A method for coating a medical implant applies at least one coating to at least one surface of the implant by plasma polymerization. The implant has pores sized in the nanometer range. The method stabilizes the pores. The plasma polymerization is conducted in the presence of a coating gas and oxygen. A coating parameter can be selected so that a rough surface of the implant is coated. An implant includes a membrane having pores sized in the nanometer range. A surface of the implant is at least partially coated with a plasma polymer. The interior of the pores is uncoated.