The purpose of this study is to determine the effect of an antenatal obesity treatment on gestational weight gain when integrated into Philadelphia WIC.

Institute of Medicine (IOM) guidelines for weight gain in pregnancy are clear, but evidence-based treatment approaches are not widely available. This evidence gap is particularly pressing for medically vulnerable women - those who are low income and often racial/ethnic minorities. These women have the highest rates of obesity, but almost no resources to support weight control in pregnancy. Without intervention, most will exceed Institute of Medicine recommended gains and incur significant morbidity for themselves and their children. There is preliminary data from the investigators supporting the efficacy of digital health platforms for delivering antenatal obesity treatment among the medically vulnerable. However, the investigators' inexpensive, easily scalable approach has not been integrated and tested in real world settings, limiting broad reach and dissemination potential. Dissemination considerations are especially pressing for socioeconomically disadvantaged and minority populations because of these groups' higher obesity risk, greater potential for experiencing obesity-related comorbidities in pregnancy, and limited finances to afford alternative treatments. The Women, Infants and Children (WIC) Food and Nutrition Program is the leading public health nutrition program for pregnant women and their children in the US, and thus, it is in a unique position to meaningfully impact the obesity epidemic among the more than 9 million disadvantaged participants it serves annually. Yet no demonstrations of effective gestational weight gain interventions exist in WIC. The investigators propose a pragmatic trial designed to rigorously test their antenatal obesity treatment approach integrated into Philadelphia WIC community clinics. The investigators have long-standing relationships with WIC staff and prior experience conducting pragmatic clinical trials in under-resourced settings. The investigators will randomize 438 African American and Hispanic Philadelphia County WIC participants with obesity in early pregnancy to one of two treatment arms: 1) standard WIC care; or 2) an antenatal obesity treatment arm, which includes empirically supported behavior change goals, regular self-monitoring text messages with automated feedback, tailored skills training materials, and counseling from WIC nutritionists. The primary outcome is prevalence of excessive gestational weight gain; the investigators will additionally examine changes in diet and physical activity, health-related quality of life, and rates of adverse pregnancy outcomes. They will use the RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) framework to evaluate the intervention's dissemination potential and cost effectiveness in the WIC setting. The proposed project will constitute the first systematic translation of a comprehensive antenatal obesity treatment program focused on low-income, racial/ethnic minorities, using the strengths of mHealth (mobile health) and WIC provider counseling for intervention delivery.

Inclusion Criteria:

• BMI ≥ 25 kg/m2
• Self-identify as African American or Hispanic
• Gestational age ≤16 weeks' (measured using last menstrual period)
• Philadelphia WIC participant
• Willingness to receive study texts
• Own a cell phone with an unlimited text messaging plan
• Able to participate in light to moderate physical activity (walking)

Exclusion Criteria:

• Prior bariatric surgery
• Pre-existing medical condition that could influence weight (e.g., diabetes, HIV, thyroid disorder, bulimia, anorexia, gallbladder disease)
• Diagnosis contraindicating weight control (e.g., hyperemesis gravidarum)
• Shared phone
• Multiple pregnancy (e.g., twins)
• Current and/or previous participant for our Temple-led obesity treatment interventions in pregnancy or the postpartum period
• Serious or unstable medical or psychological conditions that, in the opinion of the PI, would compromise the subject's safety for successful participation in the study

Dr. Herring (PI) will ensure that all publications that result from data collected as part of this project will comply with the NIH public access policy. Also, Dr. Herring agrees to develop a transportable de-identified database, codebook, and mechanism by which data can be shared with other investigators upon approval of the study's research team. The Resource Sharing Plan will be reviewed and approved by Temple University's Institutional Review Board.

Baseline analyses include all participants randomized whether or not they competed the study. 416 participants were randomized even though only 393 participants completed the study and were included in the primary outcomes analyses.

Adverse event data were collected from baseline/enrollment through end of pregnancy, up to 26 weeks total (primary outcome data collection period).

Findings need to be considered in light of the Covid-19 pandemic, which led to challenges with intervention delivery and intensity (i.e., limited in-person WIC visits, structural impediments for system-wide adaptation) along with remote weight and height measures for some participants.