Background <p>Determining the reasons for HIV test performance in women living with HIV (WLWH) is crucial for evaluating areas for improvement in early diagnosis.</p> Methods <p>The primary objective of the study was to define the reasons for HIV testing in cisgender WLWH who had their first visit in Hospital Clínic, Barcelona, between January 2000 and December 2023. Reasons were classified into: pregnancy and preconception care, AIDS-defining events (ADE), diagnosis in a sexual partner, indicator condition (IC), patient-initiated testing, physician-initiated testing, and “other”. Secondary objectives included the proportion of late and advanced diagnosis, and analysing viral load (VL), CD4 count, and patient status at 48 weeks. Data were compared between two periods (January 2000 to December 2014 and January 2015 to December 2023).</p> Results <p>The study included 537 women. The main reasons for HIV testing were pregnancy and preconception care (24%) and indicator conditions (22%). Overall, late and advanced diagnoses were observed in 56% and 32% of women, respectively. As expected, women diagnosed following an AIDS defining event presented with the lowest CD4 counts, while those tested due to an indicator condition also showed high proportions of late (66%) and advanced (43%) diagnoses. Spanish women had a lower risk of late diagnosis compared with non-Spanish women, particularly when diagnosed during pregnancy or preconception care, 0.39 (95% CI: 0.18–0.87, <i>p</i> = 0.021). At 48 weeks, CD4 counts remained below 400 cells/mm³ in late-diagnosed women across both periods.</p> Conclusion <p>These findings underscore the importance of targeted strategies to promote earlier HIV detection and improve long-term health outcomes in women.</p>