Understanding the pathways that expose women to HIV transmission are vital in improving HIV prevention, especially among a "hidden" group of women without pre-established known risk for HIV. We investigated the pathways which place certain women at greater risk for HIV in a qualitative exploratory study with theoretical sampling using an emergent theory study design in an urban setting in Indonesia. We conducted semi-structured interviews with 47 HIV-infected women, one focus group discussion with five young women who occassionally engage in sex work, participant observation at six sex work venues and two midwife clinics, and 11 informal interviews with midwives, nurses, and obstetricians. Our research found that many women not characterized as belonging to a "high-risk group" or "key population" were nevertheless at increased risk for HIV. A history of sexual abuse, premarital sex, divorce, or involvement in sex work, often precipitated by poverty coupled with discriminatory public health policies further heightened women's exposure to HIV. While reaching at-risk populations is a key strategy in HIV prevention, a novel and more tailored approach is needed to reach more hidden categories of women with less apparent risk behavior yet considerable risk for HIV infection.