Does a microbiome exist in utero, or is the environment sterile up to the moment the baby exits the womb? This has been an area of much debate in the scientific community. While some studies show the intrauterine environment to be sterile, others have uncovered bacteria in the uterus and placenta, showing that an intrauterine microbiome does in fact exist. A new review study adds evidence to the idea that if colonized, the intrauterine environment is contaminated. Researchers of the study propose that maternal stress causes a disruption of bacteria in one region of the mother’s body – oral cavity, gut, or vagina – triggering the transfer of bacteria (or what scientists refer to as bacterial translocation) to the intrauterine environment. This transfer of bacteria, scientists believe, may trigger an immune (or inflammatory) response that leads to neurodevelopment insufficiencies in the fetus. Science Direct

Takeaway: While we are far from uncovering the truth about whether it’s “natural” for an intrauterine microbiome to exist, we do know that maternal stress, nutrition, and other maternal lifestyle factors can dramatically affect fetal health and development – even before pregnancy. For a detailed look into how to prep the microbiome for pregnancy, as well as how to cultivate a balanced microbiome during pregnancy, check out Dr. Chutkan’s book The Microbiome Solution.