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..