In CuT 200, the number stands for:

Ans: A (Surface...) "The number included in the names of the devices refer to the surface area (in sq, mm) of the copper on the device. Park 21st/459 IUDs: Review of Facts# CuT-200 B being used in India , under the national family welfare programme,Later CuT 380A is introduced in the programme.# Studies have shown that the effectiveness of copper device is directly related to the amountofcopper surface area (usually this is 200 or 220 mm2')- Park 19th/395# IUD is not a method of first choice for nulliparous women. They have more problems such as expulsion, low abdominal pain Si pelvic infection.intra-Uterine Devices; Classification 1st Generation IUDs (inert or non medicated devices) 2nd Generation IUDsEarlier devices* Copper 7* Copper T - 200Newer devices* Variants of the T device(i) T Cu - 220 C(jj) T Cu - 380 A or Ag* Nova T*Multi load devices(i)-Cu-250(ii)-Cu-375 3rd Generation IUDs (Hormonal deinces)* Progestasert* LNG-20 (Mirena)13