Considering our center’s experience, albeit with a small sample size, we suggest that suspicion of T1DM during pregnancy should arise if women have two or more of the following conditions: a family history of T1DM, normal or low pre-pregnancy BMI, need for insulin therapy, higher requirement for rapid-acting insulin compared to long-acting insulin, and a family or personal history of autoimmune disease. The gene discussed is INS; the disease is type 1 diabetes mellitus.