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].