Norsteroids

Norsteroids are a derivative of a steroid that have elements removed from a side chain or ring.

Examples include:
 * desogestrel
 * ethinyl estradiol
 * ethylestrenol
 * ethynodiol diacetate
 * gestrinone
 * levonorgestrel
 * norethindrone
 * norgestrel
 * quinestrol