Incidence of thrombophilia and venous thrombosis in transsexuals under cross-sex hormone therapy

Objective: To evaluate the incidence of venous thromboembolism (VTE) in transsexual patients and the value of screening for thrombophilia in this population. Design: Retrospective cohort study. Setting: Academic research institution. Patient(s): Two hundred fifty-one transsexuals (162 male-to-female [MtF] and 89 female-to-male [FLM] transsexuals). Intervention(s): Screening for activated protein C (aPC) resistance, antithrombin 111, free protein S antigen, and protein C deficiency. Main Outcome Measure(s): Incidence of thrombophilic defects and VTE during cross-sex hormone therapy. Result(s): Activated protein C resistance was detected in 18/251 patients (7.2%), and protein C deficiency was detected in one patient (0.4%). None of the patients developed VTE under cross-sex hormone therapy during a mean of 64.2 +/- 38.0 months. There was no difference in the incidence of thrombophilia comparing MtF and FtM transsexuals (8.0% [13/162] vs. 5.6% [5/89], respectively). Conclusion(s): VTE during cross-sex hormone therapy is rare. General screening for thrombophilic defects in transsexual patients is not recommended. Cross-sex hormone therapy is feasible in MtF as well as in FtM patients with aPC resistance. (Fertil Steril (R) 20 10;93:1267-72. (C) 2010 by American Society for Reproductive Medicine.)