 [95% CI: 2.19-21.78]), and low 5-minute Apgar's score (2.5 vs. 1.5%, adjusted OR: 1.76 [95% CI: 1.10-2.82]). Conclusion  Women with prior CD may have a decrease in the rate of successful ECV. While the absolute risks are low, ECV appears to increase risks of adverse maternal and neonatal outcomes among women undergoing a trial of labor.

Vaginal birth after two previous caesarean deliveries in a patient with uterus didelphys and an interuterine septal defect

Uterus didelphys is a congenital abnormality characterised by double uteri, double cervices and a double or single vagina that affects 0.3% to 11% of the general female population. A 23-year-old woman, gravida 3 para 3003, with uterus didelphys, acquired an iatrogenic interuterine septal defect during an otherwise routine primary caesarean delivery for fetal malpresentation. The defect was repaired but noted to have dehisced during her second pregnancy. A repeat caesarean section was performed due to fetal malpresentation after an unsuccessful external cephalic version. The dehisced defect was left unrepaired. During her third pregnancy, the placenta implanted in the right uterus, but the fetus migrated to the left uterus at approximately 28 weeks gestation. The umbilical cord traversed the interuterine septal defect. With the fetus in the vertex presentation at term gestation, the patient underwent a vaginal birth after two previous caesarean deliveries without any major perinatal complications.

External cephalic version with an amniotic fluid index ⩽10: A systematic review

OBJECTIVE

To review the literature and evaluate the role of the amniotic fluid index (AFI) on the success of an external cephalic version (ECV).

STUDY DESIGN

A computerized search of MEDLINE and Cochrane databases were conducted using 'breech', 'version', 'external cephalic version', 'amniotic fluid', and 'amniotic fluid index'. References from the identified publications were manually searched to identify additional relevant articles. Articles from 1987 to 2004 were included.

RESULTS

Of the initial 33 articles discovered, only three remained after exclusions. These articles used different AFI ranges for 'borderline' or 'low-normal' fluid measurements and therefore could not be combined for analysis. All three studies demonstrated a lower success rate of ECV with lower amniotic fluid volume estimates (AFI 5-8, <10, or <8.6), although none reached statistical significance.

CONCLUSION

Due to limited and dissimilar data, it is impossible to define the lower AFI threshold for an unsuccessful ECV compared with the success of a normal AFI. Although not statistically significant, an AFI <10 may correlate with lower success rates for an ECV.

An audit on trends of vaginal delivery after one previous caesarean section

An audit of 197 patients with one previous caesarean section was undertaken over a 1-year period to determine the rates of vaginal delivery and main indications for repeat caesarean section. Trial of labour was attempted in 51.3% of women, of whom 65.3% had had a successful vaginal delivery. Vaginal birth after caesarean, however, was successful in only 33.5% of women. This low rate of vaginal birth following a previous section was due to a large number of elective caesarean sections. Maternal request was the most common indication for repeat elective caesarean section. The answer to the rising caesarean rates seems to lie in reducing the primary caesarean section rates, rigorous auditing of the unit's caesarean rates and a change in the attitude of doctors, midwives and patients towards vaginal birth after caesarean. The last might prove to be the most difficult target to achieve.

External cephalic version among women with a previous cesarean delivery: report on 36 cases and review of the literature

AIMS

Whether or not women with a previous cesarean section should be considered for an external cephalic version remains unclear. In our study, we sought to examine the relationship between a history of previous cesarean section and outcomes of external cephalic version for pregnancies at 36 completed weeks of gestation or more.

METHODS

Data on obstetrical history and on external cephalic version outcomes was obtained from the C.H.U. Sainte-Justine External Cephalic Version Database. Baseline clinical characteristics were compared among women with and without a history of previous cesarean section. We used logistic regression analysis to evaluate the effect of previous cesarean section on success of external cephalic version while adjusting for parity, maternal body mass index, gestational age, estimated fetal weight, and amniotic fluid index.

RESULTS

Over a 15-year period, 1425 external cephalic versions were attempted of which 36 (2.5%) were performed on women with a previous cesarean section. Although women with a history of previous cesarean section were more likely to be older and para >2 (38.93% vs. 15.0%), there were no difference in gestational age, estimated fetal weight, and amniotic fluid index. Women with a prior cesarean section had a success rate similar to women without [50.0% vs. 51.6%, adjusted OR: 1.31 (0.48-3.59)].

