Impact of postpartum hospital length of stay on infant gut microbiota: a comprehensive analysis of vaginal and caesarean birth

Background

The primary concern with prolonged hospitalization following birth is the risk of acquiring hospital-acquired infections (HAIs) caused by opportunistic bacteria, which can alter the early establishment of gut microbiota.

Objective

To assess the association between postpartum hospital length of stay (LOS) and the composition of gut microbiota at 3 and 12 months of age according to birth mode.

Methods

In total, 1313 Canadian infants from the CHILD Cohort Study were involved in this study. Prolonged LOS was defined as ≥2 days following vaginal delivery (VD) and ≥3 days following caesarean section (CS). The gut microbiota of infants was characterized by Illumina 16S rRNA sequencing of faecal samples at 3–4 months and 12 months of age.

Findings

Following prolonged LOS, VD infants with no exposure to intrapartum antibiotics had a higher abundance of bacteria known to cause HAIs in their gut, including Enterococcus spp. at 3 and 12 months, Citrobacter spp. at 3 months, and Clostridioides difficile at 12 months. Abundance of Enterococcus spp. or Citrobacter spp. at 3 months significantly mediated the association between LOS and low abundance of Bacteroidaceae, or higher Enterococcaeae/Bacteriodaceae or Enterobacterales/Bacteroidaceae abundance ratios at 12 months of age in VD infants without intrapartum antibiotic exposure. HAI-causing Enterobacterales were also more abundant in later infancy in infants with prolonged LOS following CS. In the absence of exclusive breastfeeding at 3 months or any breastfeeding at 12 months, Porphyromonadaceae (of Bacteroidota) were depleted in CS infants with prolonged LOS.

Conclusions

Prolonged hospital stay after birth is associated with infant gut dysbiosis.