Efficiency assessment of cord blood banking and compatibility with delayed cord clamping

There is debate whether delayed umbilical cord clamping following delivery, the current gold standard, affects the proportion of cord blood units (CBU) suitable for public cord blood banking. This study was designed to assess the impact of delayed cord clamping on the number of CBU suitable for therapeutic uses.

To minimize variability, data from the four most active collection centers within the Programa Concordia (Spain) were included. Data on CBU collected in utero from mothers following normal vaginal deliveries from July 2018 to December 2021 were analyzed. The weight of the collection bags (as a surrogate of volume) and total nucleated cell (TNC) count were analyzed according to three defined clamping times: 30 s, 60 s and ≥120 s. The CBU were stratified as suitable for stem cell transplantation (≥110 g and ≥1,500x10⁶ TNC/unit) or other clinical applications (≥100 g but TNC count below the threshold).

There were 131 (18%), 548 (76%), and 40 (5%) CBU collected at 30 s, 60 s and ≥120 s, respectively. The median weight of the CBU decreased gradually with time, with a significant difference between units collected when the cord was clamped at 30 s or 60 s (p=0.036), so significantly fewer CBU met the minimal weight criterion (100 g) at 60 s than at 30 s (p=0.002). However, this was not reflected by the TNC available, resulting in non-statistical differences in CBU eligible for banking between these times. The major predictor of collection success was the neonate's birth-weight.

Despite decreases in the volume of cord blood collected when cord clamping at 30 s or 60 s, TNC count is maintained resulting in similar numbers of CBU eligible for banking. The different clamping delays investigated in this study are, therefore, compatible with public cord blood banking needs.