The first glimpse of the endometrial microbiota in early pregnancy

Menstruation: science and society

“…Bacterial diversity was lower and Lactobacillus abundance higher ( L iners was the only bacterium found) during the healthy pregnancy. 237 These novel observations may profoundly affect our understanding and possible clinical translation of the microbiome in relation to healthy or pathologic human pregnancy.…”

Recent Insights on the Maternal Microbiota: Impact on Pregnancy Outcomes

“…Additionally, several recent studies suggest the presence of a resident microbiota in the endometrium (95)(96)(97). Yet studies that evaluate the role of the endometrial microbiota on reproductive health are in their infancy.…”

In utero human intestine harbors unique metabolome, including bacterial metabolites

“…However, recently Rackaityte and colleagues reported bacterial presence via scanning electron microscopy and limited signatures by 16S rRNA sequencing in a similar sample set (12). The discrepancy between our inability to amplify bacterial DNA and the findings by Rackaityte and colleagues exemplifies the debate over the existence of an in utero microbiome, with some studies identifying a low biomass microbiome (13)(14)(15)(16)(17)(18) and others finding no microbial signatures beyond background levels in animals and humans (7)(8)(9)(10)(11)(46)(47)(48). The controversy about the existence of a placental and fetal microbiome cannot be resolved solely with the data presented in this manuscript.…”

“…The existence of an in utero microbiome remains controversial. Multiple studies have indicated that the placenta is devoid of a microbiome (7)(8)(9)(10)(11), whereas others have reported limited bacterial colonization in fetal meconium (12) and placental and endometrial samples (13)(14)(15)(16)(17)(18). A study by Aagaard et al (13) analyzing a large number of patients suggested that the placenta has a unique microbiome that is similar to the oral microbiome of nonpregnant women.…”