All of the following is a mechanism of action of IUCD except:

Mechanism of Actions of IUCD are : 1) IUDs act mostly by preventing sperms from feilizing ova. The mechanisms of action of copper-releasing IUD are by impeding sperm transpo and inhibiting their capacity to feilize ova. 2. All unmedicated and copper devices produce an inflammatory or foreign body reaction, which in turn causes cellular and biochemical changes in the endometrium, making it inhospitable for implantation of the blastocyst. 3. Sperm motility, capacitation, and survival are also affected by the biochemical changes in the cervical mucus produced by copper. 4. Levonorgestrel-IUS (Mirena) also inhibits ovulation. 5. Foreign body in uterus increases uterine contractility which increases tubal motility and embryo arrives early for implanation