The purpose of this investigation was to measure cytokine production by maternal peripheral blood lymphocytes from women with intrauterine growth restriction (IUGR) and from healthy pregnant women, and to investigate the relationship between cytokine profiles and IUGR. Thirty-six women with IUGR and 22 control healthy pregnant women with normal fetal growth were studied. Levels of pro-inflammatory cytokines (IFNγ, TNFα, IL-8, IL-12, IL-18, IL-23) and anti-inflammatory cytokines (IL-4, IL-10, IL-13) produced by mitogen-stimulated peripheral blood mononuclear cells were measured by ELISA. Levels of the anti-inflammatory cytokine IL-4 were higher in normal pregnancy compared to IUGR, indicating an anti-inflammatory bias. Levels of the pro-inflammatory cytokines IL-6, TNFα, and IL-12 were significantly higher and levels of the anti-inflammatory cytokine IL-10 lower in IUGR with placental insufficiency than in IUGR without placental insufficiency, suggesting a stronger pro-inflammatory bias in IUGR with placental insufficiency. Ratios of pro- to anti-inflammatory cytokines suggest a dominance of pro-inflammatory cytokines. The authors conclude that an increased pro-inflammatory cytokine bias is observed in IUGR compared to normal pregnancy, and an increased pro-inflammatory cytokine dominance is seen in IUGR with placental insufficiency compared to IUGR without placental insufficiency.