The size of the follicle is 33 mm, is ovulation possible? Infertility and its treatment. Dimensions of the ovaries of a healthy woman

On different days of the menstrual cycle, the follicles have a certain size, as they mature, they increase, and before menstruation they break, releasing the sex cell. Knowing about the change in the diameter of the follicular tissue is important, as it helps to calculate the period of ovulation, as well as determine the parameters of the health of the woman's reproductive system. What is the size of the follicle on the days of the cycle and why can it stop growing?

The "rudimentary" sex cells are laid in the body of every girl even before her birth, there are about 8-10 thousand of them inside the ovaries. But initially, such rudiments are not yet ready for fertilization, because they must go through several successive divisions for maturation. To protect the egg during its growth and transformation, several layers of epidermal tissue grow around it - this is the follicle, which resembles an epithelial cocoon.

Follicular tissue is under the influence of the endocrine system, its increase and development is regulated by the hormones of the ovaries themselves, as well as the pituitary gland, an indirect effect is observed from the adrenal glands. For example, FSH (follicle-stimulating hormone) stimulates the maturation of primordial (rudimentary) follicles during adolescence and on different days of the menstrual cycle, and LH (luteinizing) helps to accelerate their growth for further release of the germ cell before ovulation.

Size by day of cycle

The size of the follicle changes on different days of the menstrual cycle. After the end of menstruation, under the influence of the active substances of the ovaries and pituitary gland, the development of several epithelial cocoons (up to 6-7 pieces) begins, but by the eighth day after the onset of development, a dominant follicle appears, in which the gene activity was the highest, so it reached the mark of 8 the fastest. -10 mm. The remaining epithelial cocoons may stop growing or undergo apoptosis, that is, planned cell death.

Dominant follicle development

After that, the body "concentrates" on this dominant follicle, and the growth of the rest stops to save nutritional resources and energy. Every day before ovulation, there is an increase in this epithelial cocoon for the egg by 1.5-2 mm in diameter. During this period, the egg begins to mature, undergoes several successive divisions, during which nutrients are concentrated inside it, the necessary membranes appear (there are 3 of them in the egg).

On the 11th day of the cycle, the size of the follicle is about 15-16 mm, after which its growth slows down a bit. During this period, the egg is already at the final stage of its development, preparation for ovulation begins. On which day it happens depends on the activity of the endocrine system and the state of health of the woman, usually this happens on the 15-16th day.

On the 15th day of the cycle (sometimes there are shifts of 2-3 days), the follicle reaches 22-24 mm in diameter and a critical point occurs, since it can no longer grow, so the epithelial cocoon breaks and the sex cell comes out - into the abdominal cavity, and then into the fallopian tubes.

It is during this period, which will last only 36-50 hours, that fertilization can occur. But it is important to understand that under the influence of hormones, ovulation, that is, the release of an egg, can occur sooner or later. If you observe the follicular tissue during the ovulatory phase, you can see how the epithelial cocoon increases dramatically, the egg is released, and after that it decreases, only its remnants (yellow body) are visible.

Follicle Growth Chart

After reading a short information about, the algorithm itself becomes clear, but it is difficult to understand the exact data, so below is a simple table that shows the size of the epithelial coating of the egg on different days of the menstrual cycle.

The indicators presented in the table are the established norm for the development of follicles on the days of the cycle, but it is not in vain that the gynecologist, in order to prescribe contraceptives or determine “safe” days of the cycle, checks the size data for the girl individually, because the rate of maturation and growth of the egg in the follicular cocoon depends on her heredity , the work of the endocrine system, the level of stress and even weight.

Why does the follicle not grow

The lack of growth and development of follicles is one of the most common causes of infertility in women. Deviation from the norm of development of follicular tissue may appear due to:

• disturbances in the work of the pituitary and hypothalamus;
• dysfunction or underdevelopment of the ovaries;
• the appearance of cysts in the ovaries or the presence of multifolliculosis;
• inflammatory or infectious processes in the organs of the reproductive system;
• hormonal imbalance;
• the appearance of cancerous neoplasms in the mammary glands, pituitary gland or ovaries;
• frequent stressful effects on the body, severe depression;
• dramatic weight loss, BMI below 17.5;
• early menopause.