CONCLUSION

Women with a previous cesarean section who undergo an external cephalic version have similar success rates than do women without. Concern about procedural success in women with a previous cesarean section is unwarranted and should not deter attempting an external cephalic version.

Cesarean risk after successful external cephalic version: a matched, retrospective analysis

OBJECTIVE

To determine the odds of cesarean, operative vaginal delivery and vaginal birth after cesarean after successful external cephalic version (ECV) compared with singleton pregnancies eligible for a trial of labor.

STUDY DESIGN

A matched case-control study was performed using the Memorial Care OBStat Database from 1 January 1998 to 31 July 2006. We identified 197 participants who underwent a successful ECV (study group) and compared them with the next two women presenting for labor management, matched for parity, gestational age, delivery history (previous cesarean delivery) and type of labor (spontaneous or induced).

RESULT

There was no significant difference in the adjusted matched odds of cesarean delivery between the study group and control group overall (16.8 vs 11.9%; odds ratio (OR) 1.70; 95% confidence interval (CI) 0.98 to 2.97), even when subanalyzed according to parity. There was also no significant difference in adjusted matched odds of operative vaginal delivery for the study group and control group, 15.9 vs 8.9% (OR 1.06; 95% CI 0.32 to 3.51). Among patients with a prior cesarean, those who underwent successful ECV had a cesarean delivery rate of 11.1% compared with 16.7% in the matched control group (OR 0.59; 95% CI 0.47 to 7.43).

CONCLUSION

Cesarean delivery and operative vaginal delivery rates following successful ECV are not increased in our data set compared with matched controls, even in patients with a prior cesarean delivery. This information may be useful when counseling patients who are contemplating an ECV attempt due to non-cephalic presentation at term.

Breech presentation: an audit project as means of pursuing clinical excellence

Clinical audit is an effective quality improvement process to evaluate important clinical issues. Breech presentation is such an issue due to its contribution to the rising caesarean section (CS) rate. We set out to assess the management of breech presentation using, as standards, the delivery suite protocol and national guidelines. Our first audit revealed a low success rate of external cephalic version (ECV) and deficient documentation of written consent for ECV, other aspects of care being satisfactory. The results were presented to a multidisciplinary meeting and disseminated to relevant stakeholders. A re-audit was then performed. It confirmed significant improvement in the documentation of consent for ECV. It also revealed a good detection rate of breech, optimal offer rate of ECV and good neonatal outcome. However, uptake of ECV as well as the success rate could both be improved so as to reduce the CS rate for breech presentation. We discuss options for improving the uptake and success rate for ECV.

Essai de travail en cas de césarienne antérieure

OBJECTIVE

The aim of this review was to relate the evolution of obstetrical management of delivery in women who had previously undergone cesarean delivery and to search the studies supporting the choice of the mode of delivery.

MATERIAL AND METHOD

We identified relevant studies through a computer search in the Medline database.

RESULTS

After a period from 1980 to 2000 when the vaginal delivery had been increasingly recommended, a growth in the use of the planned cesarean delivery was observed. Recent studies report more evidence that uterine rupture is the result of trial of labor and that adverse perinatal outcomes are associated with uterine rupture. The risk of uterine rupture is increased with labor induction. The use of prostaglandins appears to be implicated in a significant increase of uterine rupture, and subsequently might be contraindicated in this situation. The use of oxytocin induced labor appears to increase the risk of uterine rupture. However, the level of adverse perinatal outcomes is low. The choice of the mode of delivery should take into account the likelihood of a further pregnancy, due to the increased risk of placental pathologic conditions depending on the number of repeated cesarean sections.

CONCLUSION

An optimal decision for the mode of delivery should be shared with the pregnant women and all these factors should be taken into consideration.

Guidelines for Vaginal Birth After Previous Caesarean Birth

OBJECTIVE

To provide evidence-based guidelines for the provision of a trial of labour (TOL) after Caesarean section.

OUTCOME

Fetal and maternal morbidity and mortality associated with vaginal birth after Caesarean (VBAC) and repeat Caesarean section.

