Preventing postnatal maternal mental health problems using a psychoeducational intervention: The cost-effectiveness of What Were We Thinking

Objectives: Postnatal maternal mental health problems, including depression and anxiety, entail a significant burden globally, and finding cost-effective preventive solutions is a public policy priority. This paper presents a cost-effectiveness analysis of the intervention, What Were We Thinking (WWWT), for the prevention of postnatal maternal mental health problems. Design: The economic evaluation, including cost-effectiveness and cost-utility analyses, was conducted alongside a cluster-randomised trial. Setting: 48 Maternal and Child Health Centres in Victoria, Australia. Participants: Participants were English-speaking first-time mothers attending participating Maternal and Child Health Centres. Full data were collected for 175 participants in the control arm and 184 in the intervention arm. Intervention: WWWT is a psychoeducational intervention targeted at the partner relationship, management of infant behaviour and parental fatigue. Outcome measures: The evaluation considered public sector plus participant out-of-pocket costs, while outcomes were expressed in the 30-day prevalence of depression, anxiety and adjustment disorders, and quality-adjusted life years (QALYs). Incremental costs and outcomes were estimated using regression analyses to account for relevant sociodemographic, prognostic and clinical characteristics. Results: The intervention was estimated to cost $A118.16 per participant. The analysis showed no statistically significant difference between the intervention and control groups in costs or outcomes. The incremental cost-effectiveness ratios were $A36 451 per QALY gained and $A152 per percentage-point reduction in 30-day prevalence of depression, anxiety and adjustment disorders. The estimate lies under the unofficial cost-effectiveness threshold of $A55 000 per QALY; however, there was considerable uncertainty surrounding the results, with a 55% probability that WWWT would be considered cost-effective at that threshold. Conclusions: The results suggest that, although WWWT shows promise as a preventive intervention for postnatal maternal mental health problems, further research is required to reduce the uncertainty over its cost-effectiveness as there were no statistically significant differences in costs or outcomes.