TABLE 1.
1. Larger sample sizes |
2. Simultaneous use of different detection methods |
3. The elimination of extracellular DNA prior to molecular microbial profiling |
4. rigorous controls for reagents and equipment at all steps during sample processing and analysis |
5. The determination of the relative abundance of bacterial groups should be preceded by an absolute quantification of the bacterial load in samples and controls |
6. Prespecified and quantified bacterial mock communities to the examined samples will help to reveal biases and identify batch effects |
7. Demonstration of metabolically active and proliferating diverse bacteria within the placental or fetal tissue will be required to prove the existence of a viable, diverse and unique bacterial community that merits the term microbiota. |
8. Taking into consideration geographical, ethnic and societal habits of the population |
*This table is adapted from the text and advices provided in Hornef M, Penders J. Does a prenatal bacterial microbiota exist? Mucosal Immunol. 2017 May;10(3):598–601.