P909 Microbiome dynamics leading up to and during pregnancy in a matched IBD-control cohort

Abstract

Abstract Background A common feature of inflammatory bowel diseases (IBD) is dysbiosis of gut microbiota. IBD usually affects women during their childbearing years, but successful pregnancy outcomes have become a reality for many women with IBD. Pregnancy in general and pregnancy in IBD in particular, has been reported to dramatically affect gut microbial composition and function. In the present study, we have characterized the changes in the gut microbiota that occur from preconception to the first trimester of pregnancy in healthy women and in women with IBD. Methods Fecal samples were collected from 39 pregnant IBD patients and 38 pregnant healthy controls at two time-points: preconception and during the first trimester. Bacterial DNA was extracted, amplified, cleaned and sequenced (16S rRNA gene). Then, microbiome analysis was performed using QIIME2 to compare profiles between the groups and across the time points. Results The microbiomes of IBD patients were significantly different than those of healthy controls, and bacterial richness was significantly lower than controls both in preconception and first trimester samples. Even though no significant differences were observed between sampling time points, the shift in the bacterial population from preconception to the first trimester in the IBD groups was significantly larger compared to the shift in the control group. We also found that the genus Sutterella was significantly more abundant in healthy controls in samples collected during the first trimester compared to IBD patients. When specifically focusing on this genus in preconception samples, we found the same pattern of increased abundance in the control group. Conclusion While there were no differences in the microbiota across time points, the increased delta between IBD versus controls may suggest that disease phenotype permits increased microbiome plasticity than the control group. Furthermore, the results may be related to modulation of immune response that may be associated to inflammatory state and medical treatments; however, further studies are warranted.