Repeated cryopreservation is associated with poor pregnancy outcomes after frozen–thawed embryo transfer in women aged < 35 years: a propensity-score matched cohort study

Repeated cryopreservation was associated with reduced clinical pregnancy and live birth rates, particularly in younger patients. The neonatal outcomes were potentially not affected. Clinicians may consider limiting repeated cryopreservation for women under 35 years and prioritize good-quality embryos for re-vitrification when medically justified. These findings underscored the need for tailored strategies in FET cycles involving re-cryopreserved embryos.