Dysfunctional uterine bleeding: causes and pathogenesis

Causes of violations of the menstrual cycle (the correct cyclic functioning of the reproductive system) can be very diverse, sometimes combined with each other. The place of application of the damaging effect can be located at any level of regulation of the menstrual cycle, but usually, due to the close interrelation of all links of the reproductive system, the whole chain is involved in the pathological process. Often, the same causative factor leads to disruption of the function of several levels of the neuroendocrine system.

Among the etiological factors that cause menstrual irregularity in the type of dysfunctional uterine bleeding, acute and chronic infections, intoxications, occupational hazards, vitamin deficiencies, stressful situations, physical and mental fatigue, severe somatic diseases, disorders of the function of the peripheral endocrine glands (thyroid, adrenal glands ), inflammatory lesions of the reproductive apparatus, etc. Often the menstrual cycle disorders in young women are associated with incomplete the spine of the gonads and the instability of the central links of the reproductive system due to adverse effects in the antenatal period of their existence.

The pathogenesis of dysfunctional uterine bleeding is complex and multifaceted. The most vulnerable moment in the complex mechanism of the functioning of the neuroendocrine system that regulates the menstrual cycle is ovulation. Therefore, in most cases uterine bleeding occurs against the background of anovulyatsin. In a number of patients, the dominant follicle reaches a sufficient degree of maturity, but, not ovulating, persists (persists) and produces estrogen in large quantities. Hyperestrogenia leads to endometrial hyperplasia. In a different category of patients, several follicles develop, but, not reaching maturity, undergo atresia; to replace them grow new follicles, again exposed to atresia. The prolonged undulating action of a moderate amount of estrogens also leads to proliferation or hyperplasia of the endometrium. Dysfunctional uterine bleeding in both cases of anovulation can be explained by the action of two mechanisms: "cancellation" of estrogens or "estrogenic breakthrough".

In a number of patients, dysfunctional uterine bleeding is observed against a background of preserved ovulation. Bleeding can occur in the middle of the menstrual cycle due to rejection of the endometrium due to a short-term decrease in the production of estrogens. A small discharge of blood before menstruation can indicate an inadequately functioning yellow body, and prolonged menstrual bleeding about an inferior follicle. Prolonged existence (persistence) of the yellow body, which produces progesterone and estrogens in sufficient quantities, temporarily delays the rejection of the endometrium, and then leads to bleeding of the "breakthrough".

Based on the features of pathogenesis, dysfunctional uterine bleeding is classified as follows (table)

Classification of dysfunctional uterine bleeding

The nature of bleeding	Ovulatory bleeding	Anovulatory bleeding
Cyclic Acyclic	Insufficient follicle Insufficiency of the yellow body Intermenstrual Yellow body persistence	Short-term rhythmic persistence of the follicle Persistence of the follicle Atresia of the follicles

Anovulatory dysfunctional uterine bleeding. Anovulatory menstrual cycles are characterized by the continued production of 17β-estradiol without the formation of the yellow body and the formation of progesterone. Excess proliferation of the endometrium as a result of the continuing effect of estrogens ultimately outstrips the growth of blood vessels, which leads to unpredictable and non-cyclic rejection of the endometrium.

The cycle is single-phase, without the formation of a functionally active yellow body, or cyclicity is absent.

In the period of puberty, lactation and premenopause, often arising anovulatory cycles may not be accompanied by pathological bleeding and do not require pathogenetic therapy.

Depending on the level of estrogen produced by the ovaries, the anovulatory cycles are distinguished:

1. With insufficient maturation of the follicle, which later undergoes reverse development (atresia). It is characterized by an elongated cycle followed by a prolonged, prolonged bleeding; often occurs in juvenile age.
2. Prolonged persistence of the follicle (Schroeder hemorrhagic metropathy). The ripened follicle does not ovulate, continuing to produce estrogen in increased amounts, the yellow body is not formed.

