<p><strong>BACKGROUND: </strong>Few studies have addressed obesity prevention among low-income families whose infants are at increased obesity risk. We tested a Facebook peer-group intervention for low-income mothers to foster behaviors promoting healthy infant growth.</p>

<p><strong>METHODS: </strong>In this randomized controlled trial, 87 pregnant women (Medicaid insured, BMI ≥25 kg/m(2)) were randomized to the Grow2Gether intervention or text message appointment reminders. Grow2Gether participants joined a private Facebook group of 9-13 women from 2 months before delivery until infant age 9 months. A psychologist facilitated groups featuring a curriculum of weekly videos addressing feeding, sleep, parenting, and maternal well-being. Feasibility was assessed using the frequency and content of participation, and acceptability using surveys. Maternal beliefs and behaviors and infant growth were assessed at birth, 2, 4, 6, and 9 months. Differences in infant growth between study arms were explored. We conducted intention-to-treat analyses using quasi-least-squares regression.</p>

<p><strong>RESULTS: </strong>Eighty-eight percent (75/85) of intervention participants (42% (36/85) food insecure, 88% (75/85) black) reported the group was helpful. Participants posted 30 times/group/week on average. At 9 months, the intervention group had significant improvement in feeding behaviors (Infant Feeding Style Questionnaire) compared to the control group (p = 0.01, effect size = 0.45). Intervention group mothers were significantly less likely to pressure infants to finish food and, at age 6 months, give cereal in the bottle. Differences were not observed for other outcomes, including maternal feeding beliefs or infant weight-for-length.</p>

<p><strong>CONCLUSIONS: </strong>A social media peer-group intervention was engaging and significantly impacted certain feeding behaviors in families with infants at high risk of obesity.</p>