No inert IUDs are approved for use by the healthcare authorities in the USA, UK, or Canada. In China, where IUDs are the most common form of contraception, copper IUD production replaced inert IUD production in 1993.[35] However, as of 2008, the most common IUD used by immigrants presenting to Canadian clinics for removal of IUDs placed in China was still the SSR. As the SSR has no string for removal, it can present a challenge to healthcare providers unfamiliar with IUD types not available in their region.[36]