Histological changes on the chorion at failure of contraceptive intra-uterine devices.

Histolgoical changes of the chorion caused by the presence of a DANA IUD are reported. 10 choria of normal gravidity and 10 choria of pregnancy with an IUD in place were examined using light and electron microscopy. The covering of the chorionic villi did not have a homogeneous morphology. Different enzymatic activity of separated chorionic villi was shown and even in a single syncytical part of the same villus. At least 3 types of syncytiotrophoblast were observed. Photomicrographic reproductions illustrate micron microscopic findings. Results indicate that the chorion with a DANA IUD in place is characterized by syncytiotrophoblasts of higher secretory activity than in normal cases of the same month of pregnancy. Other morphologic hyperactivity of trophoblasts in syncytium was also shown. A special formation of endoplastic reticulum of parallel concentric membranes with a central area containing vesicles filled with secretion was seen. This formation had not been previously reported in chorion. Another type of syncytiotrophoblast seemed to be transient. In more recent incompleted studies choriongonadotropin values as measured in the urine taken in the morning of the operation day have been found to be doubled in IUD cases over those of normal pregnancies of the same age.