I have made more than five IVF attempts and although I have had good quality embryos I can’t get pregnant. Why?
Although ovulation suppression and stimulation protocols in IVF have been enhanced over the past years, success rates are rarely over 30% in each cycle.
What we definitely know is that a large number of unsuccessful IVF cycles is due to asynchronous endometrial and embryonic development, and is possibly related to poor egg and embryo quality as well. There are also other determining factors related to the role our immune system plays in reproduction.
After the embryos are implanted until the 8th or 9th day I have all the pregnancy symptoms, but around the 14th day my pregnancy test comes out negative. What is wrong?
In a number of cases, even though Beta human chorionic gonadotropin (B-HCG) levels rise on the 5th, 7th and 9th day after embryo transfer, which is an indirect sign of successful implantation, pregnancy test results are negative in the next days (around the 12th or 15th day). Never has the “death” of a living creature been caused by chance. Something has gone wrong. According to existing bibliography, implantation failure is attributed to immunologic causes and these are what research has focused on, so that immunological factors can be determined and suitable treatment can be given to patients.
I have experienced unexplained IVF failures. What could be the cause?
Most couples experiencing unexplained IVF failures will find great difficulty in conceiving if they do not have thorough tests to determine the exact immunologic dysfunction that causes each failure and treat it accordingly. In other words, repeated implantation failure in IVF is not rare, and rates mentioned from time to time in scientific studies vary.
Over half of the couples reporting two, three or more unsuccessful IVF cycles, are not diagnosed with any physical disorder or disease. Chromosome testing, evaluation of hormone levels, screening for uterine disorders (salpingography, hysteroscopy and laparoscopy), as well as culture for microbes do not give any effective solutions and the problem of repeated failure remains.
Immunological factors have recently been identified as the main cause for recurrent unexplained IVF failure, since the prevalent belief is that the embryo in the uterus behaves like a “transplant” of a foreign tissue, with that foreign tissue being the father’s genetic material and the mother being the “recipient” of the transplant.
Please explain to me, what are miscarriages due to immunological factors?
Generally, miscarriages fall into three main categories:
Blocking antibodies (Anti-paternal antibodies)
Paternal tissue which defines who the father-to-be is as an individual (meaning as a biological genetic unit) is carried by the spermatozoa and is imprinted on the newly formed placenta (embryotrophoblast) of the pregnant woman at the beginning of pregnancy. All the information coming from the father is encoded through a genetic process. This information then determines a genetic locus called HLA-G antigen whose role is actually to warn the mother-to-be (i.e. her immune -defensive system) that the “implant” is an embryo, in order for her organism to react accordingly (meaning in a “friendly” way), and not attack the embryo as if they were invading cells (such as a germ or cancerous cells).
As a result, the mother’s immune system produces some useful substances called blocking antibodies or protective antibodies. This is considered to be vital for the survival of the newly formed placenta and therefore, for the development of the embryo. The moment these antibodies are produced by the woman, they in a way create a shield around the placenta so that the paternal HLA-G antigen is disguised. Otherwise, as a foreign tissue it would be attacked and destroyed by the mother’s immune system.
This, however, does not happen; due to the presence of protective antibodies, the mother’s immune system does not recognise the foreign paternal tissue that the embryo carries, so her defence mechanism is not activated against the embryo (whose half tissue is foreign to her since it comes from the father).
It is obvious that failure to produce protective antibodies leads to placental and foetal death. Clearly, if the mother is potentially unable to produce protective antibodies, or if you wish, if the father fails to stimulate the mother to produce protective antibodies, the gestational tissue is rejected or in other words, the foetus is unable to survive.
In order to deal with this problem, researchers in immunology centres in America, Canada, England and Greece administer medication which stimulates blocking antibodies production.
Anti-phospholipid antibodies (APA)
Phospholipids are vital structures on the surface of many cells and some of them play an important role as “attachment” molecules and are correlated with the ability of cells to join in order to create syncytia (hives), including the development of the cytotrophoblast into a syncytiotrophoblast. This means that part of the implanted embryo becomes the placenta.
“Many times antibodies are produced against phospholipids. They are called anti-phospholipid antibodies (APA). Reasons for APA could be various diseases but in a considerable number of seemingly healthy people there are no subjective causes. Their presence is imputed to an alteration in the woman’s immune system due to various environmental and food allergens.”
APA presence indicates an acquired disorder of blood proteins (also called plasma proteins) related to vascular thrombosis. Actually, this is the most common disorder correlated with vein and arterial thrombosis, as well as reproductive failure due to vascular thrombosis of the feto-placental unit (necrotizing angiitis of the decidua). Therefore, correlation of anti-phospholipid antibodies with IVF failure has been attributed to the fact that anti-phospholipid antibodies affect the initial process of angiogenesis, which occurs during implantation and is vital for the maintenance of pregnancy.
Antibodies against certain phospholipids, such as serine and ethanolamine, may have a negative effect on foetal development due to another reason too.
The reason is that they do not allow the cytotrophoblast to develop into a syncytiotrophoblast. Their presence disrupts molecular coherence of an implanted embryo (placenta) since phospholipids play the role of a connecting link between cells. Anti-phospholipid antibodies screening should be done prior to gestation because treatment must also begin before pregnancy so that antibody levels are low at the time of implantation.
Natural Killer cells
Protection of the foetus is achieved in many ways, but mainly by protective antibodies produced by the mother’s immune system in response to paternal cells of the embryo.
There are however, other mechanisms which prevent the rejection of the implant- embryo. One of them is the partial suppression of some cells of a mother’s immune system whose role is to react negatively against any foreign invader.
These cells are called Natural Killer cells (NK). They are used by our organism as the first line of defence against viral infections and cancerous cells. Additionally, they are the most abundant cell population present in the uterus (decidua) at the time of implantation of the fertilised egg (embryo), and their role in maintaining a pregnancy is very important. Under normal circumstances, they control excessive invasion of the trophoblast into the decidua (that is to say of the embryo into the endometrium of the uterus); they control any ascending infections in the feto-maternal surface and they also play a significant role in the normal development of the trophoblast and the embryo by secreting cytokine.
On the other hand, since they do not need any special preparation to identify their target and initiate action, they might in some cases have an adverse (cytotoxic) effect on the trophoblast, meaning the implantation site, without any obvious reasons.
It is therefore vitally important to know what NK cell function is (if they have an assassin-like nature against the embryo) in women experiencing recurrent IVF failure, despite ideal conditions of stimulation- fertilisation- implantation. This methodology should be closely followed because firstly, it helps us diagnose the problem, and secondly, it provides us with guidelines for methods of treatment.
There are specialised examinations which give us essential information on whether there is high concentration of NK cells in the pre-implantation endometrium, and whether these cells have an active assassin-like nature against cells of the newly formed embryo.
Consequently, besides the number of NK cells in the blood and the uterus, we also need to check what their function is, since this could determine the course of a future pregnancy
What tests should I have?
Besides the necessary hormone tests a woman should undergo the following:
- Anti-paternal antibody test
- antiphospholipid syndrome and thrombophilia screening tests
- natural killer cells blood test
The cost of all these examinations is much lower than that of an IVF cycle of treatment. It is therefore in a woman’s best interest to get tested. The completion of these examinations under an expert’s guidance will play an essential part in making a woman’s dream to become a mother come true.