Main Findings
In this study we found an overall CS rate of 32.7% at EH from 2014 to
2019, this is close to the national CS rate of 35% 6.
Group 5 had a relative contribution of 35.2%, making it the main
contributor, followed by group 2 with a relative contribution of 26.6%
and then group 1 with a relative contribution of 10.3%. These results
are similar to other studies11, 14, 15 and also
similar to previous data from Australia 5. The CS rate
at EH increased 1.5% per year, from 30.7% in 2015 to 36.0% in 2019,
mainly due to increase at BHH. This is the same scenario experienced by
other institutions in Australia and in several other developed countries11, 13. This finding allows us to identify these as
target groups for interventions aiming to reduce CS in our institutions.
In both hospitals, nulliparous women (groups 1 and 2 together), were the
main population contributing to the overall CS rate accounting for just
over a third of all CS cases. This finding is very important as woman’s
first birth experience has a profound influence on the method likely to
be used in her next pregnancy 16.
Interventions aiming to reduce the CS rate in group 5 include increasing
the availability of vaginal birth after CS (VBAC) but also reducing the
CS rates in both groups 1 and 2. Women’s decisions on mode of delivery
after a CS are influenced by their previous birth experience and their
current expectations. Antenatal counselling and education might be
beneficial for this group to increase their awareness and perceptions
about VBAC. Additionally, hospital policies and clinician perceptions
towards VBAC are also key aspects to address 14.
The size of groups 1 and 2, (nulliparous women) are within the expected
range of 35-42% as per the Robson guidelines 9 and
previous papers 17, however, the size of groups 3 and
4, multiparous women, are slightly higher than the 30% recommended in
the guideline, suggesting that we could be serving a population with
higher fertility rates. The size of group 5 is relatively high and could
indicate that we serve many women with previous CS, perhaps many of whom
were in groups 1 or 2 in past years at our own institutions, although
our current data does not allow us to explore this. Group 8 and 10 are
both at the higher end of the expected size, which gives an indication
that EH may serve a higher risk population. However, the details of the
population variation and level of complexity of our population was not
possible to capture by looking at the Robson classification alone.
Although the nulliparous distribution is within the expected range, we
found a less than 2:1 ratio between the sizes of group 1 and 2, and
groups 3 and 4. This suggests a high incidence of induction of labour
and pre-labour CS in both nulliparous and multiparous women. Similar
finding was reported by Robson in 2015 17 and efforts
to understand indications for induction of labour and pre-labour CS were
suggested as a strategy to reduce CS rates.
Women who had Induction of labour, both nulliparous and multiparous,
(groups 2a and 4a) had a high CS rate, which was due mostly to increased
need for emergency CS. This finding is similar to what has been found in
Queensland 16 and in the Nordic countries11. Improvement of surveillance and overall management
of induction of labour, including the use of oxytocin and ripening
agents are potential interventions to consider. Interestingly for group
4, although induction of labour was still common, the CS rate was much
lower than for group 2 in our institutions, similar to results found in
Queensland 16. This suggests than perhaps inducing
labour in multiparous women does not carry the same risk of CS as when
inducing nulliparous women. However, we found differences in our CS
rates in groups 2a, 3 and 10 between BHH and AH, suggesting that perhaps
we need to provide slightly different strategies in each of our
hospitals to reduce our overall CS rate at EH.
Other independent risk factors for CS have been described18 and obstetric pathology like hypertensive
disorders, diabetes, obesity and advance maternal age are also
independent variables capable of influencing the CS rate. Other studies1 have shown how ethnicity, specially being
Asian-born, along with other maternal characteristics, were also
associated with increased risk of CS. Therefore, variables such as BMI,
maternal age, previous maternal comorbidities and pathologies and foetal
compromise should be included when analysing this type of data. In
addition, the type of population that EH serves seems to be more complex
that captured by the Robson classification and gathering further data
regarding their epidemiological and demographic characteristics could
help to better understand the CS rates and identify strategies to reduce
it 11.