The devices inserted in the uterus through vagina are called intra uterine devices ($IUDs$).

$IUDs$ are of two types : ($a$) Non medicated $IUDs$ eg. Lippes loop,copper releasing $IUDs$ ($CuT$, $Cu7$,Multiload $375$ and ($b$) Hormone releasing $IUDs$ (Progestasert, $LNG$-$20$)

$IUDs$ increase phagocytosis of sperm within the uterus and the $\mathrm{Cu}$ ions released suppress sperm motility and the fertilizing capacity of sperm. The hormone releasing $IUDs$ make the uterus unsuitable for implantation and the cervix hostile to sperms.

$IUDs$ are ideal contraceptive for the female who want to delay pregnancy and or / space children.