Endocrine Abstracts

Objective: In Edmonton, universal screening of all pregnancies is performed using a 50 g gestational diabetes screen (GDS). Canadian Diabetes Association (CDA) Practice Guidelines recommend a 75 g 2 h oral glucose tolerance test (OGTT) if the GDS glucose result is between 7.8 and 10.2 mmol/l. This study is designed to assess the frequency of OGTT requests in response to a positive GDS and the prevalence of normal OGTT in this population.

Methods: All GDS results reported from April 1 to June 30 2009 and 2010 were collected. The number of OGTT performed within 30 days of a positive GDS was determined. The diagnosis based on the OGTT is compared to that of the GDS.

Results: A total of 8801 GDS were performed, 22% of which produced abnormal results. About 3% met the CDA criteria for diagnosis of GDM (glucose >10.2 mmol/l). Although not recommended for these patients, OGTT was requested in 12 and 60% produced normal results. Of the 19% with GDS results between 7.8 and 10.2 mmol/l, 40% did not complete the OGTT within 30 days. Among those who completed the OGTT, 70% were normal.

Conclusions: Confirmatory testing of positive GDS results is not done consistently which may result in misdiagnosis of these patients. The diagnostic cut-off for GDM in the GDS may need further validation.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.