Tumor Necrosis Factor, Interleukin-1, and Interleukin-6 in Normal Human Pregnancy

Objective: Our purpose was to investigate the cytokines, tumor necrosis factor, interleukin-1, and interleukin-6 in normal human pregnancy and labor.

Study Design: Bioassays were used to measure these factors in extraembryonic coelomic fluid, amniotic fluid, placenta, and maternal and cord serum.

Results: Little or no tumor necrosis factor, interleukin-1, or interleukin-6 was found in coelomic fluid or amniotic fluid in the first trimester. Interleukin-6 appeared in second-trimester amniotic fluid. At term tumor necrosis factor was present (median 17 pg/ml) and increased with the onset of labor (median 58 pg/ml), as did interleukin-1 (median 188 to 680 pg/ml) and interleukin-6 (median 399 to 4800 pg/ml). Maternal serum interleukin-6 increased during pregnancy with a further increment with the onset of labor. Cord interleukin-6 also increased with labor but at a lower level.

Conclusion: The cytokines tumor necrosis factor, interleukin-1, and interleukin-6 may play a role in the onset of normal labor.