An intrauterine system for the retention of a biologically active compound within the uterus of a female mammal includes a deposit of the compound having a generally rod shaped element, a substantially flexible frame defining an interior space for receipt of the deposit, wherein the flexible frame and the rod shaped element interact to form a composite structure having greater stiffness than either the rod shaped element or the frame alone. One or more retention elements are provided on the frame for retaining the frame within the uterus.
