Healthy for Two/Healthy for You: Design and methods for a pragmatic randomized clinical trial to limit gestational weight gain and prevent obesity in the prenatal care setting

Objective: To compare the effect of Healthy for Two/Healthy for You (H42/H4U), a health coaching program, in prenatal care clinics that serve a racially and economically diverse population, on total gestational weight gain (GWG) (vs. usual care). We hypothesize that compared to usual prenatal care, intervention participants will have lower GWG and lower rates of gestational diabetes mellitus (GDM). Methods: We report the rationale and design of a pragmatic, parallel arm randomized clinical trial with 380 pregnant patients ≤15 weeks gestation with overweight or obesity from one of 6 academic and community-based obstetrics practices, randomized to either H42/H4U or usual prenatal care in a 1:1 ratio. The study duration is early pregnancy to 6 months postpartum. The primary outcome is total GWG, calculated as the difference between first clinic-assessed pregnancy weight and the weight at 37 weeks gestation. Key maternal and infant secondary outcomes include GDM incidence, weight retention at 6 months postpartum, infant weight, maternal health behaviors and wellness. Conclusions: This pragmatic clinical trial embeds a pregnancy health coaching program into prenatal care to allow parallel testing compared to usual prenatal care on the outcome of total GWG. The real-world design provides an approach to enhance its sustainability beyond the trial to ultimately improve maternal/child health outcomes and reduce future obesity. Trial registration: The study was first registered at clinicaltrials.gov on 1/26/21 (NCT04724330).