Exploratory study of the oral microbiota in pregnant women with hypothyroidism and their infants.

BACKGROUND

Hypothyroidism is a metabolic disorder associated with potentially adverse maternal and neonatal outcomes. Emerging evidence suggests a link between thyroid function and the microbiota; however, little is known about the oral microbiota of pregnant women with hypothyroidism and its potential impact on that of their offspring. This study aimed to characterize the oral microbiota of pregnant women with hypothyroidism and their children as part of the Oral Microbiome Prospective Unicenter Cohort Study (OMPU-CS).

METHODS

Pregnant women with hypothyroidism (Hypothyroid group, n = 31) and those with normal thyroid function (Control group, n = 30) were selected from participants in the ongoing OMPU-CS. Oral samples were collected from the women during pregnancy and at one month postpartum, and from their one-month-old infants. Microbiota composition was analyzed using 16 S rRNA metagenomic sequencing.

RESULTS

Compared with pregnant women in the Control group, those in the Hypothyroid group exhibited significantly reduced richness and evenness of the oral microbiota (observed operational taxonomic units, p = 0.034; Shannon index, p = 0.034). The overall structure of the oral microbiota differed significantly between groups at all phases-in pregnant women, postpartum women, and their infants (unweighted UniFrac distances, p = 0.002, p = 0.049, and p = 0.019, respectively). Linear discriminant analysis effect size (LEfSe) identified several differentially abundant taxa, including a consistently reduced abundance of members of the Rhizobiaceae family in the Hypothyroid group across all three phases compared with that in the Control group.

CONCLUSIONS

The oral microbiota of pregnant women with hypothyroidism and their one-month-old infants exhibited disease-specific characteristics. These findings suggest that maternal hypothyroidism may influence the oral microbiota of offspring, underscoring the importance of monitoring oral microbiota in mothers with hypothyroidism and their children.