Safety of Transdermal Estrogen

Transdermal estrogen replacement therapy is a way to administer estrogen to a woman in need of estrogen. This therapy is needed for women without a uterus or who have gone through early menopause for various medical reasons. Through transdermal therapy, a patch is placed on the skin for a week that administers the estrogen.

ERT Warnings

• Any type of estrogen replacement therapy (ERT) is not safe for women who are pregnant; have unexplained vaginal bleeding; have a history of breast cancer, ovarian cancer or endometrial cancer; smoke; or have a history of blood clots or stroke, according to the NYU Medical Center website.

Liver

• Estrogen taken in pill form has to be processed by the liver, which is difficult for an impaired liver. Transdermal ERT goes through the skin into the bloodstream and does not go through the liver first, so it is safer than oral estrogen for women with damaged or diseased livers.

Blood Clots

• Transdermal ERT is less likely than oral ERT to cause clots to form in blood vessels because it doesn't pass through the liver in large amounts, according to the University of Washington website.

CRP

• Transdermal ERT does not affect the levels of C-reactive protein (CRP), which is a strong indicator of future cardiovascular problems in postmenopausal women. Researchers at the University of Texas-Southwestern found in 2003 that Oral ERT "caused a robust increase in CRP," but higher levels of transdermal ERT showed no increase.

Heat

• The transdermal patch should not be exposed to high heat or direct sunlight. The exposure could cause the patch to administer too much estrogen at once--not having enough for the rest of the week.