- . Age 18-44 2. Confirmed singleton viable pregnancy with no fetal abnormalities at routine 18-22 ultrasonography 3. Obese: Pre-pregnancy BMI between 30 and 45 kg/m2 4. Receipt of prenatal care and plans to deliver at Barnes-Jewish Hospital 5. Inactive: < 30min of low intensity activity (>1.5 METS) all or most days of the week Physically Active: >150 minutes/week of moderate to high intensity activity 6. Completion of a normal routine, standard of care 1 hour 50 gram gestational diabetes screen