Amniotic fluid interleukin-6 and tumor necrosis factor-α at mid-trimester genetic amniocentesis: Relationship to intra-amniotic microbial invasion and preterm delivery

ObjectiveTo determine the value of amniotic fluid interleukin-6 (AF IL-6) and tumor necrosis factor-α (AF TNF-α) in the diagnosis of microbial invasion of the amniotic cavity and in the prediction of preterm delivery (PTD).Study designFollowing amniocentesis, a sample of amniotic fluid was sent for aerobic and anaerobic bacterial cultures along with Ureaplasma urealyticum culture and it was also assessed for IL-6 and TNF-α.ResultsForty-eight women who delivered preterm (<37 weeks) were matched with 96 controls. The AF IL-6 and TNF-α concentrations of women with spontaneous PTD were significantly higher than those who delivered at term (IL-6: 176.3 pg/ml [130.6–208.6] vs. 52.3 pg/ml [37.2–92.3]; TNF-α: 8.8 pg/ml [7.2–10.7] vs. 5.5 pg/ml [5.0–6.3]). AF IL-6 and TNF-α concentrations of >99.3 pg/ml and of >6.6 pg/ml respectively, had a sensitivity of 89.6% and 81.3% and a specificity of 80.3% and 79.2% for the prediction of spontaneous PTD. Moreover, AF IL-6 and TNF-α concentrations of >99.3 pg/ml and of 6.3 pg/ml respectively, had a sensitivity of 91.9% and 78.4% and a specificity of 73.8% and 70.1% for the prediction of a positive AF culture.ConclusionsElevated mid-trimester concentrations of AF IL-6, or/and of TNF-α can identify women at risk for intra-amniotic infection and for spontaneous PTD.