I read with interest the letter by Omori and Jovanovic (1) in the October 2005 issue of Diabetes Care and have the following comments.
In the Clinical Practice Recommendations from 2002 to 2005 (2–5), you will find the following statements.
“A fasting plasma glucose level >126 mg/dl (7.0 mmol/l) or a casual plasma glucose level >200 mg/dl (11.1 mmol/l) meets the threshold for the diagnosis of diabetes, if confirmed on a subsequent day, and precludes the need for any glucose challenge.”
Although these two patient populations (i.e., patients with gestational diabetes mellitus [GDM] and patients with diabetes diagnosed during pregnancy) were not formally separated in relation to patient outcome or risk of congenital malformations, we, in our institution, have adopted the policy of labeling these pregnant women, who have blood glucose levels in the diabetic range, as “diabetic patients first discovered during pregnancy.” This labeling would be even further substantiated if the index case was discovered during the first trimester.
The second point is the surprising finding in the Japanese study of having the highest frequency of both GDM and type 2 diabetes in the first trimester and the lowest in the third trimester, which is against the classical teaching and against the fact that insulin resistance, and consequently the frequency and incidence of GDM, is highest in the third trimester. This reversed incidence of GDM in different trimesters of pregnancy needs to be further analyzed and explained.
