Cyclic variation of proteinase inhibitors in human uterine fluid and influence of an IUD

Abstract

The occurrence of the serum proteinase inhibitors in uterine fluid has been evaluated using a quantitative immunoelectrophoretic method. Low concentration of inhibitors were found in the proliferative phase and at midcycle, and high concentrations in the luteal phase. In the presence of an IUD, increased concentrations of inhibitors were found in the proliferative phase and at midcycle. This may result from an increased transudation associated with local inflammation of the endometrium. Plasma proteinase inhibitors in the uterine fluid may help to balance proteinases associated with the intrauterine stages of reproduction. Increased amounts of native inhibitors in the presence of an IUD may disturb this normal balance.