Amongwomen with diabetes, theworst pregnancy outcome is seen in the subgroup of women with diabetic nephropathy. Development of severe preeclampsia that leads to early preterm delivery is frequent. Predictors and pathophysiological mechanisms for the development of preeclampsia among women with diabetes and observational studies that support antihypertension treatment for pregnant women with microalbuminuria or diabetic nephropathy preventing preeclampsia and early preterm delivery are presented here.Obtaining andmaintaining strict glycemic control before and during pregnancy is paramount to prevent pretermdelivery. The cornerstones of diabetes management are appropriate diet and insulin, although the risk of severe hypoglycemia always needs to be taken into account when tailoring a diabetes treatment plan. Pathophysiological mechanisms of the increased risk of hypoglycemia during pregnancy are explored, and studies evaluating the use of insulin analogs, insulin pumps, and continuous glucose monitoring to improve pregnancy outcomes and to reduce the risk of severe hypoglycemia in pregnant women with type 1 diabetes are reported. In addition to strict glycemic control, other factors involved in fetal overgrowth are explored, and restricting maternal gestationalweight gain is a promising treatment area. The optimal carbohydrate content of the diet is discussed. In summary, the lessons learned from this clinical research are that glycemic control, gestational weight gain, and antihypertension treatment all are of importance for improving pregnancy outcomes in pregnant women with preexisting diabetes. An example of how to use app technology to share the recent evidence-based clinical recommendations for women with diabetes who are pregnant or planning pregnancy is given.