Interpretation
Several economic evaluations of IOL have been undertaken, including comparing IOL at 39 weeks (22-24) or 41 weeks (25) to expectant management. An Australian study of outpatient (Foley) catheter with inpatient IOL (26) found non-significantly higher mean costs ($6,524 OCF and $5,876 IPG). Although not directly comparable to our study as they did not include a generic health outcome measure, they did similarly report significantly fewer antenatal ward hours in outpatient-balloon compared to inpatient-PG group. We observed a slightly longer and more expensive stay in birth suite for women in outpatient-balloon group, as was also reported in two Dutch CEA alongside RCTs (27, 28). From a health economic perspective, it is therefore tempting to consider outpatient-PG IOL, with a potential reduction in cervical priming costs and time spent in antenatal ward, especially for nulliparous women whose duration of induced labour can be prolonged. However, our findings were of more adverse perinatal outcomes amongst nulliparous women receiving PG (16). A 2014 systematic review, meta-analysis and CEA on best method of IOL (29) found most interventions compared had similar utility but differed on cost outcomes. Titrated misoprostol solution and sublingual misoprostol had the highest probability of being cost-effective. But given their increased rates of uterine hyperstimulation, compared to mechanical methods, misoprostol may also not be appropriate for outpatient cervical priming. Future outpatient IOL studies should consider the role of alternative mechanical methods, or different durations of insertion in order to determine safe, cost-effective approaches that are acceptable to women.
The decision-making around the choice of IOL method is complex and is likely influenced by best-practice guidelines, clinician/health service preferences, but also women’s’ beliefs, past experiences and willingness to undergo a certain intervention. Although a clinician’s principal focus may be to provide high-quality care, they share responsibility for making the best decisions for a health system with finite resources, by choosing cost-effective care options. In this study, outpatient-balloon IOL resulted in both cost-saving and improved health outcomes with reduced uncertainty for nulliparous women representing excellent value for money. These findings should be considered for future decision-making, along with evidence on safety and women’s preferences.