663: Intra-amniotic inflammatory response is more likely and severe according to the progression of inflammation within chorionic plate: the role of chorionic plate as another playground for the progression of ascending intra-uterine infection in preterm gestation

Abstract

Chorionic plate(CP) has been denigrated by the well-known route of extra-placental membranes(EPM) from decidua parietalis through chorion to amnion in the progression of ascending intra-uterine infection(AIUI) among preterm gestations. However, there is a good chance that CP is another playground for the progression of AIUI considering that CP is connected to the chorion of EPM and located between decidua basalis/intervillous space and amnion. We hypothesized that intra-amniotic inflammatory response(IAIR) would be more likely and severe according to the progression of inflammation within CP among preterm gestations. The objective of the study is to examine this issue. Study population included 430 singleton pregnant-women who delivered at preterm(<37weeks) and within 5 days of amniocentesis due to PTL and preterm-PROM. Patients were divided into 3 groups(i.e.,1] inflammation-free CP;2] inflammation restricted to sub-chorionic fibrin[SCF] of CP;3] inflammation in connective tissue of CP) according to the progression of inflammation within CP. We examined the intensity of IAIR and the frequency of intra-amniotic inflammation(IAI) and AF culture(+). The intensity of IAIR was determined by AF MMP-8 concentration (ng/ml) and IAI was defined in the presence of an elevated AF MMP-8(≥23ng/ml). Inflammation in SCF and connective tissue of CP was defined by the previously published criteria. 1) Inflammation-free CP, inflammation restricted to SCF of CP, and inflammation in connective tissue of CP were present in 70%, 14% and 16% in preterm gestation; 2) AF MMP-8 concentration significantly elevated according to the progression of inflammation within CP(Figure 1); 3) Moreover, the frequency of IAI and AF culture(+) significantly gradually increased according to the progression of inflammation within CP(Figure 2.a and 2.b). IAIR is more likely and severe according to the progression of inflammation within CP. This finding suggests that CP may be another playground for the progression of AIUI in addition to EPM in preterm gestation.View Large Image Figure ViewerDownload Hi-res image Download (PPT)