Cervical and Amniotic Fluid Matrix Metalloproteinase-8 and Interleukin-6 Concentrations in Preterm Pregnancies with or without Preterm Premature Rupture of Membranes

Abstract

Introduction: Intra-amniotic inflammation is defined by elevated inflammatory biomarkers in the amniotic fluid (AF), either due to microbial invasion of the amniotic cavity (MIAC) or sterile inflammation. Amniocentesis being an invasive procedure, we wanted to investigate whether elevated matrix metalloproteinase-8 (MMP-8) or interleukin-6 (IL-6) concentrations could be detected from cervical fluid samples. Materials and Methods: This prospective study included 67 women with singleton nondiabetic pregnancies with or without preterm premature rupture of membranes (PPROM) between 22⁺⁰ and 37⁺⁰ weeks of gestation. Simultaneous AF and cervical samples were obtained. Results: In women without PPROM, cervical MMP-8 concentrations correlated with AF MMP-8 concentrations (r_S = 0.466, p = 0.002), but cervical IL-6 did not correlate with AF IL-6 (r_S = 0.277, p = 0.076). In PPROM cases no correlations were found. Women with MIAC had higher concentrations of AF MMP-8 and AF IL-6 compared to women without MIAC regardless of membrane status. However, only women without PPROM had higher concentrations of cervical MMP-8 in proven MIAC. Conclusion: In women without PPROM, cervical MMP-8 concentration reflects the magnitude of AF MMP-8, thus potentially guiding the selection of patients benefitting from amniocentesis.