As in the two comparisons mentioned above, IL-23 levels were significantly higher in normal pregnancy (479 pg/mL ± 15) than in IUGR without placental insufficiency (361 pg/mL ± 13) (P < 0.0001) as were the ratios of IL-23/IL-4, IL-23/IL-10, and IL-23/IL-13 (P < 0.03, P < 0.01, and P < 0.03, resp). This evidence concerns the gene IL13 and fetal growth restriction.