All about follicles in the ovaries

A woman's ability to reproduce is determined by the well-coordinated work of her reproductive system. And the ovarian follicles play a very important role in it. It depends on small formations in the gonads of a woman whether she can conceive a child, whether her female health will be strong and long.

What it is?

A follicle is a formation inside the ovary, it is a structural component of the female reproductive gland, which consists of an immature egg and three layers of membranes (one is epithelial and two of connective tissue). The oocyte within the follicle is called the first-order oocyte.

Before maturation, the reproductive cell is carefully surrounded by a layer of glycoproteins and granulosa cells, which, in turn, are protected by the extracellular matrix - the basement membrane. Theca cells are located around it.

The structure and structure of the follicle are such that all the elements carry only one functional meaning - to preserve and protect the female reproductive cells, and when the time comes, provide them with optimal conditions for maturation.

The ovaries in female fetuses are formed during the period of intrauterine development; at 9-10 weeks of gestation, the ovaries of the crumbs have millions of follicles with a huge supply of first-order oocytes. Some cells die for natural reasons under the influence of a wide variety of external factors. At birth, a girl's ovaries contain about 500,000 follicles.

They dormant, do not act until the moment when puberty starts. By this period, the girl has about 250 thousand sex cells. But they die, and these processes are influenced by ecology, nutrition, and diseases. In this way, from the numerous ovarian reserve given to the girl by nature at birth, only 450-500 germ cells are allocated for her reproductive period.

The follicles in the ovaries are in a constant process of maturation. This process sets the cycle for the work of the female body, therefore, every month one or two follicles mature in the gonads, which release a mature and suitable egg for fertilization from their internal cavity on the day of ovulation. With age, when a woman acquires bad habits, chronic diseases, the depletion of the ovarian reserve becomes rapid. And after 35 years and the quantity and quality of follicles and oocytes leaves much to be desired. By the age of 40, a woman has no more than 3% of her initial ovarian reserve.

That is why experts do not recommend that women postpone the birth of a child for too long, arranging their career and settling other life circumstances. The reserve cannot be replenished, new primary follicles with first-order oocytes are not formed in the ovaries.

When the reserve is exhausted, menopause will come, that is, menopause. This means that your follicular reserve must be used carefully and wisely.

Ripening process and cycle

The process that occurs every month in the female body, metamorphosis concerning the follicles, is called folliculogenesis. The process of maturation of these vesicles-sacs is very complex, regulated at the hormonal level by the body itself. It runs continuously and breaks are possible only during pregnancy. Folliculogenesis ends during menopause - with a depleted ovarian reserve, new follicles do not mature, there is no menstruation.

Multiple primary follicles are very small (no more than 50 microns), they cannot be seen without a microscope, they are laid down even before the birth of the girl and are called primordial. They hatch in the ovaries at 6 weeks gestation. And the process of formation of new primordial follicles is completely completed by late pregnancy.

When a girl enters puberty, the anterior pituitary gland begins to produce a special substance in her - follicle-stimulating hormone (FSH). Under the influence of this active substance, every month immediately after the onset of the next menstruation in the right and left ovaries, the formation and growth of 5-15 follicles from the reserve simultaneously begins. As soon as they begin to grow, their status changes - they become preantral, and their size is about 200 microns.

In the process of growth, many cellular processes take place, a cavity with a liquid is formed inside the follicle bubble, in which there is a first-order oocyte. Such follicles can already be assessed by ultrasound, they are called antral. Their dimensions are already equal to 3-4 millimeters.

But all antral follicles must survive until ovulation, only one remains - the dominant one. Its growth rates are more intense. The rest of the antral counterparts undergo a reverse development and are preserved by the body for future menstrual cycles. The development of the next follicle is delayed at the hormonal level. The dominant follicle grows quickly, an egg matures inside it - before ovulation, the size of the follicle reaches 20-22 mm (sometimes 24 mm). Active production of estrogen and luteinizing hormone begins.

LH hormone acts on the follicular membrane, thinning it. A mature egg is located on a tubercle and protrudes above the surface of the ovary. The follicle is now tertiary or preovulatory. It is also called a graaf bubble. Under the influence of LH, stigma is formed - a bulging in the wall of the follicle. In the place of stigma, the membranes are ruptured and a mature egg is released.

First, the egg enters the abdominal cavity, from where it is captured by the fallopian tube. Once in the fallopian tube, the oocyte retains the ability to be fertilized for 24-36 hours. If conception does not occur, the egg dies.

