Effect of intensive counselling on physical activity in pregnant women at high risk for gestational diabetes mellitus. A clinical study in primary care

ObjectiveThe level of physical activity (PA) of pregnant women in Finland is unknown. Even more limited is our knowledge of PA of women at high risk for gestational diabetes mellitus (GDM).MethodsThe women (n = 54) were randomly assigned to a lifestyle intervention group (n = 27) including exercise advice by a physiotherapist six times during pregnancy or to a control group (n = 27) without additional exercise advice. Outcomes of the present study were required sample size, timing of counselling and change of PA. PA was retrospectively reported during 12 months before pregnancy and recorded one week monthly during pregnancy.ResultsIndividualized counselling by a physiotherapist resulted in small changes of recreational PA (2.7 MET hours/week, p = 0.056) up to gestational week 25 compared with the similar decreasing tendency of PA in the control group. The women decreased recreational PA after week 30. Sample size of 550 women at high risk for GDM per group would be needed for a PA study.ConclusionsThe optimal time window for increasing PA must be earlier than in the last trimester of pregnancy. Sample size for a study to increase PA by 2.7 MET hours/week on pregnant women at high risk of GDM should be about 550 per group.