Follicular phase of the cycle. Follicular phase

The normal course of the menstrual cycle is very important for a woman's life. Knowledge of all phases, the prevalence of hormones allows you to plan your sex life, the likelihood of pregnancy, the safest days of protection from unwanted fertilization. Also, high-quality control over the course of the menstrual cycle will help a woman determine the onset of a possible disease from the female reproductive or hormonal systems.

Menstrual cycle

The phases of the menstrual cycle are divided into 3 periods:

• Follicular;
• Ovulatory;
• Luteal.

A normal menstrual cycle lasts from 21 days to 35 days... Many do not know on what day of the cycle menstruation falls. The first day of a new cycle is considered to be the beginning of menstruation.

The ovulatory phase divides the follicular and luteal periods in half. She says that the body is ready for fertilization. You can find out about this by a sharp jump in basal temperature: immediately there is a sharp drop, then an increase. All this happens within the boundaries of one day.

Follicular phase

Follicular phase, what is it? This the period of the monthly cycle begins on the first day of menstruation... That is, at the moment when the old egg comes out, which died, because it did not have time to fertilize, a new repeated stage begins to emerge. At this time, the corpus luteum degrades, it stops producing progesterone, which contributes to the rejection of the inner layer of the uterus - the endometrium, and then bleeding begins.

On this day, a new follicle is formed - the primary one. It is so small that it cannot be seen on ultrasound. It is located in the ovary. And in order for it to start growing, it needs control and regulation of certain hormones. In the ovary, follicles do not grow one at a time, but natural selection reigns at this stage.

The strongest survives - the one who produces the most estrogen... Then a chain reaction begins. Estrogens stimulate the hypothalamus. And he begins to throw out gonadoliberin into the blood. This hormone has a positive effect on the pituitary gland, which takes precedence over the growth of the follicle, then the egg and the sufficiency of the hormonal system of all organs of the reproductive system.

Hormonal contraceptives use the same principle in reverse order to be productive. To prevent a woman from getting pregnant, the pills inhibit the work of the pituitary gland, because of this, the follicle does not develop.

The pituitary gland produces follicle-stimulating and luteinizing hormones. The follicle-stimulating hormone has a direct relationship with estrogens: the more hormones the follicle releases, the more the pituitary gland works to form follicle-stimulating hormone. The latter enters the bloodstream and is carried to the ovaries. It contributes to the correct and comfortable development of the follicle from primary to secondary, and by the end of the phase - to tertiary. This the process should usually be 14 days, but can vary from 7 to 22 days... It will end at the moment when the follicle reaches its maximum size and stops producing estrogens. Then he will be ready to rupture for the egg to come out of him.

On the 14th day of the cycle, the pituitary gland releases a powerful stream of luteinizing hormone into the bloodstream, and the follicle ruptures. At this moment, we observe a sharp drop in basal temperature, which was described earlier. This is how the follicular phase ends and the luteinizing phase begins. Measure basal temperature can be in the rectum. In order for the results to be correct, you need to do the procedure in the morning at the same time, without getting out of bed.

Instead of a ruptured follicle, there will be an organized corpus luteum, which in the luteinizing phase will produce progesterone. He will protect and develop the future bed for the ovum, attract males and develop a possible pregnancy that has come.

Reasons for disruption of the phase

The follicular phase should go to its logical conclusion in the middle of the cyclebut sometimes it doesn't. If ovulation does not occur and the first phase continues, then the body is experiencing a violation of the regulated supply of hormones.

Insufficient production of luteinizing hormone by the pituitary gland prevents the natural rupture and release of the egg.

The reasons for the violation of the normal course can be:

• Stress;
• Taking oral contraceptives;
• Hormonal adjustment;
• Premenopausal period;
• Formation of the menstrual cycle in the early years;
• Recent abortion or childbirth;
• Polycystic ovary syndrome;
• Malignant neoplasms.

Hormonal changes in the body are cyclical. The follicular phase of the menstrual cycle starts immediately after death has occurred. At the moment, as soon as the production of the hormone progesterone has ceased, and it is completely removed from the body, new follicles begin to develop.

What days of the cycle does the follicular phase occur?

Unlike, the flow of which is controlled by the corpus luteum, all processes of follicle development are triggered and regulated by the pituitary gland. Everything in the body is interconnected, and the reproductive system is regulated by hormones and controlled by receptors.

After the production of progesterone is complete, the brain receptors initiate the release of follicular phase hormones. This phase begins with menstrual bleeding, since both of these processes are caused by the same factor - a sharp drop in progesterone levels.