It’s worth starting with a hormonal imbalance, which becomes the main reason for stopping the growth of follicles in the ovary. With tumors or dysfunction of the pituitary gland in the body of a girl, there is a lack of the hormone FSH, and the regulation of the release of active substances by the ovaries and thyroid gland is also disrupted. The same effect of inhibiting the development of follicles is observed with underdevelopment or poor functioning of the ovaries.

If a girl has too low weight or there are infections of the reproductive system, the body “understands” that she will not be able to bear the child, so there is no need for ovulation and follicle growth. After STD treatment or weight gain, the follicular growth cycle usually returns to normal.

During stressful periods or prolonged depression, the girl's adrenal glands secrete more than the norm of the stress hormone - cortisol, which increases the risk of miscarriage of the fetus, so follicles will not develop in such an environment. Restoring their growth in such a situation is not so easy, it can take several months until the hormonal background stabilizes.

The growth of follicles continues from the beginning of the menstrual cycle until ovulation. First, several epithelial cocoons develop, but already on the 8-9th day, one dominant one is released, and the rest stop growing. The growth of follicular tissue lasts until ovulation, during which it ruptures and releases a mature egg. But with various disorders in the body, the follicular cycle can be suspended.

The female body is periodically rebuilt (natural cyclical changes) due to the influence of hormones that control the complex mechanisms relating to its reproductive system (the set of organs that ensure the process of fertilization). For the onset of pregnancy, a prerequisite must be observed - the growth and normal development of ovarian follicles, which act as a kind of "container" for already

Interpretation of the concept of "follicle"

This is a small anatomical formation that looks like a gland or a sac filled with intracavitary secretions. The ovarian follicles are located in their cortical layer. They are the main reservoirs for the gradually maturing egg.

Initially, the follicles in quantitative terms reach significant values ​​​​in both ovaries (200 - 500 million), each of which, in turn, contains one germ cell. However, for the entire time of puberty, women (30-35 years old) reach full maturity only 400-500 copies.

Internal processes of follicle evolution

They flow in their sacs and are characterized by the multiplication of granular or granular cells that fill the entire cavity.

Then the granular cells produce a fluid that pushes and pushes them apart, while directing them towards the peripheral parts of the follicle (the process of filling the internal cavity with follicular fluid).

As for the follicle itself, it significantly increases both in size and in volume (up to a diameter of 15-50 mm). And in terms of content, it is already a liquid with salts, proteins and other substances.

Outside, it is covered with a connective tissue sheath. And it is precisely this state of the follicle that is considered mature, and it is called the Graaffian vesicle (in honor of the Dutch anatomist and physiologist Renier de Graaf, who discovered this structural component of the ovary in 1672). A mature "bubble" interferes with the maturation of its counterparts.

How big should a follicle be?

With the onset of puberty (14-15 years), he completely completes his development. It is considered normal if during the follicular phase, when the menstrual cycle begins, several follicles mature in both ovaries, of which only one reaches a significant size, which is why it is recognized as dominant. The remaining specimens undergo atresia (reverse development). The product of their vital activity is estrogen - a female sex hormone that affects fertilization, childbirth, as well as calcium content and metabolism.

The dominant follicle, which increases in size by an average of 2-3 mm every day, reaches its normal diameter (18-24 mm) at the time of ovulation.

Generative function as a priority

On the inside, a mature follicle is lined with a multi-layered epithelium, it is in it (in a thickened area - an oviparous tubercle) that a mature, fertilizing egg cell is located. As mentioned above, the normal size of the follicle is 18-24 mm. At the very beginning of the menstrual cycle, its protrusion (resembling a tubercle) is observed on the surface of the ovary.

Due to a number of hormonal disorders, this gap may be absent, and therefore the egg does not leave the ovary and the process of ovulation does not occur. It is this moment that can become the main cause of infertility and dysfunctional bleeding of the uterus.

Folliculometry: definition, possibilities

This is an ultrasound diagnostic study, through which tracking the development and growth of follicles is available. Most often, women resort to it, suffering from infertility or menstrual irregularities. The considered manipulation allows using ultrasound to track the dynamics of ovulation.

At the beginning of the menstrual cycle, it becomes possible to observe the process of endometrial growth, and in a later period - the evolution of the follicle. So, you can determine the exact size of the follicles by day of the cycle.

