Interpretation
Global TOLAC and VBAC rates vary greatly. TOLAC rates range from as low as 5% in nationwide studies from Japan to rates of 66-72% in Denmark and the Netherlands.14–17 The TOLAC rates found in our review were higher than those in other regions of the world but similar to the findings by a prior SSA metanalysis from 1998, where the average rate was 69%. However, the VBAC rates we found were generally lower compared to other regions, where rates range from 60-89%, with the exception of two studies from China and Denmark, where the rates were 14% and 8%, respectively.15–21 These differences could be due to variations in study design and inclusion criteria but could reflect practice patterns, and may reflect a greater ability to screen for and select TOLAC candidates with a higher likelihood of success due to more robust antenatal care in regions of the world with more comprehensive health care services. It is also possible that the threshold for abandoning TOLAC and moving to repeat cesarean delivery is lower in hospitals delivering this care in SSA, as there are barriers to the close monitoring needed during TOLAC and challenges of access to expedient surgical management should complications occur.
Overall, we found a uterine rupture rate of 1.3% across all reporting studies, suggesting this is a relatively low occurrence among women with a previous CS in SSA. However, this rate is several times higher than the overall rupture rates of 0.3-0.6% reported in other regions,15,17,21,22 but lower than rates of 2.1-2.7% reported in China.18 Overall pooled maternal and perinatal mortality rates were also higher than mortality rates associated with TOLAC and ERCD in other regions of the world.14–17,19–21,23 In particularly, the pooled perinatal mortality rate of 5% among the TOLAC group in comparative studies is markedly higher than the rates reported in other regions of the world, where with the exception of one study from China reported perinatal mortality rates are less than 1%. 14,15,17–19,22–24Importantly, however, the higher rate of perinatal mortality found in the TOLAC group compared to ERCS calls for further research to understand if this finding remains true in more extensive studies, across all groups of women and settings, and if outcomes are modifiable based on antenatal screening and triage patterns and intrapartum care delivery.
Further research is needed to understand the differences in regional rates, particularly the variation in uterine rupture rates (range from 1.3% to 8.8%). There are several potential reasons for these differences. With less ability to adequately screen and counsel women with prior caesareans due to limited resources and more limited access to antenatal care, it is possible that more women with a relative contraindication to TOLAC, e.g., two or more prior caesareans, undergo TOLAC. Furthermore, women may arrive late to hospitals for adequate monitoring of TOLAC or may even avoid going to the hospital to avoid a repeat cesarean. Finally, at the hospital, there may be more limited ability to monitor women adequately, appropriately triage women to repeat cesarean when TOLAC is unsuccessful, and move expediently to surgery once the decision has been made [ref].