Changes in the Glycemic Profiles of Women With Type 1 and Type 2 Diabetes During Pregnancy

Abstract

OBJECTIVE— To examine the changes in glycemic excursions that occur during pregnancy using continuous glucose monitoring and to compare patterns of glycemia in pregnant women with type 1 and type 2 diabetes.

RESEARCH DESIGN AND METHODS— An observational data analysis was performed from a prospective randomized study of continuous glucose monitoring in 57 women with pregestational type 1 (n = 40) or type 2 (n = 17) diabetes with 7-day continuous glucose monitoring system profiles during each trimester. Serial glucose measurements were divided into periods of euglycemia (70–140 mg/dl), hyperglycemia (>140 mg/dl), and hypoglycemia (<70 mg/dl). Generalized linear mixed effects models were fitted to the repeated measures data to determine how these glycemic characteristics varied during gestation and by diabetes type.

RESULTS— A total of 180 continuous glucose profiles were examined (140 type 1 diabetes, 40 type 2 diabetes), providing 20,433 h of data for analysis (16,117 h type 1 diabetes, 4,316 type 2 diabetes). Women with type 2 diabetes spend ∼33% less time hyperglycemic throughout pregnancy than women with type 1 diabetes (P = 0.005), with a significantly more rapid reduction in time spent hyperglycemic in early pregnancy (P = 0.02). Although women with type 2 diabetes spend less overall time hypoglycemic (P = 0.04), their risk of nocturnal hypoglycemia is equivalent to that of women with type 1 diabetes (blood glucose level <70 mg/dl, P = 0.9; blood glucose level <50 mg/dl, P = 0.2).

CONCLUSIONS— Continuous glucose monitoring reveals clear differences in the level of glycemic control that exist in women with type 1 and type 2 diabetes. These data will guide therapeutic interventions aimed at optimizing glycemic control and improving the pregnancy outcomes of both type 1 and type 2 diabetes.