Birth Control and Emergency ContraceptionLevonorgestrel (LNG) is a synthetic progestogen used in contraception and hormone therapy. Levonorgestrel is known as Plan B morning after pill for emergency contraception and being the active ingredient in Levlen or Alesse for normal birth control pills. If you had "unsafe sex" without a condom and you are not sure there was cum in your vagina, you could use Levonorgestrel as a morning after pill or emergency contraception. This is proven by Princeton Universityin their research. If you are looking for more information about Levonorgestrel, to use it for normal birth control to prevent for getting pregnant, than it is also the unique pill and the most sold birth control pill worldwide, under brand names as Levlen and Alesse. Women became more independant thanks to Levonorgestrel and sometimes the brand versions are less known than the chemical name "Levonorgestrel" even though it is a difficult name.