SAT-218 Longitudinal outcomes of fertility potential in female pediatric hematopoietic stem cell transplant survivors

Abstract Disclosure: B. Mani: None. Z. Hudda: None. E. Lawhorn: None. O. Frias: None. K. Myers: None. K. Burns: None. J.C. Howell: None. Objective: Hematopoietic stem cell transplant (HSCT) contributes to gonadal toxicity in childhood survivors, but long-term fertility outcomes are understudied. We aim to describe the longitudinal fertility potential in females after HSCT. Methods: We performed a retrospective study of female subjects with allogeneic HSCT from 2015 to 2023. Subjects were ≤21y at time of HSCT, reached ≥11y during the study, and survived >1y. Those with Fanconi anemia were excluded. Anti-mullerian hormone (AMH) was used as a marker of fertility potential. AMH >0.003 ng/mL was considered detectable, while AMH ≥0.5 ng/mL was defined as the potential fertility preservation (PFP) threshold. Data was aggregated to compare AMH at early (1-4y) and late (5-8y) timepoints post-HSCT in several subgroups by chi-squared analysis. Due to small sample size, subjects over 21 years at HSCT were analyzed descriptively without statistical tests. Results: Fifty-one patients had a median follow up of 4y (range 1-8y). Eighteen patients (35%) were <11y at HSCT. Eighteen (35%) had malignancy. Thirty-six (71%) received myeloablative conditioning (MAC) and 15 (29%) received a reduced intensity regimen (RIC). Twenty-six (51%) had cyclophosphamide equivalent dosing (CED) <8 gm/m2 and 25 (49%) had >8 gm/m2. Seven (14%) had radiation. Twenty-six (51%) developed primary ovarian insufficiency (POI). Twenty-five (49%) had ovarian tissue cryopreservation (OTC). Median baseline AMH in all subjects pre-HSCT was 1.9725 ng/mL but was <0.003 ng/mL at 1y post. Longitudinal analysis showed subjects lacking POI or with lower CED were more likely to have both detectable AMH and be above PFP at both early (p<0.001, p=0.003) and late (p<0.001, p=0.019) timepoints. Subjects with RIC were significantly more likely to have detectable AMH at early and late timepoints (p<0.001) and meet PFP late after HSCT (p=0.007) vs MAC. Those with non-malignancy were significantly more likely to be above PFP at early (p=0.018) and late (p=0.025) timepoints. Females without OTC were more likely to meet PFP early after HSCT (p=0.008) but were not significantly different late after HSCT. No significant differences were seen when comparing either age at HSCT or radiation exposure. Nine patients over 21y at HSCT had a median follow-up of 2y (range 1-8y). In this cohort, 5 (56%) had malignancy, 7 (78%) received MAC, and 6 (67%) had CED >8 gm/m². Seven (78%) developed POI. Only two had detectable AMH; none above PFP. Conclusion: Improvement in AMH levels can be seen several years after HSCT in female pediatric patients with either RIC, lower CED, lack of POI, or non-malignancy. These data support the utility of long-term monitoring of AMH for fertility potential after HSCT. Additional study is needed to determine if AMH differences ultimately correlate with future adult fertility potential. Few improvements were observed in adults, although more data are needed to draw conclusions. Presentation: Saturday, July 12, 2025