CYP19A1 and sickle cell disease: <h4>Purpose</h4>To describe a patient with sickle cell disease, a prothrombotic disorder, who underwent successful embryo cryopreservation for the purposes of fertility preservation prior to hematopoietic stem cell transplant.<h4>Methods</h4>To report a successful case of gonadotropin stimulation and embryo cryopreservation using the aromatase inhibitor letrozole to maintain low serum estradiol to minimize thrombotic risk in a patient with sickle cell disease (SCD) and history of retinal artery thrombosis planning hematopoietic stem cell transplant (HSCT).