PMC

(A) Gut microbiota α-diversity of three groups. PCoA of gut microbiota of three groups based on the Bray–Curtis distance (B) and Euclidean distance (C). PCoA of the gut microbiota based on the Bray–Curtis distance between the intrauterine infection group and antibiotic group (D), between the intrauterine infection group and control group (E), and between the antibiotic group and control group (F). PCoA of the gut microbiota based on the Euclidean distance between the intrauterine infection group and antibiotic group (G), between the intrauterine infection group and control group (H), and between the antibiotic group and control group (I). “*” means P value smaller than 0.05.

Concentrations of matrix metalloproteinases in the supernatants of decidual cells from women with preterm labor (PTL), with (n = 10) or without subclinical intrauterine infection (n = 25). Data are presented as mean±SD; experiments were performed in duplicate. ***P<0.001, **P<0.005, *P<0.05 as compared to PTL without infection.

Representative immunohistochemistry of the fetal membranes from a woman with preterm labor and subclinical intrauterine infection. Open arrows show neutrophil infiltration, and filled arrows indicate damage to the extracellular matrix arrangement in amnion (A), chorion (C), and decidua (D). Light microscopy, hematoxilin stain.

HE Staining for the lungs of neonatal rats. Infiltration, reduced alveolar vesicular structure, less alveolar numbers and thickened alveolar septa of the neonatal lung in response to pregnant rat E. coli exposure (× 100). a: intrauterine infection group at P1; b: Control at P1; c: intrauterine infection group at P3; d: Control at P3; e: intrauterine infection group at P7; f: Control at P7; g: intrauterine infection group at P14; h: Control at P14