This project aims to determine whether a mobile-health (m-health) tool, accessible via smartphone or website, intervention for overweight and obese pregnant women improves physical activity, gestational weight gain, quality of life, stress and depression during pregnancy. This study will examine factors associated with using the m-health tool and the most highly utilized features of the tool, with a goal of understanding how it can be used and improved in future behavior change interventions. The hypothesis is that compared with usual care, an m-health intervention will result in increased minutes of moderate-to-vigorous physical activity and increased knowledge of the IOM GWG guidelines. The study design is a small pilot randomized trial to assess feasibility. This study will recruit and follow 70 overweight and obese pregnant women during the first trimester of pregnancy from Kaiser San Francisco and other facilities. The m-health intervention has the advantage of enabling overweight and obese women to monitor and improve their health behaviors without impacting the work flow of clinical care. Depending on the results of this initial evaluation, the clinical implications may include its implementation at the health system level and/or being evaluated and improved in the future by a larger investigation in a randomized controlled trial. The study team will assess adherence and acceptability of the intervention to inform future studies.

Inclusion Criteria:

• Pregnant
• Women aged 21 years or older receiving prenatal care at Kaiser Permanente San Francisco and Oakland and whose obstetric care clinicians approved their participation in the study;
• Pregravid BMI 25 to <40 (as determined from a measured pregravid weight in electronic medical record);
• Has access to a smartphone and Wi-Fi;
• Provides informed consent to participate.

Exclusion Criteria:

• Multiple births;
• Planning to move out of the area during the study period;
• Diagnosis of any of the following conditions: diabetes outside of pregnancy, severe disease of the cardio-pulmonary system, serious gastrointestinal disease (e.g., Crohn's disease, IBD), kidney disease, lung disease (e.g., emphysema, COPD), major psychiatric disorder, thyroid disease (diagnosed in the last month), cancer (not including non-malignant skin cancer), drug and alcohol abuse, or history of an eating disorder;
• History of bariatric surgery;
• Use of metformin or corticosteroids;
• Inability to speak, read, or understand English;
• Placed on bed rest at time of enrollment;
• >15 weeks' gestation at enrollment.

This study is only enrolling female participants.