INS and diabetes mellitus: However, a proportion of pregnancies without prior use of any ADD did not meet both criteria of our gestational diabetes algorithm definition: a diagnosis code for gestational diabetes in the 2nd or 3rd trimester and no prior diabetes mellitus diagnosis (5.8% of sulfonylurea-exposed pregnancies, 14.4% of insulin-exposed pregnancies, and 50.2% of metformin-exposed pregnancies).