How Do Spermicidal Condoms Work?
Condom use for pregnancy prevention and to reduce the risk of sexually transmitted diseases dates back to ancient times. While modern condoms bear little resemblance to their historical counterparts, contraception and disease prevention remain the primary purposes for condom use. Condoms come in many varieties.
Condom use for pregnancy prevention and to reduce the risk of sexually transmitted diseases dates back to ancient times. While modern condoms bear little resemblance to their historical counterparts, contraception and disease prevention remain the primary purposes for condom use. Condoms come in many varieties. Some male condoms are coated with a spermicidal lubricant. Although one might expect that addition of a spermicide to a condom would make it more effective for pregnancy prevention, evidence supporting this notion is lacking.
Barrier Function of Condoms
Condoms act as a contraceptive barrier, preventing pregnancy by blocking sperm from reaching and fertilizing a woman's egg. When used perfectly, male condoms are 98 percent effective in preventing pregnancy, according to the medical text "Contraceptive Technology." However, few people manage to use any form of contraception perfectly all the time. So in the everyday world of mere mortals, condoms are about 82 percent effective -- meaning about 18 out of every 100 women using male condoms only for contraception get pregnant during the first year of use.
Latex and polyurethane condoms also act as a barrier to reduce the risk of transmission of certain sexually transmitted diseases (STDs) -- especially HIV, gonorrhea, chlamydia, trichomoniasis and hepatitis B. Importantly, lambskin condoms do not provide protection against STDs.
Spermicide Function
Vaginal spermicides kill sperm in the vagina to prevent them from ascending higher into a woman's reproductive tract where they could potentially fertilize an egg. Most spermicidal products marketed in the U.S. contain the spermicide nonoxynol 9 (N-9). Spermicidal products come in several forms, including cream, jelly, foam, film and vaginal suppositories. They are effective for approximately 1 hour after application, and can be used alone or with a barrier form of contraception, including a condom, diaphragm or cervical cap. When used as the sole form of contraception, vaginal spermicide products are 82 percent effective at preventing pregnancy with perfect use, and 72 percent effective with typical use.
The Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) warn that N-9 does not reduce the risk of transmission of STDs. This warning is primarily based on the pooled results from 5 research studies involving more than 5,000 women. The researchers found that use of N-9 did not reduce the risk for HIV, gonorrhoea, chlamydia, trichomoniasis, bacterial vaginosis or vaginal yeast infections, as reported in the October 2002 issue of "The Lancet: Infectious Diseases."
No Clear Advantage With Spermicidal Condoms
One might reasonably expect that spermicidal condoms -- those that have a spermicide-infused lubricant on the outside of the sheath -- would be more effective at preventing pregnancy than condoms without a spermicidal coating. However, WHO states that research studies have found no difference in contraceptive effectiveness between condoms with or without a spermicidal coating. This could possibly be due to the fact that the amount of spermicide on spermicidal condoms is quite low, especially when compared to the dose provided in vaginal spermicide products.
Potential Disadvantages of Spermicidal Condoms
Research indicates N-9 not only fails to protect users from STDs but also might increase the risk of contracting some sexually transmitted infections, especially HIV. Scientists believe this is due to irritation of the vaginal or rectal tissues by N-9, which could make it easier for HIV to enter the body. As of 2008, the U.S. Food and Drug Administration requires manufacturers of all products containing N-9 to include warning statements that inform consumers of the lack of STD protection and the possible increased risk of contracting HIV from an infected partner.
In addition to vaginal irritation, which can cause burning or itching, some men and women might be allergic to N-9 or latex. Spermicidal condoms might also increase the risk for urinary tract infections in women, according to a study published in the "American Journal of Epidemiology."
Other Considerations
Decisions regarding contraceptive choices and protecting yourself from sexually transmitted infections can be challenging. While condoms are an inexpensive, convenient and effective option for STD prevention, you might want to discuss other contraceptive options with your healthcare provider. For example, many women opt to use hormonal contraception or an IUD for pregnancy prevention in addition to having their partners use a condom for STD protection.
Reviewed and revised by: Tina M. St. John, M.D.