Structural changes in pre-eclamptic and eclamptic placentas--an ultrastructural study.

OBJECTIVE To determine the ultrastructural changes of the placenta in women with pre-eclampsia and eclampsia compared to the placenta of normotensive patients. STUDY DESIGN Comparative descriptive study. PLACE AND DURATION OF STUDY Obstetrics Unit of North Colombo Teaching Hospital, Ragama, Sri Lanka in 2004. METHODOLOGY Placentae of 10 normotensive women and 10 hypertensive women with pre-eclampsia and eclampsia were studied. Morphological abnormalities in chorionic villi, cytotrophoblastic cells and basement membrane under electronmicroscope were detected. Findings were recorded and compared. RESULTS Microvillous surface of many chorionic villi of hypertensive placentae showed a complex appearance with many distorted microvilli and frequent cytotrophoblast cells compared to normotensive placentae. The basement membrane of chorionic villi was more thickened in hypertensive placentae. Patchy necrosis with loss of microvilli and gross thinning of the syncytium with distorted microvilli were seen in terminal villi of placentae of women with eclampsia. In areas where the syncytium was absent, the cytotrophoblast cells showed numerous vacuolated mitochondria with loss of cristae, and few rough endoplasmic reticulum, lysosomes and glycogen deposits. An accumulation of electron dense amorphous substance and number of vacuolated mitochondria were concentrated in the cytoplasm of endothelial cells of fetal capillaries. CONCLUSION Ultrastructural villous changes were found in the placentae of women with pre-eclampsia and eclampsia which are likely to influence adversely on placental function.