A realist investigation of the impact of Healthy Start on the diets of low-income pregnant women in the UK

Abstract

Healthy Start is the United Kingdom government’s food voucher programme for low-income, pregnant women and young children. Eligible women receive vouchers worth £3.10 per week, which can be exchanged for fruit and vegetables, plain cow’s milk or infant formula. There has been no robust evaluation of the impact of Healthy Start on nutritional outcomes since its introduction in 2006. Therefore, this study aimed to explore potential outcomes of the programme (including intended and unintended outcomes) and develop explanations for how and why these outcomes might occur.
A realist review was conducted in two iterative and overlapping stages: 1) developing theories or hypotheses about how the Healthy Start programme works, for who, in what circumstances and why; 2) testing those theories using relevant evidence from existing studies of Healthy Start and a similar food voucher programme in the United States. The review findings comprised three ‘evidence-informed programme theories’ about how low-income pregnant women use Healthy Start vouchers and why.
A qualitative study was undertaken to further refine and consolidate the programme theories derived from the realist review, and to develop new and emerging programme theories. Semi-structured interviews were conducted with 11 low-income women from North West England, who received Healthy Start vouchers during pregnancy. An innovative combination of realist interview techniques and vignettes was used to communicate and exchange theories with low-income women. A realist logic of analysis was applied to generate clear and transparent linkages between outcomes and explanations. Five ‘evidence-based programme theories’ were developed to explain why low-income pregnant women may experience one or more of the following outcomes from the Healthy Start programme: dietary improvements, shared benefits, financial assistance, stockpiling formula, misuse of vouchers.
These programme theories were integrated with existing behaviour change theories and an overarching theoretical model for Healthy Start was developed. This model illustrates the combination of context and resources needed to generate the intended outcome of dietary improvements for low-income pregnant women, and the mechanisms by which this outcome may be generated.