Reproductive immunology

Reproductive immunology is a field of study that looks at how a woman’s immune system reacts when she becomes pregnant. Usually, your immune system works by fighting off any invading cells that it doesn't recognise because they don't share your genetic code. In the case of an embryo, the immune system learns to tolerate it even though it has a different genetic code from the mother.

Some scientists believe that in some cases of miscarriage or infertility, the mother’s immune system may fail to accept the embryo due to these differences in their genetic codes.

There are various different treatments associated with reproductive immunology, which are used to suppress the body’s natural immunity, and all of which have risks:

• Steroids (e.g. prednisolone): Risks include high blood pressure, diabetes and premature birth.

• Intravenous immunoglobulin (IVIg): Side effects can include headache, muscle pain, fever, chills, low back pain, and rarely thrombosis (blood clots), kidney failure and anaphylaxis (a bad allergic reaction to the drug).

• Intralipid infusions: Side effects include headache, dizziness, flushing, nausea and the possibility of clotting or infection.

There is no convincing evidence that a woman’s immune system will fail to accept an embryo due to differences in their genetic codes. In fact, scientists now know that during pregnancy the mother’s immune system works with the embryo to support its development.

Not only will reproductive immunology treatments not improve your chances of getting pregnant, there are risks attached to all these treatments, some of which are very serious.

We concur that there is no convincing evidence of randomised trial level to support immune testing and as such do not offer it as a first line treatment.

The most extensively studied group of immune cells are a type of lymphocyte (white blood cell) called natural killer cells (NK cells), that act as frontline in the protection mechanism of the body to attack infection and potential cancerous cells and are the most abundant immune cell in the uterine lining after ovulation.

Our reproductive immunology research team at the Lister Fertility Clinic, led by Dr Yau Thum, has been involved in research in the area of natural killer cells and immunological aspects of recurrent failed implantation since 2003 and have published papers demonstrating that an "overactive" immune system may negatively affect pregnancy outcomes and IVF success rates.

See Dr Yau Thum's profile

Following this research performed in conjunction with an immunologist, we historically offered an immune screening test based on these research findings. This test is not offered as a first line test in any couple and is now only occasionally performed in those limited couples with multiple cycle failure of top quality blastocysts with no other cause of cycle failure found. The information provided is in keeping with the HFEA / RCOG recommendations and given to all patients prior to testing or treatment.

Currently, we are conducting several in-depth Reproductive Immunology PhD Research projects in collaboration with Imperial College, all of which have national ethical committee approval. These Immunology projects are looking into any potential association of cellular immunology and metabolomics with recurrent failed implantation.

A fertility "add-on" is an "optional extras that you may be offered on top of your normal fertility treatment, often at an additional cost. They’re typically emerging techniques that may have shown some promising results in initial studies but haven’t necessarily been proven to improve pregnancy or birth rates."

The HFEA "traffic light rating" for treatments relating to reproductive immunology is "red", suggesting that no good evidence to show that they are effective and safe.