Wombs aren't sterile after all, hosting microbes that resemble those in women’s mouths
Nicolle R. Fuller
The placenta harbors an unexpected collection of bacteria. Its mix of microbes may promote healthy pregnancies or lead to premature births.
Doctors and scientists have long thought that the womb was sterile. They figured that babies pick up their microbiomes — the collections of bacteria and other microbes that exist in and on them for the rest of their lives — during birth and early childhood.
Last year, however, researchers found that microbes make it to the side of the placenta where it fuses to the mother’s uterus. Many scientists assumed the placenta acts as a barrier preventing bacteria from reaching the fetus, says pediatric infectious disease specialist Anna Bakardjiev of the University of California, San Francisco.