OBJECTIVE To develop a model based on factors available at the first prenatal visit that predicts chance of successful vaginal birth after cesarean delivery (VBAC) for individual patients who undergo a trial of labor. METHODS All women with one prior low transverse cesarean who underwent a trial of labor at term with a vertex singleton gestation were identified from a concurrently collected database of deliveries at 19 academic centers during a 4-year period. Using factors identifiable at the first prenatal visit, we analyzed different classification techniques in an effort to develop a meaningful prediction model for VBAC success. After development and cross-validation, this model was represented by a graphic nomogram. RESULTS Seven-thousand six hundred sixty women were available for analysis. The prediction model is based on a multivariable logistic regression, including the variables of maternal age, body mass index, ethnicity, prior vaginal delivery, the occurrence of a VBAC, and a potentially recurrent indication for the cesarean delivery. After analyzing the model with cross-validation techniques, it was found to be both accurate and discriminating. CONCLUSION A predictive nomogram, which incorporates six variables easily ascertainable at the first prenatal visit, has been developed that allows the determination of a patient-specific chance for successful VBAC for those women who undertake trial of labor. LEVEL OF EVIDENCE II.

The preponderance of published data derived from TOL/VBAC patients indicate that (1) if there is no contraindication to spontaneous cervical ripening, there is no contraindication to use of prostaglandin gel or tents to ripen the cervix; and (2) if there is no contraindication to the spontaneous onset of labor, there is no contraindication to use of oxytocin or amniotomy to induce labor. Both conclusions are based on the assumption that treatment and care is provided in a safe, modern obstetric service with staff and resources compatible with national standards.

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.

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.

HASH(0x1d5ef2b0)

OBJECTIVE To provide evidence-based guidelines for the provision of a trial of labor (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 labor (TOL) with appropriate discussion of maternal and 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 labor after Caesarean section, a woman should deliver in a hospital where a timely Caesarean section is available. 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 min should be considered adequate in the set-up of an urgent laparotomy (IIIC). 6. Continuous electronic fetal 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 (II-2A). 9. Medical induction of labor with oxytocin may be associated with an increased risk of uterine rupture and should be used carefully after appropriate counseling (II-2B). 10. Medical induction of labor 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 counseling (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 labor 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 18-24 months of a Caesarean section should be counseled about an increased risk of uterine rupture in labor (II-2B). 18. Postdatism is not a contraindication to a 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 previous delivery is helpful in determining the likelihood of a low transverse incision. If the likelihood of a lower 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.