Comment on "Structural changes in the rat placenta during the last third of gestation discovered by stereology".
We read with great interest the article by Serman LJ et al. [1] about evaluation of the structural changes in the rat placenta during the last third of gestation, assessed by stereology. The authors concluded that the absolute volume of the whole placenta as well as the labyrinth had increased from day 16 to day 19 of gestation. In contrast, the volume density of glycogenic cells and trophoblast giant cells was higher on gestation day 16 than on day 19, probably due to the intensive trophoblast invasion during that time. Since stereological analysis assigns numerical values to analyzed structures, such outcomes ensure valid and exact comparison of healthy and pathologically altered tissue. In addition, comparison can be done between the tissues in different developing phases of an organ, as it was represented in this article.