EVIDENCE

MEDLINE database was searched for articles published from January 1, 1995, to February 28, 2004, using the key words "vaginal birth after Caesarean (Cesarean) section". The quality of evidence is described using the Evaluation of Evidence criteria outlined in the Report of the Canadian Task Force on the Periodic Health Exam.

RECOMMENDATIONS

1. Provided there are no contraindications, a woman with 1 previous transverse low-segment Caesarean section should be offered a trial of labour (TOL) with appropriate discussion of perinatal risks and benefits. The process of informed consent with appropriate documentation should be an important part of the birth plan in a woman with a previous Caesarean section (II-2B). 2. The intention of a woman undergoing a TOL after Caesarean section should be clearly stated, and documentation of the previous uterine scar should be clearly marked on the prenatal record (II-2B). 3. For a safe labour after Caesarean section, a woman should deliver in a hospital where a timely Caesarean section is possible. The woman and her health care provider must be aware of the hospital resources and the availability of obstetric, anesthetic, pediatric, and operating-room staff (II-2A). 4. Each hospital should have a written policy in place regarding the notification and (or) consultation for the physicians responsible for a possible timely Caesarean section (III-B). 5. In the case of a TOL after Caesarean, an approximate time frame of 30 minutes should be considered adequate in the set-up of an urgent laparotomy (III-C). 6. Continuous electronic monitoring of women attempting a TOL after Caesarean section is recommended (II-2A). 7. Suspected uterine rupture requires urgent attention and expedited laparotomy to attempt to decrease maternal and perinatal morbidity and mortality (II-2A). 8. Oxytocin augmentation is not contraindicated in women undergoing a TOL after Caesarean section (11-2A). 9. Medical induction of labour with oxytocin may be associated with an increased risk of uterine rupture and should be used carefully after appropriate counselling (II-2B). 10. Medical induction of labour with prostaglandin E2 (dinoprostone) is associated with an increased risk of uterine rupture and should not be used except in rare circumstances and after appropriate counselling (II-2B). 11. Prostaglandin E1 (misoprostol) is associated with a high risk of uterine rupture and should not be used as part of a TOL after Caesarean section (II-2A). 12. A foley catheter may be safely used to ripen the cervix in a woman planning a TOL after Caesarean section (II-2A). 13. The available data suggest that a trial of labour in women with more than 1 previous Caesarean section is likely to be successful but is associated with a higher risk of uterine rupture (II-2B). 14. Multiple gestation is not a contraindication to TOL after Caesarean section (II-2B). 15. Diabetes mellitus is not a contraindication to TOL after Caesarean section (II-2B). 16. Suspected fetal macrosomia is not a contraindication to TOL after Caesarean section (II-2B). 17. Women delivering within 18 to 24 months of a Caesarean section should be counselled about an increased risk of uterine rupture in labour (II-2B). 18. Postdatism is not a contraindication to TOL after Caesarean section (II-2B). 19. Every effort should be made to obtain the previous Caesarean section operative report to determine the type of uterine incision used. In situations where the scar is unknown, information concerning the circumstances of the delivery is helpful in determining the likelihood of a low transverse incision. If the likelihood of a low transverse incision is high, a TOL after Caesarean section can be offered (II-2B).

VALIDATION

These guidelines were approved by the Clinical Practice Obstetrics and Executive Committees of the Society of Obstetricians and Gynaecologists of Canada.

[External cephalic version: experience about 237 versions at Port-Royal maternity]

OBJECTIVES

To evaluate the effectiveness of external cephalic version for reducing the rate of cesarean section by preserving fetal safety.

MATERIALS AND METHODS

A retrospective review of 237 external cephalic versions between January 1, 1998 and December 31, 2000 was conducted at Port Royal maternity.

RESULTS

The success rate of external cephalic version was 50.6%. When version failed vaginal birth could be allowed after strict evaluation. The rate of cesarean section was 12.5% in the success group and 53% in the unsuccessful group, two thirds were planned. The overall rate of vaginal birth among breech presentations was 67%. After version there were 3.4% abnormal fetal heart rate tracings and 2.9% positive Kleihauer tests. No major complications occurred. Successful external cephalic version was associated with statistically significant higher multiparity, complete breech out of the pelvis and normal amniotic fluid Volume.

