Effectiveness
The manufacturer of the Today sponge reports effectiveness for prevention of pregnancy of 89% to 91% when used correctly and consistently. When packaging directions are not followed for every act of intercourse, effectiveness rates of 84% to 89% are reported. Other sources cite poorer effectiveness rates for women who have given birth - 74% during correct and consistent use, and 68% during typical use.
Studies of Protectaid have found effectiveness rates of 77% to 91%.
Studies of Pharmatex have found perfect use effectiveness rates of over 99% per year. Typical use of Pharmatex results in effectiveness of 81% per year. Sponges may be used in conjunction with another method of birth control such as condoms to increase effectiveness.
Read more about this topic: Contraceptive Sponge