Effects of delayed umbilical cord clamping on peripheral blood hematopoietic stem cells in premature neonates.

AIM: To investigate the effects of delayed cord clamping (DCC) on peripheral hematopoietic progenitor cells (HPCs) and hematological parameters in premature infants (<32 weeks) during the neonatal period.

METHODS: This was a prospective, randomized, and controlled, single-center study. Prior to delivery, 21 infants were randomly assigned to immediate cord clamping (ICC) at 5-10 s and 21 infants to DCC at 30-45 s. One milliliter blood sample was taken in the first 30 min of life. HPCs were measured by three-color flow cytometry using monoclonal antibodies.

RESULTS: There were no significant differences between groups in either maternal or neonatal demographics. All HPC counts were higher in the ICC group, but the difference was not significant. CD34+ cell counts were 45.3 ± 36.6/μL in the ICC and 33.2 ± 26.6/μL in the DCC group (P=0.33); multi-potent progenitor cell counts were 43.2 ± 35/μL in the ICC and 31.1 ± 26.6/μL in the DCC group (P=0.28); and hematopoietic stem cell counts were 2.1 ± 2.1/μL in the ICC and 2.1 ± 3.1/μL in the DCC group (P=0.66).

CONCLUSION: Contrary to our expectation, all HPC counts were lower in the DCC group.