Importance: Excess gestational weight gain (GWG) increases risk of adverse maternal and infant outcomes. With efficacy of antenatal lifestyle interventions now proven, US Prevention Task Force recommends implementation to optimise GWG and outcomes.
Objective: To evaluate an evidence-based lifestyle intervention implemented into routine antenatal care using the RE-AIM framework.
Design: Nonrandomised controlled trial comprising intervention allocation until a service capacity limit was reached, with remaining women allocated to standard care.
Setting: Large Australian maternity healthcare service.
Participants: Women <23 weeks gestation, with pre-pregnancy body mass index of 35-43kg/m².
Intervention: embedded behavioural lifestyle intervention delivered by a health coach, supported by a physician over five sessions. Both intervention and standard care received routine antenatal care.
Outcomes: Primary: effectiveness in reducing excess GWG. Secondary: reach, adoption, implementation, maintenance outcomes, and maternal and neonatal outcomes.
Results: Reach: 404 women (202 in intervention, 202 in standard care]). Efficacy: There was no difference in proportion exceeding GWG recommendations or mean GWG between groups. A subgroup analysis was undertaken, excluding women who developed gestational diabetes (GDM) and received related lifestyle intervention: a lower proportion of women in the intervention had GWG above recommendations (β coefficient 0.5, 95% CI 0.3,0.99) p=0.05, with less GWG (-2.1kg (-3.8,-0.2),p=0.02). Adoption: Qualitative analysis of staff and participants demonstrated strong support for service implementation. Implementation: Strong fidelity and staff and participant acceptability. Maintenance: maintained 3 years post study with plans and funding for expansion across the health service.
Conclusions and relevance: This implementation-effectiveness study demonstrates successful implementation and maintenance of an antenatal lifestyle intervention in routine antenatal care, generating new knowledge aligned with RE-AIM framework. Intervention did not alter proportion exceeding recommended GWG or total GWG, however, the intervention was effective for women without GDM who received lifestyle intervention. Further implementation studies are underway, including remote delivery across diverse settings and populations.