What is reproductive immunology?

Reproductive immunology is the study of how the immune system and reproductive system interact during conception and throughout pregnancy. The immune system is the body’s defence mechanism, protecting against infection. When a foreign body is identified, it is seen as a threat and destroyed. Reproductive immunology studies how the body accepts a pregnancy, despite the immune system constantly fighting foreign bodies. It is a new and complex science that aims to identify whether the mother’s immune system is modified to prevent the rejection of a fertilised embryo and if so, how this happens.

Reproductive immunology tests are carried out by fertility specialists.

Why is reproductive immunology important?

Although there is no definitive explanation as to how, the female body’s immune and reproductive systems have evolved in a complex and unique way that allows the mother to accept a fertilised egg. For example, the implantation of the embryo is only possible due to an optimally inflamed lining of the uterus, which is the result of an immune response. In some cases, however, the body does not accept the implanting of the embryo or the development of the foetus. This may be due to an immune system imbalance. Studying how the immune system adapts during a pregnancy is critical to be able to understand and treat various pregnancy complications correctly.

What complications can be caused by the interference of the immune system?

The immune system may incorrectly identify a fertilised embryo as a foreign body and treat it as a threat. In such cases, the following complications may be caused by an immune imbalance:

• infertility
• unexpected difficulties conceiving
• miscarriages and RPL
• repeated IVF failure

Miscarriage (or pregnancy loss) is a common experience that occurs in between 10-20% of known pregnancies. Miscarriages are normally a result of the abnormal development of the foetus and are generally random or isolated occurrences. However, if someone experiences recurrent pregnancy loss (RPL), they have had two or three consecutive pregnancy losses and it may be due to an immunology disorder, which is determined through testing. Tests are carried out by reproductive immunologist aim to determine the cause of these complications. The reproductive immunologist will also take into consideration the patient’s history of immune disorders or thyroid diseases, as well as placenta related complications experienced in previous pregnancies.

What tests are offered?

There are numerous tests that are carried out to determine what the cause of infertility or complications is. Some examples are:

• Reproductive immunophenotype (RIP) measures the white blood cells to see if they are being abnormally elevated causing an immune response to the developing embryo. 
• Antinuclear antibodies (ANA) tests, used for high levels of antibodies which complicate pregnancy. 
• Antiphospholipid antibodies (APA) tests that look for proteins capable of increasing blood clot risk or pregnancy loss.
• ANTI-DNA tests determine if the woman’s immune system registers the embryo as a foreign body and mounts an immune attack to protect the mother.
• Thrombophilia tests, to determine the likelihood of blood clots in the placenta and womb, leading to loss pregnancy loss.

What other factors affect conception and pregnancy?

While the immune system plays a vital role in pregnancy, there are other, non-related factors which may affect a woman’s fertility, such as:

•  age
• other health conditions
• health of the reproductive system
• lifestyle

If you are having difficulties conceiving, your GP or gynaecologist will be able to assess your general health and if necessary, refer you to a fertility specialist to determine the cause of the complications.