Amniotic fluid matrix metalloproteinase-9 levels in women with preterm labor and suspected intra-amniotic infection.

Abstract

OBJECTIVE:

To determine the accuracy of amniotic fluid (AF) matrix metalloproteinase-9 measurements for diagnosing intra-amniotic infection in women with preterm labor.

METHODS:

We performed amniocenteses in 44 women between 22 and 35 weeks' gestation who presented to our center with preterm labor and clinical suspicion of intra-amniotic infection. Each sample was analyzed by glucose measurement, Gram stain, and culture for aerobes, anaerobes, and mycoplasmas. We tested the AF for matrix metalloproteinase-9 using gelatin zymography and a commercial enzyme-linked immunosorbent assay (ELISA) system. We calculated accuracy and confidence intervals (CIs) for AF matrix metalloproteinase-9, glucose, and Gram stain for diagnosing intra-amniotic infection, using culture as the criterion standard.

RESULTS:

All patients who had matrix metalloproteinase-9 detectable by ELISA also demonstrated matrix metalloproteinase-9 by zymography. Six cases of intra-amniotic infection were confirmed by culture (prevalence 14%). The performance statistics of AF matrix metalloproteinase-9 for diagnosing intra-amniotic infection were: sensitivity 83% (95% CI 53, 99), specificity 95% (95% CI 88, 99), positive predictive value 71% (95% CI 37, 99), and negative predictive value 97% (95% CI 92, 99). Two women had false-positive results; one had gram-negative rods on the AF Gram stain and developed clinical signs and symptoms of chorioamnionitis several hours after amniocentesis and the other had a purulent vaginal discharge and an AF glucose level less than 15 mg/dL. Both delivered within 24 hours of amniocentesis.

CONCLUSION:

Measuring matrix metalloproteinase-9 in the AF appeared to be reliable for diagnosing intra-amniotic infection. An elevated matrix metalloproteinase-9 concentration in the AF at a preterm gestational age may portend imminent delivery regardless of microbiologic confirmation of intra-amniotic infection.

• Authors: G J Locksmith, P Clark, P Duff, G S Schultz
• Journal: Obstetrics and gynecology (Obstet Gynecol) Vol. 94 Issue 1 Pg. 1-6 (Jul 1999) ISSN: 0029-7844 [Print] United States
• PMID: 10389708 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Collagenases
• Matrix Metalloproteinase 9

Topics

• Adult
• Amniotic Fluid (chemistry)
• Chorioamnionitis (complications, enzymology, microbiology)
• Collagenases (analysis)
• Female
• Humans
• Matrix Metalloproteinase 9
• Obstetric Labor, Premature (complications, enzymology, microbiology)
• Predictive Value of Tests
• Pregnancy
• Reproducibility of Results
• Sensitivity and Specificity