AUTHOR=Wu Min , Yang Yuxi , Fan Yali , Guo Shan , Li Tianhe , Gu Muqing , Zhang Tingting , Gao Huimin , Liu Ruixia , Yin Chenghong 

TITLE=Characteristics of the Intestinal Flora of TPOAb-Positive Women With Subclinical Hypothyroidism in the Second Trimester of Pregnancy: A Single-Center Prospective Cohort Study

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.794170

DOI=10.3389/fcimb.2022.794170

ISSN=2235-2988

ABSTRACT=<p>Pregnant women are at high risk of developing subclinical hypothyroidism (SCH), and anti-thyroid peroxidase antibody (TPOAb) positivity can further inhibit thyroxine synthesis. Emerging evidence indicates that intestinal flora can modulate metabolic and immune homeostasis. The characteristics of intestinal flora of TPOAb-positive women with SCH in their second trimester of pregnancy have not been reported. This single-center prospective observational cohort study investigated gut microbial composition and metabolic function using sequencing of the 16S rRNA gene in fecal samples from 75 TPOAb-positive women with SCH and 90 TPOAb-negative women with SCH during their second trimester of pregnancy. Women were treated with no levothyroxine (LT<sub>4</sub>), low-dose LT<sub>4</sub> (≤50ug/d), or high-dose LT<sub>4</sub> (&gt;50ug/d). Taxonomic analysis showed <italic>Firmicutes</italic> and <italic>Bacteroidetes</italic> were the dominant phyla, followed by <italic>Actinobacteria</italic> and <italic>Proteobacteria. Faecalibacterium</italic>, <italic>Bacteroides</italic>, <italic>Prevotella 9</italic>, <italic>Bifidobacterium</italic>, <italic>Subdoligranulum</italic>, <italic>Lachnospira</italic>, and <italic>Megamonas</italic> were the predominant genera. The intestinal flora of TPOAb-positive women with SCH who received no LT<sub>4</sub> was characterized by bacterial amplicon sequence variants (ASVs)/operational taxonomic units (OTUs) enriched in the genus <italic>Subdoligranulum</italic>. The intestinal flora of TPOAb-positive women with SCH who received low-dose or high-dose LT<sub>4</sub> were characterized by bacterial ASVs/OTUs depleted of the species <italic>Ruminococcus</italic> sp.<italic>_</italic>or <italic>Bacteroides massiliensis</italic>, respectively. A total of 19 metabolic functions of intestinal flora, mainly involving lipid and amino acid metabolism, discriminated TPOAb-positive and TPOAb-negative women with SCH. Our study suggests that there are differences in the composition and metabolic function of intestinal flora of TPOAb-positive and TPOAb-negative women with SCH treated with different doses of LT<sub>4</sub> in the second trimester of pregnancy. The findings provide insight into intestinal flora as novel targets for the treatment of TPOAb-positive women with SCH during pregnancy.</p>