Histopathological changes in placenta in pre-eclampsia/eclampsia: a case-control study in a tertiary care center
- Kathmandu, Nepal ; Kathmandu University & Nepal Health Research Council (NHRC) ; 2025.
- 63p.
In partial fulfilment of the requirements for the degree of Master in Medical Research.
Background: Hypertensive disorders of pregnancy, especially pre-eclampsia and eclampsia, are major global causes of maternal and perinatal morbidity and mortality. In Nepal, pre-eclampsia and eclampsia affect 2.6% and 0.5% of pregnancies, respectively. The placenta plays a central role in pre-eclampsia, which stems from abnormal placentation due to poor trophoblastic invasion and spiral artery remodeling. Histopathological analysis generally reveals lesions like chorionic vessel thrombosis, chorioamnionitis, infarction and calcification in affected placentas, correlating with adverse outcomes like IUGR and stillbirth. In contrast, normal placentas exhibit well-formed villi and vasculature. Comparing these histological differences helps clarify disease mechanisms and identify diagnostic markers. This study aims to evaluate and compare placental histopathology in pre-eclamptic/eclamptic versus normotensive pregnancies, offering insights into disease progression and aiding in diagnostic and prognostic advancements.
Material and Methods: This case-control study was conducted in the Department of Pathology in collaboration with the Department of Obstetrics and Gynecology at Nobel Medical College, over a specified period (Sep 2024 to Feb 2025). Placentas from 28 clinically diagnosed cases of pre-eclampsia/eclampsia were collected and compared with 28 placentas from normotensive, uncomplicated pregnancies serving as controls. Detailed maternal history and clinical information were recorded. After delivery, placentas were collected fresh, weighed, and grossly examined for size, shape, infarcts, calcification, and cord abnormalities. Representative tissue sections were taken, fixed in 10% neutral buffered formalin, processed, embedded in paraffin, and stained with Hematoxylin and Eosin (H&E). Histopathological parameters were examined and documented. Data were statistically analyzed using appropriate tests (Student t-test, Chi Square test and Fisher exact test) to determine the significance of observed differences between the case and control groups. Ethical approval was obtained from the Institutional Review Committee of Nobel Medical College and Teaching Hospital.
Result: Mean weight of newborn in normal pregnancy and hypertensive pregnancy were 3.1kg and 2.9kg respectably. Average placental weight in hypertensive pregnancy (253.5g) was significantly less than that in normotensive pregnancy (341.7g) with p value of 0.0001. Similarly mean birth weight of newborn delivered in normal pregnancy (3.1kg) was significantly greater that in hypertensive pregnancy (2.9kg) with p value of 0.018. The length of umbilical cord was not significantly different in the two groups. Histopathological changes like calcification, infarction, sub chorionic fibrin deposition, placental floor infarction, chorionic vessel thrombosis and chorioamnionitis were significantly associated with hypertensive disorders of pregnancy compared to normotensive uncomplicated pregnancy with p value less than 0.05 for each.
Conclusions: Newborn from hypertensive pregnancies have significantly lower birth weights than those from normotensive pregnancies. This study found notable gross and histopathological changes in placentas from pre-eclamptic and eclamptic cases, including low placental weight, eccentric cord insertion, infarction, calcification, thrombosis, and chorioamnionitis. In contrast, normal placentas showed preserved villous structure. These findings highlight the placenta’s central role in hypertensive disorders, and routine histopathology can help assess disease severity.