34: Effect of a randomized controlled trial of an intensive medically supervised exercise program designed to improve maternal glucose control on gestational weight gain

Abstract

OBJECTIVE: To evaluate whether women with a body mass index (BMI) >29.9kg/m2 enrolled in an intensive medically‐supervised exercise intervention demonstrate a lower incidence of excessive gestational weight gain (GWG) compared to women undergoing routine care. STUDY DESIGN: This is a prospective single‐blinded randomized trial of obese women. Exclusion criteria were pre‐existing diabetes mellitus, medications, no English, and BMI <30kg/m2. Women were randomly assigned to: (1) routine prenatal care or (2) medically‐supervised exercise intervention including three supervised exercise classes per week, invitation to a secret Facebook group to create a sense of community among participants and deliver healthy lifestyle advice. The study was adequately powered to detect a 7.2g/dL (0.4mmol/L) difference in mean fasting plasma glucose (FPG) levels on 2hOGTT. BMI and body composition were measured using bioelectrical impedance (Tanita MF 180CA ) at the first prenatal visit and serially at 24‐28 and 36 weeks gestation and at 6 weeks postpartum. Third trimester GWG was calculated at 36 weeks gestation. FPG was also measured. Excessive GWG was defined as >9kg for obese women as recommended by the Institute of Medicine (IOM). Independent t‐test and chi‐squared were used where appropriate. RESULTS: Of 88 women randomized, 44 were assigned to intervention and 44 received routine care. Maternal age, race, parity, initial BMI were similar between groups (all P>0.05). There was no difference in mean 3rd trimester FPG between groups (p=0.66). The follow up rates were similar (95.5% v 85.7%; P=0.09) between groups. Anthropometric measurements are shown in Table 1. Excessive gestational weight gain was lower in the intervention group (22.2% v 43.2%; P<0.001). CONCLUSION: Women with a BMI >29.9kg/m2 enrolled in this medically‐supervised exercise intervention program demonstrate a lower incidence of excessive gestational weight gain at 36 weeks' gestation. The same effect, however, is not seen on the mean GWG or mean fasting plasma glucose results. Clinicians should focus on improving pre‐pregnancy BMI in this high risk population.