• • Transmission of common sexually transmitted diseases (STDs), including trichomoniasis and human papillomavirus (HPV), has been reported in women who have sex with women (WSW).
  
• • Transmission likely is mediated through exchange of infected cervicovaginal secretions or direct contact.
  
• • Most WSW, including self-defined lesbians, have had sex with men.
  
• • Barriers to care exist for many WSW, including lack of provider education about relevant issues.
  
• • Papanicolaou (Pap) smear screening should be performed in WSW according to routine national guidelines.

Relatively few data are available to inform estimates of the risk of female-to-female sexual transmission of STDs. The available data come primarily from four sources.

First, review of records from clinics that provide STD services (STD clinics) has provided estimates of some outcomes, including diagnosis of STD syndromes, laboratory results, and risk reporters. Such studies have the advantages of capturing a reproducible population of women who can be characterized relative to heterosexual women attending the same venue and of relying on clinician-based or laboratory-defined reports of outcomes, but are limited primarily by the relatively small number of WSW who attend these clinics.

Second, several studies have recruited women who either self-identify as lesbian or who report recent same-sex behavior, regardless of stated identity. Although this type of study may capture a more representative sample of WSW and frequently includes laboratory diagnosis of STDs, the sample of women included is likely biased due to self-selection for enrollment.

Third, although population-based surveys attempt to enroll a more representative sample of women, including WSW, because these surveys are generally expensive and complex to undertake, most do not include laboratory-confirmed assessment of STDs but rely on self-reported STD history.

Finally, case reports of STD transmission between women provide the only documented evidence available for some STDs. Despite their obvious limitations, these reports are valuable in that they can demonstrate the potential for STD transmission between women and, as such, help to emphasize the need for more robust, population-based data to inform WSW patients and their providers about the true risks associated with same-sex behavior between women.

Numerous studies have demonstrated that important barriers to health care exist for WSW. These barriers include, but are not limited to, lack of patient educational materials aimed at their specific risks and circumstances, lack of knowledge among providers, low socioeconomic status, absence of spousal benefits, and impact of negative experiences within the health care system. Among the latter are included outright instances of homophobia and general invisibility. For example, many office registration materials still list options for marital status as “single” or “married”—terms that do not apply to WSW who may be in domestic partnerships, particularly those that are not recognized by regulatory authorities. Even providers who are comfortable assessing STD-related risks may not be knowledgeable about the sexual practices engaged in by many WSW, or about the limited disease-specific information in the literature. For these reasons, education of providers in this area is paramount.

Because recent national surveys indicate that same-sex behavior among women is relatively common, providers should familiarize themselves with information about this patient population, and be aware of referral options for more detailed information. Available information on transmission of specific STDs in WSW is discussed later, under Laboratory Studies.

Risk Assessment

Risk assessment in WSW should begin the way all STD-related risk assessment begins in every patient: with a thorough sexual history. Most importantly, providers should not make assumptions about sexual practices based on the patient’s self-reported identity—in this case, specifically, as a lesbian. Assuming that a self-identified lesbian has not previously been or is not currently sexually active with men is usually incorrect. In one study, 74% of self-identified lesbians had male partners in the past, and of self-identified bisexual women, 98% had prior or current male partners. Among lesbians recruited for studies in Seattle, 80–86% reported prior sex with men, 23–28% had had sex with a man in the last year, and the median number of male and female lifetime partners was the same. In a sample of women evaluated at a London STD clinic, 69% of those identifying as lesbian had prior male partners, and at another London clinic specializing in the sexual health of lesbians, 91% had prior male partners. Heterosexual intercourse transmits the full range of STDs, some of which (notably, chronic viral infections, including HPV, genital herpes, hepatitis B virus, and HIV) may remain undetected for years.