Contraceptive sponge

The contraceptive sponge is a doughnut shaped sponge. It is made of polyurethane foam and is impregnated with the spermicide Nonoxynol-9. This spermicide is essential to the contraceptive ability of the sponge.
Before intercourse, a woman pushes the sponge up into her vagina (as she would insert a tampon). The spermicidal sponge should then act as a barrier in order to prevent sperm from reaching the cervix. Once in place, the sponge provides protection for up to 24 hours without the need for additional spermicide.
The sponge must remain in the vagina for at least 6 hours after intercourse. However, the same sponge should never remain in the vagina for more than a total of 30 hours because of the risk of toxic shock syndrome. (Toxic shock syndrome is an uncommon and potentially very serious illness that is caused by a type of bacteria. This illness occurs when certain types of products, such as tampons, are left in place for excessive periods of time. This is why package instructions of these products are careful to specify how long they may be safely kept in place.) Each sponge is used only once and then thrown away.
The sponge is generally an effective birth control method. Some users of the contraceptive sponge may experience irritation and allergic reactions. The sponge can also be difficult to remove from the vagina. Removal has been made easier by the addition of a woven polyester loop.
The estimated effectiveness of the sponge as a contraceptive is 64% to 82%. As for protection from sexually transmitted infections, the spermicide may provide some protection against chlamydia and gonorrhea, but otherwise, the degree of protection is unknown.