FEMALE INFERTILITY AND ITS CAUSES

For a long time, the thought spread that it was the woman who was responsible for the generation of the couple's children. So if the couple had no children, the problem was with the woman. At that time, these conclusions were validated more by prevailing social concepts than by science. However, partly thanks to these thoughts, a more detailed study of the physiology of female reproduction occurred so that the many facts connected with the feminine side of reproduction could be better clarified.

Nowadays, although it is known that the causes of infertility are equal between men and women, the study of female physiology, started earlier, has left a legacy in terms of diagnosis and treatment more massive than the male studies.

In general, the causes of conjugal infertility linked to the female factor can be divided into 4 groups:

1. Ovarian and ovary causes
2. Tubal and endocervical canal causes
3. Causes linked to Fertilization (Union of sperm and egg)
4. Causes associated with implantation of the embryo (passage from the tubal embryo to the uterine cavity and penetration into the endometrium)

1. Ovarian and Ovary Causes

One of the diseases that occur with lack of ovulation is the so-called polycystic ovary syndrome (or chronic anovulation syndrome) in which the patient has irregular uterine bleeding, usually every 2 to 3 months, and ultrasound examination shows the ovarian follicles (pockets of fluid that may each contain an ovum) often located at the periphery of the ovary (see figure). As these patients may have increased male hormones (androgens), they sometimes have increased hair and, more rarely, hair loss. They may also present obesity and the body's difficulty in assimilating carbohydrates (present in sweets and farinaceous foods: cakes, pies, etc.), due to insufficient insulin action.

In premature ovarian failure (or early menopause), the ovaries stop maturing the eggs, so that ovulation ceases. In general, patients have no menstrual cycle and menopause-like symptoms (especially hot flashes or hot flashes). The causes of the disease are manifold: radiation, chemotherapy, genetic syndromes, ovarian infections, autoimmune diseases and others.

Excess secretion of prolactin ( hyperprolactinemia ) alters the control mechanisms of the ovaries and induces several failures in the menstrual cycle, which can culminate in a lack of menstrual cycle and ovulation. Similarly, diseases that affect the thyroid (especially hypothyroidism) make it possible to produce similar changes.

Another very important cause of egg reduction is the age of the woman. With aging, the woman progressively produces fewer and lower quality eggs. This process basically starts at age 37.

2. Tubal and endocervical canal causes

The tubal blockage prevents the egg collection and transport so that there is no possibility of fertilization by sperm. Eventually, the tubas dilate a lot, which is visible in the specialized examination. There are two main causes of this disease: endometriosis and pelvic infections.

In endometriosis, fragments of the endometrium penetrate the tubas (retrograde menses) and produce inflammation, which ultimately changes the function of the tuba, which is the transport of gametes. Sometimes, endometriosis also extends to the ovaries, damaging the formation of follicles. There are patients who have a more severe form of endometriosis, which begins when they begin to menstruate: in general, they are younger patients and in that case, the risk for fertility is greater due to the more aggressive potential of the disease.

A very typical symptom of this disease is pain during sexual intercourse and very strong menstrual cramps.

The pelvic infections, which in many cases are asymptomatic, are caused by microorganisms that can migrate from the vagina to the uterus and oviducts. Like endometriosis, it produces inflammation whose healing promotes healing that ultimately changes the functioning of the tubes. The greater the frequency of gynecological infections, the greater the chance of tubal involvement.

The cervical mucus, secreted by the cervix (cervix), must be penetrated by the spermatozoa, on its way to fertilize the egg. Its secretion depends on hormones produced by the ovarian follicles (estradiol); therefore, changes in ovulation may, indirectly, hinder the production of mucus. Other conditions that alter the secretion of this mucus and contribute to infertility: are cauterizations of the cervix and surgeries for cancer of the cervix.

3. Causes of Fertilization

Fertilization depends on the vigor of the sperm and egg. First, the spermatozoid must pierce the outer layer of the egg and penetrate the inside of that cell. On that occasion, by means of a process that involves the chromosomes of the two gametes, the egg or zygote is formed that initiates a cellular division and will form, in the future, the embryo. If there are defects in the chromosomes or other structures that regulate the fusion of the two gametes, there will be no fertilization. The greater the age of the patient (especially the woman) the greater the difficulty for fertilization. Likewise, exposure to risk factors (X-rays, radiation, toxic medications) can make it difficult or prevent it.

4. Causes associated with implantation of the embryo

Implantation is the penetration of the embryo into the lining of the uterine cavity, called the endometrium. This coating is prepared to receive the embryo formed after ovulation and fertilization. Female hormones (estrogen and progesterone) are responsible for preparing the endometrium during the menstrual cycle. Therefore, hormonal failures may produce an endometrium that is unsuitable for implantation. The conditions that reduce the probability of implantation are:

• Inadequate development of the endometrium: even with normal hormones, it can react exaggeratedly and produce a non-favorable condition for pregnancy: hyperplasia. Sometimes, this hyperplasia is localized, forming a polyp. When the endometrium does not grow or grow very little, we speak of hypoplasia, also negative for implantation;
• Endometrial infections ( endometriosis ), caused by sexually transmitted diseases or by manipulation of the endometrial cavity (in dressings, for example).
• The adhesions uterine: areas scars within the uterine cavity from infections or curettage. In addition to making implantation difficult, they cause abortion;
• The uterine malformations: although some such changes do not completely prevent pregnancy, may hinder obtaining and cause abortion (as the uterus or bi unicorn);
• The fibroids: although they are attached to abortion processes, it is believed that if large and located immediately below the cavity, invading it can also impair embryo implantation.