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The Safety of Transdermal Estrogen: No Increased Risk of Blood Clots

Hormone Replacement Therapy (HRT) is a crucial treatment for many women experiencing the challenging symptoms of menopause. However, one common concern among patients and healthcare providers is the risk of blood clots associated with estrogen therapy. Recent research has provided reassuring evidence that transdermal estrogen, a form of estrogen delivered through the skin via patches, gels, or creams, does not increase the risk of blood clots.

Understanding Blood Clots and Estrogen

Blood clots, medically known as venous thromboembolism (VTE), can be a serious and life-threatening condition. The risk of developing VTE has been a significant factor in determining the safety of various forms of HRT. Oral estrogen has been associated with an increased risk of blood clots, likely due to its first-pass effect through the liver, which can increase the production of clotting factors.

The Benefits of Transdermal Estrogen

Transdermal estrogen bypasses the liver, entering the bloodstream directly through the skin. This delivery method has been shown to maintain normal clotting factor levels and not increase the risk of VTE. Several studies have supported these findings:

  1. The ESTHER Study: This landmark study highlighted that transdermal estrogen does not elevate the risk of VTE compared to oral estrogen. The study emphasized that women using transdermal patches had a similar risk of blood clots as those not using HRT at all (Canonico et al., 2007).

  2. A Meta-Analysis of Transdermal Estrogen: A comprehensive review and meta-analysis published in "Menopause" journal consolidated data from multiple studies, confirming that transdermal estrogen does not increase VTE risk. This analysis included over 20,000 women and reinforced the safety profile of transdermal administration (Vinogradova et al., 2019).

  3. The European Menopause and Andropause Society (EMAS): EMAS guidelines recommend transdermal estrogen as a safer option for women, particularly those at higher risk for VTE. Their position is based on extensive research and clinical evidence (Stuenkel et al., 2015).

Clinical Implications

For women considering HRT, particularly those with risk factors for blood clots or those who are concerned about this risk, transdermal estrogen offers a safer alternative. Healthcare providers can confidently recommend transdermal estrogen to alleviate menopausal symptoms without the added worry of increased VTE risk.


Transdermal estrogen is a valuable option in the management of menopause symptoms, providing effective relief without the heightened risk of blood clots associated with oral estrogen. This method's safety and efficacy make it an excellent choice for many women navigating the menopausal transition.


  1. Canonico, M., Oger, E., Plu-Bureau, G., Conard, J., Meyer, G., Lévesque, H., ... & Scarabin, P. Y. (2007). Hormone therapy and venous thromboembolism among postmenopausal women: impact of the route of estrogen administration and progestogens: the ESTHER study. Circulation, 115(7), 840-845.

  2. Vinogradova, Y., Coupland, C., & Hippisley-Cox, J. (2019). Use of hormone replacement therapy and risk of venous thromboembolism: nested case-control studies using the QResearch and CPRD databases. BMJ, 364, k4810.

  3. Stuenkel, C. A., Davis, S. R., Gompel, A., Lumsden, M. A., Murad, M. H., Pinkerton, J. V., & Santen, R. J. (2015). Treatment of symptoms of the menopause: an Endocrine Society Clinical Practice Guideline. The Journal of Clinical Endocrinology & Metabolism, 100(11), 3975-4011.

By Dr Purity Carr

GP & Menopause Doctor

Harvey, WA

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