But after an increase in growth, that is, after the follicle, in fact, fulfilled its role and ensured the maturation and release of the egg, matured and burst, development does not end. From the remnants of the membranes, a new formation is grouped - the corpus luteum. It is a temporary gland that releases progesterone bolt doses. This hormone prevents the rejection of the endometrium and the onset of menstruation, the layer of the inner lining in the uterus under its influence grows and prepares to accept the ovum.

Implantation, if a woman conceives a baby in the current cycle, usually occurs 6-8 days after ovulation. And in this case, within a day, the production of another hormone that is well known to women starts - hCG (it is he who makes pregnancy tests "strip"). This hormone maintains the corpus luteum in an efficient state until 12-14 weeks of pregnancy, until all endocrine functions are taken over by the young placenta.

If there was no conception or the embryo for some reason could not implant, the corpus luteum dies 10-12 days after ovulation, the production of progesterone stops, the concentration of estrogen rises, which leads to the onset of menstrual bleeding, in which endometrial rejection occurs. And already in the first days of the cycle, everything starts from the very beginning - the growth of primordial follicles.

The entire female cycle is divided into two phases - follicular and luteal. In the first, the follicle matures, and the luteal phase begins after ovulation. Typically, the luteal phase in women of different ages and different health conditions lasts about 14 days. This helps determine the expected day of ovulation - subtract 14 from the duration of the menstrual cycle.

Inspection methods

The only way to track the processes associated with the maturation of follicles is folliculometry. This is the name of the type of ultrasound. The ovaries are examined, the examination is carried out in dynamics several times in one cycle with a break of several days during the cycle. An ultrasound study allows you to establish how well the ovarian follicular reserve is (antral follicles are counted), as well as to determine the fact that ovulation is approaching, the size of the dominant follicle and to state the fact that ovulation has taken place.

Folliculometry is especially indicated in preparation for IVF, in the search for the cause of female infertility, in preparation for intrauterine insemination. This study in some cases helps to find the cause of the disorder of the female cycle.

The first procedure should be carried out after the end of menstruation. On the 5-7th day of the cycle, the doctor can count the number of antral follicles. Then the procedure is repeated every 2-3 days (at the discretion of the doctor). The study can be carried out both with an abdominal sensor (through the anterior abdominal wall) and intravaginally. In the first case, it is important that the woman comes to the ultrasound diagnostic room with a full bladder. In case of vaginal ultrasound, on the contrary, it is recommended to visit the toilet on the eve of the examination, since the bladder must be empty.

The quantitative indicator of antral follicles is a way to assess a woman's reproductive capabilities (there are options in the table):

over 26 - this is too much, which is regarded as a manifestation of polycystic disease, the cause of which often lies in a serious endocrine disruption, usually pregnancy cannot occur until the causes of the failure are eliminated;
11-25 - the norm indicating that a woman should not have problems with self-conception;
6-10 - reduced ovarian reserve; in some cases, hormonal stimulation of ovulation may be recommended;
less than 5 (single follicle, lack of follicles) - infertility, in which even stimulation does not make much sense.

The follicles do not mature during menopause during menopause. In turn, the probability of depletion of the reserve is at any age. So, often the reason that there are too few antral follicles may be chemotherapy or radiation treatment that a woman has undergone, exposure to radiation, poisons and toxins, severe hormonal disruptions caused by abortion, prolonged use of hormonal drugs.

Important! When calculating according to the world standard, doctors take into account only those antral follicles that are well visualized, have clear boundaries and a size of at least 2 mm.

Further on the days of the cycle, small follicles regress, the dominant one begins to be determined, the size of which becomes the main indicator of the approach of ovulation.

4-5 day of the cycle - antral follicles from 2 to 4 mm in diameter;
6-7 day of the cycle - the size increases to 5 mm, the follicles remain antral, there is a decrease in the number due to natural regression and involution;
8 day cycle - a dominant follicle of about 9-11 mm is determined;
9-10 day of the cycle - the size of the follicle is 13-15 mm, a fluid cavity with an egg is visualized inside. Two follicles in one ovary during this period means that ovulation can be double, which increases the likelihood of a multiple pregnancy;
Day 11 - the follicle reaches a size of 17 mm;
12-13 day - the cavity inside the dominant follicle grows and expands, its diameter reaches 19-20 mm, stigma is clearly visible on the surface.

