placental microbiome

Culturable and non-culturable bacterial species in the placenta obtained following normal term pregnancy have been identified.

{{cleanup section|reason=Current table contains too many phylum-level names (-ota, -bacteria) with very dubious informative value -- for one thing, it's nigh impossible to determine any one of Commensal/Transient/Potentially-pathogenic from the phylum alone. Antony et al. 2014 is used for the source of many such rows, but the article actually has more detailed values down to the species level.|date=January 2025}}

In a healthy placental microbiome, the diversity of the species and genera is extensive. A change in the composition of the microbiota in the placenta is associated with excess gestational weight gain, and pre-term birth.{{cite journal |vauthors=Antony KM, Ma J, Mitchell KB, Racusin DA, Versalovic J, Aagaard K |title=The preterm placental microbiome varies in association with excess maternal gestational weight gain |journal=American Journal of Obstetrics and Gynecology |volume=212 |issue=5 |pages=653.e1–16 |year=2015 |pmid=25557210 |pmc=4892181 |doi=10.1016/j.ajog.2014.12.041 }}

The placental microbiota varies between low birth weight infants and those infants with normal birth weights.{{cite journal |vauthors=Zheng J, Xiao X, Zhang Q, Mao L, Yu M, Xu J |title=The Placental Microbiome Varies in Association with Low Birth Weight in Full-Term Neonates |journal=Nutrients |volume=7 |issue=8 |pages=6924–37 |year=2015 |pmid=26287241 |pmc=4555154 |doi=10.3390/nu7085315 |doi-access=free }}

While bacteria are often found in the amniotic fluid of failed pregnancies, they are also found in particulate matter that is found in about 1% of healthy pregnancies.

In non-human animals, part of the microbiome is passed onto offspring even before the offspring are born. Bacteriologists assume that the same probably holds true for humans.

The fact that germ free animals can be routinely generated by sterile cesarean section provides strong experimental evidence for the sterile womb hypothesis.

Future research may find that the microbiota of the female reproductive tract may be related to pregnancy, conception, and birth. Animal studies have been used to investigate the relationship between oral microbiota and the placental microbiota. Mice inoculated with species of oral bacteria demonstrated placental colonization soon afterwards.{{Cite book|title=The Human Microbiota : How Microbial Communities Affect Health and Disease|date=2013|publisher=Wiley-Blackwell|others=Fredricks, David N.|isbn=9780470479896|location=Hoboken, New Jersey|pages=156, 169|oclc=794922809}}

Investigations into reproductive-associated microbiomes began around 1885 by Theodor Escherich. He wrote that meconium from the newborn was free of bacteria. This was interpreted as the uterine environment being sterile. Other investigations used sterile diapers for meconium collection. No bacteria were able to be cultured from the samples. Bacteria were detected and were directly proportional to the time between birth and the passage of meconium. A 1927 study demonstrated the presence of bacteria in the amniotic fluid of those that were in labor for longer than six hours.{{cite journal |vauthors=Perez-Muñoz ME, Arrieta MC, Ramer-Tait AE, Walter J |title=A critical assessment of the "sterile womb" and "in utero colonization" hypotheses: implications for research on the pioneer infant microbiome |journal=Microbiome |volume=5 |issue=1 |pages=48 |year=2017 |pmid=28454555 |pmc=5410102 |doi=10.1186/s40168-017-0268-4 |doi-access=free }}

• Human microbiome
• Human microbiome project
• Human virome
• List of bacterial vaginosis microbiota
• Microbiota of the lower reproductive tract of women
• Vaginal microbiota in pregnancy

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Category:Placenta

Category:Bacteriology

Category:Microbiology

Category:Feminine hygiene

Category:Vagina

Category:Microbiomes