When is folliculometry required?

This diagnostic study allows you to:

The value of indicators of the norm and pathology of the development of the follicle

At the very beginning of its evolution, the indicator in the “norm” status is the size of the follicle in diameter of 15 mm. Further, as mentioned earlier, it increases per day by 2-3 mm.

Many women are interested in the question: “What is the size of the follicle during ovulation?” Normally it is considered - about 18-24 mm. Then the corpus luteum appears. At the same time, the level of progesterone in the blood is necessarily increased.

A single ultrasound is unable to build a complete picture of the development (maturation) of the follicle, since it is especially important to control each individual stage.

The main pathologies that disrupt the maturation of follicles are:

1. Atresia - involution of a non-ovulated follicle. To be precise, after formation, it develops up to a certain point, and then freezes and regresses, thus ovulation never occurs.

2. Persistence - the persistence of the virus, when it is still functionally active, in the cells of tissue or organism cultures over the period characteristic of an acute infection. In this case, the follicle is formed and develops, but its rupture does not occur, as a result of which it does not increase. This form of anatomical formation is preserved until the very end of the cycle.

3. Follicular cyst - a kind of functional formation, localized in the ovarian tissue. In this situation, the unovulated follicle does not rupture, it continues to exist, and fluid most often accumulates in it, and subsequently a cyst larger than 25 mm is formed.

4. Luteinization - the formation of a corpus luteum, which sometimes forms without rupture of the follicle, which subsequently also develops. This situation is possible if there was an earlier increase in the value of LH or damage to the structure of the ovary.

Follicle sizes by day of cycle

From the very first days of the next cycle, with the help of ultrasound, one can notice that there are several antral anatomical formations under consideration in the ovaries, which will subsequently grow. Their increase is due to the influence of special hormones, the main ones being (FGS) and estradiol. Provided that their level corresponds to the established norm for the content of these substances in the blood, a woman most often has stable ovulation, and anovulatory cycles are observed no more than twice a year.

After the moment when the size of the follicles during stimulation according to the first scheme reaches 18 mm in diameter (at 8 mm), triggers are introduced (drugs that mimic the LH surge). Then, after the introduction of hCG, ovulation occurs approximately two days later.

The second scheme of manipulation is applicable mainly to women who have a low and low probability of the effect of small doses of FSH.

Mandatory indications for this manipulation:

• female age over 35 years;
• FSH value over 12 IU / l (on the 2nd-3rd day of the cycle);
• ovarian volume up to 8 cu. cm;
• secondary amenorrhea and oligomenorrhea;
• the presence of operations on the ovaries, chemotherapy or radiotherapy.

A visible result should appear by the sixth day. A significant side effect affecting the ovaries during this ovulation is the risk of their hyperstimulation syndrome. In the case when, during the next ultrasound, follicles in the ovaries are detected, the size of which exceeds 10 mm in diameter, the doctor regards this as a signal to carry out preventive procedures for this syndrome.

Control ultrasound examination

It is necessary to confirm ovulation through transvaginal ultrasound. This is as important as the monitoring itself. It was previously mentioned what size the follicle is before ovulation (18-24 mm in diameter), however, even when the required size is reached, the capsule may not break through, and the mature egg will not be released into the abdominal cavity. Control ultrasound is performed 2-3 days after the estimated moment of ovulation.

At this session, the doctor will check the condition of the ovaries for signs of ovulation that has taken place:

• the dominant follicle is absent;
• a corpus luteum is present;
• there is some fluid in the space behind the uterus.

It is important to note that if the specialist conducts a follow-up ultrasound at a later period, he will no longer detect either fluid or corpus luteum.

Finally, it would be useful to once again answer the question: “What is the size of the follicle during ovulation?” This dominant anatomical formation at the time of ovulation matures to a size of approximately 18 - 24 mm in diameter. It is worth remembering that the size of the endometrium and follicles varies depending on the day of the menstrual cycle.

The follicle is the component of the ovary that is surrounded by connective tissues and is made up of an ovum. The follicle contains the nucleus of the oocyte - the "embryonic vesicle". The oocyte is located inside a glycoprotein layer surrounded by granulosa cells. The granulosa cells themselves are surrounded by a basement membrane, around which are theca cells.