The release of a large amount of FSH and LH hormones into the bloodstream stimulates the rudimentary follicles to start growing. As you know, the number of eggs is laid in the ovaries of a girl at the age of about 6 weeks of embryo. After puberty until menopause begins, each month the pituitary gland stimulates 5 to 10 follicles to start growing. This process takes 7 to 23 days.

Normally, from the beginning of menstruation to its end, the dominant follicle has time to form and can be seen on ultrasound as early as 2 - 3 "clean" day. The follicular phase of the menstrual cycle does not manifest itself in any way outwardly, however, its passage is influenced by the woman's lifestyle.

Follicular phase hormones

The pituitary gland and hypothalamus are parts of the brain that regulate the entire reproduction process, including the production of hormones. After their receptors receive a signal to stop the secretion of progesterone, they start the process of stimulating the ovaries. They produce a whole complex of hormones that affect the reproductive system, but it was possible to identify two main ones - FSH and LH.

It determines and significantly affects the differentiation of the cells of their membranes. This hormone prepares the receptors in the ovaries for the effects of other hormones. FSH begins to be produced during puberty in both girls and boys. In men, it is subsequently produced evenly in small quantities, and in women, its level varies greatly depending on the stage of the cycle.

It is released by a signal from the pituitary gland after follicles have begun to develop. Under the influence of LH in the follicular phase of the normal menstrual cycle, the final separation of the follicular membrane cells occurs and the production of androgens begins. Androgens are converted to estrogens over time, and by the time of ovulation, the level of these hormones is at its maximum.

Simultaneously with FSH and LH, estradiol is also produced, which reaches a peak at the end of the follicular phase and its concentration should directly correlate with the level of LH. The relationship of these two hormones affects the secretory activity of the pituitary and hypothalamus, and if the ratio fluctuates or the levels of hormones are prohibitive, serious diseases such as a brain tumor should not be ruled out.

Follicular phase - hormone norms

The hormone levels are determined using a blood test. According to the general rules, the material is handed over on an empty stomach in the morning on certain days of the cycle. In addition, it is important to remember that the production of FSH does not occur evenly, it enters the bloodstream in portions, every 1 to 4 hours, the ejection period is 15 minutes.

The hormones produced in the first phase and affecting fertility are analyzed on the 3rd - 8th day of the cycle.

• FSH - 2.8 - 11.3 mU / l;
• LH - 2 - 14 mU / l;
• Prolactin - 130 - 540 mU / l;
• Progesterone - 0.33 - 2.22 nmol / L;
• Estradiol - 110 - 330 nmol / l.

Insufficiency of the follicular phase of the cycle

A decrease or an increase in the amount of production of a hormone can lead to an imbalance in the entire system of interconnection. The growth and development of the follicle depends on external hormonal regulation, therefore the balance and sequence of hormone production determines whether a woman can become pregnant. There are several reasons for the failure of the first phase, they can be detected from the pituitary gland or from the ovaries.

Stress, fears, constant tension states negatively affect the receptors of the pituitary gland and hypothalamus, which are extremely susceptible to mental overload. In medicine, a special term has been created for this phenomenon - psychogenic. The state of the brain structures is extremely negatively affected by bad habits.

Polycystic ovary disease in the follicular phase of any menstrual cycle causes a pathological response to the effects of FSH and LH, stimulates the release of uncharacteristic hormones into the blood and destroys the entire regulatory system, as a result of which the development of the follicle becomes impossible.

The follicular phase is the first phase of the ovarian cycle, which is characterized by the growth and maturation of the follicle.

The follicular phase, or, as it is also called, estrogen, begins from the very first day of menstruation and lasts until one or several dominant follicles mature in the ovaries. The end of this phase is ovulation.

Its duration can be completely different. Most often they occur precisely because of the slow maturation of the follicle. The main factor that affects the duration of this process is the time it takes for the body to reach the maximum level of estrogen.

According to functional and morphological changes in the ovary, the monthly cycle can be divided into the following phases:

1) Follicular phase;

2) Ovulatory;

3) Luteal;

4) Menstrual.

The phase of the cycle that leads to ovulation is called follicular. It usually takes only the first half of the cycle, but it can sometimes take longer. The average cycle time is 28 days. Any deviations from this number are caused only by the duration of the follicular phase.

The follicular phase is characterized by an increasing increase in the synthesis and release of inhibin and estradiol. Moreover, the concentration of these hormones increases not only in the systemic circulation, but also in the follicular fluid. Somewhere in 2 days before the onset of menstruation, the follicle begins to develop from its resting or primordial form.

It is during this period of time that the ovary dies off, which was formed in the previous cycle. The result of this process is a sharp decrease in the concentration of estradiol, progesterone and inhibin (the latter two to a lesser extent).

