Abstract Body: Preeclampsia (PE) is a hypertensive disorder associated with pregnancy, usually occurring after the 20th week of gestation, followed by proteinuria or signs of end-organ dysfunction. Early-onset preeclampsia is associated with placental dysfunction, while late-onset preeclampsia is recognized as a maternal disorder, influenced by risk factors like maternal obesity, diabetes mellitus, or chronic hypertension. During physiological pregnancy, lipid metabolism changes to adequately supply the fetoplacental unit with nutrients and energy, consequently changing the composition of LDL and HDL particles. However, in preeclampsia, these changes become atherogenic. The study aimed to examine changes in advanced lipid status parameter concentrations and the dominant diameter of LDL and HDL particles during pregnancies affected by PE. In this study, 92 pregnant women at high risk for complication development were followed longitudinally throughout the first (T1), second (T2), and third (T3) trimesters. They were classified into high-risk (HR) (72 women) and PE (20 women) groups based on pregnancy outcomes. Total cholesterol (TC), HDL-C, triglycerides (TG), apoAI, and apoB concentrations were measured using commercial kits, while LDL-C concentrations and the atherogenic index of plasma (AIP) were calculated using established equations. Dominant LDL and HDL particle sizes were determined by gradient gel electrophoresis. TG levels were significantly higher in the PE group compared to the HR group across all trimesters (p<0.05; p<0.05; p<0.01), while AIP was significantly elevated in T2 (p<0.01) and T3 (p<0.01). HDL-C levels were lower in the PE group than in the HR group in T2 (p<0.05). In the HR group during pregnancy, concentrations of TC, TG, LDL-C, apoB, as well as HDL-C increased significantly (p<0.05 for all parameters), while the dominant LDL diameter decreased markedly (p<0.001) between all trimesters, without changes in the dominant HDL diameter. There were no changes in HDL-C concentration during pregnancy in the PE group. In contrast, TG concentrations increased significantly (p<0.01), accompanied by a significant decrease in dominant LDL particle diameter (p<0.05). In conclusion, pregnant women with PE exhibit atherogenic changes in lipid status parameters, including no increase in HDL-C concentration, potentially leading to a loss of HDL's protective effect.