In order for a woman to become pregnant, there must be at least 1 follicle. In the absence of follicles, pregnancy is impossible.

If a woman is preparing for an in vitro fertilization procedure, then the maximum follicle size is not expected. It is necessary to obtain eggs for fertilization in the laboratory, and therefore when the follicles reach (in the plural, since there are several dominant ones, which was caused by hormonal therapy), the size of 17-18 mm is prescribed a follicle puncture procedure.

In the second half of the menstrual cycle, a woman can, based on the results of an ultrasound, find out if she has ovulated. This will help the detection of the corpus luteum in the ovary. To confirm the fact of ovulation, it is better to contact the diagnostic room 3-4 days after the expected day of ovulation, so that the size of the corpus luteum would allow the doctor to visually determine and measure it.

The fact that ovulation has taken place is indicated by the absence of a follicle, the presence of a corpus luteum and the presence of a small amount of free fluid in the abdominal cavity... If ovulation was double, that is, two follicles burst, then two yellow bodies are determined, which can be located both in one ovary and in different ones. If, for some reason, there was no rupture of the follicle, there was no maturation, ovulation does not occur, a woman in this cycle is not capable of conceiving, the cycle itself is called anovulatory.

Such cycles occur from time to time in any perfectly healthy woman. Normally in young women and girls - up to 1-2 times a year, after 35 years - up to 5-6 times a year. And this is another answer to the question why it becomes more difficult to get pregnant with age, even if a woman is healthy.

In addition to folliculometry, laboratory blood tests for sex hormones are used (the levels of FSH, LH, estradiol, progesterone and testosterone can tell a lot). Analyzes are referred to as clarifying techniques that help to more accurately understand the reasons for the violation of the process of follicular maturation, if any.

Potential Problems - Symptoms and Treatment

The examination can reveal a wide variety of disorders of folliculogenesis, and in most cases they all, to one degree or another, lead to the fact that a woman cannot conceive a child, and menstrual irregularities occur. Let's consider the most common pathologies.

Persistence

They speak of a persistent follicle when the process of follicle maturation proceeded at a normal pace, the dominant one was clearly recorded, but its membrane did not rupture. The egg does not come out, it is overripe and dies inside the follicular cavity. There is no ovulation, conception is impossible. Most often, such a follicle appears with a reduced level of the LH hormone. It still exists on the surface of the ovary for about 10 days, and then transforms into a follicular cyst or resolves.

Most often, persistence is found in adolescent girls and in women during premenopausal changes. There are two types of persistence:

rhythmic - an unopened follicle exists from 20 to 40 days, and then menstrual bleeding begins, the cycle is restored in 95% of cases;
Schroeder's disease - This is a prolonged persistence, which often develops in older women, when a persistent follicle can exist for several months, producing estrogens, until profuse uterine bleeding occurs due to follicle atresia.

Most reproductive women have exactly the rhythmic form of pathology. Persistence symptoms are not characteristic or striking. This is usually manifested by a delay in menstruation. New follicles do not mature during the delay, the woman cannot conceive, and menstruation is absent. Some people report slight pulling pains in the lower abdomen on the right or left side.

Persistence in itself is not dangerous, but there is a possibility that high concentrations of estrogen can lead to the degeneration of the endometrium into malignant cells, the risk of breast cancer is also increased.

And it is for this reason that it is important to consult a doctor in time for a delay in menstruation in order to receive qualified assistance in a timely manner.

For persistence, it is most often used hormone therapy aimed at normalizing the cycle. A woman who is not planning to conceive can be recommended modern oral contraceptives. In some cases, therapy is carried out in phases of the cycle with the intake of replacement hormones - estrogens and hCG before ovulation and progestins - after.

Atresia

With such an ovulatory disorder, the follicle grows and develops at a normal rate, but at the stage of growth of the dominant vesicle, a sudden stop in growth occurs and involution starts. Ovulation does not happen with atresia; in some cases, when the development of the vesicle stops at the stage of the tertiary follicle, a cyst may form.

Symptoms also consist in a violation of the cycle - women have rather long periods of amenorrhea (absence of menstruation), bloody spotting is possible, long in time, but not abundant in quantity.

Treatment is also mainly based on hormone therapy to normalize ovulatory processes.

Cyst

Cystic formations of the ovaries are different: there is a corpus luteum cyst, there is a follicular cyst, retention type, there are cysts that appear before pregnancy and are present for quite a long time, there are formations that first appear during pregnancy. They are cavities filled with fluid, sometimes interspersed with blood or pus.

