Maternal circulating endothelial progenitor cells in normal singleton and twin pregnancy.

OBJECTIVE: The objective of the study was to determine the levels of circulating endothelial progenitor cells (EPCs), which are peripheral blood mononuclear cells (PBMNCs) that contribute to vascular repair in normal pregnancy. STUDY DESIGN: The concentration of EPCs in maternal blood was measured in healthy nonpregnant women (group A, n = 8), normal singleton pregnancies (group B, n = 24), and normal twin pregnancies (group C, n = 21). RESULTS: In group A, the mean (SD) level of EPCs was 77.0% (8.6%) adherent PBMNCs. In group B, the mean level was lower than in group A and decreased with gestation from 61.3% (14.9%) in the first trimester to 56.0% (16.2%) in the second trimester and 52.0% (8.7%) in the third trimester (P = .001). Similarly, the level of EPCs in group C was lower than in group A and decreased with gestation from 64.6% (9.6%) in the first trimester to 65.2% (12.7%) in the second trimester and 56.4% (12.6%) in the third trimester (P = .002). CONCLUSION: Normal pregnancy is associated with a decrease in maternal circulating levels of EPCs.