HYPOTHESIS/AIMS OF STUDY: The prevalence of diabetes mellitus in pregnant women is increasing. Physiological hyperlipidemia is usually developed during the last third of gestation, increases during pregnancies complicated by diabetes mellitus. Abnormal lipid profiles are associated with adverse perinatal outcomes. However, the associations between maternal dyslipidemia and pregnancy complications in women with different diabetes mellitus types remain unclear. The aim of this study was to assess the lipid profile in women with different types of diabetes mellitus (Type 1, Type 2, and gestational diabetes) based on the therapy in the third trimester of pregnancy, to investigate the associations between serum lipid profile and perinatal complications, and to determine possible prognostic value of lipids in the development of adverse pregnancy outcomes. STUDY DESIGN, MATERIALS AND METHODS: The study included 277 women who were divided into several groups depending on the type of diabetes mellitus and its therapy method, a group of patients with preeclampsia, and the control group. We analyzed the clinical and laboratory data of outpatient and inpatient cards of pregnant women in the period between 2010 and 2017. Maternal blood samples were collected between 28 and 32 weeks of gestation. The samples were assayed for fasting triglycerides, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and very-low-density lipoprotein cholesterol concentrations, as well as the atherogenic index of plasma. We also assessed the incidence of gestational arterial hypertension, preeclampsia, intrauterine growth restriction, and preterm birth. RESULTS: Pregnant women with various types of diabetes mellitus were characterized by a significant rise in serum triglycerides and very-low-density lipoprotein cholesterol levels, an increase in the atherogenic index of plasma, and a significant decrease in antiatherogenic, high-density lipoprotein cholesterol levels. These changes were most pronounced in pregnant women with pregestational diabetes mellitus types and in groups receiving insulin therapy. Correlation analysis revealed weak positive correlations between serum triglycerides concentrations and macrosomia (r = 0.26) and between the atherogenic index of plasma and severe preeclampsia (r = 0.26). The analysis of the ROC curve showed that triglycerides, very-low-density lipoprotein cholesterol, and the atherogenic index of plasma are predictors of severe preeclampsia. CONCLUSION: Diabetic pregnancies are associated with increased dyslipidemia, which plays an essential role in the pathogenesis of perinatal complications. Evaluating lipid profile markers in the third trimester of diabetic pregnancy may be valid predictors of severe preeclampsia.