Recurrent miscarriage is a fairly common cause of infertility, and even in fertile women, as many as one in four pregnancies ends in miscarriage.
In some cases there are complex medical reasons behind the miscarriage, which may be causing infertility. One of these medical conditions is known as embryo toxic factor.
What Is Embryo Toxic Factor?
This is a condition where the woman's white blood cells, which are part of her immune system, produce a substance called a cytokine in excess amounts. Cytokines are a normal part of our body's defenses, but sometimes the immune system will react to the growing embryo as if it were a foreign body and try to eliminate it, resulting in miscarriage.
How Do I Know If I Have Suffered From Embryo Toxic Factor?
If you have had more than three miscarriages you will be offered standard fertility tests such as ovulation tests and sperm tests for your partner to try and establish why you are miscarrying. If no cause for the problem can be found, it may be possible to have a test for the condition.
However, testing for embryo toxic factor is still new and considered experimental so you may not automatically be offered the test.
If you are offered the test, a blood sample will be taken to see whether your white blood cells are producing excess cytokines. These white blood cells will be isolated from your sample and left to grow in a lab for several days. Then some mouse embryos will be added to the blood to see if the blood cells kill them. If the mouse embryos die, you have embryo toxic factor, and if they continue to develop, you don't.
What Treatments Options Are Available?
As the immune system is over-reacting, or reacting in an abnormal manner, an agent to suppress the immune system into accepting a pregnancy is the usual course of treatment. This is done with the hormone progesterone which can be given by vaginal pessary, regularly, up to week 20 of pregnancy. Sometimes injections are given instead of pessaries.
Progesterones can help to increase fertility hormones as well as acting as an immune system suppressant in higher doses. You will need a full medical history taken to ensure you are a suitable candidate for this type of hormone therapy.
A blood transfusion can be given to replace the cytokines with 'embryo friendly' blood, and this would be done on a regular basis.
How Do I Obtain Treatment?
If you have been diagnosed, you can ask your IVF doctor for treatment, or get a referral to a fertility specialist from your family doctor.
