Physical activity during pregnancy in obese and normal-weight women as assessed by pedometer

Objective. To compare physical activity as assessed by a pedometer in obese and normal-weight pregnant women at different gestational ages. To evaluate the use of a pedometer in pregnancy. Design. Cross-sectional study. Setting. Department of obstetrics and gynecology in a university hospital in Copenhagen. Population. 338 pregnant women, 175 normal-weight women with body mass index (BMI) 20-25 kg/m(2) and 163 obese women with BMI 30 kg/m2. Methods. Physical activity was assessed by a pedometer (Yamax Digiwalker SW-700/701) on seven consecutive days in six different groups: normal-weight or obese at gestational ages 11-13, 18-22, and 36-38, and expressed as median number of daily steps during a whole week, working days, and weekends. Main outcome measures. Relation between BMI and physical activity during pregnancy and compliance with wearing the pedometer. Results. Noncompliance was more frequent in obese than in normal-weight women (19 vs. 10%, p < 0.001). Physical activity was lower in obese women at all gestational ages (6,482, 7,446, 4,626 steps/day in obese vs. 7,558, 8,865, 6,289 steps/day in normal-weight, p < 0.05-0.11). The greatest difference between obese and normal-weight women was seen during weekends. The level of physical activity was higher in both groups at mid-gestation than during earlier and later gestational ages. Conclusion. Physical activity in pregnant women can be assessed by the pedometer and the method was well accepted by the women; however, the compliance was lower in the obese. The level of physical activity differs between different gestational groups and is lower in obese than in normal-weight women, especially during leisure time.