During 4-5 days of this phase, the primordial ovarian follicles continue to emerge and develop from the dormant state. begins to induce cell proliferation, the activity of which also increases. The result of this is an increase in the formation of estrogens from androgens, which are synthesized by interstitial cells.

The forming follicles at this point usually have more than one layer of follicular cells surrounding the oocyte. In addition, a small accumulation of follicular fluid appears between these cells. Follicle-stimulating hormone begins to induce the appearance of even more LH receptors and its own receptors. And this increases their sensitivity to luteinizing hormone.

The follicular phase is also characterized by the fact that on the 6-7th day of the cycle, one of the forming follicles begins to dominate. It is he who will receive further development and then ovulate by about 13-15 days of the cycle. It is characterized by the highest mitotic activity of follicular cells, the highest accumulation of follicle-stimulating hormone in the follicular fluid.

Non-dominant follicles have an increased ratio of androgens to estrogens, which suggests that aromatase activity is reduced in follicular cells. Such non-dominant follicles undergo regression (atresia). Androgens are a key factor in the induction of atresia.

The late and middle follicular phase is characterized by an even greater increase in the synthesis of inhibin B and estradiol, and this leads to inhibition of the production of follicle-stimulating hormone by the pituitary gland and the growth of new follicles stops. An increase in the content of estradiol also leads to an increase in the secretion of luteinizing hormone and an increase in the sensitivity of the ovary to gonadotropins. In addition, the high estrogen content causes the growth of the endometrium. Such changes are called the "proliferation phase".

In women, the menstrual cycle includes several phases. The very first of them is called the follicular phase, since in women during this period, eggs ripen in the follicles. Then this phase goes into ovulatory, and after it - in.

Phase duration

The beginning of the follicular phase is the first day of menstruation, that is, when the woman noticed discharge. Its duration is determined by the period of full maturation of one dominant follicle. Sometimes there are two or even more, but such cases are quite rare. The follicular phase ends with ovulation. Its duration can be different. Often, the duration of this particular phase of the female cycle determines the delay in menstruation. For example, in cases where the follicle matures very slowly or does not mature at all (while the corpus luteum phase is characterized by predominant constancy).

The main factor that affects the duration of this physiological process is the time it takes for the body to reach the maximum amount of estrogen in the blood. Estrogens such as estriol and estrone are indispensable in the female body. They are involved in stimulating the secretion of cervical mucus, an environment that is essential for the nourishment and movement of sperm. Normally, at the end of the follicular phase, this mucus is similar in consistency to raw egg white - the same slippery, elastic and transparent. If the mucus does not exist, the sperm, unfortunately, will die. Estrogens also contribute to the sudden release of luteinizing hormone. Two to four days after this, ovulation itself occurs. It is on the indicated sharp surge in hormones that the action of most tests that help to accurately determine the ovulatory peak is based. Estrogens promote endometrial growth and regeneration by preparing the uterus for the action of progesterones. They also lower body temperature.

The end of the follicular phase means that the level of estrogen in the follicle has reached a threshold, and it ruptures, which leads to ovulation. In general, it is believed that the follicular phase of the cycle is the preparation of the female body for probable conception.

Disorders and dysfunctions

The duration of the follicular phase may vary in some cases. If the follicle matures faster than normal, then a shortening of the follicular phase is observed. At the same time, no other deviations are observed, since the short follicular phase in most cases does not affect ovulation and subsequent possible pregnancy.

The opposite situation develops as the duration of this phase increases. At the same time, the follicle matures for a long time, and sometimes does not mature at all. This makes ovulation impossible. The reasons for the lack of ovulation in women can be:

• pregnancy;
• lactation;
• canceling or taking hormone-containing drugs;
• teenage years;
• menopause;

A variety of diseases, a sudden change in climate, travel, professional sports, stress, obesity or weight loss can also temporarily affect the duration of the follicular phase, causing it to be deficient or protracted.

If a woman does not become pregnant, then after ovulation and the luteal phase, which lasts from 10 to 12 days, the formed corpus luteum stops its activity. The level of progesterone, estrogen is sharply reduced, which provokes the synthesis of prostaglandins. The uterus begins to contract, spasms are observed in the vessels. These phenomena are accompanied by the rejection of the two outer layers of the endometrium. And then the next follicular phase begins again, indicating the beginning of a new menstrual cycle.

Menstruation is an essential part of every woman of childbearing age. Every schoolchild knows what is happening to the female body today. But in most cases, we have only a general idea of \u200b\u200bthe cycle: bleeding begins every month, lasting 3 to 5 days. At this time, the body gets rid of what was not useful. And, you can think about a possible pregnancy.

