Implantation failures

In recent years, thousands of women and couples have resorted to assisted reproduction techniques to achieve pregnancy. One of the main factors is the age at which, on many occasions, patients attempt to conceive. Unfortunately, the more advanced the age is, the more incompatible it becomes with a natural pregnancy. It is at this point that many patients seek the help of the clinics to diagnose the problem that hinders pregnancy and begin the most appropriate treatment to achieve it.

Today, In Vitro Fertilisation (IVF) treatments, a procedure in which the oocytes of the patient are fertilised with a sperm sample from her partner (if any) or from an anonymous donor, currently offer high success rates. However, after the selected embryo is transferred to the uterus of the patient, it may fail to implant and thus not result in pregnancy. There are many possible causes as to why this may occur. You will find them explained below.

WHAT ARE IMPLEMENTATION FAILURES?

When we are faced with a possible implantation failure, it is important to understand that not only factors related to the embryo itself can play a role in this occurrence. We can also find factors affecting the patient herself that hinder the correct implantation of the embryo.

TO EXPLAIN THE POSSIBLE CAUSES OF IMPLANTATION FAILURE, WE WILL DIFFERENTIATE BETWEEN THE CAUSES ASSOCIATED WITH THE EMBRYO ITSELF AND THOSE RELATED TO THE PATIENT

Implantation failure due to embryonic causes:

When the failure is associated with any sort of problem in the embryo, the most frequent cause is a genetic alteration, appearing spontaneously in the embryo or having its origin in any of the progenitors.

In this regard, and even more so if one or both members of the couple are close to or over 40 years of age, it is advisable to carry out a genetic analysis of the embryos as part of an In Vitro Fertilisation treatment. By this means, we can select only those embryos that are free of any chromosomal alteration and thus increase the chances of achieving pregnancy and the conception of a healthy baby.

Implantation failure due to patient-related causes:

When the causes that prevent the adhesion of the embryo in the uterus of the patient are linked to factors related to the woman herself, there is a wider range of problems that can lead to implantation failure. From endometrial problems, uterine malformations to even immunological causes that make it unfeasible for the embryo to implant in the uterus.

THE MOST COMMON MATERNAL CAUSES ARE:

Anatomical alterations:

In some cases, the patient may present a myoma, polyp or malformation that affect the endometrial cavity and, consequently, hinder the implantation of the embryo. The patient may also present fallopian tube damage which indirectly impairs the embryo, as occurs in the case of hydrosalpinx.

Endometrial problems:

As mentioned above, the endometrium is not always ready for the embryo to implant, which occurs during certain days within the menstrual cycle.

The period of time in which the endometrium is receptive is called “implantation window” and should coincide with the time at which the embryo is transferred. Nowadays, we have tests that allow us to determine what the implantation window of a patient is and thus, as part of an In Vitro Fertilisation treatment, perform the embryo transfer on the most convenient day.

Immunological disorders:

In some cases, our own body may provoke an inflammatory reaction that rejects the implantation of the embryo. This may occur as a consequence of chronic endometritis or in cases in which our body reacts to the embryo as if it were a “foreign body”, as for example in patients who present signs of autoimmunity with alterations in their defence mechanisms.