Increased blood vessel density in decidua parietalis is associated with spontaneous human first trimester abortion

Spontaneous pregnancy loss affects 15-18% of couples, and a number of poten tial causes are being discussed. The purpose of the present study was to as sess if angiogenic disorders in the decidua of early human pregnancy could be related to spontaneous abortions. First trimester human decidua from ele ctive terminations of normally progressing pregnancies and from missed abor tions were investigated immunohistochemically. We quantified vessel density in decidua from normal pregnancies and from abortions by von Willebrand fa ctor (vWF), platelet endothelial cell adhesion molecule (PECAM-1) and CD34 staining. Decidual blood vessel expression of alpha v beta 3 integrin was a lso investigated. Significant increase (P < 0.02) in vessel density was obs erved in decidua parietalis of abortions, compared to decidua basalis. This increase was detected on slides stained for VWF and CD34, but not for PECA M-1. We observed a 15% increase analysing with vWF and a 77% increase with CD34 staining. alpha v beta 3 integrin expression was not significantly dif ferent, neither in decidua parietalis from abortion, nor parietalis from no rmal pregnancies. Our data suggest that the increased vascularization in de cidua parietalis from abortions could reflect complex disorders, such as sp ecific cytokine expressions and hypoxia phenomena during the development of the decidua.