Some embryos absorb some of their own cells on their second or third day of life. This was considered anomalous until now. However, a study by the Institut Marquès shows that, with this process, nature manages to repair itself and move on.
Embryos can repair themselves and continue their development.
The discovery of the Institut Marquès has been made possible thanks to Embryoscope, embryo incubators with a video camera that films the development. In In Vitro Fertilization (IVF) treatments, embryos are classified according to guidelines based on their appearance and way of development. Thus, those that are considered to have the best prognosis to implant and continue to evolve are transferred to the patient.
For this purpose, it is considered correct for an embryo to have 4 cells on the second day of life, and 8 on the third day. Some embryos, suddenly, on the second or third day have one of their cells disappear. Thus, they go, for example, from 4 to 3, and then continue dividing. This phenomenon is called reverse division and, until now, was considered a sign of poor prognosis.
According to current standards, embryos that do not follow the marked patterns are less likely to develop. However, Institut Marquès is re-evaluating these guidelines, demonstrating that many of these standardized criteria are not correct.
Study on 23,340 embryos demonstrating their survivability
The study conducted by Institut Marquès was presented at the Congress of the European Society of Human Reproduction and Embryology (ESHRE). He demonstrated that embryos that absorbed cells and continued dividing until blastocyst (first stage of embryonic development, between the 5th and 6th day after fertilization) have the same rate of implantation, evolutionary pregnancy and healthy child at birth.
Dr. López-Teijón, director of the Institut Marquès and specialist in Assisted Reproduction, explains that the human being, on the second or third day of life, is already capable of detecting that one of its cells has been altered, and has the capacity to eliminate it in order to continue growing healthily.
The study was performed on retrospective video of 23,340 embryos, from the moment of fertilization to the blastocyst stage. In 303 of these embryos there was complete absorption of one of the cells. These embryos had a slight decrease in the proportion reaching blastocyst stage. On the other hand, that of born embryos is maintained, which suggests that early detection of errors by the cells would be involved in this absorption. Embryos that pass the repair have the same reproductive potential as the others.
Independent and distinct from the beginning of life
Just as no two people are physically the same (with the exception of identical twins), no two embryos are the same. The number of genetic combinations is infinite. Hence, from the moment of fertilization, we all have our exclusive characteristics that have made us unique ever since.
This happens in all embryos. Dr. López-Teijón explains that each embryo functions as a team of cells controlled by a leader, whose goal is to live. If some cells divide abnormally and uncontrolled, the bad cells will win and the embryo will not be able to develop. From the beginning of life, human beings are able to eliminate their weaknesses in order to follow the right criteria and move forward in life.