The primordial follicle consists of an oocyte, a stroma cell, and a follicular cell. The follicle itself is almost invisible, its size averages 50 microns. This follicle is formed before birth. It is formed due to germ cells, they are also called oogonia. The development of primordial follicles is facilitated by puberty.

A single-layer ordinary follicle consists of a basal plasty, a follicular cell that forms a transparent membrane, and a multilayer primary follicle consists of a transparent membrane, an inner cell, and granulosa cells. During puberty, follicle-stimulating hormone (FSH) begins to be produced. The oocyte grows and is surrounded by several layers of granulosa cells.

The cavitary (antral) follicle consists of a cavity, the inner layer of Theca, the outer layer of Theca, granulosa cells, a cavity containing follicular fluid. Granulosa cells are already starting to produce progestins. The diameter of the antral follicle averages 500 µm. The gradual maturation of the follicle with the formation of its layers gives rise to the production of female sex hormones, including estrogen, estradiol, androgen. Thanks to these hormones, this follicle turns into a temporary organ of the endocrine system.

A mature follicle (Graaffian vesicle) consists of an outer layer of the theca, an inner layer of the theca, a cavity, granulosa cells, a radiant crown, and an oviparous tubercle. Now the egg is located above the egg tubercle. The volume of follicular fluid increases by 100 times. The diameter of a mature follicle varies from 15 to 22 mm.

How big should a follicle be?

It is impossible to answer this question unambiguously, since the size of the follicles change during the menstrual cycle. Follicles are fully formed by an average of fifteen years. Their sizes are determined only with the help of ultradiagnostics.

We will most accurately analyze the norm for the size of the follicle by the days of the menstrual cycle.

In the first phase of the menstrual cycle (1-7 days or the beginning of menstruation), the follicles should not exceed 2-7 mm in diameter.

The second phase of the menstrual cycle (8-10 days) is characterized by the growth of follicles, mainly their diameter reaches 7-11 mm, but one follicle can grow faster (it is commonly called dominant). Its diameter reaches 12 - 16 mm. On the 11-15th day of the menstrual cycle, the dominant follicle should normally increase by 2-3 mm every day, at the peak of ovulation it should reach a diameter of 20-25 mm, after which it bursts and releases the egg. Meanwhile, other follicles simply disappear.

This is what the follicle growth looks like. This is repeated monthly until the onset of pregnancy. For a more visual and understandable definition, we provide you with a table by which you can understand whether your follicles are maturing normally.

What is a dominant follicle

The dominant follicle is considered to be the follicle that is ready for successful ovulation. With natural ovulation, it stands out for its size. As we said earlier, although all follicles begin to grow, but only one of them (in rare cases, several) grows to a size of 22 - 25mm. It is he who is considered dominant.

Generative function as a priority. Let's figure out what it is.

There are two components of ovarian function.

The generative function is responsible for the growth of follicles and the maturation of an egg capable of fertilization. The hormonal function is responsible for steroidogenesis, which changes the lining of the uterus, helps not to reject the fetal egg, and regulates the hypothalamic-pituitary system. It is generally accepted that the generative function is in priority, so if it fails, the second one loses its abilities.

At what size follicle does ovulation occur?

Ovulation is the release of an egg from a burst mature follicle. In this case, the size of the follicle during ovulation becomes 15 - 22 mm (in diameter). To make sure that you have a full-fledged follicle by the time you ovulate, you need an ultrasound.

empty follicle syndrome

Currently, two types of this syndrome are described: true and false. Distinguishes their level of hCG. It can be said that thanks to IVF technology, scientists have examined under a microscope the phenomena when the follicle is “empty”.

According to statistics, in women under 40 years of age, this syndrome occurs in 5-8% of cases. The older a woman gets, the higher the number of empty follicles. And this is no longer a pathology, but the norm. Unfortunately, it is impossible to accurately and immediately diagnose this syndrome. To do this, you will need to completely exclude damage to the ovaries (structural anomaly), lack of ovarian response to stimulation, premature ovulation, hormonal failure, defects (pathologies) in the development of the follicles, and premature aging of the ovaries. That is why there is no such diagnosis as an “empty follicle”.

