Copper releasing intrauterine devices are Cu-T, Paragard T-380A, Cu-7 & multi-load 375.
They act as an effective means of contraception in human females as these IUDs release copper ions inside the female reproductive tract that suppress the motility of sperm.
The fertilization capacity is affected due to the same, resulting in contraception.
Final Answer
Thus the copper releasing IUDs such as Cu-T and Cu-7 acts by increasing sperm’s phagocytosis within the uterus.