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.

A fresh application of spermicide must also be used for each act of intercourse.

Douching should be avoided for at least 8 hours after the last intercourse.

The effectiveness of spermicides in preventing pregnancy varies from 70 to 90%. This depends on the amount of spermicide and how it is used, the timing of use prior to intercourse, and how well the instructions on the package are followed.

Not all spermicides protect the woman or the man from sexually transmitted infections (sexually transmitted diseases, or STDs). Spermicides may be only partially protective against certain organisms that cause sexually transmitted infections, including chlamydia and gonorrhea. They also do not protect against the Human Immunodeficiency Virus (HIV) and Acquired Immunodeficiency Syndrome (AIDS).

The main objection voiced about spermicides is that they are “messy.” A small percent (2 to 4%) of people may have an adverse reaction to Nonoxynol-9, which is experienced as an irritation or a burning sensation.

Spermicides, however, have some positive features. They are relatively inexpensive and they are available over-the- counter (OTC) without a prescription.

Note that some lubricating jellies also available over-the-counter do not contain spermicide and are not meant to be used as a form of birth control. It is important to check the information on the package to be sure that the product contains spermicide or the word “Contraceptive” appears on the label.

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SOURCE: Archives of Pediatrics & Adolescent Medicine