Impact of infectious disease outbreaks and regulatory policies on cord blood banking: a two-decade single-center analysis in Korea.

Public cord blood (CB) banks face declining inventories worldwide, but the relative contributions of regulatory changes, declining birth rates, and infectious disease outbreaks remain unclear. We performed a retrospective analysis of 73 925 CB units submitted to a Korean public cord blood bank from 2006 to 2025, encompassing two regulatory transitions in total nucleated cell (TNC) criteria and three major outbreaks (H1N1, MERS, and COVID-19), using interrupted time series, correlation, and multivariable analyses. Of 73 925 submissions, 27 684 (37.4%) were banked. The 2011 TNC ≥ 8 × 108 criterion produced a moderate reduction in banking rate from 37.7% to 33.6%, while the 2021 TNC ≥ 11 × 108 revision caused an abrupt decline from 52.6% to 24.4%. H1N1 and MERS had minimal effects, whereas the COVID-19 period showed a sustained decline coinciding with the 2021 TNC revision. Birth decline correlated strongly with submissions (R2 = 0.94). Regulatory criteria changes were the primary driver of banking rate fluctuations, while declining births affected submission volume. Among three outbreaks, only the COVID-19 period overlapped with a sustained decline, likely reflecting concurrent regulatory change rather than the pandemic itself. CB quality and safety were maintained throughout all disruptions. These findings have direct translational implications for sustaining the global CB inventory as a critical source of hematopoietic stem cells for transplantation.