• estrogens;
  • hormone replacement therapy;
  • pulmonary embolism;
  • recurrence;
  • venous thrombosis



The optimal duration of anticoagulation for women who had venous thromboembolism (VTE) associated with estrogen use is unknown.


To test the hypothesis that women who had a first VTE while using estrogens have a low risk of recurrence.


A Prospective cohort study of 630 women (333 estrogen users, 297 non-users) with a first VTE, who were followed for an average of 69 months after anticoagulation withdrawal. Women with a previous or secondary VTE, coagulation inhibitor deficiency, lupus anticoagulant, cancer, pregnancy, requirement of long-term antithrombotic therapy or homozygosity or double heterozygosity for factor V Leiden and/or the G20210A prothrombin mutation were excluded. The endpoint was objectively documented symptomatic recurrent VTE.


VTE recurred in 22 (7%) estrogen users and in 49 (17%) non-users. After 1, 2 and 5 years, the cumulative probability of recurrence was 1% (95% confidence interval [CI], 0–2), 1% (95% CI, 0–2) and 6% (95% CI, 3–9) among estrogen users and 5% (95% CI, 2–7), 9% (95% CI, 6–13) and 17% (95% CI, 12–22) among non-users. Compared with non-users, estrogen users had an adjusted relative risk (RR) of recurrent VTE of 0.4 (95% CI, 0.2–0.8). Compared with non-users in the respective age groups, the RR of recurrence was 0.4 (95% CI, 0.2–0.8) among estrogen-containing-contraceptive users and 0.7 (95% CI, 0.3–1.5) among women using estrogen-containing menopausal hormone therapy.


Women who had their first VTE while using estrogens have a low risk of recurrent VTE. These women might not benefit from extended anticoagulant therapy.