Is a foetus developing in a sterile environment?

Abstract

Novel findings in microbiology question the long-standing paradigm that a healthy pregnancy implies a sterile uterus. It now seems that the placenta is frequently colonized with bacteria, and a placental microbiome has been identified. Recent literature findings are summarized here, and an attempt is made to separate pathological bacterial presence from a naturally occurring microbiome.

Keywords: amniotic fluid; breast milk; neonatal sepsis; newborn colonization; placenta microbiome; placental microbiome; preterm birth.