Background: Pregnancy alters many physiological systems, including the maternal gut microbiota. Diet is a key regulator of this system and can alter host inflammation. Multiple perinatal disorders have been associated with inflammation, maternal metabolic alterations, and gut microbiota dysbiosis, including gestational diabetes mellitus, preeclampsia, preterm birth, and mood disorders. However, the effects of high inflammatory diets on the gut microbiota during pregnancy has yet to be fully explored. Objective: To use a systems-based approach to characterize associations among dietary inflammatory potential, a measure of diet quality, and the gut microbiome during pregnancy. Methods: Forty-nine pregnant persons were recruited prior to 16 weeks of gestation. Participants completed a food frequency questionnaire (FFQ) and provided fecal samples. Dietary inflammatory potential was assessed using the Dietary Inflammatory Index (DII) from FFQ data. Fecal samples were analyzed using 16S rRNA amplicon sequencing. Differential taxa abundance with respect to DII score were identified, and microbial metabolic potential was predicted using PICRUSt2. Results: Inflammatory diets were associated with decreased vitamin and mineral intake and dysbiotic gut microbiome structure and metabolism. Gut microbial compositional differences revealed a decrease in short chain fatty acid producers such as g_Faecalibacterium, upregulation of vitamin B12 synthesis, methylglyoxal detoxification, galactose metabolism and multi drug efflux systems in pregnant individuals with increased DII scores. Conclusions: Dietary inflammatory potential was associated with depletion of vitamins & minerals and gut microbiota metabolic dysregulation.

The authors have declared no competing interest.

This study was funded by K12HD101373, R03HD095056, the Arnold O. Beckman Postdoctoral Fellowship, and the University of Illinois Medical Scientist Training Program

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

IRB of the University of Illinois, Chicago gave ethical approval for this work (IRB #2014-0325).

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The R notebook containing all analyses and de-identified data can be found at https://github.com/LabBea/Perinatal_DII All data will be made available through the SRI repository.

https://github.com/LabBea/Perinatal_DII