A. Bashiri et al., Elevated concentrations of interleukin-6 in intra-amniotic infection with Ureaplasma urealyticum in asymptomatic women during genetic amniocentesis, ACT OBST SC, 78(5), 1999, pp. 379-382
Background. Intra-amniotic infection is an important cause of preterm deliv
ery and interleukin-6 (IL-6) determination was recently applied for identif
ication of microbial invasion of the amniotic cavity. Our aim was to determ
ine the levels of IL-6 in culture-positive amniotic fluids at genetic amnio
centesis and to evaluate their significance in relation to pregnancy outcom
e.
Methods. Seven culture-positive and 23 culture-negative amniotic fluids, ob
tained at 17-19 weeks of gestation, were analyzed for IL-6 levels by an imm
unoassay (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 Ureapla
sma urealyticum (1834, 1342 and 2832 pg/ml). Low levels of IL-6, ranging fr
om 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 infect
ion 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 cul
ture-positive but IL-6 negative amniotic fluids, had normal pregnancy outco
me 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 ureaplasmas resulting in adverse pregnancy outcome, while cu
lture-positive amniotic fluids with normal IL-6 levels, may suggest a state
of contamination.