A critical assessment of the “sterile womb” and “in utero colonization” hypotheses: implications for research on the pioneer infant microbiome

After more than a century of active research, the notion that the human fetal environment is sterile and that the neonate’s microbiome is acquired during and after birth was an accepted dogma. However, recent studies using molecular techniques suggest bacterial communities in the placenta, amniotic fluid, and meconium from healthy pregnancies. These findings have led many scientists to challenge the “sterile womb paradigm” and propose that microbiome acquisition instead begins in utero, an idea that would fundamentally change our understanding of gut microbiota acquisition and its role in human development. In this review, we provide a critical assessment of the evidence supporting these two opposing…

• CA
  Crohn's and Colitis Foundation of America
• UO
  University of Nebraska-Lincoln
• UO
  University of Calgary
• CA
  Crohn's and Colitis Foundation
• NC
  Nebraska Corn Board
• UO
  University of Alberta
• AI
  Alberta Innovates
• NI
  National Institutes of Health

  Awards: 5R01GM099525-02, P20GM104320
• DF
  Directorate for Biological Sciences
• NI
  National Institute of General Medical Sciences

  Award: P20GM104320