A contraceptive sponge is a are small, disposable sponge usually made of polyurethane foam and that is are infused with spermicides. The contraceptive sponge is placed inside the vagina and it works by blocking sperm from entering the uterus and also by absorbing and killing off the sperm.
Before using the sponge, it is first being moistened with water so that it becomes foamy. Then, it is being inserted it into the vagina, positioning it so that it sits over the cervix. Like the diaphragm, a contraceptive sponge can be worn for 12 to 24 hours. However, unlike the diaphragm, a contraceptive sponge offers continuous protection during that time, regardless of how often you have sex. After having sex, it is necessary to wait six hours before removing the sponge.

Failure rates for the sponge can vary widely depending on whether or not you have had a child as well as whether or not the sponge has been inserted into the vagina properly. Anywhere between 8% and 32% of women using the sponge will become pregnant per year. Failure of the sponge is observed more frequently in women who have given birth vaginally. Contraceptive sponges do not offer any protection against sexually transmitted diseases (also known as sexually transmitted infections). Therefore it is necessary to still use a condom to help protect against STDs when you have sex.

Contraceptive sponges do not use hormones to prevent pregnancy, so there are few side effects associated with their use. Some women who use the sponge may experience more vaginal yeast infections, and women who are allergic to spermicide may experience irritation when they use a contraceptive sponge.

As with other barrier methods, there is a risk, albeit rare, of developing toxic shock syndrome. For this reason, sponges should not be left in for more than 30 hours, including the necessary six hours waiting period after having sex. The sponge should also not be used during the menstrual period or in women who have a history of toxic shock syndrome.