Original Title: Avis: sécurité du lieu et conditions de succès de l'accouchement vaginal après une césarienne

Authors' objectives: The practice of vaginal birth after cesarean (VBAC) is recognized as being safe and is recommended in most of the current guidelines for women who meet the eligibility criteria. Women who attempt a VBAC may decide to do so at a hospital, a birthing centre or at home under the supervision of a physician or a midwife. More than 82,000 deliveries were recorded in Québec in 2016-2017, most of which were performed by physicians. Approximately 3.5% of them were started under the supervision of a midwife. Cesareans accounted for about 25% of all births in 2016-2017. Of the women with a previous cesarean, approximately 29% attempted a trial of labour after cesarean (TOLAC), with 70% of these trials ending in a vaginal birth. During the same period, there were 2184 completed VBACs with physicians and 95 with midwives. Most of the VBACs under the supervision of midwives took place at birthing centres. To ensure an offer of quality care and services to the Québec population while at the same time taking into consideration differences in VBAC practices, the MSSS asked INESSS to:1) evaluate the safety of VBAC settings; 2) identify the practices and factors that contribute to successful VBACs.

Authors' results and conclusions: RESULTS: (PROBABILITY OF A COMPLETED VBAC by setting) - The pooled results of 17 studies of VBAC showed that the hospital, home and birthing centre VBAC completion rate is 69%, 85% and 78%, respectively. The rate was significantly different when non-hospital settings were compared to hospitals (p = 0.01). However, there was greater heterogeneity (p < 0.0001). A sensitivity analysis showed that women who had had a prior vaginal birth were more likely to have a completed VBAC than those who had not, regardless of the birthing setting. However, it should be pointed out that women selected to give birth at a birthing centre or at home meet various eligibility criteria and have different characteristics than those who give birth at a hospital. This constitutes a selection bias that can favour the out-of-hospital VBAC completion rate. (MATERNAL COMPLICATIONS BY SETTING) - Uterine rupture is the main complication of TOLAC, its frequency being approximately 1/200 to 1/300 TOLACs, regardless of the setting. In the fourteen studies that were selected, no significant difference was observed in the probability of maternal complications by TOLAC setting, including uterine rupture, maternal death, transfusions, intensive care admissions, and hysterectomies. The low incidence of complications and the paucity of data by setting limit the studies' power and the interpretation of their results. Women selected to give birth at a birthing centre or at home generally have a lower risk of complications, which creates potential selection bias that could give the impression that fewer complications occur at non-hospital settings. The hospital transfer rate for women attempting a VBAC varies from 21% to 44%, according to the literature. Most of the transfers are done for preventive reasons. This figure is higher in women with no previous vaginal delivery. (PERINATAL COMPLICATIONS BY SETTING) - Uterine rupture is the main complication of TOLAC and is associated with significant infant morbidity and mortality. Eight studies were selected to examine the risk of perinatal complications by setting. It was found that the risk of convulsions, encephalopathies and a low Agpar score is greater in women who have attempted a TOLAC at home or at a birthing centre than at a hospital. However, these results should be nuanced because of the low quality of the evidence, which is due essentially to the observational design of the studies in question and affects their external validity. Indeed, the heterogeneity of the organizational contexts invites caution when applying these results to the Québec context. On the other hand, studies that used the actual VBAC setting the rather than the planned one are likely to underrate the risks associated with non-hospital birthing. A trend was also observed for the difference by setting (hospital vs. non-hospital) for the risk of perinatal mortality, but not for neonatal intensive care unit admissions. No comparative study or meta-analysis had the statistical power to demonstrate a significant difference. Furthermore, it should be mentioned that potential information and selection biases may have resulted in an underestimation of the mortality rate in non-hospital settings.

Authors' recommendations: A trial of labour after cesarean (TOLAC) should be encouraged when the eligibility criteria are met. However, given the increased risk of uterine rupture and the time-sensitive nature of this obstetrical emergency, here are the recommendations: 1. The TOLAC be the preferred practice for women with a prior cesarean and that women who wish to attempt a TOLAC have the option of giving birth under the supervision of a midwife or a physician; 2. Hospitals be midwifery-friendly and that they respect midwives' professional autonomy; 3. A single information and decision support tool be adopted by all the professionals involved in supporting women during informed consent and the shared decision-making when choosing a TOLAC; 4. TOLAC risk assessment tools and validated and standardized intervention methods, which would be used by all health professionals involved in antepartum care and during delivery, be adopted; 5. An interdisciplinary ministerial committee propose concrete action for improving collaborative practice between midwives and physicians who practice obstetrics, and with hospital personnel, if applicable; 6. Québec put in place a system for evaluating and monitoring, using medico- administrative data, TOLAC quality and safety to ensure the progression of TOLAC practice and safety in this province.

Authors' methods: In the interest of knowledge mobilization and integration, a multidimensional approach was used, integrating scientific, contextual and experiential data. A systematic search of the scientific and grey literature was conducted in medical databases (PubMed and Embase) for the years 2007 to 2018, as well as on the websites of medical organizations and associations. For the issue of setting safety, meta-analyses of proportions were performed, when the results so permitted. Contextual and experiential data were gathered from stakeholders by means of committees, focus groups, individual telephone interviews, and an online questionnaire. As well, a quantitative descriptive analysis was performed of the MED-ECHO and I-CLSC medico-administrative databases for the 2016-2017 fiscal year. All the data collected by the project team were submitted to the expert advisory committee and the project steering committee for comments and suggestions. All the data and findings, as well as draft recommendations, were submitted to the Comité d’excellence clinique en services de santé for deliberation with a view to making final recommendations.

Project Status: Completed

URL for project: https://www.inesss.qc.ca/publications/repertoire-des-publications/publication/securite-du-lieu-et-conditions-de-succes-de-laccouchement-vaginal-apres-une-cesarienne.html

Year Published: 2019

URL for published report: https://www.inesss.qc.ca/publications/repertoire-des-publications/publication/securite-du-lieu-et-conditions-de-succes-de-laccouchement-vaginal-apres-une-cesarienne.html

Requestor: Minister of Health

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: Canada

Province: Quebec

Organisation Name: Institut national d'excellence en sante et en services sociaux

Contact Address: L'Institut national d'excellence en sante et en services sociaux (INESSS) , 2021, avenue Union, bureau 10.083, Montreal, Quebec, Canada, H3A 2S9;Tel: 1+514-873-2563, Fax: 1+514-873-1369

Contact Name: demande@inesss.qc.ca

Contact Email: demande@inesss.qc.ca

Copyright: Gouvernement du Québec