Babies receive essential microbes regardless of the type of delivery

Do babies born by cesarean section lose essential microbes? New data suggests that the answer may be "no".

Maria Zavialova

Babies born via cesarean section receive less of their mother’s microbiome during birth. However, they make up for this by ingesting maternal microbes through breast milk.

How babies acquire microbiome

Research indicates that mothers can pass on necessary microbes to their children through alternative compensatory pathways. A recent study by Dutch scientists, published in the journal Cell Host & Microbe, confirms this.


Most microbiome research has focused on the gut. However, beneficial microbial communities also exist in other parts of our body, such as the respiratory tract and skin. This study helps to clarify how infants, who are typically considered sterile at birth, acquire the necessary microbes.

We wanted to have a better idea of how the infant microbiome develops in different parts of their bodies and how it’s influenced by factors such as birth mode, antibiotic use, and lack of breastfeeding

Senior author Wouter de Steenhuijsen Piters, a physician and data scientist at the University Medical Center Utrecht in the Netherlands

The methodology of the study

To understand how the microbiota develops during the first month of life, researchers collected and sampled from 120 Dutch mothers and babies who were soon to be born. Samples were taken from the infants’ skin, nose, saliva, and gut two hours after birth. Then the scientists have collected data after one day, one week, two weeks, and one month.

The team also collected six different types of microbiome samples from the mothers, including skin, breast milk, nose, throat, gut, and vagina, to determine which of these sources seeded different infant microbiomes. They then analyzed these results in the context of several factors believed to affect the transmission of the microbiota, such as mode of delivery, antibiotic use, and breastfeeding.

Results: babies have everything they need anyway

Researchers have discovered that approximately 58.5% of a child’s microbiome comes from their mother, regardless of their birth method. However, different maternal microbial communities contribute to the formation of different infant microbiomes. Babies born through C-sections receive fewer microbes from their mother’s vaginal and gut flora, but receive more microbes from breast milk.

The transmission and development of microflora are so crucial that evolution has facilitated the transfer of these microbes from mother to child. For C-section babies who do not receive gut and vaginal microbes from their mother, breastfeeding becomes even more vital.

Dr. Wouter de Steenhuijsen Piters explained that excess routes of microbiome transmission make sense from an evolutionary perspective as they allow for a suitable “starter set” for beginning life.

Next steps for scientists

The next step for scientists is to gain further insight into non-maternal influences on the development of infants’ microflora. Researchers aim to understand the correlation between the development of microflora in infants and long-term health.

We could see that the maternal microbiome explains almost 60% of the infant’s total microbiome, but there’s still 40% that we don’t know about. It would be interesting to stratify that unknown fraction to see where all the microbes come from; whether fathers contribute, for example, or siblings, or the environment.

Dr. Wouter de Steenhuijsen Piters

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