But scientists have found the reasons that accompany the development of the syndrome. Namely: Turner's syndrome, incorrect time of administration of the hCG hormone, incorrect dose of hCG, incorrectly selected IVF protocol, incorrect technique for sampling and washing the material. As a rule, a competent reproductologist, before making this diagnosis, carefully collects an anamnesis.

polycystic ovary syndrome

Otherwise, it is called the Stein-Leventhal syndrome. It is characterized by dysfunction of the ovaries, the absence (or altered frequency) of ovulation. As a result of this disease, follicles do not mature in the body of a woman. Women with this diagnosis suffer from infertility, lack of menstruation. A variant is possible when menstruation is rare - 1-3 times a year. Also, this disease affects the violation of the hypothalamic-pituitary functions. And this, as we wrote earlier, is one of the functions of the proper functioning of the ovaries.

Treatment here can proceed in two ways. It is operational and medical (conservative). The operative method often involves resection with the removal of the most damaged area of ​​ovarian tissue. This method in 70% of the case leads to the restoration of a regular menstrual cycle. For a conservative method of treatment, hormonal drugs are mainly used (Klostelbegit, Diana-35, Tamoxifen, etc.), which also help regulate the menstrual process, which leads to timely ovulation and the desired pregnancy.

Folliculometry: definitions, possibilities

Under the name folliculometry, it is customary to understand the observation of the reproductive system of a woman during the menstrual cycle. This diagnostic tool allows you to recognize ovulation (whether it was or not), determine the exact day, and monitor the dynamics of follicle maturation during the menstrual cycle.

Monitoring the dynamics of the endometrium. For this diagnosis, a sensor and a scanner are used (it is more common for us to call this ultrasound). This procedure is absolutely identical to the procedure for ultrasound of the pelvic organs.

Folliculometry is prescribed for women to determine ovulation, evaluate the follicles, determine the day of the cycle, for timely preparation for fertilization, to determine whether a woman needs to stimulate ovulation, to reduce (in some cases increase) the likelihood of multiple pregnancy, to determine the reasons for the absence of a regular menstrual cycle , detection of diseases of the pelvic organs (myomas, cysts), to control treatment.

This procedure does not require strict preparation. It is recommended only during these studies (usually ultrasound is done more than once) to exclude from the diet foods that increase bloating (soda, cabbage, brown bread). The study can be carried out in two ways: transabdominally and vaginally.

The values ​​of indicators of the norm and pathology of the development of follicles

The norms of indicators both by day and during ovulation, we described above (see above). Let's talk a little about pathology. The main pathology is the lack of follicle growth.

The reason may be:

• in hormonal imbalance
• polycystic ovaries,
• dysfunction of the pituitary gland,
• inflammatory processes of the pelvic organs,
• STD,
• neoplasms,
• severe stress (frequent stresses),
• breast cancer,
• anorexia,
• early menopause.

Based on practice, health workers distinguish such a group as hormonal disorders in a woman's body. Hormones inhibit the growth and maturation of follicles. If a woman has a very small body weight (plus there are still STD infections), then the body itself recognizes that it cannot bear a child, and the growth of the follicle stops.

After normalization of weight and treatment of STDs, the body begins the proper growth of follicles, and then the menstrual cycle is restored. During stress, the body releases hormones that contribute to either miscarriage or follicle growth.

After a complete emotional recovery, the body itself begins to stabilize.

Stimulation of ovulation

Under stimulation, it is customary to understand a complex of hormonal therapy, which helps to achieve fertilization. It is prescribed for women with a diagnosis of infertility for IVF. Infertility is usually diagnosed if pregnancy does not occur within a year with regular sexual activity (without contraception). But there are also contraindications for stimulation: impaired patency of the fallopian tubes, their absence (except for the IVF procedure), if it is not possible to conduct a full-fledged ultrasound, low follicular index, male infertility.

The stimulation itself occurs using two schemes (they are usually called protocols).

First protocol: increase in minimum doses. The purpose of this protocol is the maturation of one follicle, which excludes multiple pregnancy. It is considered sparing, since when using it, ovarian hyperstimulation is practically excluded. When stimulated with drugs according to this scheme, the size of the follicle usually reaches 18-20 mm. When this size is reached, the hCG hormone is injected, which allows ovulation to occur within 2 days.

