Estradiol-containing birth control pill
Combined birth control pills that contain natural estradiol or an estradiol ester include:
- Estradiol valerate and cyproterone acetate – introduced in Finland in 1993
- Estradiol valerate and dienogest – introduced in Europe in 2009 and the in 2010
- Estradiol and nomegestrol acetate – introduced in Europe in 2011
As of 2021, more than 95% of prescriptions are for combined hormonal birth control forms containing the synthetic estrogen ethinylestradiol. Hence, estradiol-based birth control pills are still not widely used.
Side effects
Birth control pills containing estradiol have less impact on liver protein synthesis than ethinylestradiol-containing birth control pills, and it is thought that for this reason, they may pose less of a risk of venous thromboembolism. In accordance, although birth control pills containing estradiol valerate/dienogest are associated with a significantly increased risk of VTE, they are associated with a significantly lower risk of venous thromboembolism than birth control pills containing ethinylestradiol and a progestin. The risk of VTE with estradiol/nomegestrol acetate birth control pills is under study.Incidence of irregular vaginal bleeding may be higher with estradiol-containing birth control pills in relation to the fact that estradiol is a weaker estrogen than ethinylestradiol in the endometrium.
Pharmacology
The pharmacodynamics and pharmacokinetics of estradiol in the context of use in birth control pills have been studied and reviewed.Research
Experimental estradiol-containing birth control pills that were studied but never marketed include:- Estradiol/norethisterone
- Estradiol/estriol/norethisterone
- Estradiol/estriol/norethisterone acetate
- Estradiol/desogestrel
- Estradiol cyclooctyl acetate/desogestrel
- Estradiol/ethinylestradiol/dienogest