Differences found in the percentage of normal embryos, according to the embryo lab
A recently published study by Munne et al in Human Reproduction showed how the rates of chromosomally normal embryos differ according to the embryo lab.
Many times some people wonder what the difference is between one medical center and another. What is the difference between two fertility programs that offer, apparently, the same service? How large could be the difference if I see Doctor A or B? And how large is the difference in the outcome if my embryos grow here or there? In this study, it is shown some of those differences that are crucial to understanding why patients arrive faster, happier and safer in one way than another.
Interestingly, in this study they evaluated a total of 1645 egg donor cycles and 13,282 biopsies of blastocysts for PGS, in 42 US fertility clinics. It should be noted that the PGS was always performed in the same laboratory with the same technology, so no differences due to the evaluated method are expected. The PGS is a technique in which the number of chromosomes of each embryo is evaluated. The average of euploid (ie, normal, 46 chromosomes) embryos in each center ranged from 39.5% to 82.5%. This is a retrospective study with some limitations and, therefore, we cannot talk of causality (since, for example, we might think that the donors of some center, for some reason, are different than those of another center) . However, the magnitude of such differences is so great that it makes us hypothesize about a causal factor between the laboratory and the physician who stimulated that donor, and the results found.
Where is the difference?
This is a good argument for explaining why there are so large differences between one reproduction center and another, or between one doctor and another. One explanation might be that doctors stimulate different in each center and that could lead to those results (obtaining better and worse eggs). Another explanation could be that each embryo lab has its own recipe (type of incubators, gas levels in the incubators, media culture, etc.), and this could lead to embryos suffering less or more alterations during the first cell divisions.
In summary, although often two programs appear the same, when they are evaluated more deeply, they show huge differences. It is worth exploring a little bit because, these differences, can be enormous when analyzing the results.