Biomaterials in Menstrual Cup Design: Challenges, Innovations and Future Perspectives

Menstrual cups are an expanding alternative in menstrual hygiene management, positioned at the intersection of biomaterial science, women's health, and sustainability. Because these intravaginal devices are intended for prolonged, repeated mucosal contact, their safety, functionality, and user acceptance largely depend on material selection and engineering design. This review critically evaluates the biomaterials used in contemporary menstrual cup manufacturing, focusing on medical-grade silicone (MGS), thermoplastic elastomers (TPEs), and natural rubber and compares their physicochemical properties, mechanical behaviour, biocompatibility, sterilisation compatibility, and chemical safety. Beyond material comparison, we draw on clinical, microbiological, and post-market surveillance data to contextualise tissue response, vaginal microbiome stability, and rare but clinically significant adverse events such as toxic shock syndrome. We also examined emerging innovations, including surface and interface engineering, biodegradable elastomers and composite blends, and advances in manufacturing and design. We argue that menstrual cup development is best understood as a multidisciplinary biomaterials challenge integrating polymer chemistry, surface engineering, microbiological safety, regulatory science, and user-centred design. Realising safer, more functional and more sustainable cups will require rigorous biocompatibility testing, long-term studies, and transparent material characterisation.