Women on Blood Thinners Can Take Hormones and the Pill Safely

Women taking blood thinners can also take estrogen or hormone replacement therapy (HRT) safely, without increasing their risk of blood clots or uterine bleeding. This new information comes from a study performed by Italian researchers at the A. Bianchi Bonomi Hemophilia and Thrombosis Center in Milan.

The Study Results

Currently, females who have been diagnosed with blood clots are advised to stop hormone therapy or oral contraceptives, due to an increased risk of blood clots, even if they are already on a blood thinner. The reason being is that doctors are concerned these medications, when used in combination, may wind up raising the risks for blood clots even more.

Dr. Ida Martinelli, of the A. Bianchi Bonomi Hemophilia and Thrombosis Center in Milan states, “There has been no evidence to support this decision.”

She went on to further explain, “We conducted this study to address the fear felt by both the physician and patient when making the decision to stop or continue hormone therapy in this setting.”

In the study, Dr. Martinelli and her team compared cases with recurrent blood clots and abnormal uterine bleeding in almost 1,900 women who were prescribed blood thinner medications, with or without hormone therapy.

Of the females in the study, 475 had used hormone replacement therapy, such as estrogen–only pills, combination estrogen-progestogen contraceptives and progestin-only pills. The women were asked if they had experienced any signs or symptoms of blood clots, bleeding, or uterine bleeding during each follow-up appointment.

Of the women who were taking HRT, seven had experienced recurrent blood clot events.
Thirty-eight blood clot events happened during a period when women were not using these treatments, according to the study which was published online in December 2015, in the journal Blood.

Researchers came to the conclusion that the women on blood thinners and HRT experienced recurrent blood clots at a rate of 37.7 percent yearly, less than the 4.7 percent per year for those not on HRT.

Conclusion to the Study

Dr. Martinelli said of the results, “For the first time, we demonstrate that women suffering from blood clots can safely take hormone-containing contraceptives or hormone replacement therapy with anticoagulants (blood thinners), providing women the freedom to choose the method of birth control and other hormone-containing medications they prefer.”

She further stated, “While further investigation is needed to evaluate the inconvenience of abnormal uterine bleeding with rivaroxaban (Xarelto) and other direct oral anticoagulants, these results dispel former misconceptions and should allow clinicians to confidently treat their patients who take blood thinners and hormones.”

Dr. Suzanne Steinbaum, director of women’s heart health at Lenox Hill Hospital in New York City said, “For those women who suffered from clots while on hormones, previous studies have not been clear as to the safety of taking the hormones with blood thinners. This trial provides some insight and reassurance that women can safely continue their hormones while being treated for blood clots.”


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