Second protocol: lowering high doses. This protocol is prescribed for women with a low follicular reserve. But there are also requirements for it that are considered mandatory indications: age over 35, previous ovarian surgery, secondary amenorrhea, FSH above 12 IU / l, ovarian volume up to 8 cubic meters. With the stimulation of this protocol, the result is already visible on the 6th - 7th day. With this protocol, the risk of ovarian hyperstimulation is high.

Control ultrasound examination. This study is usually carried out transvaginally. The purpose of the study is to confirm ovulation. This ultrasound should normally show that there is no dominant follicle, but there is a corpus luteum. There may be some free fluid behind the uterus. Ultrasound is performed strictly 2-3 days after the expected ovulation, since if you are late, you can not see the corpus luteum, and the same fluid.

The growth of the follicle and the subsequent ovulation of the mature egg in it are key processes that ensure the readiness of the female reproductive system for conception. Violation of this natural mechanism is one of the most common causes of infertility. And all IVF programs include a stage of stimulation of follicle growth to induce hyperovulation.

Depending on the protocol used, it is performed on the biological mother or on the egg donor. At the same time, folliculometry is required to track the number of maturing follicles, their size and readiness for ovulation.

A bit of theory

Follicles are called special formations in the ovaries, consisting of an oocyte of the 1st order (an immature egg) and several layers of special cells surrounding it. They are the main structural formations of the female gonads, performing endocrine and reproductive functions.

Follicles are laid in utero. They are based on oogonia - primary germinal germ cells that migrate to the germinal ovary at about 6 weeks of gestation. After meiotic division and proliferation, these precursors form first-order oocytes. These immature germ cells are covered with cuboidal epithelium and form the so-called primordial follicles. They will remain in a dormant state until the onset of the sexual development of the girl.

Subsequently, primordial follicles are successively transformed into preantral, antral, and preovulatory follicles. This process is called folliculogenesis. Normally, it ends with ovulation - the release of a mature and ready for fertilization egg. In place of the follicle, an endocrine-active corpus luteum is formed.

At the onset of conception, it is stored under the action of chorionic gonadotropin. The progesterone produced by them contributes to the prolongation of pregnancy. In all other cases, the corpus luteum is reduced, which occurs before menstruation. The accompanying sharp drop in progesterone levels provokes the onset of menstruation with rejection of the overgrown glandular (functional) layer of the endometrium.

A situation is possible when a mature follicle does not ovulate. At the same time, it can continue to increase in size, transforming into a reduced egg. Such formations can be single and gradually absorbable. But sometimes cysts persist for a long time, deforming the surface of the organ. In this case, one speaks of . Such a diagnosis is prognostically unfavorable for conception, it is usually accompanied by persistent dyshormonal disorders and infertility.

How many follicles are in the ovaries?

Not all ovarian follicles initially laid in utero are preserved by the time of puberty and subsequently develop. About 2/3 of them die and resolve. This natural process is called apoptosis or atresia. It begins immediately after the laying of the gonads and continues throughout life. A girl is born with approximately 1-2 million primordial follicles. By the beginning of puberty, their average number is 270-500 thousand. And during the entire reproductive period, only about 300-500 follicles ovulate in a woman.

The sum of all follicles capable of further development is called the ovarian reserve. It determines the duration of the woman's reproductive period and the onset, the number of productive (flowing with ovulation) menstrual cycles and, in general, the ability to re-conceive.

The process of progressive depletion of the ovarian reserve in the ovaries is noted on average after 37-38 years. This means not only a decrease in a woman's ability to naturally conceive, but also the beginning of a natural decrease in the level of basic sex hormones. The cessation of the development of follicles in the ovaries means the onset of menopause. It can be natural, early and iatrogenic.

Graafian bubble formation phase

The amount of follicular fluid progressively increases, it pushes the entire epithelium and the egg to the periphery. The follicle grows rapidly and begins to protrude through the outer shell of the ovary. The egg in it is located on the periphery on the so-called egg-bearing mound. Approximately 2 days before ovulation, the amount of secreted estrogen increases significantly. This feedback triggers the release of luteinizing hormone from the pituitary gland, which triggers the ovulation process. A local protrusion (stigma) appears on the surface of the Graafian vesicle. This is where the follicle ovulates (ruptures).

