ABSTRACT
OBJECTIVE: Preeclampsia is the major cause of prenatal mortality and morbidity. The functional disorder of uteroplacental insufficiecy is caused by the impaired uteroplacental blood flow and diffusion barrier in the villi. Functional disorders like placental circulating disorders results in morphological changes of terminal. villi as functional unit of placenta. We studied to investigate the differences in villous stoma of placental terminal villi and fetal capillary between growth restricted pregnancies with severe preeclampsia and normal preterm pregnancies. METHOD: Terminal villi was examined using light microscopy and by immunohistochemical localization of matrix molecule (alpha-smooth muscle actin and collagenIV) and the immunoreactivity of alpha-smooth muscle actin and collagenIV were evaluated in 17 cases of severe preeclampsia with intrauterine growth restriction as a study group and in 17 cases of gestational age matched normotensive preterm pregnancies as a control group. Fetal capillary congestion in terminal villi was also evaluated by Hematoxylin-Eosin staining. The patterns of immunohistochemical staining were all determinated in a visual qualitative manner (0-25%: -, 25-50%: +, 50-75%: ++, 75-100%: +++) by one pathologist. Congestion was considered to be present in a failed where the majority (>90%) of the capillaries demonstrated densely packed erythrocyte. RESULT: Expression of alpha-smooth muscle actin in the terminal villous stroma was significantly increased in study group compared with control group (P=0.0001). Expression of collagen IV in the terminal villous stroma was significantly increased in study group compared with control group (P=0.0001). Fetal capillary congestion was also significantly increased in study group compared with control group (P=0.049). CONCLUSION: The result suggests that there be the structural or biochemical difference in the villous stroma between normotensive preterm pregnancies and severe preeclampsia with intrauterine growth restriction and that the extravascular contractile system might be in the villous stroma in the severe preeclampsia intrauterine growth restriction.