Allcombination birth control pillscontain estrogen (typically ethinyl estradiol) and aprogestin.
In contrast to estrogen, there are many types of progestin found in various oral contraceptive brands.
Classification of Progestins
Combination birth control pills include one estrogen and one progestin.
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Most synthetic progestins are chemical derivatives of testosterone (known as 19-nortestosterone derivatives).
Typically the third- and fourth-generation progestins tend to be highly selective and possess minimal androgenic properties.
These include norgestimate, desogestrel, and drospirenone.
There has been some evidence to suggest that the third-generation progestins may carry a higherrisk of blood clots.
UpToDate.Combined estrogen-progestin oral contraceptives: patient selection, counseling, and use.
