A Startling Discovery: Infection Control and ... Contraception?

March 1, 2003

A Startling Discovery: Infection Control and ... Contraception?

by Kathy Dix

Since the 1950s, nonoxynol-9 has been used as a contraceptive, and, accordingto the Planned Parenthood Federation of America, is the active ingredient in allU.S. spermicides. In the 1980s, it was discovered that nonoxynol-9 couldinactivate human immunodeficiency virus (HIV) in a test tube. Research was thenput in place to test nonoxynol-9's ability to prevent sexually transmitteddiseases (STDs) in the field, not just in the lab.1

Based on results of those studies, the Centers for Disease Control andPrevention (CDC) and the World Health Organization (WHO) recently advised againstnonoxynol-9 for prevention of sexually transmitted infections.2

Although nonoxynol-9 is somewhat effective in preventing pregnancy (after sixmonths of typical use, 25 percent of women using a contraceptive film and 28percent of women using foaming contraceptive tablets became pregnant), studiesabout its efficacy in preventing STDs is conflicting. Older studies showed aslight reduction in risk of several types of STDs, but more recent studiesconcluded in 2002 by CDC and WHO determined that nonoxynol-9 does not provideprotection against STDs and that it may actually increase the risk oftransmission instead.

Nonoxynol-9 apparently irritates the epithelium of the vagina and anus, whichmay increase the risk of STD transmission. Two recent studies -- one of femalesex 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 filmhad a slightly higher risk of gonorrhea, a slightly lower risk of chlamydia andno change in risk for HIV. The second study showed a 20 percent higher incidenceof gonorrhea or chlamydia in women using a contraceptive gel compared to womenwho used only condoms; the risk of contracting gonorrhea was 50 percent greaterin women who used the gel compared to those who did not, but the risk ofchlamydia infection was comparable.

A study of 991 sex workers published in 2000 found that the risk of HIVinfection was increased by 50 percent with the use of a contraceptive gel. Andwomen who used gel the most frequently (as often as 20 times a day) had thegreatest risk.

Nonoxynol-9 can irritate the skin of the vulva, vagina or penis, and greaterfrequency of use and higher doses exacerbate epithelial disruption. Thecontraceptive seems to have a stronger disruptive effect on the rectum; thus,the CDC and WHO both recommend against using nonoxynol-9 for protection duringanal sex.

In January, the Food and Drug Administration (FDA) proposed thatover-the-counter vaginal contraceptives be sold with a new label warning thatnonoxynol-9 does not protect against HIV and other STDs. The label would alsoinclude a statement that nonoxynol-9 can increase vaginal irritation, thusincreasing the possibility of transmitting STDs from infected partners. Publiccomment about this proposed labeling is being accepted through mid-April.3

There are occasions when nonoxynol-9 appears appropriate for use. Women atlow risk of HIV infection can keep nonoxynol-9 as a contraceptive option, butwomen who have multiple daily acts of vaginal intercourse should steer clear ofnonoxynol-9 in favor of other contraception. Because nonoxynol-9 is not amicrobicide, it should not be used to protect against STDs. WHO recommends thatlatex or polyurethane condoms should be used to prevent against infectioninstead. Although condoms may not completely prevent skin-to-skin contact, theyserve as the most effective means of protection against STDs by inhibiting theexchange of body fluids like semen, genital discharge or infectious secretions.