Do We Know How to Find Gestational Diabetes Mellitus?

It is now a common practice to identify women with gestational diabetes mellitus (GDM) and initiate treat-ment aimed at preventing hyperglycemic episodes and improving outcome for the woman and her unborn child (1–3). However, since before the 1st Workshop Confer-ence on Gestational Diabetes Mellitus in 1979 (4), there has been heated discussion about how this is best done. By the 4th international workshop in 1997 (5), a compro-mise was agreed on that either of 2 protocols would be acceptable. The first protocol was to continue the previ-ously recommended 50-g glucose challenge test with a diagnostic 3-h 100-g oral glucose tolerance test (OGTT) if the glucose concentration was increased at 1 h after the 50-g load. A diagnosis of GDM required that glucose thresholds be met or exceeded at 2 or more of the 4 time points during the 100-g test. In 1997, the only change to this protocol was that the cutpoints for glucose concen-trations at each of the 4 time points were lower than previously recommended to reflect more accurately the change from measuring glucose in whole blood to mea-suring it in plasma (6). The second protocol was to administer a 2-h 75-g OGTT and, using the same glucose thresholds, a diagnosis was to require meeting or exceed-ing the thresholds at 2 or more of the 3 time points. The 5th International Workshop Conference, held in Novem-ber 2005, did not address the issues of screening and diagnosis of gestational diabetes, but the conference par-ticipants recommended endorsing the recommendation