| Abstract: | An antiprogesterone (RU-486) was administered to women undergoing voluntary interruption of pregnancy. Five patients received 100 mg 12 h before surgical interruption, 5 others received 100 mg twice, 24 and 12 h before interruption, respectively, and another 5 received no drug at all and served as controls. Placentas and deciduae were examined morphologically with the light microscope and by electron microscopy. No specific lesions were detected in placental tissue. With conventional histology, the deciduae showed various degrees of interstitial edema and necrosis, changes which did not enable a distinction between treated cases and controls, although stromal disintegration tended to be more marked in RU-486-treated patients. At the ultrastructural level, the endothelium of decidual capillaries showed striking hyperplasia of the endoplasmic reticulum. Morphometric evaluation showed a statistically significant difference between RU-486-treated patients (2 X 100 mg) and controls. A possible link between these morphological changes and the induction of prostaglandin synthesis by the antiprogesterone is suggested. However, the full significance of the observed lesions remains uncertain and does not allow definite conclusions concerning the abortifacient effect of RU-486. |
