Four cases of VTE with oral estradiol, one on Premarin and five on transdermal estrogen (currently most prescribed E2 ), were reported., One surgical center reported a low but significant incidence of postoperative VTE with LMWH and stopping of hormones. One center did not stop hormones before operation and observed no postoperative VTE in > 100 operated patients with only LMWH prophylaxis. No VTE was observed in the other centers which all stopped hormones and used LMWH.
The incidence of VTE in estrogen-treated MtF has much decreased in recent years, probably due lower estrogen dose and avoiding EE. However, the risk of VTE appears still increased compared to women (3/10,000), even to estrogen-using women (OC and HRT). Postoperative VTE incidence is low but significant, even in subjects who stopped estrogen before surgery. Peri-operative prophylaxis with LMWH is mandatory. Stopping estrogens before surgery seems prudent but we have insufficient data to recommend it.