A Startling Discovery: Infection Control and ... Contraception?
by Kathy Dix
Since the 1950s, nonoxynol-9 has been used as a contraceptive, and, according to the Planned Parenthood Federation of America, is the active ingredient in all U.S. spermicides. In the 1980s, it was discovered that nonoxynol-9 could inactivate human immunodeficiency virus (HIV) in a test tube. Research was then put in place to test nonoxynol-9's ability to prevent sexually transmitted diseases (STDs) in the field, not just in the lab.1
Based on results of those studies, the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) recently advised against nonoxynol-9 for prevention of sexually transmitted infections.2
Although nonoxynol-9 is somewhat effective in preventing pregnancy (after six months of typical use, 25 percent of women using a contraceptive film and 28 percent of women using foaming contraceptive tablets became pregnant), studies about its efficacy in preventing STDs is conflicting. Older studies showed a slight reduction in risk of several types of STDs, but more recent studies concluded in 2002 by CDC and WHO determined that nonoxynol-9 does not provide protection against STDs and that it may actually increase the risk of transmission instead.
Nonoxynol-9 apparently irritates the epithelium of the vagina and anus, which may increase the risk of STD transmission. Two recent studies -- one of female sex workers, one of non-sex workers who were still at a high risk for STDs -- had some interesting results. The female sex workers using a contraceptive film had a slightly higher risk of gonorrhea, a slightly lower risk of chlamydia and no change in risk for HIV. The second study showed a 20 percent higher incidence of gonorrhea or chlamydia in women using a contraceptive gel compared to women who used only condoms; the risk of contracting gonorrhea was 50 percent greater in women who used the gel compared to those who did not, but the risk of chlamydia infection was comparable.
A study of 991 sex workers published in 2000 found that the risk of HIV infection was increased by 50 percent with the use of a contraceptive gel. And women who used gel the most frequently (as often as 20 times a day) had the greatest risk.
Nonoxynol-9 can irritate the skin of the vulva, vagina or penis, and greater frequency of use and higher doses exacerbate epithelial disruption. The contraceptive seems to have a stronger disruptive effect on the rectum; thus, the CDC and WHO both recommend against using nonoxynol-9 for protection during anal sex.
In January, the Food and Drug Administration (FDA) proposed that over-the-counter vaginal contraceptives be sold with a new label warning that nonoxynol-9 does not protect against HIV and other STDs. The label would also include a statement that nonoxynol-9 can increase vaginal irritation, thus increasing the possibility of transmitting STDs from infected partners. Public comment about this proposed labeling is being accepted through mid-April.3
There are occasions when nonoxynol-9 appears appropriate for use. Women at low risk of HIV infection can keep nonoxynol-9 as a contraceptive option, but women who have multiple daily acts of vaginal intercourse should steer clear of nonoxynol-9 in favor of other contraception. Because nonoxynol-9 is not a microbicide, it should not be used to protect against STDs. WHO recommends that latex or polyurethane condoms should be used to prevent against infection instead. Although condoms may not completely prevent skin-to-skin contact, they serve as the most effective means of protection against STDs by inhibiting the exchange of body fluids like semen, genital discharge or infectious secretions.