Histomorphometrical Study of Placental Villi in Preeclampsia: A Case-control Study

Abstract

Introduction: Preeclampsia is a leading cause of maternal and perinatal morbidity and mortality. In this disorder, placental morphology and cellular arrangement are altered so that oxygen delivery from mother to foetus is greatly disturbed, which ultimately results in cellular oxidative stress. Morphological and histological changes are both indicative of the pathogenesis of maternal and foetal morbidity and mortality in women with preeclampsia. Aim: To study the gross and histomorphometric features of placenta in patients with preeclampsia. Materials and Methods: This case-control study was conducted from January 2017 to December 2017 at Jawaharlal Nehru Medical College Hospital in Belagavi, Karnataka, India. Total 120 placentas of preeclampsia patients (60) and normal controls (60) were studied, which were received at Pathology Department of the institute. Immediately after delivery, gross parameters were recorded. For histomorphometrical study, full-depth tissue samples of placenta were fixed in 10% neutral buffered formalin solution for 24-48 hours, and then they were processed by graded concentrations of alcohol and embedded in paraffin to make blocks. The 5 μm thick sections were cut and slides were stained with hematoxylin and eosin and the sections were studied. Values were calculated by mean±SD using Students unpaired t-test and chi-square test, p-value of <0.05 was considered as significant. Results: The mean maternal age of the study participants was 23.93±4.40 years in preeclampsia group and 23.85±3.44 years in control group. The gestational age was 36.42±2.69 weeks in preeclampsia group and 38.20±2.11 weeks in control group, the difference was statistically significant. Other parameters such as neonatal weight, placental weight, placental thickness and placental diameter had statistically significant difference between both the groups. Morphological findings of placental terminal villi showed that the mean surface area was larger (2500.05±245 µm2) in preeclampsia group compared to control group (1878.01±214.53 µm2) and this difference was statistically significant. Conclusion: The gross reduction of the preeclampsia placenta like decreased placental weight and diameter disturbs the normal placentation and pathologically these results in histological and morphometric changes in the placenta. Due to oxidative stress in preeclampsia placental morphology is altered.