Over 2 million women in the United States describe themselves as lesbians, and even more women report that they have sex with other women. Despite the fact that cervical neoplasia develops in women who report that they have never had sex with men, little is known about the prevalence of human papillomavirus (HPV) infections in this population. The frequency with which lesbians and bisexual women acquire sexually transmitted diseases is assumed to be similar to that of heterosexual women. However, these women tend to have Papanicolaou smears less frequently than their heterosexual counterparts. Marrazzo and associates evaluated the prevalence of HPV infection in this population and the frequency with which they report having Pap smears.

Women recruited for the study reported having sex with other women within the past year. On entry to the study, a detailed medical and sexual history was obtained, and a pelvic examination and colposcopy of the cervix were performed. Specimens were collected so that a Pap smear and HPV DNA testing by polymerase chain reaction (PCR) could be completed. All Pap smears were read by the same cytopathologist, and the HPV DNA testing was done in one laboratory.

A total of 149 women qualified for the study. Most reported having had sex with a man sometime in the past, but only 24 percent reported doing so within the previous year. More than one half of the women had had sex with only one female partner within the past year. HPV infection was detected by PCR in 45 women, but none of these gave a history of genital warts and only two had had sex with a man who had genital warts. Cigarette smoking, history of abnormal Pap smear and age between 25 and 30 years were also associated with a higher risk for HPV DNA. Thirteen women in this group had abnormal results on their Pap smears. Of these, three reported that they had not had sex with a man, and three reported having sexual contact with a woman who had genital warts. Squamous intraepithelial lesions (SIL) were found in six women, and atypical squamous cells of undetermined significance (ASCUS) were found in seven others. HPV DNA was found in five of the six women with SIL. The mean interval for Pap smears in this group was 21 months, compared with eight months in heterosexual women who were matched for age and attended the same clinic.

The authors conclude that HPV infection can be sexually transmitted between women. In this study, 30 percent of the women had HPV infections, along with a significant number of abnormal results on Pap smears. Despite these results, women who have sex with women wait longer between Pap smears than do their heterosexual counterparts. The authors concede that because the size of their study group was small, more research is needed. Until more definitive data are obtained, the recommended interval between Pap smears should be the same for all women, regardless of sexual orientation.