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Bacteria begin to inhabit the human body as early as the womb of the mother
Last reviewed: 01.07.2025
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Scientists from Spain have proven that bacteria begin to populate the human body in the mother's womb. The results of the scientific work of Pilar Francino from the Institute of Valencia were published in Current Microbiology.
It is believed that the baby in the mother's womb develops in sterile conditions, and the first bacteria settle in it during childbirth and after birth under the influence of the environment. The entire set of microorganisms that inhabit the human body is called the microbiome.
The very first data that the microbiome can form in mammals before birth were noticed 4 years ago. Esther Jimenez from the Complutense University of Madrid gave pregnant mice milk containing labeled microorganisms. The day before the scheduled birth date, the mice underwent a cesarean section under sterile conditions. Then the scientists examined the meconium (first feces) of the newborn mice and found labeled bacteria in it.
A similar method was used by Pilar Franzino's group - they collected and froze meconium from 20 newborns. The scientists then removed the outer layers of the samples in order to eliminate those microorganisms that entered the baby's body from the surrounding environment after birth, and studied the remainder. They found DNA of microbes that produce lactic acid, including lactobacillus, and also DNA of E. coli in the meconium. In about half of the newborns, lactobacilli were dominant, while in the other half, E. coli prevailed.
Scientists assume that the composition of the microbiome has a great influence on the formation of the newborn's immune system, the risk of developing diseases and depends on the lifestyle of the pregnant mother. As a result, the composition of bacterial colonies can be influenced by dietary nutrition and sports procedures. Among other things, Franzino found that lactobacilli dominate in children whose mothers received higher education. In children whose mothers did not study at institutes, E. coli dominates in the microbiome.
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