Whether born by natural birth or cesarean section, all babies receive essential bacteria from their mothers during birth and immediately afterwards. That’s because this transfer of bacteria occurs through several routes, such as through the gut and breastfeeding. For example, after a caesarean section, a child still gets all the bacteria – collectively referred to as the microbiome – that it needs through breast milk. This is what researchers led by UMC Utrecht and the University of Edinburgh write this week in the journal ‘Cell Host & Microbe’.
“We wanted to get a better idea of how the microbiome of infants develops in different parts of their body and how it is influenced by factors such as mode of birth, antibiotic use and breastfeeding,” says last author Wouter de Steenhuijsen Piters, physician-researcher and data scientist at UMC Utrecht. To this end, the team examined 120 Dutch mothers and newborn babies. From the babies, the team collected samples of the skin, nose, saliva and gut microbiome two hours after birth and then when they were one day, one week, two weeks and one month old. The team also collected six different types of microbiome samples from the mothers: skin, breast milk, nose, throat, stool and vagina. Subsequently, it was investigated to what extent the different microbiomes of the mother determined the microbiome of her baby.
Alternative routes
“We saw that mothers can transmit bacteria through several routes and if some of these routes are blocked for some reason – in this case we saw that happen at the caesarean section – then transmission of microbes to the child can still occur through other routes. take place,” said de Steenhuijsen Piters. Regardless of birth route, the researchers found that about 58 percent of a baby’s microbiome comes from the mother. However, the transfer of microbial communities from mother to infant was not the same for every route: Babies born via caesarean section received fewer microbes from their mother’s vaginal and fecal microbiomes, but received more microbes from their mother’s milk – apparently to compensate. Nevertheless, it cannot be ruled out that children born via caesarean section are still missing essential microbes.
Breastfeeding even more important after caesarean section
“Microbiome transfer and development are so important that evolution has allowed those microbes to be passed from mother to child in some way,” says first author Debby Bogaert, a professor at the University of Edinburgh. “Breastfeeding becomes even more important for children who are born by cesarean section and who, as a result, do not receive intestinal and vaginal microbes from their mothers.” De Steenhuijsen Piters adds: “It’s a smart system, and it makes sense from an evolutionary perspective that these kinds of microbiome transfer pathways are in abundance to ensure that the child can start life with the right ‘starter kit'”.
Long-term health
Now the team wants to know more about other possible influences on the development of the microbiome of infants. Ultimately, the researchers want to understand how the development of the microbiome in infants relates to long-term health. “We want to investigate whether early microbiome development, influenced by the mother, influences not only short-term infection risk in the first year of life, as our previous studies showed, but also longer-term health, particularly in allergies and asthma,” says Bogart. “In the future, we may be able to use this knowledge to help prevent, diagnose or treat health problems.”
Publication
Bogaert D, Beveren GJ van, Koff EM de, Lusarreta Parga P, Balcazar Lopez CE, Koppensteiner L, Clerc M, Hasrat R, Arp K, Chu MLJN, Groot PCM de, Sanders EAM, Houten MA van, Steenhuijsen Piters WAA de. Mother-infant microbiota transmission and infant microbiota development across multiple body sites. Cell Host & Microbe, 2023;31:1-14
Questions, comments or tips for the editors?