Pregnancy in women with pre-existing diabetes is associated with a doubled, or even up to four-fold increased risk of preeclampsia, preterm delivery, and perinatal mortality compared to the risk observed in a background population. Diabetic nephropathy (DN) is a progressive disease that affects about one third of diabetic patients and is among the most frequent causes of the end stage renal disease (ESRD) worldwide. In the random population, it is present in up to 7% of women with type 1 diabetes mellitus (T1DM), and it represents the most common chronic kidney disease occurring in graviditas, complicating between 2.5% and 5% of T1DM pregnancies. Although maternal and perinatal morbidity and mortality rates in the pregnancies complicated with DN have declined over time, pregnancy related health complications are still more common in women with DN compared to those observed among diabetic women without DN. The adequate pre-pregnancy counseling and a tailored approach to the treatment of women with DN during the pregnancy are crucial for an avoidance of the adverse maternal and fetal outcomes. This paper is highlighting the impact of DN on maternal and fetal outcomes in women with T1DM, through presentation of the cases from a real-world clinical practice.