Neutrophils and the mechanism of IUD action in rats.

Current research on the mechanism of action of the IUD has focused on a local, low-grade endometritis in preventing blastocystic implantation. With rabbit antisera to rat neutrophils, a neutropenic state was induced in rats having a silk suture in one uterine horn. Assay for nidation sites in the severely polymorphdepleted rats revealed no implantation sites in the IUD horn and an average of 5.8 sites in the control horn, suggesting that inflammation plays a relatively minor role, if any, in the mechanism of action of the IUD.