The Acute Effect of Physical Activity on Blood Glucose in Pregnant Women

Cases: 15 pregnant women recruited at the routine ultrasound scan at gestational week 19 at the Department of Obstetrics and Gynecology, Aarhus University Hospital. Subjects will receive both written and oral information before entering the trial. Subjects with a prepregnancy BMI > 27 and no other risk factors of diabetes will be included in the study. The women will be examined during gestational week 27-30 where the routine Oral Glucose Tolerance Test (OGTT) will take place. The routine OGTT will serve as control.

Intervention: The subjects will perform two OGTT separated by a minimum of two days. One - the regular OGTT will serve as control and the second OGTT will be the intervention. The two days in between will function as a "wash out period" to avoid potential carry over effect. During the OGTT subjects will consume a liquid containing 75g of glucose. The control OGTT will be followed by inactivity. The intervention OGTT will be immediately followed by 20 minutes of exercise on a bicycle ergometer with a fixed intensity.

Study variables: Blood glucose will be monitored continuously using the IPro2 Continous Glucose Monitor (CGM) from Medtronic. A sensor is inserted into interstitial fluid and continuously generates an electrical current proportional to the glucose concentration. A recorder stores the average sensor current every 5 minutes.

In both control and intervention, blood tests will be taken at time 0, 1 and 2 hours after the OGTT. Blood samples will be analyzed for blood glucose, HbA1c, C-peptide and insulin.

Data on demography, family history of diabetes, prepregnancy BMI, gestational weight gain and complications during pregnancy are collected from medical records of the patients and their offspring.