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