Association of stress during delivery with increased numbers of nucleated cells and hematopoietic progenitor cells in umbilical cord blood

OBJECTIVE: Umbilical cord blood can be used as a source of bone marrow repo pulating cells for allogeneic stem cell transplantation. Large variations i n the frequencies of white blood cells and hematopoietic progenitor cells h ave been found for umbilical cord blood. These variations may be due in par t to specific circumstances during labor and delivery. STUDY DESIGN: In this study we analyzed the relationship between stress fac tors occurring during parturition and the frequencies of nucleated cells, l eukocyte subsets, CD34(+) cells, and hematopoietic progenitor cells, as det ermined in semisolid medium cultures of umbilical cord blood. RESULTS: We observed that a prolonged first stage of labor resulted in incr eases in the numbers of nucleated cells, granulocytes, CD34(+) cells, and h ematopoietic progenitor cells in umbilical cord blood. Evaluation of parame ters that indicate stress of the infant during delivery demonstrated higher numbers of nucleated cells, granulocytes, CD34(+) cells, and hematopoietic progenitor cells in umbilical cord blood from children with lower venous p H. CONCLUSION: Longer duration stress during delivery increased the numbers of nucleated cells, granulocytes, CD34(+) cells, and hematopoietic progenitor cells, possibly by causing mobilization of various cell populations by end ogenous cytokines. As long as umbilical cord blood harvesting does not inte rfere with the delivery, umbilical cord blood collected after stressful del iveries may provide optimal units for hematopoietic stem cell transplantati on.