The relationship between amniotic fluid matrix metalloproteinase-8 and funisitis

OBJECTIVE: The fetal inflammatory response syndrome is a multisystem disord er associated with impending preterm delivery and adverse neonatal outcome. Inflammation of the umbilical cord-funisitis-is the histologic counterpart of fetal inflammatory response syndrome and has been associated with an in creased risk for the development of cerebral palsy. Neutrophils found in th e amniotic cavity are of fetal origin. Therefore, neutrophil secretory prod ucts may be an index of the fetal inflammatory response syndrome. To test t his hypothesis, we examined the relationship between levels of amniotic flu id matrix metalloproteinase-8 and funisitis. STUDY DESIGN: The relationship between the presence of funisitis and concen trations of amniotic fluid matrix metalloproteinase-8 was examined in 255 c onsecutive patients who delivered preterm singleton neonates (gestational a ge, < 36 weeks) within 72 hours of amniocentesis. Amniotic fluid was cultur ed for aerobic and anaerobic bacteria and for mycoplasmas. Funisitis was di agnosed in the presence of neutrophil infiltration into the umbilical vesse l walls or Wharton jelly. Matrix metalloproteinase-8 was measured by use of a specific immunoassay. Nonparametric statistics were used for analysis. RESULTS: Funisitis was present in 23% (59/255) of cases. Patients with funi sitis had a significantly higher median concentration of amniotic fluid mat rix metalloproteinase-8 than those without funisitis (median, 433.7 ng/mL [ range, 1.5-3836.8 ng/mL] vs median, 1.9 ng/mL [range, <0.3-4202.7 ng/mL]; P < .001). The diagnostic indices of matrix metalloproteinase-8 (cutoff, 23 ng/mL) in the identification of funisitis were: sensitivity of 90% (53/59), specificity of 78% (153/196), positive predictive value of 55% (53/96), an d negative predictive value of 96% (153/159). CONCLUSIONS: There is a strong association between increased levels of amni otic fluid matrix metalloproteinase-8 and funisitis. We propose that determ ination of amniotic fluid matrix metalloproteinase-8 concentrations may ass ist the assessment of the fetal inflammatory status, thereby eliminating th e need for fetal blood sampling.