Changes in Cytokine Production During and After Normal Pregnancy

PROBLEM: The systemic T helper 1/T helper 2 (Th1/Th2) cytokine balance during normal human pregnancy is controversial, and observations about the balance in the postpartum period have only been reported for up to 3 months. METHOD: Whole‐blood, from 83 healthy pregnant women, 80 healthy postpartum women, and 31 healthy non‐pregnant women was stimulated with phorbol 12‐myristate 13‐acetate (PMA) and ionomycin, and the levels of cytokines in the supernatant were measured by enzyme‐linked immunosorbent assay (ELISA). RESULTS: The production of all measured cytokines decreased during pregnancy, especially in the second trimester. After delivery, interferon‐Γ (IFN‐Γ) and interleukin‐2 (IL‐2) increased from 2 to 11 months postpartum, and IL‐4 increased from 6 to 11 months postpartum. CONCLUSIONS: These data indicate that 1) decreases in production of both Th1‐ and Th2‐type cytokines during pregnancy may be related to the pregnancy‐induced amelioration of autoimmune diseases; 2) increases in production of both Th1‐ and Th2‐type cytokines in the postpartum period may be related to the postpartum aggravation of autoimmune diseases.