[Maternal serum type III procollagen peptide (P-III-P) and 7S domain of type IV collagen (7S) as indicators of placental damage caused by toxemia of pregnancy].

By means of immunohistochemical techniques, we studied the localization of type III and IV collagen in normal and toxemic placentas. We also studied the maternal serum levels of type III procollagen peptide (P-III-P) and type IV collagen 7S domain (7S) in non-pregnant women, normal term women and cases toxemia of pregnancy. Immunohistochemical studies revealed that type III collagen exists in the connective tissues composing the villous core and type IV in the basement membranes of trophoblast cells and fetal vascular elements. Even in normal-appearing toxemic placenta, the amount of type III and IV collagen appeared to be increased compared with that in normal term placenta, but the amount of type III and IV collagen appeared to be decreased in the necrotized chorionic villi of severe toxemia. Measurement of the collagen-related substances revealed that those levels in toxemic pregnancy were much higher than those in normal term pregnancy. In toxemic pregnancy, the incidence of IUGR in the high P-III-P level group was increased significantly, and increased more apparently in both the high P-III-P and 7S groups. We believe that our data support our that P-III-P and 7S in maternal serum flow from the necrotized chorionic villi into the intervillous space, and that these measurements are significant indicators of placental damage caused by toxemia of pregnancy.