Fourfold increase in prevalence of gestational diabetes mellitus after adoption of the new International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria

Background: The aim was to evaluate the influence of the new International Association of Diabetes and Pregnancy Study Groups (IADPSG) guidelines for screening of gestational diabetes mellitus (GDM) on GDM prevalence in a cohort from a Swiss tertiary hospital. Methods: This was a retrospective cohort study involving all pregnant women who were screened for GDM between 24 and 28 weeks of gestation. From 2008 until 2010 (period 1), a two-step approach with 1-h 50 g glucose challenge test (GCT) was used, followed by fasting, 1-and 2-h glucose measurements after a 75 g oral glucose tolerance test (OGTT) in case of a positive GCT. From 2010 until 2013 (period 2), all pregnant women were tested with a one-step 75 g OGTT according to new IADPSG guidelines. In both periods, women with risk factors could be screened directly with a 75 g OGTT in early pregnancy. Results: Overall, 647 women were eligible for the study in period 1 and 720 in period 2. The introduction of the IADPSG criteria resulted in an absolute increase of GDM prevalence of 8.5% (3.3% in period 1 to 11.8% in period 2). Conclusions: The adoption of the IADPSG criteria resulted in a considerable increase in GDM diagnosis in our Swiss cohort. Further studies are needed to investigate if the screening is cost effective and if treatment of our additionally diagnosed GDM mothers might improve short-term as well as long-term outcome.