Letter by Micheletti and Chevallier Regarding Article, “Hormone Therapy and Venous Thromboembolism Among Postmenopausal Women: Impact of the Route of Estrogen Administration and Progestogens: The ESTHER Study”

To the Editor: We read with interest the report by Canonico and colleagues1 that shows a differential association of oral and transdermal estrogen with venous thromboembolism (VTE) risk among postmenopausal women. In addition, their data suggest that norpregnane derivatives may be thrombogenic (with a 4-fold-increased VTE risk), whereas micronized progesterone and pregnane derivatives appear safe with respect to …