The scientific and technological development we have witnessed in reproductive medicine in recent times has generated diagnostic studies and sometimes highly complex treatments, which have undoubtedly increased the probability of obtaining offspring.
However, despite the great scientific advances, there is still much to be studied and discovered. This is the cause of the so-called implantation failure. This diagnosis is reserved for those couples in which, in spite of having performed several high-quality embryo transfers, pregnancy is not achieved, without any apparent cause.
The study of implantation failure is one of the most complexes in assisted reproduction since in principle we do not know its cause and, therefore, we will not have a specific treatment. That is to say since we do not know exactly what the problem is, it is not possible to carry out a targeted treatment.
Thus, implantation failure has become a real challenge for researchers and clinicians in reproductive medicine. Various diagnostic tests have emerged from the various investigations and various treatments have been suggested. However, given their youth, it is often not possible to ensure the effectiveness of these treatments. In fact, many of them are still being discussed by the international scientific community. However, explaining all this and being accepted by the patient, these therapies are usually used, because they are safe and the alternative (we recall that they are aimed at couples who have had several unsuccessful cycles) is to do nothing new.
And so it is in this context that reproductive immunology appears, which must always be evaluated in the context of implantation failure, and whose concepts are still being discussed today.
Many possible immunological alterations have been described that could be the cause of embryo non-implantation or even miscarriages. Thus, the concept of "immunological infertility" that leads to treatment should be forgotten, but in reality, immune problems can be many (in fact, it is more than likely that not all of them are known for the most part) and therefore the associated treatments will also be diverse.
Once the diagnosis is obtained, there are complex algorithms that will determine the best treatment for the patient. There are many drugs that have been used as immunomodulators (Intralipid, IVIG, Tracolimus, Prograf, hydroxychloroquine...). It is the patient's physician who must define the treatment to be used and its specific doses in each case.
Finally, it should be noted that there is research suggesting that the genetic compatibility of the couple is important in the pregnancy process. The absence of this compatibility would generate implantation problems due to immunological causes only when the couple joins together to have offspring. This would not occur, for example, if other people were involved in the search for offspring or, for example, if suitable gamete donors were used. Certain medical treatments can reduce - but not eliminate - this possible incompatibility, thus helping to improve the probability of gestation.