Microbiome and Fetus: A Relationship for Life

The impact of the microbiome has become relevant to the world of pre- and
perinatal psychology and medicine. The microbiome is defined as the microbes which inhabit
our body. Many scientists consider the microbiome to be a “super organ,” which plays a much
greater than expected role in our health. The startling new realization over the last decade
or so is that the acquisition of microbiome begins in utero. Since the 1900’s, it has been
presumed that the fetus is sterile and the first acquisition of microbes occurs as the infant is
delivered. Over the last decade, research has provided strong evidence that the fetus is not
sterile in the womb, and bacteria are “transmitted” from mother to fetus primarily through
the placenta. This paradigm shift—that the womb is not sterile—opens a new frontier in
exploring our complex relationship with microbes. Given the research suggesting significant
effects of microbiome on infants, children, and adults, what might we find is the effect of
those microbes on the developing human fetus? This review article looks at some of the areas
of study in this vast topic and proposes additional questions for further research.