A 12-Week Exercise Program for Pregnant Women with Obesity to Improve Physical Activity Levels: An Open Randomised Preliminary Study

Objective To evaluate whether a 12-week supervised exercise program promotes an active lifestyle throughout pregnancy in pregnant women with obesity. Methods In this preliminary randomised trial, pregnant women (body mass index >= 30 kg/m(2)) were allocated to either standard care or supervised training, from 15 to 27 weeks of gestation. Physical activity was measured by accelerometry at 14, 28 and 36 weeks, while fitness (oxygen consumption (VO2) at the anaerobic threshold), nutrition (caloric intake and macro-nutrients percentage) and anthropometry were assessed at 14 and 28 weeks of gestation. Analyses were performed using repeated measures ANOVA. Results A total of fifty (50) women were randomised, 25 in each group. There was no time-group interaction for time spent at moderate and vigorous activity (p(interaction) = 0.064), but the exercise group's levels were higher than controls' at all times (p(group) (effect) = 0.014). A significant time-group interaction was found for daily physical activity (p = 0.023); similar at baseline ((22.0 +/- 6.7 vs 21.8 +/- 7.3) x 10(4) counts/day) the exercise group had higher levels than the control group following the intervention ((22.8 +/- 8.3 vs 19.2 +/- 4.5) x 10(4) counts/day, p = 0.020) and at 36 weeks of gestation ((19.2 +/- 1.5 vs 14.9 +/- 1.5) x 10(4) counts/day, p = 0.034). Exercisers also gained less weight than controls during the intervention period despite similar nutritional intakes (difference in weight change = -0.1 kg/week, 95% CI -0.2; -0.02, p = 0.016) and improved cardiorespiratory fitness (difference in fitness change = 8.1%, 95% CI 0.7; 9.5, p = 0.041). Conclusions Compared with standard care, a supervised exercise program allows pregnant women with obesity to maintain fitness, limit weight gain and attenuate the decrease in physical activity levels observed in late pregnancy.