These synthetic progestins will compete with progesterone receptor binding sites and compete with progesterone rendering progesterone useless.

些合成的黄体素会与黄体素接争，并使黄体素无。

Approved by the FDA in 2001, the patch is sold by prescription and releases ethinyl estradiol (a type of estrogen), and a progestin called norelgestromin via the skin into the bloodstream.

FDA在2001年就已经证实，过渗透皮肤来释放雌激素和孕激素的贴膜是一处方类药物。