Barrier Methods of Contraception

Spermicides

During sexual intercourse, hundreds of millions of sperm are normally released into a woman's vagina. The large majority of these sperm die. They die because of the unfriendly environment of the vagina, which is acidic, and because the mucus in the cervix above the vagina acts as a selective filter for the sperm. Only 1% of all the sperm released in an ejaculation successfully pass through the woman's vagina and cervix to reach the uterus (the womb). But remember, it only takes one sperm to fertilize the ovum (the egg) and to achieve conception.

Spermicides are a type of contraceptive agent. They kill sperm.

Spermicides need to be in place in a woman's vagina before intercourse if they are to prevent viable sperm from reaching her uterus. Spermicides come in a wide variety of forms, including jellies, creams, foams, films, and suppositories. The active ingredient in essentially all spermicides is Nonoxynol-9. This is a detergent-like chemical that kills sperm.

Once placed inside the vagina, the spermicide melts into a liquid that coats the vagina in order to set up a chemical barrier between the sperm and the cervix. Spermicidal foams are more effective than creams or jellies. Not only is it possible to achieve a better distribution with foam, but foam adheres better to the vaginal walls and cervix.

Suppositories are solid or semi-solid and need to be inserted in the vagina 15 minutes before intercourse in order to liquefy with vaginal moisture.

Vaginal contraceptive film needs to be in place in the vagina about 5 minutes prior to sexual intercourse in order to liquefy and become effective.

Spermicides are like all other methods of birth control in that they must be used properly in order to prevent pregnancy. Each type of spermicide has a unique method of use. For example, spermicidal creams, gels, and foam need to be deposited high up in the vagina near the cervix. Spermicidal suppositories must be used unwrapped and inserted in the vagina; not the rectum by mistake. Squares of spermicidal film should be inserted into the vagina with a woman's finger, not with the man's erect penis. It is important to follow exact instructions on the package for each different type of spermicide.

A spermicide should be placed in the vagina prior to the man's penis getting anywhere near the vagina. It is a common mistake for a couple to wait too long before using the spermicide.

There are two basic concerns with any given spermicide. One has to do with how long it stays in the desired place. The other has to do with how long it is active in killing sperm. Therefore, the timing of its use must take into account both of these factors.

In general, spermicides tend to be effective soon after their application. They can be inserted 15 minutes or more before intercourse. However, if there is a significant delay before intercourse (for example an hour), more spermicide must be added.