Introduction: Preeclampsia disease represents a spectrum of hypertensive disease in pregnancy, beginning with gestational hypertension and progressing to develop severe features, ultimately leading to its more severe manifestations, such as eclampsia and HELLP syndrome. In Mongolia, the incidence of preeclampsia was 26.3% in 2020. In our country, the International Amsterdam Consensus Guidelines have been adopted since 2022, and the placenta has been evaluated according to these guidelines. Goal: To evaluate the pathological changes in the placenta of pregnant women with preeclampsia according to the Amsterdam guidelines and compare them with healthy pregnant women. Materials and method: This study was conducted using a retrospective, case-control design. Based on clinical data, 100 placentas from pregnant women with pre-eclampsia and 100 placentas from healthy pregnant women were randomly selected from the 1046 placentas that arrived at the Laboratory Department of the National Center for Mothers, Newborns and Women. The study was conducted after obtaining approval from the research ethics committee of “Ach” Medical University.
Statistical analysis of study results: Data collected during the study were analyzed using SPSS software [Version 26.0, SPSS Inc., Chicago, IL, USA]. Study parameters were calculated using descriptive statistics; the impact of factors influencing pre-eclampsia was assessed via logistic regression analysis with 95% confidence intervals, and a P-value <0.05 was considered statistically significant. Pearson’s Chi-square test was used to analyze placental morphometric parameters, and Pearson’s correlation was used to assess the relationships between various placental structural characteristics Ethical approval: The study was reviewed and approved by the Medical Ethics Committee of "Ach" Medical University during its meeting on February 11, 2026, and was conducted following the receipt of ethical approval. Results: Our study included placentas from 200 individuals aged 18-45 years. Placental weight was statistically significantly lower in severe preeclampsia than in mild preeclampsia [390.8±66.4 g vs 489.7±52.0 g, t=8.32, p<0.001]. This indicates that as the severity of the disease increases, the proliferation tends to be delayed. Multiple logistic regression analysis showed that decidual arteriopathy was 70 times more likely to be associated with the predisposition to preeclampsia [OR=69.7; 95% CI: 18.5–261.3; p<0.001], and Accelerated villous maturation was 30 times more likely to be associated with the predisposition to preeclampsia [OR=24.9; 95% CI: 2.8–221.7; p=0.004]. Conclusion
1. When comparing the gross structure of the placenta in the two groups, in the preeclampsia, the placental weight and length were reduced, while the rate of para-marginal placental umbilical cord insertion site was statistically significantly increased.
2. When comparing the histological changes of the placenta in the pre-eclamptic and healthy groups, the incidence of infarction, distal villous hypoplasia, accelerated villous maturation, and decidual arteriopathy was statistically significantly higher in the pre eclamptic group.
3. Placental weight loss was 2-fold, decidual arteriopathy was 70-fold, and accelerated villous maturation was 30-fold which contributed to the predisposition to preeclampsia pregnancy.