There is a big debate in the scientific world as to when the human microbiome actually starts. To date, the going hypothesis has been that babies are sterile while in the womb, and then begin to acquire flora as they pass through the birth canal.
However, this paradigm has been challenged now several times, as a growing body of evidence suggests that in fact, the womb is not the “sterile” place it was once thought. [i] Most recently, a team of scientists took samples from placentas and found that about 1/3rd of them had non-pathogenic bacteria – and no signs of “infection,” such as inflammation. The samples were completely healthy.
Should this prove true – that is, that the microbiome starts much earlier than thought – these microbes may play a big role in the development of the brain and immune system.
Skeptics believe the samples were contaminated and at least one other team failed to find any bacteria. Since this bacterial content is so low, it’s much more difficult to spot than in say, an ordinary saliva sample. Also, no microbiome has ever been found in mouse placenta, adding to the evidence that no pre-birth microbiome actually exists. For now, the debate continues.
How interesting would it have been to follow the health of the various babies involved in the study? Is that 1/3rd healthier or not? Are developmental disabilities more common in one group versus the other? Is there any difference in antibiotic use in the mothers? First though, I guess, the existence of the prenatal microbiome needs to be established! 🙂
Stay tuned – I’ll follow this continuing story.