IL13 and placental insufficiency: On the other hand, the anti-inflammatory cytokine IL-13 is produced at lower levels by PBMC from IUGR without placental insufficiency (5.8 pg/mL ± 1) than by PBMC from normal pregnant controls (15.3 pg/mL ± 2.6) (P < 0.002) (Figures 1 and 2).