The Prenatal Microbiome: A New Player for Human Health

Abstract

The last few years have featured an increasing interest in the study of the human microbiome and its correlations with health status. Indeed, technological advances have allowed the study of microbial communities to reach a previously unthinkable sensitivity, showing the presence of microbes also in environments usually considered as sterile. In this scenario, microbial communities have been described in the amniotic fluid, the umbilical blood cord, and the placenta, denying a dogma of reproductive medicine that considers the uterus like a sterile womb. This prenatal microbiome may play a role not only in fetal development but also in the predisposition to diseases that may develop later in life, and also in adulthood. Thus, the aim of this review is to report the current knowledge regarding the prenatal microbiome composition, its association with pathological processes, and the future perspectives regarding its manipulation for healthy status promotion and maintenance.

Association of maternal prenatal psychological stressors and distress with maternal and early infant faecal bacterial profile

“…Until recently, the foetus has been considered to exist in a sterile environment with initial microbial colonization of the newborn taking place during birth (51). Recent studies have reported the detection of microbes from amniotic fluid, placenta and meconium, suggesting that microbial colonization may begin in utero (52, 53).…”

“…In addition, a number of studies have reported bacterial communities from meconium specimens (54). Dysbiosis of faecal bacterial profiles early in life has been associated with a number of neonatal diseases, including asthma, allergic diseases, and obesity (51), which further emphasises the importance of in utero colonization on the health of newborns.…”

Emerging Priorities for Microbiome Research

“…Our gut, food, and microbiome are also connected with our nervous system. Humans might get their prenatal microbiome (Aagaard et al, 2014;Parnell et al, 2017;D'Argenio, 2018) or at least be exposed to some bacteria (de Goffau et al, 2019) while in the uterus, and it is suggested that the gut-brain-bidirectional axis originates in utero (Borre et al, 2014;Jasarevic et al, 2017;Martin et al, 2018). Our gut and brain communicate via neurobiochemical, neuroendocrinal, and neuroimmune mechanisms, which are still unclear, and can be the result of different stages of development.…”

The Evolving Microbiome from Pregnancy to Early Infancy: A Comprehensive Review

“…Several findings using both culture and metagenomic techniques have suggested the presence of a low biomass microbial community in the healthy placenta [39][40][41][42][43]. The abundance of different species of Lactobacillus, Propionibacterium, and members of the Enterobacteriaceae family have been detected by DNA-based studies in placental tissue of pregnant women at term and it is under debate [16].…”