(P27-053-24) Associations Between Pre-Pregnancy BMI or Fiber Intake and the Gut Microbiome During Pregnancy

Objectives: To determine if pre-pregnancy BMI (n = 52) or dietary fiber intake (n = 84) are associated with the pregnancy gut bacterial community.

Methods: Study participants for this analysis were recruited from the Michigan Archive for Research on Child Health (MARCH). The pregnant women included in this study were in their third trimester of pregnancy. Fecal samples were collected by participants and returned to the lab by US mail. Genomic DNA was extracted from stool samples, and PCR was performed to amplify the V4 region of the 16S rRNA gene. These amplicons were sequenced using 250 base pair, paired-end sequencing on an Illumina MiSeq. Using mothur, sequences were cleaned, aligned to the Silva reference alignment, binned into OTUs, and classified using the RDP reference. Statistical analyses were conducted in R using the vegan package.

Results: Gut microbiota alpha diversity was significantly different for pregnant women by pre-pregnancy BMI category (normal, overweight, obese). Beta diversity was unique for the gut microbiotas of pregnant women within each BMI category. Multivariable models suggested that pre-pregnancy BMI was a predictor of microbial diversity of the pregnancy gut microbiota. Women who met the pregnancy fiber recommendation (n = 7) had gut microbiotas that were more diverse (Shannon and Inverse Simpson p-value < 0.05) than those who did not meet the recommendation. However, neither the membership nor community structure of the pregnancy gut microbiota differed between those who met and those who did not meet the recommendations for fiber consumption during pregnancy.

Conclusions: This research suggests that there is a significant association between pre-pregnancy BMI and gut microbiota, whereas fiber intake during pregnancy potentially has only a modest association with the gut microbiota bacterial community.

Funding Sources: This research was funded in part by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), the Office of the Director at the National Institutes of Health, the Michigan Health Endowment Fund, and by other institutional support.