Disclosed herein is an implantable prosthesis for breast augmentation or reconstruction procedures. The prosthesis comprises a biocompatible and biodegradable fabric structure comprising one or more individual yarns comprised of sericin-extracted native fibroin fibers, wherein the yarns are intertwined to produce the fabric structure. The fabric structure extends in at least a first dimension and has at least a first surface that is adapted to engage and support natural breast tissue and/or a prosthetic breast implant in a patient. Also disclosed are methods of supporting breast tissue or a breast implant in a patient by inserting the prosthesis between the skin of the patient and the breast tissue and/or implant within the patient.
