Babies who missed out on their mothers鈥� gut bacteria because they were born by Caesarean section receive more bacteria from their mother鈥檚 milk, if they are breastfed, compared with breastfed babies born naturally, a Dutch study has shown.
The research also found that bacteria in breast milk, saliva and on a mother鈥檚 skin are large contributors to the microbes that colonise newborn babies and their impact on an infant鈥檚 microbiome is about the same, regardless of how the baby was born. 鈥淚f you have a C-section and you can鈥檛 breastfeed, all is not lost,鈥� says at University Medical Center Utrecht in the Netherlands.
high-income countries such as the UK. Babies delivered by C-section have different gut bacteria to those born vaginally, which is probably because bacteria enter an infant鈥檚 mouth as it passes through the vagina.
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Microbiome differences have been proposed as an explanation for why babies born by C-section have higher rates of certain health conditions, such as obesity and asthma, although the evidence is inconclusive.
Nevertheless, some people who have had a C-section daub their vaginal fluid onto their baby鈥檚 face, a practice sometimes called vaginal seeding. This isn鈥檛 recommended without a medical check to ensure there aren鈥檛 any pathogenic infections.
To find out more about how babies鈥� microbiomes develop, de Steenhuijsen Piters and his colleagues took multiple bacterial samples from 120 pairs of babies and their mothers, who had given birth either vaginally or by C-section, for up to one month after the infant was born.
They collected faecal, saliva, skin and nasal samples from both mothers and babies. The mothers also provided samples of breast milk and vaginal fluid.
Twenty-nine babies were breastfed, with bacteria from their mother鈥檚 milk contributing to 32 per cent of the bacteria in their faecal, saliva, skin and nasal samples.
Across all the 120 babies, the next biggest sources of bacteria for the infants were the mothers鈥� skin (contributing 26 per cent), saliva (19 per cent) and nose (9 per cent). On average, about 59 per cent of the babies鈥� bacteria came from any maternal source, both for those born vaginally and via C-section.
The overlap in gut microbes between infants born vaginally and their mothers was 22 per cent, when the babies were two weeks old. As the researchers expected, at the same age, there was less similarity between the gut microbiomes of babies born by C-section and those of their mothers, with the overlap being 10 per cent.
But among babies who received any amount of breast milk, bacteria in the milk had a larger impact in the C-section babies than in those born vaginally, with similarities of 32 per cent and 11 per cent, respectively.
鈥淭here may be compensatory pathways 鈥� if you can鈥檛 get microbes from [one] source, you find a source where you can get your microbiome from,鈥� says de Steenhuijsen Piters.
at Rutgers University in New Jersey says we could harness this information to decipher which bacteria some babies are missing out on and then deliver them via probiotics.
Cell Host and Microbe