As a result of ovulation, the egg, ready for fertilization, leaves the ovary and enters the abdominal cavity. Here she is captured by the villi of the fallopian tubes and continues her natural migration towards the spermatozoa.

How is the “correctness” of folliculogenesis assessed?

The stages of folliculogenesis have a clear relationship with the days of the ovarian-menstrual cycle. Moreover, they do not depend on the age and race of the woman, but on her endocrine status.

The growth and development of the follicle is primarily regulated by the follicle-stimulating hormone of the pituitary gland. It begins to be produced only with the onset of puberty. At a certain stage, folliculogenesis is additionally controlled by sex hormones, which are produced by the cells of the wall of the developing follicle itself.

Any hormonal imbalance can disrupt the process of maturation and ovulation of the egg. At the same time, determining the level of hormones does not always provide the doctor with all the necessary information, although it allows you to identify key endocrine disorders. Therefore, the diagnosis of violations of the folliculogenesis process is the most important stage in the examination of a woman at the stage of pregnancy planning and in identifying the cause of infertility.

At the same time, the doctor is interested in how large the follicle grows and whether it reaches the stage of the Graafian vesicle. Be sure to monitor whether ovulation occurs and whether a corpus luteum of sufficient size is formed. In anovulatory cycles, the maximum size of developing follicles is determined.

An accessible, informative and at the same time technically simple method is. This is called monitoring the maturation of follicles using ultrasound. It is performed on an outpatient basis and does not require any special preparation of the woman. Folliculometry is a dynamic study. Several repeated ultrasound sessions are required to reliably monitor changes occurring in the ovaries.

In the process of folliculometry, the specialist determines the number, location and diameter of maturing follicles, monitors the formation of a dominant vesicle, and determines the size of the follicle before ovulation. Based on these data, you can predict the most favorable day of the cycle to get pregnant naturally.

With IVF protocols, such monitoring allows you to evaluate the response to ongoing hormonal therapy, set a date for the introduction of drugs to stimulate ovulation and subsequent puncture egg retrieval. The key parameter of folliculometry is the size of the follicle by day of the cycle.

Norms of folliculogenesis

Folliculometry is performed on certain days of the cycle, corresponding to the key stages of folliculogenesis. The data obtained during repeated studies are compared with the average statistical norms. What size of the follicle should be on different days of the ovarian-menstrual cycle? What fluctuations are considered acceptable?

Normal follicle size on different days of the cycle for a woman aged 30 years with a 28-day cycle, not taking oral contraceptives and not receiving treatment with hormonal stimulation of ovulation:

• On days 1-4 of the cycle, several antral follicles are found, each of which does not exceed 4 mm in diameter. They can be located in one or both ovaries. Their number depends on the age of the woman and her ovarian reserve. The norm is if in both ovaries a total of no more than 9 antral follicles mature simultaneously.
• On the 5th day of the cycle, antral follicles reach a size of 5-6 mm. Their development is quite uniform, but already at this stage atresia of some vesicles is possible.
• On the 7th day, the dominant follicle is determined, its size is on average 9-10 mm. It is he who begins to actively develop. The remaining bubbles will gradually decrease, while they can be determined in the ovaries and during ovulation.
• On the 8th day of the cycle, the size of the dominant follicle reaches 12 mm.
• On day 9, the bubble grows to 14 mm. It clearly defines the follicular cavity.
• Day 10 - the size reaches 16 mm. The remaining bubbles continue to decrease.
• On day 11, the follicle increases to 18 mm.
• Day 12 - the size continues to grow due to the follicular cavity and reaches 20 mm.
• Day 13 - Graafian vesicle with a diameter of 22 mm (this is the minimum size of the follicle for ovulation in the natural cycle). On one of its poles, a stigma is visible.
• Day 14 - ovulation. Usually the follicle bursts when it reaches 24 mm in diameter.

Deviations from these normative indicators in the direction of decrease are prognostically unfavorable. But when evaluating the results of folliculometry, the duration of the woman's natural cycle should be taken into account. Sometimes early ovulation occurs. In this case, the follicle reaches the required size for 8-12 days of the cycle.

IVF follicle size

With IVF protocols, ovulation is drug-induced and pre-planned.