The disease is characterized by often abundant, prolonged bleeding to three months, which may be preceded by a delay of monthly to 2-3 months. It occurs more often in women after 30 years with concomitant hyperplastic processes of the target organs of the reproductive system or in early premenopause. It is accompanied by anemia, hypotension, impaired function of the nervous and cardiovascular systems.

Ovulatory dysfunctional uterine bleeding. Spotting bleeding from the genital tract in the middle of the menstrual cycle, which occur after lifting the concentration of luteinizing hormone, is usually physiological. Polymenorrhea most often occurs due to the shortening of the follicular phase of the menstrual cycle. On the other hand, polymenorrhea may be due to lengthening of the luteal phase during the persistence of the yellow body.

Ovulatory bleeding is characterized by the preservation of biphasic cycle, but with a violation of rhythmic production of ovarian hormones of the type:

• Shortening of the follicular phase. There is a bowl during puberty and menopause. In the reproductive period, they can be caused by inflammatory diseases, secondary endocrine disorders, vegetative neurosis. In this case, the interval between monthly decreases to 2-3 weeks, the monthly pass through the type of hyperspolymenorei.

When studying the TFD of the ovaries, the elevation of the rectal temperature above 37 ° C begins on the 8th-10th day of the cycle, cytological smears indicate a shortening of the 1 st phase, histological examination of the endometrium gives a picture of the secretory transformations of its type of 2-phase insufficiency.

Treatment is primarily aimed at eliminating the underlying disease. Symptomatic treatment is hemostatic (vikasol, dicinone, synthocinone, calcium preparations, rutin, ascorbic acid). In cases of heavy bleeding, oral contraceptives (non-vellon, ovidon) for contraceptive (or initially hemostatic - up to 3-5 tablets a day) scheme - 2-3 cycles.

• The shortening of the luteal phase is more often characterized by the appearance of usually small bloody discharge before and after the menstrual period.

According to the TFD of the ovaries, the rise in rectal temperature after ovulation is noted only for 2-7 days; cytologically and histologically, there is a lack of secretory transformations of the endometrium.

Treatment consists in prescribing the preparations of the yellow body - gestagens (progesterone, 17-OPK, dufaston, utero, norethisterone, norkolut).

• Lengthening of the luteal phase (persistence of the yellow body). It occurs when the function of the pituitary gland is disturbed, it is often associated with hyperprolactinemia. Clinically it can be expressed in a slight delay in menstruation followed by hyperpolymenoreia (meno-, menometrorrhagia).

TFD: elongation of rectal temperature rise after ovulation up to 14 days or more; histological examination of scraping from the uterus - insufficient secretory transformation of the endometrium, scraping is more often moderate.

Dysfunctional uterine bleeding in systemic diseases. The pathology of the menstrual cycle can be the first manifestation of such diseases as hyperthyroidism and hypothyroidism. Diseases of the blood (von Willebrand's disease) are often manifested by profuse uterine bleeding in adolescence. Severe lesions of various organs (renal or hepatic insufficiency) can sometimes be accompanied by severe irregular bleeding.

Iatrogenic dysfunctional uterine bleeding. Oral contraceptives (PKP) often cause irregular bleeding during the first 3 months of use if the dose is inadequate, or if the woman smokes. Also, irregular bleeding often causes long-acting contraceptives containing only progestins (Depo-Provera), levonorgestrel (Nornlant). In some cases, dysfunctional uterine bleeding may be due to the use of phytopreparations affecting the endometrium.

Each period of a woman's life leaves its imprint on the course of dysfunctional uterine bleeding, requires a special approach to diagnostic activities and therapy. Therefore, in clinical practice, it is customary to allocate:

1. dysfunctional uterine bleeding period of puberty (juvenile bleeding) in girls under 18;
2. dysfunctional uterine bleeding reproductive period;
3. dysfunctional uterine bleeding of the pre-menopausal period (menopausal bleeding) in women older than 40 years.

[1], [2], [3], [4], [5], [6]