Placenta is the primary organ between fetus and mother it has many effects on the health of fetus and mother. Placenta transfers the gases, nutrients and performed many immunity based function between maternal and fetus development and maintenance of activities. In this review we can discuss placental composition, whether it has microbiome or not. Microbial communities present in it is real or it is just a contamination. Is the presence of bacteria leads toward preterm birth or not and what is the expected route for microbes transfer to fetus? What are the composition of microbial flora in placenta at different delivery conditions?
Placenta is not explored too much with respect to other body organs. So, the effects of placenta on fetus is also not completely understood. Placenta has many functions such as, exchange of nutrients, gases and blood between fetus and mother and it also performs some critical metabolic roles in the development of fetus and maintenance of fetus and maternal tolerance system. If placenta is damage then it becomes the cause for serious complications during pregnancy period, which can cause pre term birth. We have seen many cases which shows that placental abnormalities becomes a major reason for the world wide perinatal morbidity and mortality. With the background of fetal environment as a sterile, we have to know many examples and patternswhich make us sure that during and after birthmicrobes can transfer to the fetus through mother and from the environment too. There is a lot of literature on the basis of metagenomics and culture methods suggested that a healthy placenta has microbial community with low biomass.
Contrarily, many scientific proofs are present which supports both hypothesis of “in utero colonization” and “sterile womb”. Many scientists suggests that womb is a sterile environment and it can be contaminated very easily if we did not use any proper control system. Due to this contamination microflora is colonized in utero.
In well controlled set up when they study different samples from placenta, vaginal and oral sites, and analyzed them by using molecular methods, they found an undistinguishable placental samples from contaminated one. They summarize that unique microbial flora is present in oral and vaginal sample and placental microbiome was not present which give evidence in the favour of womb as a sterile environment.
In the past decades. Placenta is considered as a sterile organ if there is no clinical infection. When advance cultivation dependent methods are introduced for analysis of placental tissues, then it is confirmed that it has microflora in it. Studies which are cultivation depended underestimate the proofs of microbial flora in the placenta may be because of very difficult culture conditions of these bacteria such as anaerobic environmental conditions or due to their requirement for unidentified nutrients. DNA-based studies shows the presence of Propionibacterium, lactobacillus and members of Enterobacteriaceae in the placental tissues of pregnant women with normal delivery. It is under debate till now.(1, 2,5)