THE DIAGNOSTIC AND PROGNOSTIC VALUE OF AMNIOTIC-FLUID WHITE BLOOD-CELL COUNT, GLUCOSE, INTERLEUKIN-6, AND GRAM STAIN IN PATIENTS WITH PRETERM LABOR AND INTACT MEMBRANES

OBJECTIVE: Our goal was to compare the value of amniotic fluid tests i n the detection of microbial invasion of the amniotic cavity and in th e relationship with the amniocentesis-to-delivery interval and neonata l complications in patients with preterm labor and intact membranes. S TUDY DESIGN: Amniotic fluid was retrieved by transabdominal amniocente sis from 120 patients with preterm labor and intact membranes. Fluid w as cultured for aerobic and anaerobic bacteria and for mycoplasmas. Am niotic fluid analysis included a Gram stain, white blood cell count, g lucose and interleukin-6 determinations. Logistic regression and Cox's proportional hazards model were used for analysis. RESULTS: (1) The p revalence of positive amniotic fluid cultures was 9.2% (11/120); (2) p atients with microbial invasion had a shorter amniocentesis-to-deliver y interval and a higher neonatal complications rate than patients with a negative culture; (3) the most sensitive test for the detection of microbial invasion of the amniotic cavity was amniotic fluid interleuk in-6 determinations (cutoff 11.3 ng/ml) (sensitivity; for interleukin- 6 100%, for glucose 81.8%, for white blood cell count 63.6%, and for G ram stain 63.6%; p < 0.05 for all comparisons); (4) the most specific test was the Gram stain of amniotic fluid (specificity: for Gram stain 99.1%, for white blood cell count 94.5%, for interleukin-6 82.6%, and for glucose 81.6%; p < 0.01 for all); (5) of all amniotic fluid tests , interleukin-6 determinations were the only ones that had significant relationship with the amniocentesis-to-delivery interval and neonatal complications. CONCLUSION: Interleukin-6 concentrations in amniotic f luid are better indicators of microbial invasion of the amniotic cavit y, amniocentesis-to-delivery interval, and neonatal complications than the amniotic fluid Gram stain, glucose concentration, or white blood cell count.