STDs are often silent in women, and even when symptoms of STD occur, they may not arouse suspicion of an STD. For example, 30 to 80 percent of women with gonorrhea are asymptomatic, while fewer than 5 percent of men have no symptoms (Hook and Handsfield, 1990; Judson, 1990). Similarly, as many as 85 percent of women with chlamydial infection are asymptomatic compared to 40 percent of infected men (Fish et al., 1989; Judson, 1990; Stamm and Holmes, 1990). When an STD is suspected, it is often more difficult to diagnose in a woman because the anatomy of the female genital tract makes clinical examination more difficult (Aral and Guinan, 1984). For example, a urethral swab and a Gram stain are sufficient to evaluate the possibility of gonorrhea in men, but a speculum examination of the cervix and a specific culture for gonorrhea have been required for women (Hook and Handsfield, 1990). Thus, women with gonorrhea or chlamydial infection are often not diagnosed with an STD until complications, such as pelvic inflammatory disease, occur. Even then, symptoms of pelvic inflammatory disease due to chlamydial infection may be absent or non-specific, resulting in as many as 85 percent of women delaying seeking medical care, thus increasing their risk for long-term complications (Hillis et al., 1993). Fortunately, the advent of newer tests for detecting gonococci and chlamydia in urine may permit testing women for these organisms without pelvic examination in the future, as described in Chapter 4.
Once infected, women are more susceptible than men to complications of certain STDs. For example, women infected with certain types of human papillomavirus are at risk for cancers of the cervix (a relatively common malignancy), as well as cancers of the vagina, vulva, and anus; whereas heterosexual men infected with these human papillomavirus types are at risk only for cancers of the penis (a relatively uncommon malignancy). Another example is the risk of infertility caused by gonorrhea or chlamydial infection, which is much higher in women than in men. Finally, pregnant women and their infants are particularly vulnerable to complications of STD during pregnancy or parturition.
Every year, approximately 3 million American teenagers acquire an STD (CDC, DSTD/HIVP, 1993). During the past two decades, sexual intercourse among adolescents has steadily increased, resulting in an enlarging pool of young men and women at risk for STDs (CDC, 1995c). As a result, STDs, unintended pregnancies, and other health problems that result from sexual intercourse have increased among adolescents in the United States (AGI, 1994). Adolescents (10-19 years of age) and young adults (20-24 years of age) are the age groups at greatest risk for acquiring an STD, for a number of reasons: they are more likely to have multiple sex partners; they may be more likely to engage in unprotected intercourse; and their partners may be at higher risk for being infected compared to most adults (Cates, 1990; Quinn and Cates, 1992; AGI, 1994; CDC, DSTDP,