How effective is the sponge/spermicides?

Question

How effective is the sponge if used in conjunction with spermicides? Is it still effective in water?

Please no "abstinence is best" answers, it's not an option.

Answer 1

The contraceptive sponge, marketed in the U.S. under the brand "Today," combines barrier and spermicidal techniques to prevent conception.

The sponges are inserted vaginally prior to intercourse, and must be placed over the cervix to be effective. An elastic band across the sponge is present to facilitate removal.

Effectiveness for prevention of pregnancy when used correctly is about 89% to 91%, but can be used in conjunction with a condom making the contraceptive sponge as effective as any other reversible method of contraception. When improperly applied without the use of a condom its effectiveness is somewhere around 84% to 89%.