Contraception. View of a contraceptive sponge which is used to prevent pregnancy. This device is a disposable circular polyurethane foam sponge about 5cm in diameter and 5cm thick that is impregnated with spermicide. The sponge incorporates a loop for easy removal. It is inserted high into the vagina and prior to that it should be moistened in order to activate the spermicide. It should be left in position for at least six hour after intercourse.