Why the Placental Microbiome Should Be a Cautionary Tale
For decades, scientists believed that babies encounter microbes for the very first time when they are born. Both a healthy womb and the placenta that nourishes the growing fetus, they said, are sterile. If bacteria do sneak in, they’re intruders and bad news for the fetus. But in 2014, Kjersti Aagaard from Baylor College of Medicine challenged that dogma. In placental tissue samples from 320 women, she found DNA from many kinds of bacteria, which made up a “unique placental microbiome,” she argued. Aagaard suggested that this microbiome is part of natural pregnancy and might seed a fetus’s body with microbes in utero.
“The placenta is not teeming with bacteria, but we can find them,” she told The New York Times, “and we can find them without looking too hard.”
More placental-microbiome studies have since been published. Aagaard’s team and others have looked at how this community of microbes varies with body weight, how it affects the , whether it’s linked to or , and whether it’s a “” between gum disease and pregnancy problems.
