Pathological changes in placentas from pregnancies with preeclampsia and eclampsia with emphasis on persistence of endovascular trophoblastic plugs

Abstract

Aim: To assess the frequency and types of histopathological changes in placentas from pregnancies complicated by preeclampsia/eclampsia.

Methods: Placentas routinely sent for pathological examination (n=1,689) were studied microscopically and compared to findings of 50 placentas from uncomplicated pregnancies.

Results: Out of 1,689 placentas from singleton pregnancies, 279 (16.5%) were from pregnancies complicated by preeclampsia/eclampsia. Seventy five placentas (26.8%) were appropriate for gestational age; other findings included: infarcts of various stage and volume in 63 cases (22.6%), minimal hypoxic damage in 27 cases (9.7%), accelerated maturation in 42 cases (15.1%), chronic villitis in 18 cases (6.5%), mixed findings in 18 cases (6.5%), intervillous thrombosis in 15 cases (5.4%), sub-choral thrombosis in 9 cases (3.2%), immaturity of the villi in 6 cases (2.1%), and findings suggestive of placental insufficiency in 6 cases (2.1%). Normal findings were significantly more frequent in the control group (P<0.001), but no other significant differences between the groups were found. In 4 (1.4%) placentas from pregnancies complicated by preeclampsia/eclampsia (gestational age 32 to 36 weeks), remnants of endovascular trophoblastic plugs in the vessels of the basal decidua were found.

Conclusion: No significant difference was found between the group of placentas from pregnancies complicated with preeclampsia/eclampsia and the control group with regard to ischemic changes of the placenta. Endovascular trophoblastic plugs in the basal plate vessels from the third trimester placentas may play an additional role in the development of ischemic lesions in the placentas from pregnancies complicated with preeclampsia/eclampsia, but may also simply represent indirect evidence of the abnormal expression of certain adhesion molecules in this disorder.