Continuous Glucose and E-Monitoring to Support Healthy Weight Gain in Pregnancies - The GEM Study

The purpose of this study is to assess the feasibility of delivering a remotely administered behavioral lifestyle intervention for pregnant women with overweight and obesity, adapted from the established SmartMoms framework, using a simulated (mock) control arm for comparison. This pilot study will enroll approximately 12-16 participants and will focus on evaluating feasibility, acceptability, and preliminary signals of impact to inform a future randomized controlled trial.

The intervention is tailored to the needs of women in Arkansas and aims to promote healthy gestational weight gain through motivational interviewing, physical activity promotion, education on dietary recommendations and self-monitoring. Participants will be encouraged to meet current pregnancy exercise guidelines (>= 30 minutes of moderate-intensity activity on most, if not all days) and to follow a balanced diet consistent with caloric intake recommendations for appropriate gestational weight gain based on individual pre-pregnancy BMI.

Each participant will be provided with an internet connected bodyweight scal, and pedometer for daily self-monitoring. These devices will automatically transmit weight and step data to the study team. Participants will also wear a continuous glucose monitor (CGM) throughout their pregnancy to track temporal glucose patterns, which will be reviewed with the study's registered dietitian (RD) and health coaches.

Intervention delivery will include weekly virtual motivational interview sessions with a trained health coach. Sessions will review weight gain trajectory, dietary intake, physical activity patterns, and CGM data, and will provide tailored behavioral strategies for meeting gestational weight gain goals. Educational materials will be delivered electronically to participants' smartphones. A closed online forum will be available for peer support, following the SmartMoms framework.

The simulated control arm will be generated post hoc by matching trial participants to publicly available datasets based on gestational age, BMI category, and other relevant covariates. This mock control will serve only as a comparator for preliminary analyses; all enrolled participants will receive the active intervention.

The intervention will begin between 16-20 weeks' gestation and continue until delivery (20-24 weeks per participant). All motivational interviewing sessions will be delivered remotely, and participants will be trained individually on safe and effective use of study tools.

The formative phase (Phase I), classified as exempt by the institutional review board will seek participation from individuals meeting the following criteria:

• Currently pregnant or pregnant within the past 36 months.
• Community partners with relevant perspectives to inform recruitment, adaptation approaches and feasibility of the phase 2 pilot trial.

Clinical Trial (Phase 2)

Inclusion criteria

• pregnant women less than 20 weeks of gestation at time of screening
• 18-45 years of age
• BMI of 25 - 40 kg/m-2
• Expecting a singleton pregnancy
• Smartphone and/or reliable internet access
• Willing to be identifiable to other study participants in the study program .

Exclusion criteria

• Smoker
• Preexisting medical conditions that might be exacerbated by pregnancy (e.g., diabetes mellitus, chronic renal failure, hypertension, malignancies, seizure disorder, lupus, drug or alcohol abuse, serious psychiatric disorders)
• Current mental health or eating disorder
• Contraindication to exercise (OB/GYN release is obtained prior to consent)
• Conceived with assisted fertility treatments
• Medications during pregnancy known to influence fetal growth (e.g., thyroid hormone, glucocorticoids, insulin, oral hypoglycemic agents)
• Plans to move out of the state in the next 6 months following screening.