Elevated concentrations of interleukin-6 in intra-amniotic infection with Ureaplasma urealyticum in asymptomatic women during genetic amniocentesis

Acta Obstet Gynecol Scand. 1999 May;78(5):379-82.


Background: Intra-amniotic infection is an important cause of preterm delivery and interleukin-6 (IL-6) determination was recently applied for identification of microbial invasion of the amniotic cavity. Our aim was to determine the levels of IL-6 in culture-positive amniotic fluids at genetic amniocentesis and to evaluate their significance in relation to pregnancy outcome.

Methods: Seven culture-positive and 23 culture-negative amniotic fluids, obtained at 17-19 weeks of gestation, were analyzed for IL-6 levels by an immunoassay (ELISA). Pregnancy outcomes of all 30 women were obtained from the medical charts.

Results: The mean level of IL-6 in the culture-negative amniotic fluids was 78+/-206 pg/ml. Among the seven culture-positive, high levels of IL-6 were found only in three amniotic fluids that were culture-positive for Ureaplasma urealyticum (1834, 1342 and 2832 pg/ml). Low levels of IL-6, ranging from zero to 60 pg/ml, were found in four AFs that were culture-positive for Staphylococcus epidermidis (n=3) and Bacillus Gram-positive (n= 1). Adverse pregnancy outcome occurred in the three women who had intra-amniotic infection with U. urealyticum accompanied by high levels of IL-6 (two fetal loss and one preterm delivery at 28 weeks of gestation). The four women with culture-positive but IL-6 negative amniotic fluids, had normal pregnancy outcome and term delivery. Two of the 23 women with culture-negative had preterm delivery, one with high (1000 pg/ml) and one with low (80 pg/ml) levels of IL-6.

Conclusion: High levels of IL-6 are suggestive of a genuine intra-amniotic infection with urea-plasmas resulting in adverse pregnancy outcome, while culture-positive amniotic fluids with normal IL-6 levels, may suggest a state of contamination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amniocentesis*
  • Amniotic Fluid / chemistry*
  • Amniotic Fluid / microbiology*
  • Bacillus / isolation & purification
  • Chorioamnionitis / complications
  • Chorioamnionitis / diagnosis*
  • Chorioamnionitis / microbiology
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Fetal Death / etiology
  • Genetic Testing
  • Humans
  • Interleukin-6 / analysis*
  • Obstetric Labor, Premature / etiology
  • Pregnancy
  • Staphylococcus epidermidis / isolation & purification
  • Ureaplasma Infections / complications
  • Ureaplasma Infections / diagnosis*
  • Ureaplasma urealyticum* / isolation & purification


  • Interleukin-6