CXCL12 mRNA is greater in white blood cells from jugular and uterine vein samples during pregnancy, while CXCR4 mRNA did not change. CXCL12 (A) was significantly (P < 0.05) elevated in white blood cells from the jugular vein on Day 35 compared to Days 12, 13, 14, or 15 of gestation. CXCL12 (B) in white blood cells from uterine vein blood samples were also significantly (P < 0.05) elevated on Day 35 compared to Days 15 and 50 of pregnancy. CXCR4 (C, D) was detected in white blood cells collected on each day of pregnancy, but did not differ. Data are represented by graphing 2-ΔCt values, where ΔCt indicates GAPDH normalized Ct values. Data represent the mean ± SEM.