Unexplained Infertility — Causes and diagnostic
In some cases, couples who face infertility problems learn that their diagnosis is sterility of unknown origin (unexplained Infertility). However, do not despair. In such situations, it is necessary to use all the existing methods of diagnosis that can shed light on the problem. Most of these diagnostic tests are carried out in research clinics.
For the first time, the diagnosis of unexplained infertility was made (got its name) in 1951. However, in our time, despite the progress in science and technology, this diagnosis still exists. 10 to 30% of infertile couples face this diagnosis.
Sterility of Unknown Origin: Diagnostic Criteria
The diagnosis of unexplained infertility is made when conception does not occur despite
- normal fertilizing capacity of the sperm;
- normal ovulation in a woman of reproductive age;
- fallopian tubes are clear and open;
- absence of any pathological processes in reproductive system.
Thus, sterility of unknown origin is a condition, under which conception does not occur, and the main modern methods of diagnosis fail to identify the specific cause of this pathological condition.
Often, when couples face the problem of unexplained infertility, the real causes of infertility are:
- Minimum forms of endometriosis;
- Obstruction of the fallopian tubes, which is not detected by diagnostic methods;
- Immune incompatibility at different stages of fertilization and implantation;
- Decreased ovarian reserve (decreased number of oocytes)
- A pathological condition of the endometrium, which disrupts normal implantation
- Change of the genetic material of germ cells
- Minimal imbalances in the hormonal regulation of the complex process of conception.
Immunological causes of Unexplained infertility.
In most cases, the real causes of sterility of unknown origin are immunological. They include the following pathogenetic conditions:
- presence of antiphospholipid antibodies that damage cell membranes;
- presence of antibodies to thyroid hormones or their receptors;
- presence of antibodies to sperm, which reduce sperm motility and/or its ability to fertilize;
- presence of antibodies to ovary tissues, which can disrupt hormonal regulation of the menstrual cycle;
- changes in the system of helper and suppressor immune cells that cause tissue damage;
- increased activity of natural killer cells (a special type of immune cells);
- presence of antibodies to gonadotropins (hormones produced by the pituitary gland and stimulates the synthesis of female sex hormones);
- increased immune sensitivity to chorionic gonadotropin, which stimulates ovulation and promotes normal process of implantation.
Due to the multifactorial nature of the causes of unexplained infertility couples are to undergo diagnostic testing. First and foremost, you need to test your thyroid gland, hormone levels, and presence of antibodies to the thyroid tissue. So, in numerous studies it has been shown that diseases of this organ (e.g., autoimmune thyroiditis) significantly increase the risks of infertility, and the frequency of early pregnancy termination.
The immune status of the couple is also to be tested. In this context, it is necessary to assess the level of helper and suppressor cells, natural killers, and also examine the condition of the major histocompatibility complex. Immunophenotyping allows to obtain very valuable diagnostic information.
Women who are diagnosed with unexplained infertility of unknown origin should test the ovarian reserve. It allows to estimate the state of the follicular apparatus (both qualitative and quantitative). Scientific research has allowed to establish the major factors that increase the risk of developing ovarian failure. Special attention is paid to:
- The age of the patient;
- The level of follicle-stimulating hormone;
- The concentration of inhibin B;
- The level of antimullerian hormone;
- The level of estradiol;
- Ultrasonic criteria (the number of follicles in the antral stage of development, the total volume of the right and left ovaries separately, Doppler characteristics of blood flow in the ovaries);
- Hormonal tests.
It should be noted, that the concentration of the aforementioned hormones (estradiol, antimullerian hormone, inhibin, follicle-stimulating hormone) should be performed simultaneously. The best time is the second or third day of menstrual cycle i.e. early follicular phase.
The level of antimullerian hormone indirectly indicates the number of follicles of small diameter, as this hormone is developed in them. Larger follicles are unable to affect the concentration of this hormone. Therefore, it is possible to estimate the quantitative characteristic of the antral follicles.
In conclusion, it should be noted that of unexplained infertility is a serious problem in medicine. Still effective treatment is possible by means of eliminating the most likely causes.