Obstetrics & Gynecology Science  2013;56(3):167-175

doi:10.5468/ogs.2013.56.3.167

The frequency and clinical significance of intra-amniotic inflammation defined as an elevated amniotic fluid matrix metalloproteinase-8 in patients with preterm labor and low amniotic fluid white blood cell counts.

Chan Wook PARK 1 ; Bo Hyun YOON ; Sun Min KIM ; Joong Shin PARK ; Jong Kwan JUN

Affiliations

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Keywords

Amniotic fluid; Chorioamnionitis; Inflammation; Matrix metalloproteinase-8; Preterm labor; White blood cell

Country

Republic of Korea

Language

English

Abstract

OBJECTIVE: To determine the frequency and clinical significance of intra-amniotic inflammation (IAI) defined as an elevated amniotic fluid (AF) matrix metalloproteinase-8 (MMP-8) concentration in patients with preterm labor and intact membranes (PTL) and low AF white blood cell (WBC) counts. METHODS: Adverse pregnancy outcomes were compared according to the presence or absence of IAI in 220 singleton gestations who underwent amniocentesis due to PTL (gestational age<35.7 weeks) and had low AF WBC counts (<19 cells/mm3). Adverse pregnancy outcomes included preterm birth within 5 days of amniocentesis, acute histologic chorioamnionitis (acute-HCA) and positive AF culture. IAI was defined as an elevated AF MMP-8 concentration (> or =23 ng/mL). RESULTS: IAI was present in 19% of study population. Adverse pregnancy outcomes were significantly more frequent in patients with IAI than in those without IAI (preterm birth within 5 days of amniocentesis, 88% vs. 41%; acute-HCA, 47% vs. 11%; positive AF culture, 10% vs. 2%; each for P<0.05). Patients with IAI had a significantly shorter median amniocentesis-to-delivery interval than those without IAI (7.8 hours [0.01-3,307.3 hours] vs. 310.3 hours [0.01-2,973.8 hours]; P<0.001 from survival analysis). Multiple logistic regression analysis demonstrated that only an IAI (odds ratio, 3.3; 95% confidence interval, 1.5-7.3; P<0.005) retained a statistical significance in the prediction of acute-HCA after other confounding variables were adjusted. CONCLUSION: Approximately one-fifth of patients with PTL and low AF WBC counts have an evidence of IAI and are at risk for impending preterm delivery and acute-HCA when AF MMP-8 concentration is used.