Spermicides and Sponges
Spermicides and sponges are barrier contraceptives that work by killing sperm or providing a barrier between the male's sperm and the uterus. Both are available in most drugstores without a prescription.
Spermicides come in several different forms including foams, creams, jellies, and suppositories. Before intercourse, the spermicide must be inserted into the upper part of the vagina. It should usually be inserted no less than ten minutes before intercourse. The effectiveness of the spermicide lasts no more than one hour. Another application of spermicide should be used if additional intercourse takes place. According to Planned Parenthood spermicide's rate of effectiveness varies from 71 to 85 percent, depending on how much of the product is used, the timing of insertion, and how well the packaging instructions are followed. Spermicidal effectiveness is greatly increased when used with another barrier method such as a condom.
The sponge is a round, soft, spongy synthetic material about two inches in diameter and filled with spermicide. Like the diaphragm, the sponge combines a barrier with a spermicide to prevent pregnancy. For the spermicide to be activated, the sponge must be moistened with water before being inserted into the upper part of the vagina. It is removed using a cloth loop attached to its back side. It can be worn up to 24 hours and must be left in place for at least 6 hours after intercourse.
Be sure to visit The American College of Obstetricians and Gynecologists website for more information on this subject.