Natural Killer Cell Testing

The Role of Natural Killer Cells in Recurrent Implantation Failure in Women Undergoing Treatment using Assisted Reproductive Techniques

What is the purpose of this study?

During pregnancy the foetus develops in the womb attached to the mother’s blood supply. This is a unique situation when a tissue, which is substantially different from that of the mother, survives for a long period without rejection. The mechanisms that allow this process to happen are far from understood.

Recently a specific type of cell in the human immune system, so called Natural Killer (NK) cell, have received attention both in the scientific community and in the media. Small studies claim that increased numbers or increased activity of NK cells in the mother’s blood may result in the failure of a fertilised egg being implanted in the lining of the uterus, potentially causing infertility or poor outcome in vitro fertilisation (IVF).


natural killer cells The Role of Natural Killer CellsTo the contrary, NK cells present in the lining of the womb have been claimed to be beneficial for the development of pregnancy, by supporting the development of the placenta. A lack of such cells in experimental animals causes abortions or results in small babies.

There are several treatment options offered to women wishing to become pregnant via assisted fertility, such as IVF or intrauterine insemination. However, the scientific justification of these treatments is weak while the risks could be substantial.

The purpose of this study is to investigate further whether measuring the characteristics of NK cells either in the blood or the womb of non pregnant women could be used to identify individuals who are likely to experience problems in conceiving.

Women who have a history of failed pregnancies or failed IVF attempts. An