title: Midtrimester amniotic fluid matrix metalloproteinase-8 (MMP-8) levels above the 90th percentile are a marker for subsequent preterm premature rupture of membranes.
abstract: OBJECTIVE
  We sought to determine whether midtrimester amniotic fluid levels of matrix metalloproteinase-8 were associated with subsequent preterm premature rupture of membranes.
  
  
  METHODS
  We conducted a case-control study examining 57 asymptomatic women who underwent genetic amniocentesis from 14 to 21 weeks' gestation and subsequently had preterm premature rupture of membranes (<35 wk) and 58 women with subsequent term delivery. Measurement of total matrix metalloproteinase-8 level in amniotic fluid was conducted using a commercially available enzyme-linked immunosorbent assay and association with preterm birth due to preterm premature rupture of membranes was assessed.
  
  
  RESULTS
  The overall distribution of matrix metalloproteinase-8 concentrations was similar in women who had preterm premature rupture of membranes and term controls (median 2.39 ng/mL, 25th to 75th percentile 1.1-10.1 vs 2.37 ng/mL, 25th to 75th percentile 1.5-4.7, P = .94). However, 26% of women who had preterm premature rupture of membranes had a matrix metalloproteinase-8 concentration above the 90th percentile (8.7 ng/mL), compared with only 10% of term controls (odds ratio 3.1, 95% CI 1.1-8.7; P = .03). Elevated matrix metalloproteinase-8 remained associated with preterm premature rupture of membranes after adjustment for maternal age, race, parity, gestational age, and year of amniocentesis (odds ratio 3.4, 95% CI 1.2-9.9; P = .03).
  
  
  CONCLUSIONS
  The overall distribution of midtrimester amniotic fluid matrix metalloproteinase-8 levels did not differ between women who had preterm premature rupture of membranes and those delivered at term. However, marked elevations of midtrimester amniotic fluid matrix metalloproteinase-8 were highly associated with subsequent preterm premature rupture of membranes, suggesting that the pathophysiologic processes that contribute to preterm premature rupture of membranes may begin in early pregnancy.
authors.affiliation: Department of Obstetrics and Gynecology, University of Alabama at Birmingham, USA.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Biggio
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Ramsey
authors.forename: Suzanne P
authors.initials: SP
authors.lastname: Cliver
authors.forename: Martha D
authors.initials: MD
authors.lastname: Lyon
authors.forename: Robert L
authors.initials: RL
authors.lastname: Goldenberg
authors.forename: Katharine D
authors.initials: KD
authors.lastname: Wenstrom
mesh_terms: D000328:Adult; D000653:Amniotic Fluid / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000175:diagnosis* / Q000378:metabolism; D006801:Humans; D020784:Matrix Metalloproteinase 8 / Q000378:metabolism*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D012372:ROC Curve; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D020784:Matrix Metalloproteinase 8