In fact, not everything is so simple. is divided into three main phases, each of which plays a very important role in preparing the female body for conceiving a child. And the first of them is the follicular phase, when the maturation of the egg occurs. Without this period, everyone else will lose their meaning. Knowing what the follicular phase in women is, and what exactly is happening now, you can understand a lot about her health and how the reproductive system works.

The essence and duration of the follicular phase

The follicular phase of the cycle begins on the very day when the first discharge appears. From that day, an egg cell begins to ripen in the follicles in order to begin its movement along the fallopian tube on the appointed day to meet with the sperm. The first phase lasts for everyone in different ways, from a week to twenty days. This is normal and not a disease. Thereafter . Accordingly, if the follicle has not matured for some reason, then ovulation will not occur. There may be several reasons for this:

• taking or canceling hormonal drugs;
• lactation;
• menopause;
• climate change;
• weight loss or, conversely, obesity;
• some diseases.

The female body is quite fragile, and many factors can affect the functioning of the reproductive system. In order to understand whether the follicular phase is proceeding normally, specialists prescribe a blood test to study the content of hormones and an ultrasound scan. The follicular phase of the cycle is important not only for reproduction, but also for showing women. That is why a blood test is prescribed exactly 3 to 5 days after the onset of menstruation.

In addition to what day the study will be conducted, it is important that certain conditions are met. Failure to comply with them can affect the rate of hormones in the follicular phase. Before donating blood, you should definitely have a good sleep, do not engage in heavy physical work the day before, avoid stressful situations and nervous tension. Also, it is recommended to exclude sex one day before the analysis. It is necessary to donate blood for hormones in the morning, on an empty stomach. But you should drink about half a liter of water. This is elementary in order for laboratory staff not to find it difficult to take blood for analysis. Alternatively, you can have a glass of water at home and take a small bottle with you to drink while you wait for your turn. This will prevent the blood from being too thick and you will not suffer from an overflowing bladder.

Hormonal background in the follicular phase

Probably, there is not a single woman who would not be sent to donate blood for hormones. These data can tell a lot about the state of women's health and will allow prescribing adequate treatment. Most often, it is the failure of these indicators that is an obstacle to.

The most important indicator is follicle-stimulating hormone. It is he who is responsible for the normal development and growth of follicles. During the study, the follicular phase of FSH should show from 3 to 11 mU / ml. Elevated FSH in the follicular phase or decreased FSH means either illness or pregnancy.

Also, together with the previous hormone, a study of the luteinizing hormone is prescribed. He is responsible for the release of the egg from the mature follicle. Its norm is from 2 to 14 mU / ml. Elevated LH in the follicular phase also means adrenal or pituitary disease. A lower reading means a decrease in the level of eggs.

Equally important is the ratio of these two indicators. The ratio of FSH and LH in the follicular phase should be 1.5 - 2 in favor of follicle-stimulating hormone. That is, in the first half of the cycle, it should be more than LH. In the second half of the cycle, the ratio changes in favor of the second hormone. Again, if the ratio deviates from the norm, this may also indicate the presence of certain diseases. For example, tumors of the adrenal or pituitary glands.

Another hormone, the study of which occurs during this period, is estradiol. It is responsible for the growth of the endometrium and for the development of the follicle. The norm of estradiol in the follicular phase is 110 - 330 pmol / l. Elevated estradiol in the follicular phase indicates disease. But its level can change during pregnancy and when taking certain medications, which must also be taken into account.

The indicator of such a hormone as prolactin is also important. It usually rises during breastfeeding and blocks the function of conception. If the woman is not pregnant and is not breastfeeding, the prolactin rate should be 130 - 540 mU / ml.

These were all exclusively female hormones, the indicators of which indicate the readiness of the body for conception and the presence or absence of diseases. But male hormones can also affect this process. Therefore, doctors often prescribe. Its rate should be 0.32 - 1.2 ng / ml. Increased 17-OH progesterone in the follicular phase, if we are not talking about pregnancy, may indicate disruption of the adrenal glands and ovaries or congenital adrenal hyperplasia. Increased progesterone in the follicular phase usually leads to acne, increased body hair growth, and changes in blood sugar levels.

Naturally, hormonal indicators alone are not enough to conclude on the state of women's health. Often after this, an ultrasound examination is prescribed. Only on the basis of blood examination and ultrasound can one judge the presence or absence of diseases. Treatment is chosen accordingly. If the ultrasound did not show anything, then most often it is simply a hormonal imbalance, which today is successfully treated with industrial drugs.

Usually, treatment is not immediately prescribed, a second blood test is performed in a month. Now, knowing what the follicular phase in women is, you have an idea that any circumstances can affect hormonal levels. If after a month the indicators remain at the same level, hormone therapy is prescribed. Accurate adherence to the doctor's recommendations and timely monitoring allow you to quickly bring women's health back to normal.