Cycle Study:an Exercise Intervention to Prevent Gestational Diabetes in Overweight and Obese Chinese Pregnant Women

An increasing number of women are entering pregnancy in an overweight or obese state. The overweight/obesity epidemic among women of reproductive age has led to an increasing incidence of gestational diabetes mellitus (GDM)，and other metabolic and obstetric complications, such as fetal macrosomia, maternal obesity and type 2 diabetes.

Exercise may be a non-invasive therapeutic option for preventing and managing GDM that can be readily applied to the antenatal population.But so far, the effects of exercise interventions on the incidence of GDM and other adverse perinatal outcomes have been scarce, especially in Chinese pregnant women.

So the aim of the investigators study is to evaluate whether exercise intervention in overweight/obese(prepregnancy BMI≥24kg/m^2） Chinese pregnant women can reduce their risk of GDM and GDM related adverse pregnant outcomes.

Overweight/obese Chinese pregnant women (prepregnancy BMI≥24kg/m^2） will be randomly divided into exercise intervention group and control group in their first trimester（less than 13 gestational weeks), pregnant women randomised to the exercise intervention group will complete three supervised, exercise sessions each week by using a stational bike, and exercise sessions will be completed on alternate days. Both exercise group and control group have regular prenatal care.

During 24-28 gestatioanl weeks,GDM will be diagnosed by an oral glucose tolerance test (OGTT) according to the new World Health Organization criteria as fasting glucose level in fasting whole blood 5.1 mmol/L or more, or 2-hour value 8.5mmol/L or more.Then the investigators can compare the GDM risk in each group, and find out if exercise intervention can reduce the risk of GDM in overweight/obese Chinese pregnant women.