Impact of Postpartum Hospital Length-of-Stay on Infant Gut Microbiota: A Comprehensive Analysis of Vaginal and Caesarean birth

Objectives: This study aimed to assess the association between postpartum hospital length-of-stay and the composition of gut microbiota at 3 and 12 months of age in different birth modes. Design: Prospective cohort of Canadian infants from the Canadian Healthy Infant Longitudinal Development (CHILD) Study born between 2008 and 2012. Setting: General community. Sample 1313 infants from three study sites (Edmonton, Vancouver, and Winnipeg) of the CHILD cohort Methods: Duration of hospital stay was documented in hospital records. Infants’ gut microbiota was characterized by Illumina 16S rRNA sequencing of fecal samples at 3 and 12 months. Main outcome measures Infant gut microbiota profiles. Results: : In the absence of maternal intrapartum antibiotic (IAP) exposure, vaginally delivered infants (VD) with a longer hospital length-of-stay (LOS) had a higher abundance of bacteria in their gut known to cause hospital-acquired Infections (HAI), including Enterococcus at 3 months and 12 months and Citrobacter at 3 months of age. Moreover, HAI-causing bacteria Enterobacteriaceae were more abundant in later infancy in postnatal prolonged hospital stayed IAP-exposed caesarean section (CS) infants. Enterococcus or Citrobacter abundance at 3 months significantly mediated the association of LOS with low relative abundance of Bacteroidaceae and a high relative abundance of Enterococcaeae/Bacteriodaceae or Enterobacteriaceae/Bacteroidaceae ratio at 12 months of age in VD infants without IAP exposure. Conclusions: LOS after birth is associated with infant gut dysbiosis. Further research is needed to explore the health outcomes of these associations.