Main findings
The STan Australian Randomised Trial (START) is the first of its kind in
an Australian setting. Previous European trials have been conducted in
relatively low intervention environments (17-19), which, with less
clinically contentious caesarean sections being performed, we
hypothesised may have resulted in a lower likelihood of demonstrating
reduction in caesarean section. This rationale was supported by the
results of our pilot study with 162 women (7) suggesting the potential
for STan as an adjunct to CTG to reduce EmCS when implemented in a
clinical setting of high caesarean section. Our findings here, while not
significant, suggest that neonatal, but not maternal costs may be
reduced with the use of CTG+STan. The study was underpowered to detect a
difference in the main clinical outcome, EmCS (1), and the final sample
size also proved to be insufficient to make conclusive statements about
costs. Nevertheless the consistent direction of effect favouring the use
of CTG+STan warrants further research.
The average (non-statistically significant) cost reduction of about
2,000 AUD per mother-baby pair was largely explained by neonatal cost
reductions in the CTG+STan arm. STan monitoring is associated with less
complexity of neonatal care (with less requirment for higher level
neonatal care). Sizable reductions are shown for the sample overall, for
re-admissions, and for the various sensitivity analyses, both
per-protocol and with outlier exclusion.
This concurs with comparable European research. An analysis (20) based
on Individual Patient Data Meta-analysis (IPDMA) (21) incorporated data
from three European trials of STan monitoring (12,987 mother/baby
dyads). There was consistent reduction in neonatal metabolic acidosis.
Although the this reduction was not statistically significant, the
authors argued that this was not unexpected as even meta-analysis were
underpowered (requiring a over 24,000 patients before sufficient power
would determine a difference in metabolic acidosis if it existed, at α =
0.05). The results suggested that metabolic acidosis was reduced from
1100 to 900 per 100 000 newborns if a CTG+STan-based strategy was
followed. and the cost effectiveness of CTG+STan depends on the
association between metabolic acidosis and cerebral palsy. it was
estimated that CTG+STan use could prevent one case of metabolic acidosis
at a cost of 14 509 euros, and that STan becomes a cost effective
strategy if > 1.0% of the patients exposed to metabolic
acidosis developed cerebral palsy. The consistency of direction of
effect and similarity in magnitude of the reduction in our study with
regard to metabolic acidosis is comparable to published trials (absolute
difference of about 7%).
These results suggest that STan may have a role to play in efforts to
improve quality and safety of care. Whilst the focus of improving fetal
monitoring has been directed at reducing maternal intervention,
particularly caesarean section, recent developments in the UK have
necessitated a renewed emphasis on neonatal safety (22). This
re-positioning of policy (23) is partly motivated by concerns about
costs for compensating for harm (24-26).
Neonatal costs may be a sensitive proxy for adverse neonatal outcomes. A
failure to implement, correctly interpret and appropriately act in
response to intrapartum fetal monitoring has been identified as an
important association with excessive mortality and morbidity in recent
reviews of under-performing maternity health services. The 2022 Ockenden
report (26), recommended improvements in monitoring of fetal wellbeing,
ensuring that clinicians keep abreast of developments in the field.
Earlier reviews (27) of excessive neonatal mortality in the Morecombe
Bay Report made similar recommendations, (27), as did a 2022 report by
the same author concernimg the East Kent Maternity services (24).
Reviews of excessive fetal mortality in Australia has also identified
underutilisation and misinterpretation of fetal heart rate monitoring by
“inadequately skilled” staff and a lack of “high quality staff
education” as associated with preventable fetal morbidity and
mortality. It is suggested that inadequate intrapartum fetal
surveillance, and inadequate use or misinterpretation of
cardiotocography contributed to excessive mortality, and part of this
has been attributed to an inadequately skilled workforce (28, 29).
The work also goes towards redressing the dearth of published evidence
of the cost effectiveness of different techniques and technologies of
fetal monitoring. We are aware of only one published economic evaluation
of CEFM in an Australian context (30). reported on a trial of 600 women
randomised to CTG or fetal pulse oximetry (FPO), finding a non
significant 23% relative risk reduction in operative delivery..