Objective: To analyze the experience of women aged 35 or over regarding the transition to unplanned motherhood. Method: A descriptive qualitative study, with semi-structured interviews with six women in this age group, selected by convenience, carried out in a high-risk prenatal clinic between July 2022 and July 2023. Analysis was based on Transitions Theory. Results: Three main categories were identified: Transition properties (attributes of late motherhood); Transition conditions (personal, social and community factors as facilitators or inhibitors); and Response patterns (coping and adaptation strategies). The results highlight the emotional and psychosocial complexity, including the impact of social stigma, health challenges and the duality of old age, which brings both challenges and maturity. Conclusion: The need for public policies and specialized support to promote mental health, well-being and social integration is emphasized, aiming for a healthier and more empowered transition to motherhood.