The Scale-up of a Digital Health Intervention (Healthy Beginnings for HNEKids) Targeting the First 2000 Days: Protocol for a Randomised Controlled Trial (Preprint)

BACKGROUND Digital health interventions (DHIs), delivered directly to parents’ mobile phones could transform the delivery of healthcare during the first 2000 days of a child’s life. Healthy Beginnings for Hunter New England Kids (HB4HNEKids) is an innovative text-message-based model of care that provides age-and-stage relevant preventative health information to parents during the first 2000 days. While HB4HNEKids demonstrates promise for population wide scale-up, the optimal method for achieving universal, cost-efficient and equitable scale-up remains unclear. OBJECTIVE This protocol outlines a randomised controlled trial (RCT) that evaluates two models for scaling up HB4HNEKids: an ‘opt-in’ clinician-initiated model (intervention) and an ‘opt-out’ system-initiated model (control). The trial will assess program reach (the number and proportion of eligible parents receiving HB4HNEKids) and participant representativeness, to identify the most effective, equitable, and efficient approach to scaling up care for families during the first 2000 days. METHODS A randomised controlled trial will be conducted in six Child and Family Health Service (CFHS) sectors (39 CFHS units) within the Hunter New England region of New South Wales (NSW), Australia. The six CFHS sectors will be randomised in a 1:1 ratio to one of two arms, stratified by sector location and average number of births per annum. The intervention arm (a clinician-initiated opt-in model of care) will involve a series of implementation support strategies delivered to CFHS staff (i.e. training, audit and feedback) to support clinicians in connecting eligible families to the HB4HNEKids program. The control arm (a system-initiated opt-out model of care) will use existing health service data to identify participants meeting the predefined eligibility criteria to automatically initiate the commencement of HB4HNEKids messages to families (i.e. will not require input from CFHS staff). The primary outcome will assess the reach and representativeness of participants receiving HB4HNEKids. Secondary outcomes will include child health behaviours (breastfeeding rates; age of introduction to solids; child fruit, vegetable and discretionary food intakes; as well as child immunisation rates) captured via parent survey; as well as the cost effectiveness. RESULTS This trial commenced in July 2024, and as of July 2025 enrolled 4,212 participants. Data collection (via parent survey) commenced in January 2025 and is projected to end in July 2027. CONCLUSIONS Currently, little is known about the most effective model of scaling-up DHIs. This trial will generate novel evidence for informing the effective scale-up of evidence-based health promotion programs that aim to provide universal care, which are needed to maximise the potential population health gains. CLINICALTRIAL ACTRN12624000655549p