In a surprise find, placentas harbor bacteria
Wombs aren't sterile after all, hosting microbes that resemble those in women’s mouths
EARLY FRIENDSHIP Babies and bacteria become acquainted during pregnancy when microbes set up shop in the placenta, new research indicates. An abnormal mix of these friendly microbes may trigger premature birth.
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.
But research in the May 21 Science Translational Medicine also found bacteria on the baby’s side of the organ, near where the umbilical cord originates, indicating that the placenta has a microbiome of its own.
