Related topics: •  Condoms (for Men) •  Diaphragm •  Sexually Transmitted Diseases

You can, but they're tricky to use. For that reason, women who rely only on spermicides for contraception have a 29 percent chance of getting pregnant within a year. It's a better idea to use spermicides as backup for other contraceptives, such as condoms, diaphragms, cervical caps, or IUDs. When combined with spermicides, these methods are generally about 98 percent effective in preventing pregnancy.

They come in the form of foams, creams, dissolving films, and suppositories, which you insert into your vagina either with your finger or with an applicator. (Most spermicidal jellies are used only with diaphragms.) It's important to get the spermicide deep in your vagina, so that it completely covers the cervix. Application methods can vary widely; follow the instructions on the product label. Foams and creams are usually effective as soon as you insert them, but films and suppositories must go in about ten minutes before you have sex. As a suppository melts, they may cause a warming sensation. One dose of spermicide is generally good for about half an hour. Afterward, the spermicide (along with semen) may trickle out of your vagina for some time. This can be messy, but you should wait at least six hours before rinsing or douching, so that the chemicals have a chance to kill all the sperm.

Spermicidal products are usually sold next to condoms in drugstores and supermarkets, as well as on the Web. A tube of foam with an applicator costs about $8 and contains enough for several uses. Refill tubes cost less.

Unfortunately, yes. The chemicals that kill sperm by dissolving their outer membranes also kill bacteria, viruses, and skin cells. As a result, the most effective of these chemicals, such as nonoxynol-9 (N-9), are most irritating to the skin of the genitals, causing rashes or burning.

Recently the Centers for Disease Control and Prevention also cautioned that N-9 isn't effective in preventing gonorrhea, chlamydia, or HIV infection. In fact it may contribute to the development of genital lesions that in turn make it easier for you to be infected with these and other sexually transmitted diseases. N-9 also does away with a lot of beneficial bacteria in the vagina, making the area more hospitable to the nasty bugs that cause urinary tract infections. (It doesn't taste that great either, which can lessen the appeal of oral sex.) Researchers are currently testing the effectiveness of a gentler alternative -- an organic compound called vanadium, which seems to immobilize sperm by shutting down the "motors" in their tails.

References

First published July 15, 1999
Last updated April 24, 2007
Copyright © 1999 Consumer Health Interactive

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