In southern Kenya, indigenous medicinal knowledge coexists and is often integrated with biomedical healthcare. Understanding the sustainability of these practices is important for holistic maternal and reproductive health, yet detailed contemporary ethnographic studies are scarce. This study documented and analysed the characteristics of sustainable medicinal practices from local community perspectives in southern Kenya. It aimed to identify the principles, methods of knowledge transmission, and ecological relationships that support the resilience of these practices within obstetrics and gynaecology. A longitudinal ethnographic study was conducted using participant observation, in-depth interviews, and focus group discussions. Participants included traditional healers, midwives, community elders, and women of reproductive age. Data were analysed thematically to identify core patterns and cultural logics. Three interconnected pillars of sustainability were identified: ecological stewardship, intergenerational knowledge transmission, and adaptive integration. A key practice was the deliberate limitation of harvesting specific botanicals for postpartum recovery to ensure species regeneration. Knowledge was curated and transmitted through gendered apprenticeship systems. These practices demonstrated a dynamic, embedded relationship with the local ecology and social structures. Sustainable medicinal practices in this context are dynamic systems deeply embedded in socio-ecological relationships. Their continuity is actively managed through community protocols and adaptive learning, presenting a viable complement to biomedical care. Policymakers and health planners should engage with local knowledge systems to develop integrated maternal health programmes that support sustainable practices. Further research should investigate specific applications of these practices for common obstetric conditions. Ethnography, traditional medicine, sustainability, maternal health, Kenya, indigenous knowledge, obstetrics, gynaecology This study provides a community-centred analysis of the mechanisms underpinning the sustainability of indigenous medicinal practices relevant to obstetrics and gynaecology in southern Kenya.