Effective copper surface area of

conclude that 40% of the copper wire is ‘ineffective’. With the frameless GyneFix® IUD, all surface areas are exposed to the uterine environment. This is a fundamental difference compared to conventional IUDs. Copper-release studies with the standard GyneFix 330® IUD removed after more than 10 years of use have shown that the copper surface area decreases very little over that period, only 7% after 12 years of use (Contrel, manufacturer’s data on file). This could explain the high efficacy of the small GyneFix® 200 IUD (Figure 1), less than 1.0 at 3 years of use,4 and the absence of increase in annual pregnancy rate with GyneFix as the surface area of the GyneFix IUD decreases very little over time. The copper content of the GyneFix 200 is 280 mg, which is higher than the copper content of TCu380A (244.7 mg of copper) having a lifespan of at least 10 years. The smaller the size of the GyneFix the less the effect on menstrual blood loss. Women wearing the small GyneFix 200 IUD report a similar bleeding pattern when compared with the bleeding pattern before insertion of the IUD.5 At the same time, the small surface area optimises tolerance. This could be important since abnormal bleeding and pain are the two major reasons for IUD discontinuation.