Glucose levels vary in pregnancy by diabetes type
By Scott Baltic
NEW YORK (Reuters Health) - In the first study to use continuous monitoring throughout pregnancy to examine changes in glucose levels, researchers found that levels of glycemic control differ significantly between women with type 1 diabetes and those with type 2.
In one respect, however, the two groups did not differ. In the critical stage of early pregnancy, the diabetic women had normal glucose levels for an average of only half of a 12-hour day, a "particularly alarming" finding, researchers report in the November issue of Diabetes Care.
Dr. Helen R. Murphy at Ipswich Hospital NHS Trust in the UK and colleagues analyzed data from continuous glucose monitoring for 7 days during each trimester of pregnancy in 40 women with type 1 diabetes and 17 women with type 2 diabetes.
The researchers found that as the pregnancies advanced, more time was spent with blood glucose in a normal range (70 mg/dL to140 mg/dL), and women with type 2 diabetes spent about one third more time within a normal glucose range that the women with type 1 diabetes.
Elevated glucose levels (greater than 140 mg/dL), or "hyperglycemia," decreased as the pregnancies advanced, with type 2 diabetics spending only two thirds as much time with elevated glucose as the women with type 1. Type 2 diabetes was also associated with shorter durations of extreme hyperglycemia (greater than 200 mg/dL).
Although the proportion of time spent with low blood sugar (hypoglycemia), defined as less than 70 mg/dL, did not change significantly over the course of pregnancy, women with type 1 diabetes spent more time hypoglycemic than did those with type 2 diabetes.
These findings illustrate just how difficult it is to maintain treatment targets for glucose levels, particularly among the women with type 1 diabetes, Murphy and colleagues conclude.
This information is important for physicians and other healthcare professionals who are trying to maximize glycemic control and for researchers trying to improve upon treatments in diabetic women who are pregnant.
SOURCE: Diabetes Care, November 2007.