This study is being conducted to better understand how physical activity programs can support pregnant individuals with obesity and to explore ways to improve health outcomes for both parent and baby during and after pregnancy. Participants will be assigned to either a community-based exercise group or a standard care group and followed throughout pregnancy and up to one year after delivery. Those in the exercise group will take part in small-group training sessions led by certified trainers three times per week, with both in-person and virtual options available. The study will collect information on physical activity, health outcomes, and participant experiences to evaluate how well this program works in real-world community settings.

You may be eligible for this study if you meet the following criteria.

Inclusion Criteria:

• Pregnant with a single baby (singleton pregnancy)
• 18 years of age or older
• Body mass index (BMI) of 30 or higher
• Less than 15 weeks pregnant at the time of enrollment
• Not currently meeting recommended physical activity levels (150 minutes of moderate exercise per week or more)
• Able to receive approval from a doctor to participate

Exclusion Criteria:

• Preeclampsia–eclampsia
• Premature rupture of the membranes
• Antepartum hemorrhage
• Placenta previa

If you choose to participate, your involvement in the study may last from early pregnancy (before 15 weeks) through up to 12 months after delivery.

In-Person / Clinic-Based Activities

You will be asked to complete study-related assessments at the following timepoints:

• Early pregnancy (before 15 weeks)
• Third trimester
• Approximately 6 weeks after delivery
• Approximately 12 months after delivery

At these timepoints, you will:

• Have health information collected from your healthcare provider (such as weight, blood pressure, and other routine measures)
• Complete questionnaires about your physical activity, stress, mood, and overall health
• Allow the study team to collect basic health information from your baby’s healthcare provider during routine visits in the first year

At-Home and Community-Based Activities

Throughout the study, you will also be asked to complete activities at home and in your community. These include:

• Wearing a fitness tracker (Fitbit) to monitor your daily activity and step counts
• Reporting your weekly step counts or allowing the study team to access this information
• Completing short surveys about your health, mood, and stress at different timepoints
• Receiving optional text messages or emails with reminders to complete study activities

If you are assigned to the exercise group, you will also be asked to:

• Participate in exercise sessions 3 times per week (progressing to about 45 minutes per session)
• Attend at least 2 live sessions per week (in-person or virtual), with the option to complete 1 session using a recorded workout
• Take part in aerobic, strength, and stretching exercises led by a certified trainer

Participants may receive up to $450 total for completing study activities throughout pregnancy and up to 12 months after birth. Payment is based on completed parts of the study, including health assessments ($25 each), surveys on mood and stress ($15 each), step tracking activities (up to $50), child health assessments ($25 each), and an optional final interview ($25). Participants may also receive up to $150 for completing exercise sessions (if in the exercise group), plus $2 per completed workout if they do not finish all sessions, and a Fitbit device at the start of the study.

Participants in the exercise group also receive non-monetary support, including a free trainer-led exercise program, gym membership during pregnancy, a gym membership for a support person, and postpartum exercise support for up to 12 months. Participants in the control group may receive up to $285 total for completing assessments and tracking activities.

There is no cost for you to participate in our research study.