Gestational diabetes mellitus (GDM) is defined as the onset of abnormal glucose tolerance during pregnancy. In Australia, diagnostic criteria for GDM are guided by the Australasian Diabetes in Pregnancy Society (ADIPS). In 2012, these guidelines were updated to mirror those of the International Association of Diabetes and Pregnancy Study Group (now endorsed by WHO). Lower diagnostic thresholds were recommended based on the correlation between maternal hyperglycaemia and adverse perinatal outcomes demonstrated by the Hyperglycaemia and Adverse Pregnancy Outcome study1. Since the change in criteria, GDM rates have increased worldwide by 20-62%2-4 although some centres have not experienced the increase predicted 5.
We aimed to describe the change in GDM incidence since our transition to the new diagnostic criteria in January 2015. Of note, we moved from the glucose challenge to the pregnancy oral glucose tolerance test (pOGTT) 2 years prior, in April 2013. We performed a single-centre retrospective observational study at a multiethnic metropolitan maternity hospital, documenting the number of GDM diagnoses between 2012 and 2016 (see table 1). Proportionate to the total number of pregnant patients, we note a 29.7% percentage increase in GDM diagnosis over the first year since changing over (from 2014 to 2015) and a 39.6% increase when comparing the 2 years before and after the change. Of interest, there was a 6% increase from 2013 to 2014 corresponding to the switch to the pOGTT.
This absolute increase in GDM and incidence overall is consistent with other reports2-4. The consequential demand on medical, dietician, and nursing educator services, has necessitated the implementation of compensatory measures such as doubling medical staff numbers and modifying our model of care. Our presentation will summarise these measures and estimate of the cost thereof.