Within 6 months of delivery, women who had gestational diabetes mellitus should be screened for type 2 diabetes with a fasting plasma glucose test and/or a 2-h postchallenge glycemia in a 75-g oral glucose tolerance test. However, not all women are screened. The objective of this study is to compare the screening test for type 2 diabetes done at 48 hours post-partum versus 8 weeks post-partum. The investigators want to measure the specificity, sensitivity, false and true predictive values of the screening test at 48 hours post-partum compared to the gold-standard.