Less risk of blood clots with topical estrogen versus oral estrogen.

Oral Estrogens have a higher risk of blood clots than Transdermal Estrogens.

October 2011 · Vol. 23, No. 10

VTE risk in hormone therapy: Lower with transdermal estradiol than with oral estrogen, study finds

A large, population-based study found that women who took transdermal estradiol had a 30% lower incidence of venous thromboembolism than those in the oral estrogen group.
Deborah RealeManaging Editor

Experience from research and practice have demonstrated that venous thromboembolism (VTE) is a common complication of hormone therapy. Now, that obstacle to safe treatment of the symptoms of menopause may be tempered by the results of a large population-based study, suggesting that patients who take transdermal estradiol have a 30% lower incidence of VTE than those who take oral estrogen only. The lower risk of VTE was also statistically significant when transdermal estradiol was at high dose.1,2

Study results were presented at the 22nd Annual Meeting of the North American Menopause Society (NAMS) in Washington, DC, in September.

In the retrospective, matched-cohort study that compared high-dose transdermal estradiol and oral estrogen-only HT agents, 115 of 27,018 users of the estradiol transdermal system (ETS) and 164 of 27,018 users of the oral estrogen developed VTE. In those taking high-dose ETS (0.1 mg/day), 32 of 8,956 ETS users and 65 of 8,956 oral users of high dose oral estrogen developed VTE.1,2

“The incidence of hospitalization related to VTE events among the ETS users was also significantly lower, relative to the oral-only hormone therapy users,” said Eric Beresford, PharmD, presenter and coauthor of the study and director of medical affairs at Forest Research Institute, Secaucus, NJ, who previously worked at Novartis.1


2011-2012 NAMS President JoAnn Manson, MD, DrPH, HCMP, commented that the study “provides further reassurance that transdermal estrogen may not increase the risk of venous thrombosis.”1

“We do know that transdermal products don’t go directly to the liver and don’t increase the production of clotting proteins to the same extent as the oral estrogen products,” Manson added, “so it’s biologically very plausible. I do think that it’s a reasonable choice for trying to avoid venous thrombosis risk.”1

For details: www.medscape.com/viewarticle/750558.


1. Yin S. Transdermal Estradiol Safer Than Oral Estrogen. MedScape.com.http://www.medscape.com/viewarticle/750558. Published September 28, 2011. Accessed September 29, 2011.

2. Kahler KH, Nyirady J, Beresford E, et al. Does route of administration for estrogen hormone therapy and estradiol transdermal system dosage strength impact risk of venous thromboembolism. Washington, DC: North American Menopause Society (NAMS); September 23, 2011. Abstract S-4.http://www.menopause.org/meetings/AGMasithappens.aspx. Accessed September 29, 2011.


One thought on “Less risk of blood clots with topical estrogen versus oral estrogen.

  1. Wendy, great summary of our Hormone Therapy Position Statement! We thhogut women who have had a hysterectomy would be pleased to know that they can use estrogen longer than 3-5 years if they need to without concern about an increased risk of breast cancer. Thanks for sharing the good news.Margery Gass, MDExecutive DirectorThe North American Menopause Society

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