A cyst may indicate a significant excess in follicle size. In the overwhelming majority of cases, you should not be intimidated, since the cystic formations of the follicles are of a physiological nature, that is, they are prone to independent involution during two or three menstrual cycles. But even if the cyst did not dissolve before pregnancy, it often happens in women already in an "interesting position."

With such a diagnosis, it is important to visit a doctor more often, since it is not a cyst that is dangerous, but its possible complications, although they do not happen often. These include torsion of the pedicle and rupture of the cyst. In both cases, the woman experiences severe cutting pains, atypical for the phase of the cycle of excretion appear, a sharp decrease in blood pressure is possible.

In this case, it is important to deliver the patient to a medical facility with a surgical department as soon as possible.

Luteinization

In this condition, folliculogenesis is disrupted, the corpus luteum begins to develop before the follicle ruptures. The follicles remain immature, and ovulation also does not occur.

The condition has no special symptoms, the only complaints women have are for a shortening of the cycle and infertility. The treatment is again based on hormonal therapy after an analysis of the concentration of different hormones on different days of the cycle and folliculometry.

Important! Women are often interested in how follicles can be grown using folk remedies, are there ways to increase the size of the ovarian reserve. In fact, there are no such ways. Neither woman nor doctors can increase the size of the follicle.

The follicular reserve is likewise not subject to medicine. And the only way to stimulate ovulation is to administer certain doses of the hormone hCG or LH analogs at the moment when the dominant follicle reaches a large size. But such methods are used only in a medical institution, since the consequences of unauthorized treatment with hormones can be very tragic.

As for dietary supplements and complex preparations for women, the manufacturers of which describe the miraculous effect of their funds on the female reproductive system and cycle, their action has not been proven, the effectiveness of experts is highly questionable. If a woman has problems with ovulatory processes and endocrine background, then such funds usually do not help. If there are no problems, then there is no need to take dietary supplements.

Follicular disorders reasons

The processes of follicle maturation are completely dependent on the ratio and concentration of certain hormones, and therefore the most common cause of irregularities in the cycle and ovulation is endocrine imbalance, which can be temporary or long-term. Temporary violations can cause:

chronic fatigue, lack of sleep, lack of sleep at night, working night shifts;
excessive physical exertion, professional sports, hard work;
the harmful effects of poisons, toxins, varnishes and paints, the most dangerous is chronic poisoning in small doses for a long time;
flights and travel, business trips and tourist trips in which a woman experiences changes in her usual climate and a change in time zones;
stress, anxiety, severe emotional upheaval.

Violations for such reasons often go unnoticed at all, because the cycle is restored on its own in a short time, and few people immediately pay attention to the delay in menstruation.

Folliculogenesis disorders, which develop as a result of diseases and conditions of the following nature, lead to more serious and prolonged forms of endocrine infertility:

pathologies of the pituitary gland, hypothalamus;
diseases and dysfunction of the ovaries, violations of their morphological characteristics;
trauma and postoperative changes in the tissue of the gonads;
dysfunctions of the thyroid gland and adrenal cortex.

Problems with hormonal disorders that prevent the normal maturation of the follicles occur in women after childbirth and after abortion. And also in women who abuse smoking and alcoholic beverages. In addition, folliculogenesis disorders often develop against the background of long-term intake of antidepressants, antibiotics, hormones, including oral contraceptives.

Follicle puncture with IVF

If a woman cannot conceive on her own and IVF is indicated for her, then she will have to go through this procedure. The more eggs the fertility specialist receives, the higher the chances of successfully completing the treatment protocol of in vitro fertilization. First, the growth of follicles is stimulated with hormones - as a result, not one, but several dominant follicles mature. As soon as their diameter reaches 17-20 mm, an injection of hCG is injected. The next day, oocytes are taken.

The procedure takes place under general anesthesia, as the puncture itself is quite painful. A puncture is made in the fornix of the vagina and access to the sex glands is obtained. Each mature follicle is punctured with a needle and all of its contents are sucked out. Embryologists isolate oocytes, assess their quality, and perform laboratory fertilization.

Puncture is also used for the preservation of eggs. Some women, knowing that they will have to undergo treatment for cancer or are not yet tuned in to procreation for career or other reasons, want to leave good "young" eggs for the future in the cryobank.