We often have good quality, healthy embryos, but in spite of this we are unable to obtain a viable pregnancy (cases of repeated implantation failure), or we obtain a pregnancy but it does not progress (cases of recurrent miscarriage). Although not always the case, there are often underlying immune problems which prevent the mother from accepting the embryo.

Immunology is one of the physiological pillars essential to achieving a pregnancy, as the success of a pregnancy depends on correct immune balance.

Pregnancy is a challenge and an immunological paradox for the mother, as her immune system must allow a semiallogeneic embryo to implant (an embryo that shares 50% of her genetic material) or even an allogeneic embryo to implant (100% of the embryo’s genetic material is different from the mother’s). According to the laws of transplantation immunology, the mother should reject this different genetic material. However, under normal conditions embryo implantation is tolerated.

The necessary immune tolerance processes which prevent the mother from rejecting the embryo are extremely complex, and at present we do not even understand all the mechanisms which allow for normal implantation and development of the embryo inside the mother’s womb.

Immune system tolerance or rejection conditions implantation. In reproductive immunology we strive to pinpoint the factors involved in the early stages of pregnancy so that we can adjust them as necessary to offer personalised solutions on a case-by-case basis.

Several groups around the world are studying these processes of tolerance and rejection, as well as how changes in the immune system make it possible for abnormal embryos to implant but to later end in miscarriage, or how they prevent genetically healthy embryos from implanting.

We also study whether interaction between the mother and the embryo is correct or not, as this can lead to gestations that stop developing before they can be seen with an ultrasound (chemical pregnancy) or after they’ve already been seen on an ultrasound (anembryonic gestation – blighted ovum - or delayed miscarriages).

New studies are showing the relationship between implantation issues and pregnancy conditions such as pre-eclampsia or intrauterine growth restrictions.