Tumor necrosis factor, interleukin-1, and interleukin-6 in normal human pregnancy

Abstract

Our purpose was to investigate the cytokines, tumor necrosis factor, interleukin-1, and interleukin-6 in normal human pregnancy and labor. Bioassays were used to measure these factors in extraembryonic coelomic fluid, amniotic fluid, placenta, and maternal and cord serum. 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. The cytokines tumor necrosis factor, interleukin-1, and interleukin-6 may play a role in the onset of normal labor.