Delivery mode impacts newborn gut colonization efficiency

Abstract

Delivery mode is the variable with the greatest influence on the infant gut microbiome composition in the first few months of life. Children born by Cesarean section (C-section) lack species from the Bacteroides genus in their gut microbial community, and this difference can be detectable until 6-18 months of age. One hypothesis is that these differences stem from lack of exposure to the maternal vaginal microbiome, as children born by C-section do not pass through the birth canal; however, Bacteroides species are not common members of the vaginal microbiome, thus this explanation seems inadequate. Here, we set out to re-evaluate this hypothesis by collecting rectal and vaginal samples before delivery from 73 mothers with paired stool from their infants in the first two weeks of life. We compared microbial profiles of infants born by planned, pre-labor C-section to those born by emergent, post-labor surgery (where the child was in the birth canal, but eventually delivered through an abdominal incision), and found no significant differences in the microbiome between these two groups. Both groups showed the characteristic signature lack of Bacteroides species, despite their difference in exposure to the birth canal. Surprisingly, this signature was only evident in samples from week two of life, but not in the first week. Children born by C-section often had high abundance of Bacteroides in

The Effects of Urbanization on the Infant Gut Microbiota and Health Outcomes

“…These findings complement those from other studies that demonstrated that maternal gut microbes can be transmitted to infants via vaginal delivery (35,36). Transmission and colonization of the maternal gut microbiota in infants delivered vaginally is thought to have protective and advantageous functions, as these microbiota are suited to the environment of the gut and have the capacity to contribute to nutrient acquisition in early life (28).…”

“…However, two recent studies of the neonate gut microbiota showed that the prevalence and abundance of Lactobacillus species were similar in both vaginally delivered and C-section groups (27,28). Instead, Bifidobacterium, Escherichia, Bacteroides, and Parabacteroides species ( Table 1) were enriched in the gut microbiota of vaginally delivered infants, and were possibly inherited from maternal fecal microbes (27,28). These findings complement those from other studies that demonstrated that maternal gut microbes can be transmitted to infants via vaginal delivery (35,36).…”

“…Initially, infants born by vaginal delivery were thought to be exposed to and colonized by the resident microbes of the lower genital tract of the mother, with Lactobacillus species being the most dominant (25,26). However, two recent studies of the neonate gut microbiota showed that the prevalence and abundance of Lactobacillus species were similar in both vaginally delivered and C-section groups (27,28). Instead, Bifidobacterium, Escherichia, Bacteroides, and Parabacteroides species ( Table 1) were enriched in the gut microbiota of vaginally delivered infants, and were possibly inherited from maternal fecal microbes (27,28).…”

“…In contrast to vaginally delivered infants, infants delivered by C-section are initially colonized by microbes present in the delivery environment, in the maternal mouth and on the maternal skin [ Table 1; (3,7,8,25)]. Infants delivered by Csection have a relatively low initial abundance of Bacteroidetes (due to inefficient colonization of the gut) and a higher relative abundance of opportunistic pathogens in comparison to vaginally delivered infants (27)(28)(29). The effects of C-section delivery on the gut microbiota have been shown to impact the immune and metabolic development of an infant (7,37,38).…”

Remodeling of the maternal gut microbiome during pregnancy is shaped by parity

“…Our observation that the sow gut microbiome was influenced by parity, together with recent evidence suggesting that maternal gut microbes are likely candidates for vertical transmission to offspring [33, 34], prompted us to characterize the relationship between maternal and offspring gut microbes. As expected, Bray-Curtis beta diversity analysis of metagenomic data from piglets born to each sow (n=54) showed that maternal gut microbiomes were markedly distinct from those of the piglet gut ( P =1e-5, R 2 =0.27), such that the gut microbiome composition of a sow is more similar to that of other sows than to that of her infant offspring (SFig 3A) .…”