(OR24-05-26) Maternal Anemia and Iron Supplementation Are Associated With Taxonomic Composition of Maternal and Newborn Microbiome

Objectives: Iron deficiency anemia (IDA) in pregnancy is a persistent public health concern. IDA may adversely impact the gut microbiome by promoting colonization of harmful taxa and triggering intestinal inflammation. However, less is known about how IDA affects the gut microbiome during pregnancy, or how this may influence the establishment of the newborn microbiome. Here we evaluate associations between maternal anemia, prenatal iron supplementation, and the taxonomic composition and abundance of bacterial species in the maternal and newborn gut.

Methods: ‘EcoMiD’ is a recently completed Ecuadorian birth cohort of N=521 mother-infant dyads. Afro-descendant pregnant women were recruited from northwestern Ecuador. As a sub-study, shotgun metagenomic sequencing of the fecal microbiome was conducted for 55 women at ~37 weeks of pregnancy and their ~1-week-old infants. Taxonomic profiles were derived from 16S rRNA gene regions identified in the metagenomic sequences.

Results: 28% of women were mildly anemic, and 39.6% were moderately or severely anemic. 32.7% reported prenatal iron supplementation. In pregnancy, moderate/severe anemia was associated with increased gut microbiota alpha diversity; in contrast, iron supplementation was associated with decreased alpha diversity, primarily through decreases in the relative abundance of potentially harmful Gammaproteobacteria. No statistically significant associations between anemia and specific taxa were noted, however, women who reported iron supplementation had increased levels of Preovotella and Roseburia, and decreased levels of Faecalibacterium and Bacteroides in their gut microbiome. Newborns whose mothers reported iron supplementation had a marginally higher relative abundance of Actinobacteria (p=0.072) and decreased abundance of Negativicutes (p=0.023). Streptococcus and Staphylococcus were less abundant among newborns whose mothers reported iron supplementation.

Conclusions: Maternal anemia and prenatal iron supplementation were associated with distinct taxonomic composition in the gut microbiome of both mothers and newborns. Further research is needed to understand the influence of prenatal iron supplementation on the establishment of the infant gut microbiome.

Funding Sources: National Institutes of Health (R01AI137679 to KL and JNSE, K01AI145080 to GOL).