In 1972, micronization of estradiol was studied in women and was likewise found to improve the absorption and potency of estradiol by the oral route. Subsequently, oral micronized estradiol was introduced for medical use in the United States under the brand name Estrace in 1975. However, oral micronized estradiol valerate had been introduced by Schering in 1968. Oral micronized estradiol and oral estradiol valerate have similar bioavailability and are both now widely used throughout the world.After the introduction of oral micronized estradiol, vaginal and intranasal micronized estradiol were evaluated in 1977 and both subsequently introduced.The first transdermal estradiol gel, a hydroalcoholic gel known as EstroGel, was initially described in 1980 and was introduced in Europe around 1981. Transdermal estradiol gel did not become available in the United States until 2004, when EstroGel was introduced in this country as well. A transdermal estradiol emulsion, Estrasorb, was marketed in the United States in 2003 as well. One of the earliest reports of transdermal estradiol patches was published in 1983. Estraderm, a reservoir patch and the first transdermal estradiol patch to be marketed, was introduced in Europe in 1985 and in the United States in 1986. The first transdermal matrix estradiol patches to be introduced were Climara and Vivelle between 1994 and 1996, and were followed by many others.Ethinylestradiol, a synthetic derivative of estradiol, was synthesized from estradiol by Inhoffen and Hohlweg in 1938 and was introduced for oral use by Schering in the United States under the brand name Estinyl in 1943.
Breast cancer
High-dose estrogen therapy is effective in the treatment of about 35% of cases of breast cancer in women who are at least 5 years menopausal and has comparable effectiveness to antiestrogen therapy with medications like the selective estrogen receptor modulator (SERM) tamoxifen. Although estrogens are rarely used in the treatment of breast cancer today and synthetic estrogens like diethylstilbestrol and ethinylestradiol have most commonly been used, estradiol itself has been used in the treatment of breast cancer as well. It has been used orally at very high doses (30 mg/day) in the treatment of therapy-naive breast cancer and orally at low doses (2 to 6 mg/day) in the treatment of breast cancer in women who were previously treated with and benefited from but acquired resistance to aromatase inhibitors. Polyestradiol phosphate is also used to treat breast cancer. Other uses
Infertility
Estrogens may be used in treatment of infertility in women when there is a need to develop sperm-friendly cervical mucous or an appropriate uterine lining.It is also commonly used during in vitro fertilization (IVF). Estrogen helps maintain the endometrial lining of the uterus and help prepare for pregnancy. Research shows higher pregnancy rate if the mother takes estrogen in addition to progesterone. Estradiol is the predominant form of estrogen during reproductive years and is most commonly prescribed. Lactation suppression
Estrogens can be used to suppress and cease lactation and breast engorgement in postpartum women who do not wish to breastfeed.