596: Factors that influence the maternal gut microbiome in early pregnancy

Abstract

A mother’s health before, during, and after pregnancy is crucial in determining the ultimate health outcome of the newborn. The maternal gut microbiome is thought to influence the colonization of the infant gut and thus, understanding the factors that affect it may provide an opportunity to optimize this crucial developmental step. One hundred and seventeen women were recruited in early pregnancy (16 weeksʼ gestation) as they presented for antenatal care in a tertiary level maternity unit, National Maternity Hospital, Dublin. Baseline demographic details were recorded from the health care record and antibiotic usage was self-reported. Microbial data were extracted from stool samples and subjected to metagenomic shotgun sequencing. Whole metagenome sequencing was performed on an Illumina NextSeq 500. Taxonomic profiling was performed using MetaPhlAn2 and all downstream analyses were performed in R using the vegan, psych and compareGroups packages. Pairwise Pearson correlations were performed and beta-diversity was calculated using Bray-Curtis dissimilarity and PCoA. Kruskal-Wallis was used to identify differentially abundant microbial species. P < 0.05 was considered significant following Benjimani- Hochberg FDR correction. The mean age of participants was 33 years and the mean body mass index (BMI) was 24.7kg/m2. 69 of the participants were nulliparous, while the remaining 48 had one or more children. 12 women reported antibiotic usage prior to 16 weeks gestation. A more diverse microbiome was seen in women who had one or more children (image 1) and a less diverse microbiome was seen in those with a BMI ≥30kg/m2 (image 2), however these did not reach statistical significance. Antibiotic usage caused a decrease in Shannon and Simpson diversity but no overall change in the observed species. Although the number of pregnant women with obesity in our cohort is low, our results are in keeping with previous studies that indicate a less diverse microbiome in this population. Interestingly, the microbiome appears more diverse with increasing family size. This may be due to a more biodiverse environment with horizontal transfer of microbes among family members. This is important for future studies regarding the microbiome and gut health.View Large Image Figure ViewerDownload Hi-res image Download (PPT)