A comparative study of the diagnostic value of amniotic fluid interleukin-6 and culture for the antenatal diagnosis of intrauterine infection and prediction of perinatal morbidity in patients with preterm premature rupture of membranes

Park, Kyo Hoon; Yoon, Bo Hyun; Kim, Mi Ha; Kim, Gil Ja; Kim, Teresa; Lee, Hong Kyoon; Syn, Hee Chul

Abstract

OBJECTIVES
Our purpose was (1) to determine whether amniotic fluid concentrations of interleukin-6 are of value in the diagnosis of histologic chorioamnionitis of preterm placenta and in the prediction of significant perinatal morbidity and mortality in patients with preterm premature rupture of membranes and (2) to compare the diagnostic performance of amniotic fluid interleukin-6 with that of amniotic fluid microbial culture for these outcome variables. METHOD: The relation among placental histologic finding, perinatal outcome, amniotic fluid culture, and amniotic fluid interleukin-6 concentrations were examined in 65 patients with preterm premature rupture of membranes who delivered preterm neonates within 72 hours after transabdominal amniocentesis. Interleukin-6 level was determined by enzyme-linked immunosorbent assay. Receiver-operator characteristic curve, Mann-Whitney U test, and Fisher's exact test were used for analysis.
RESULTS
1) Patients with acute histologic chorioamnionitis had significantly higher median amniotic fluid interleukin-6 concentrations than those without histologic chorioamnionitis (median 12.6 ng/ml, range 0.03 to 142.2 ng/ml vs median 0.5 ng/ml, range 0.03 to 16 ng/ml; P < 0.0001). 2) Amniotic fluid having interleukin-6 concentrations higher than 3.2 ng/ml had a sensitivity of 78% (35/45) and specificity of 95% (19/20) in the diagnosis of acute histologic chorioamnionitis and sensitivity of 74% (25/34) and specificity of 65% (20/31) in the prediction of significant neonatal morbidity and mortality. 3) These sensitivities were significantly higher than those of amniotic fluid culture, but there were no significant difference in specificities between amniotic fluid interleukin-6 and culture (histologic chorioamnionitis: 78% vs 51%, p<0.01; significant neonatal morbidity and mortality: 74% vs 47%, p<0.01, respectively).
CONCLUSIONS
Test of amniotic fluid interleukin-6 is of value and more sensitive than amniotic fluid culture for the antenatal diagnosis of histologic chorioamnionitis and for the prediction of perinatal outcome in patients with preterm premature rupture of membranes.