It has been described that the implantation of an embryo in the maternal uterus is considered a successful allograft. In the fetus, half of its genetic information belongs to the father, and as a consequence half of its antigens should be recognized as foreign by the mother’s immune system. We know that the mammalian placenta has developed two fundamental functions during evolution, to eliminate pathogens and to protect the fetus from immune rejection.

For gestation to be successful immunologically speaking, it requires the interaction of multiple factors, such as: hormones, cytokines and factors that suppress T-lymphocyte activity. A correct interaction will determine that the mother develops tolerance towards the fetus and vice versa.

But what is implantation failure?

It is defined as the failure to achieve pregnancy after IVF treatment, either because it does not implant from the beginning or because of miscarriage.

If everything went well, why not implant my embryo?

Implantation failure is one of the challenges that causes the most headaches for patients and reproductive specialists. There are many couples who go to assisted reproduction centers, and after a normal IVF treatment, with good quality embryos and where everything went well, they do not achieve the desired pregnancy. In many occasions we must think about implantation failure when we do not see any other cause that justifies this non-pregnancy.

Why does it happen?

The cause of repeated pregnancy loss is multifactorial, and can be divided into embryological causes (mainly due to an abnormal embryonic karyotype), maternal causes, affecting the endometrium and/or placental development (Aplin, 2000) and hormonal causes, although more than 60% of the cases are of unknown cause. (Kwak, 2003) .

The study of the genetics of the progenitors as well as that of the embryo can clarify this failure and shed light on the anguish and despair that patients suffer when they do not know why, but their embryo does not implant.

What tests can we take to learn more about this failure?

Well, nowadays a multitude of tests and trials are still being developed in order to advise the couple as well as possible before starting an in vitro fertilization treatment.

We can perform exhaustive studies of the male, female and embryo.

In the male, we could perform a seminogram analyzing DNA fragmentation, sperm FISH and karyotyping.

In the case of women, it would be convenient to perform karyotype, thrombophilias study, cytokine study, detailed hormonal analysis and thyroid function.

  • Study of thrombophilias: That is, the tendency to cause thrombosis as a consequence of hereditary or acquired hemostasis alterations.
  • Cytokine study: By means of cytokines we study the immunological behavior of rejection against the embryo. The ratio of the different types of cytokines varies during each woman’s period and can predict the success or loss of the pregnancy ( Laird, 2003).

In the embryo, once the assisted reproduction treatment has started, we could perform genetic diagnostic tests by means of
in the IVF laboratory. These tests do not allow us to anticipate the cause of implantation failure a priori, but would help us to transfer the chromosomally normal embryo or embryos. This would help reduce the abortion rate.

Once the pertinent studies have been carried out, if we know the cause of this implantation failure, we can carry out the most suitable treatment to treat it. Our priority is to achieve a full term pregnancy with a healthy child, therefore, we will perform all the necessary tests to find the cause of infertility and treat it correctly.

If you have any other questions, our gynecological and biological team will be happy to help you.

E. Gonzálvez

Contact our fertility clinic.

Vithas Perpetuo Internacional. Plaza del Doctor Gómez Ulla 15, in Alicante.

Phone: 965230397 / +34 606437458


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