CONCLUSION

External cephalic version reduces the cesarean section rate by about 20.5% among breech presentations and so, lowers maternal morbidity. External cephalic version could be proposed to the patients when safety criteria are respected and close fetal monitoring is maintained.

External cephalic version: a safe procedure? A systematic review of version-related risks

BACKGROUND

The Term Breech Trial has considerably increased the number of cesareans. External cephalic version (ECV) might be an effective method of lowering the rate of cesareans; its efficacy has been well established. However, although in the absence of anesthesia the risks are thought to be low, most studies have used populations too small to allow definite conclusions on version-related risks.

METHODS

In an attempt to make an inventory of these risks, we have systematically analyzed 44 studies, covering a total of 7377 patients from 1990 to 2002. The studies used were derived from a Medline and Embase search.

RESULTS

The most frequently reported complications were transient abnormal cardiotocography (CTG) patterns (5.7%). Persisting pathological CTG readings (0.37%) and vaginal bleeding occur rarely (0.47%). The incidence of placental abruption was even lower, at 0.12%. Fetomaternal transfusion was absent in five out of seven studies, with a mean incidence of 3.7%. Emergency cesareans were performed in 0.43% of all versions. Perinatal mortality was 0.16%.

CONCLUSIONS

External cephalic version seems to be a safe procedure.

Predicting vaginal birth after cesarean delivery: a review of prognostic factors and screening tools

OBJECTIVE

Our purpose was to identify the factors associated with vaginal delivery after trial of labor in patients with a prior cesarean and to evaluate the effectiveness of existing screening tools.

STUDY DESIGN

Studies were identified through MEDLINE and HealthSTAR (1980-2002), reference list reviews, and suggestions of national experts.

RESULTS

Thirteen of the 100 eligible studies provided fair to good quality evidence for the predictive nature of 12 factors. Two of the six screening tools were considered promising and demonstrated reproducibility through validation studies.

CONCLUSIONS

There is little high-quality data to guide clinical decisions regarding which women are likely to have a successful trial of labor. Although we identified two validated screening tools that may be reasonable for practitioners to use, further development is needed to deliver them in a user-friendly manner and further research is needed to determine the clinical setting in which they are most useful. Conducting high-quality research on the factors that delineate women who are at higher likelihood of vaginal delivery without complications and developing accurate user-friendly screening tools to integrate these data should be a national research priority.

Vaginal birth after Caesarean section: review of antenatal predictors of success

OBJECTIVE

To determine antenatal factors that may predict successful vaginal birth after Caesarean (VBAC).

DATA SOURCES

The MEDLINE database was searched for all English-language articles describing the impact of various factors on outcomes when VBAC is attempted. Articles reviewed included published abstracts, retrospective and prospective studies, and meta-analyses. CRITERIA FOR STUDY SELECTION: Studies were included if they reported both a control group of pregnant women without the factor under evaluation and a study group with this factor, both undergoing a trial of labour (TOL). Other criteria included accountability for all individuals enrolled at study outset, and vaginal delivery rates in both study and control groups stated or easily calculated.

RESULTS

A nonrecurrent indication for previous Caesarean section (CS), such as breech presentation or fetal distress, is associated with a much higher successful VBAC rate than recurrent indications, such as cephalopelvic disproportion (CPD). Even with a history of CPD, two-thirds of women will have successful VBAC, though rates decrease with increasing numbers of prior CS. Prior vaginal deliveries are excellent prognostic indicators of successful VBAC, especially if the vaginal delivery follows the prior CS. A low vertical uterine incision does not seem to adversely affect VBAC success rates as compared to a low transverse incision. Maternal obesity and diabetes mellitus adversely affect VBAC outcomes. Fetal macrosomia does not appear to be a contraindication to VBAC, as success rates exceeding 50% are achieved and uterine rupture rates are not increased. Twin gestation does not preclude VBAC. Post-dates pregnancies may deliver successfully by VBAC in greater than two-thirds of cases.

CONCLUSION

There are few absolute contraindications to attempted VBAC. Attempted VBAC will be successful in the majority of attempted cases.