Background/Objectives: To analyze the prevalence and risk factors associated with the onset of urinary incontinence (UI) in primiparous non-menopausal women with no personal history of pregestational UI, as well as its impact on quality of life. Methods: An ambispective observational cohort study was conducted among primiparous women between 5 and 10 years after childbirth. Sociodemographic and health characteristics were analyzed, along with the presence of UI using the International Consultation on Incontinence Questionnaire–Urinary Incontinence Short Form (ICIQ-UI-SF). Results: Of the 425 women analyzed, 228 (53.6%) presented UI. After adjusting for confounding factors, women who delivered by cesarean section showed a lower risk of developing UI (aOR = 0.52; 95% CI: 0.32–0.85; p = 0.009). Conversely, a family history of UI (mother or sister) (aOR = 2.03; 95% CI: 1.25–3.32; p = 0.004) and the presence of medical history (chronic diseases/comorbidities) were associated with a higher risk of UI (aOR = 1.58; 95% CI: 1.02–2.45; p = 0.040). Regarding quality of life, 25.88% of participants responded affirmatively to the specific interview question on UI, whereas 58.65% presented some degree of UI when assessed with the ICIQ-UI-SF. This discrepancy likely corresponds to mild-to-moderate cases. Conclusions: In primiparous, non-menopausal women without prior incontinence, the occurrence of UI in subsequent years following childbirth is associated with vaginal delivery, family history of UI, and the presence of chronic diseases or comorbidities. Evidence-based strategies for detection and prevention should be further developed and implemented.