Correlation Between Gut Microbiota and Hematological Inflammatory Indices in Full‐Term Pregnant Women: An Exploratory Study

ABSTRACT Aim To explore correlations between hematological inflammatory indices and oral immunity, systemic immunity, and gut microbiota in healthy term pregnant women. Methods Twenty healthy term pregnant women were enrolled. Fecal, saliva, and peripheral blood samples were collected. Hematological inflammatory indices were correlated with immune parameters and gut microbiota using routine blood tests, flow cytometry, cytokine measurements, and 16S rRNA sequencing. Results Salivary IL‐1β correlated positively with the Monocyte‐to‐Lymphocyte Ratio (MLR), the Systemic Immune‐Inflammation Index (SII), and the Pan‐Immune‐Inflammation Value (PIV). The salivary IFN‐γ/IL‐4 ratio correlated positively with the Hemoglobin‐to‐Lymphocyte Ratio (HbLR). Peripheral IL‐5 correlated positively with the Systemic Inflammation Response Index (SIRI) and PIV. CD4 + T cells correlated with HbLR, while the Th17/Treg ratio correlated with SII and MLR. Th1/Th2 ratio and Th1 cells correlated with the derived Neutrophil‐to‐Lymphocyte Ratio (dNLR) and Neutrophil‐to‐Lymphocyte Ratio (NLR); conversely, CD56brightCD16 − NK cells correlated negatively with SIRI and PIV. Gut microbiota analysis showed negative correlations between Collinsella and SII/NLR, Blautia and SII, and Bifidobacterium and MLR, while Fusobacterium correlated positively with NLR, dNLR, and MLR; Phascolarctobacterium with NLR; and Bacteroides with platelet‐to‐lymphocyte ratio. Conclusions Hematological inflammatory indices in healthy term pregnant women are closely associated with oral and systemic immunity, suggesting their potential as indicators of immune balance. These indices also show strong correlations with gut microbiota, indicating that probiotics may help maintain immune homeostasis, whereas certain microbial taxa may promote inflammatory responses.