Prenatal Maternal Physical Activity and Stem Cells in Umbilical Cord Blood.

Purpose: Early life processes, through influence on fetal stem cells, affect postnatal and adult health outcomes. This study examines the effects of physical activity before and during pregnancy on stem cell counts in umbilical cord blood.

Methods: We isolated mononuclear cells from umbilical cord blood samples from 373 singleton full-term pregnancies and quantified hematopoietic (CD34(+), CD34(+)CD38(-), and CD34(+) c-kit(+)), endothelial (CD34(+)CD133(+), CD34(+)CD133(+)VEGFR2(+), CD34(+)VEGFR2(+), and CD133(+)VEGFR2(+)), and putative breast (EpCAM(+), EpCAM(+)CD49f(+), EpCAM(+)CD49f(+)CD117(+), CD49f(+)CD24(+), CD24(+)CD29(+), and CD24(+)CD29(+)CD49f(+)) stem/progenitor cell subpopulations by flow cytometry. Information on physical activities before and during pregnancy was obtained from questionnaires. Weekly energy expenditure was estimated based on metabolic equivalent task values.

Results: Prepregnancy vigorous exercise was associated positively with levels of endothelial CD34(+)CD133(+), CD34(+)CD133(+)VEGFR2(+), CD34(+)VEGFR2(+), and CD133(+)VEGFR2(+ )progenitor cell populations (P = 0.02, P = 0.01, P = 0.001, and P = 0.003, respectively); positive associations were observed in samples from the first births and those from the second or later births. Prepregnancy moderate and light exercises and light exercise during the first trimester were not significantly associated with any stem/progenitor cell population. Light exercise during the second trimester was positively associated with CD34(+)VEGFR2(+) endothelial progenitor cells (P = 0.03). In addition, levels of EpCAM(+)CD49f(+) and CD49f(+)CD24(+) breast stem cells were significantly lower among pregnant women who engaged in vigorous/moderate exercise during pregnancy (P = 0.05 and P = 0.02, respectively).

Conclusions: Vigorous exercise before pregnancy increases the number of endothelial progenitor cells in umbilical cord blood and thus could potentially enhance endothelial function and improve cardiovascular fitness in the offspring. Findings of lower levels of putative breast stem cell subpopulations could have implications on exercise and breast cancer prevention. Prenatal effects of exercise on fetal stem cells warrant further studies.