Reproduction is a complex process that requires a set of genetic and biochemical steps and interactions that go through the formation of gametes, fertilization of the egg by the sperm, implantation in the uterus and the subsequent formation and development of the embryo.
All these steps cause fertilization to lose efficiency in each one of them, finally reaching 20% efficiency in humans, which is not a very high percentage. In recent years, these difficulties in conceiving are beginning to be a real social problem that affects 15% of couples.
Such complications can come from several factors on one side and on the other side of the couple. Currently, it is estimated that 35% of infertility has its origin in the man, another 35% in the woman and the remaining 30% to problems that come from both partners.
Adequately detecting the origin of infertility can save us a lot of suffering. Going through this uncertainty generates anxiety, sadness and impotence in those who wish to successfully carry a pregnancy to term; and with each failed attempt these feelings are only accentuated and rejection of possible new techniques or treatments develops.
What are the differences between sterility and infertility?
Although we use these terms interchangeably in our daily lives, they do not mean the same thing: sterility is the inability of an individual or couple to conceive, while infertility prevents a couple from carrying a pregnancy to term with a live newborn.
Among the types of infertility, idiopathic infertility is the one that usually causes the most problems in its identification because its origin is unknown.
What is the relationship between telomeres and infertility?
Short and/or damaged telomeres have often been related to many processes involved in infertility, such as the interruption of gametogenesis, defects in synapsis and recombination between homologous chromosomes, also affecting the formation of the meiotic spindle. It has also been shown that short telomeres are related to reproductive aging, increase the incidence of aneuploidy (alteration in the number of chromosomes) in human oocytes II and induce DNA fragmentation and disruption of telomere-telomere interactions in human spermatozoa.
Similarly, a direct link has been found between male infertility and an enzyme that is very important for telomeric health, telomerase. This enzyme is expressed in early embryos and most cancer cells, and has the ability to restore shortened telomeres. The presence of telomerase activity in male germ cells ensures the maintenance of telomere length at maximal levels during spermatogenesis despite telomere attrition due to DNA replication or other genotoxic factors.
These gamete telomere problems cannot currently be detected with generic infertility screening techniques; they require more advanced technologies for diagnosis.
¿What techniques are used to detect infertility?
In men, the best known technique is the performance of a seminogram, that is, the analysis of a semen sample. Once obtained, several characteristics are analyzed, both of the spermatozoa and seminal plasma: concentration or number of spermatozoa per millimeter, their motility and morphology. Applying an effective treatment to improve these parameters is quite complicated and so far nothing has been found that substantially improves any of them.
On the other hand, a genital examination of all parts of the reproductive tract can be performed to rule out any physical abnormalities.
It is much rarer to find that the problem occurs in alterations in coitus, but if so, an attempt should be made to find the cause and apply appropriate treatment as far as possible.
The last test that can be performed is a genetic study where hereditary diseases or other factors such as telomeric alteration can be observed, which would explain some infertilities that are undetectable with the other tests.
The study of telomeres is quite complicated if you do not have sufficient means, but Life Length has the TAT® technique, which allows us to observe telomeres at a tiny size, reaching nanometers; and detect these cases that go unnoticed and are classified within idiopathic infertility. For this reason, we are in the process of developing an IVD test that could be implemented in the future with the rest of the tests that are routinely performed today.
In the case of women, one of the first steps is to perform hormonal tests to detect abnormalities in the hormones involved in fertility:
- Progesterone: hormone directly associated with ovulation.
- Follicle stimulating hormone (FSH): promotes the production of eggs and estradiol. A high FSH content could indicate ovarian failure or menopause and a low one that the woman has stopped producing eggs.
- Antimüllerian (AMH): blood levels indicate the presence of growing ovarian follicles.
In addition, other tests can be performed to examine the female reproductive system, such as checking for obstructions in the fallopian tubes that prevent the exit of the egg, evidence of polycystic ovaries, or the study of scars, fibroids or polyps inside the uterus through vaginal ultrasound, hysteroscopy or sonohysterography.
Genetic studies can also be performed in women, but they present a greater number of problems. On the one hand, gamete retrieval is much more costly and traumatic for the woman than for the man and, on the other hand, there is a much smaller number of gametes available for analysis. Sometimes these genetic studies can be performed in other parts of the reproductive system, such as in the endometrium, since many problems in carrying a pregnancy to term are detected in the implantation of the embryo.
We can definitely speak of a diagnosis of idiopathic infertility in men when normal values have been recorded in the semen, as well as physical and endocrine abnormalities have been ruled out, in addition to a female factor of infertility. The percentage is 15%, although in the published articles it varies between 6% and 37%.
In women this diagnosis is made following the same criteria, studying irregularities in the reproductive and endocrine apparatus, and ruling out male infertility.
What assisted reproduction treatments are available?
The vast majority of assisted reproduction treatments are currently focused on women due to the biological restrictions they suffer. After a certain age, egg quality is gradually lost, in addition to the possibility of suffering from diseases that prevent good implantation in the uterus, as is the case of endometriosis, which we mentioned previously.
This is in addition to the fact that some techniques solve problems such as reduced sperm motility or low sperm count, since in these cases we would only need one healthy sperm to fertilize an egg under controlled laboratory conditions.
Assisted reproduction treatments are usually expensive and have a high impact on the woman:
- In vitro fertilization: externally fertilizing an egg with a sperm under laboratory conditions and subsequently implanting it in the uterus.
- Insemination: consists of introducing a semen sample in the uterus at the optimum moment of ovulation under the best conditions.
- Ovodonation: egg donation.
- Vitrification: freezing one’s own eggs at a younger age in order to be able to pursue pregnancy at another time.
In the vast majority of cases these techniques are associated with taking medication to produce the appropriate level of hormones in the woman and thus carry to term the implantation in the uterus optimally and achieve a pregnancy.