Measuring glucose exposure and variability using continuous glucose monitoring in normal and abnormal glucose metabolism in pregnancy

In pregnancy complicated by diabetes periods of hyperglycemia lead to accelerated fetal growth, resulting in a large for gestational age (LGA), or macrosomic, infant. Consequently, our aim was to measure the average volatility or variability in glucose control in women with and without diabetes in pregnancy. Methods: Continuous glucose monitoring (CGM) was employed in 82 pregnant study subjects to collect and record unbiased self-monitored glucose values. We obtained results from 51 women with normal glucose tolerance in pregnancy (NGTP), 25 gestational diabetes (GDM) and 6 women with pregestational diabetes (PreGD) between 18 and 45 (32±6) years of age. Results: Significant differences (p<0.001) were found in glucose exposure between NGT and all but PreGD; whereas the percent of time in hypoglycemia was significantly (p<0.0001) higher in all pregnancy groups when compared to the nonpregnant sample. We conclude that CGM confirmed that diurnal glucose patterns differ throughout the day by 20% when pregnant and nonpregnant states are compared. Indeed, maintenance of a narrow range in pregnancy is characteristic in women without diabetes, and CGM throughout pregnancy is critical, if mimicking normal glucose patterns is to be achieved.