Testing women's low libido

Women's sexual problems -- whether they care about them and, if they do, how to solve them -- are the subject of two scientific studies that get to the heart of what qualifies as a medical disorder and what risks might be involved in taking drugs to treat them.

Last week Dr. Jan Shifren, director of the Vincent Menopause Program at Massachusetts General Hospital, reported in Obstetrics and Gynecology that while almost half of women surveyed said they have sexual problems, only about one in eight said the problems caused them distress. The study was funded by pharmaceutical company Boehringer Ingelheim International, which makes a drug targeting women's low libido.

Shifren and her colleagues asked more than 31,000 women if they had difficulties with desire, arousal, or orgasm and whether these problems caused them unhappiness. About 43 percent said they had one or more problems, but only 12 percent said they were troubled by them.

"You could certainly argue that something that occurs in 40 percent of otherwise healthy women is probably normative and we shouldn't be calling it a disorder," Shifren said in an interview.

The second, smaller study, appearing in tomorrow's New England Journal of Medicine, examined women who did say their lack of desire was distressing. Procter and Gamble, makers of a testosterone patch used in the study, funded the trial and was also involved in its design, data collection, and data analysis.

About 800 postmenopausal women were randomly chosen to wear patches that delivered daily doses of high or low levels of testosterone or no hormone at all. The trial, which lasted a year, excluded women who were receiving estrogen therapy, another hormone prescribed to ease sexual and other problems that follow menopause.

After a year, women who wore the higher-dose testosterone patch experienced a "modest but meaningful" improvement in their sex lives. That translates into 2.1 additional satisfying sexual encounters a month, the authors. write. Shifren, who was not an author of the study but a principal investigator for the trial at Mass. General, said that increase might not seem like much, but the women said it was meaningful to them.

"These are women for whom less desire was truly associated with personal distress," she said. "Clearly it's only for that group of women for whom any potential risk would be justified."

The study did reveal some possible risks.

Among the two-thirds of women who were receiving testosterone, four cases of breast cancer were diagnosed compared to none among women receiving a placebo. Unwanted hair growth, deepening voice, and facial acne also occurred in the testosterone group.

"This is probably the largest study to date where we have one full year of double-blinded randomized safety data," Shifren said. "Clearly long-term safety data is what we really need."

In an editorial published with the New England Journal article, Julia R. Heiman of the Kinsey Institute for Sex, Gender, and Reproduction at Indiana University also advises caution.

"The results of the present report support previous findings that testosterone has positive effects on sexuality and that higher doses show greater effects," she writes. "At the same time, the findings suggest the need for caution in using testosterone until we understand more about its possible link with breast cancer and are better able to predict which patients are more likely to be subject to negative effects."