You can continue your HRT treatment before, during and after your FFS. You will receive an anti-thrombotic injection the day before surgery to prevent blood clotting. We prefer you to continue taking your hormones because FFS is emotionally already perturbing enough without messing with your hormone balance.
Only for implant surgery of the buttock and hips we ask to stop one week before the surgery. The day after surgery you can continue your HRT treatment. This because this type of surgery implies some immobilisation (obliged) after the surgery. In this case the risk for blood clots is higher.