Protocol for cost-effectiveness analysis of a randomised trial of mHealth coaching (Bump2Baby and Me) compared with usual care for healthy gestational weight gain and postnatal outcomes in at-risk women and their offspring in the UK, Australia, Ireland and Spain

IntroductionGestational diabetes mellitus and overweight are associated with an increased likelihood of complications during birth and for the newborn baby. These complications lead to increased immediate and long-term healthcare costs as well as reduced health and well-being in women and infants. This protocol presents the health economic evaluation to investigate the cost-effectiveness of Bump2Baby and Me (B2B&Me), which is a health coaching intervention delivered via smartphone to women at risk of gestational diabetes.Methods and analysisUsing data from the B2B&Me randomised controlled trial, this economic evaluation compares costs and health effects between the intervention and control group as an incremental cost-effectiveness ratio. Direct healthcare costs, costs of pharmaceuticals and intervention costs will be included in the analysis, body weight and quality-adjusted life-years for the mother will serve as the effect outcomes. To investigate the long-term cost-effectiveness of the trial, a Markov model will be employed. Deterministic and probabilistic sensitivity analysis will be employed.Ethics and disseminationThe National Maternity Hospital Human Research and Ethics Committee was the primary approval site (EC18.2020) with approvals from University College Dublin HREC-Sciences (LS-E-20-150-OReilly), Junta de Andalucia CEIM/CEI Provincial de Granada (2087-M1-22), Monash Health HREC (RES-20-0000-892A) and National Health Service Health Research Authority and Health and Care Research Wales (HCRW) (21/WA/0022). The results from the analysis will be disseminated in scientific papers, through conference presentations and through different channels for communication within the project.Trial registration numberACTRN12620001240932.