Association between maternal gut microbiome and macrosomia

Abstract Background: Fetal macrosomia is defined as birthweight≧4000g and causes harm to pregnant women and infants. Studies reported that maternal intestinal microbiome plays a key role in the establishment, growth and development of fetal intestinal flora; however, the relationship between maternal gut microbiota and macrosomia remains unclear. Our study aimed to investigate whether maternal gut microbiome is associated with macrosomia and explored the potential microbiome biomarkers at early pregnancy to prevent macrosomia .Methods: We conducted a nested case control study based on an early pregnancy cohort (ChiCTR1900020652) in Maternity and Child Health Hospital of Hunan Province, fecal samples of 93 women(31 delivered macrosomia as case group and 62 delivered normal birth weight newborns as the control group) collected and included in this study. And we performed metagenomic analysis to compare the composition and function of gut microbiome between cases and controls. Correlation analysis was used to explore the association of differential species with differential functional pathways and clinical parameters.Results: There are more phylum Bacteroidetes, order Bacteroidales and Burkholderiales, class Betaproteobacteria and Bacteroidia and Bacteroides ovatus in the intestinal flora of macrosomias’mothers compared with fetuses with normal birth weight. Functional pathways of gut microbiome including gondoate biosynthesis (anaerobic), L-histidine degradation III, cis-vaccenate biosynthesis and mannitol cycle were more abundant in macrosomia group. Significant correlations were discovered between taxa associated in macrosomia and triglycerides. Furthermore, Bacteroidetes (phylum), Bacteroidia (class), Bacteroidales (order) and Bacteroides ovatus were significantly associated with the pathway of gondoate biosynthesis, L−histidine degradation III, cis−vaccenate biosynthesis and Bacteroides ovatus was correlated with mannitol cycle pathway.Conclusions: Maternal gut microbiota may play an important role in the development of macrosomia and can be used as predictors to prevent macrosomia.