Treatment of acute leukemia with intensive chemotherapy leads to an increased risk of myelosuppression. Luteinizing hormone (LH) blockade improves hematopoietic recovery in mice after radiation or chemotherapy, through protection of the hematopoietic stem cells which express the LH receptor. We hypothesized that LH blockade improves hematopoietic recovery following intensive chemotherapy in patients with leukemia. We conducted a retrospective analysis on pre-menopausal women with acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL) who received intensive chemotherapy and leuprolide given for abnormal uterine bleeding prevention or treatment. Given that leuprolide was more commonly administered in younger patients, we performed propensity score matching between the leuprolide (AML N=64; ALL N=49) and control groups (AML N=128; ALL N=98 patients). Patients with AML who received leuprolide had an additional increase of 13.8 x 109/L/year in their platelet count, and a 0.19 x 109/L/year increase in their lymphocyte count after chemotherapy compared to control (P=0.02; P=0.03 respectively). Those with ALL who received leuprolide had an additional increase of 0.37 x 109/L/year in their absolute neutrophil count (P=0.02). In AML, leuprolide was associated with higher long-term hemoglobin levels (P.