At present, physicians in the United States typically diagnose GDM using a two-step approach. First a woman is given a 1-hour screening test; if the results are abnormal, the woman undergoes a more advanced 3-hour glucose tolerance test. This approach identifies approximately 5% to 6% of the population as having GDM. In contrast, newly proposed diagnostic strategies rely on the administration of a 2-hour glucose tolerance test (a one-step approach).
A panel of experts convened by the National Institutes of Health considered whether the one-step approach to the diagnosis of GDM should be adopted in place of the two-step approach. The panel found that the one-step approach offered a consistent, international diagnostic standard, allowing for better standardization of best practices in patient care and comparability of research outcomes. The one-step approach also held potential advantages for women and their health care providers because it would allow a diagnosis to be achieved within the context of one visit as opposed to two.
However, the panel noted that the one-step approach was expected to sharply increase the number of women diagnosed with GDM. It is not well understood whether the additional women identified by this approach will benefit from treatment, and if so, to what extent. Moreover, the care of these women would generate additional direct and indirect health care costs. The panel also identified evidence that the labeling of these women may have unintended consequences, such as an increase in cesarean delivery and more intensive newborn assessments. Available studies did not provide clear evidence that a one-step approach was cost effective compared to the current two-step approach.
After much deliberation, the panel concluded that there is not sufficient evidence to adopt a one-step approach at this time, and recommended that the current two-step approach be continued.
The panel’s findings are available at: http://consensus.nih.gov/2013/gdm.htm.