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The menstrual cycle is a very complicated process that allows a woman to remain fertile. Its length is very individual and depends on the body of a given woman. However, it usually takes about 28 days. It consists of successive phases. Every woman’s menstrual cycle begins with the follicular phase on the first day of her period.
The follicular phase is the first stage of the menstrual cycle. The beginning of this phase is considered to be the first day of menstruation and the end is the beginning of ovulation. During this time, certain changes occur in the woman’s body. See what the follicular phase looks like.
Follicular phase – menstrual cycle
The follicular phase starts a normal looking menstrual cycle. Its beginning is the first day of menstruation and therefore the beginning of bleeding. The follicular phase ends with ovulation. The next stage is the ovulatory phase and finally the luteal phase.
During the entire cycle, a woman’s body undergoes certain changes. They can be seen in the appearance of the mucosa as well as in the ovaries and are characteristic of each phase of the cycle. The purpose of the whole process is to prepare the uterus to receive an embryo.
The duration of the follicular phase is very individual and variable under the influence of many factors. On average, the follicular phase lasts about 14 days, assuming that the entire cycle lasts 28 days.
Faza follicularna – hormones
All changes in a woman’s body are associated with changes in the levels of sex hormones. During the follicular phase, progesterone levels remain low. It only rises after ovulation. On the other hand, the level of estrogen increases the day before the end of the follicular phase. It is thanks to him that it is possible to thicken the uterine mucosa.
During the follicular phase, however, the most important hormone is FSH. This is called follicle-stimulating hormone, whose task is to stimulate the development of ovarian follicles. It is produced by the anterior pituitary gland. A woman’s body enters the follicular phase with an increase in FSH concentration.
Follicle stimulating hormone levels should be between 1,4 – 9.6 IU / L. If its level is higher, it may mean disturbances in the work of the ovaries, and the result below is about disturbances in the work of the pituitary gland.
The level of FSH is measured in venous blood. At the same time, other hormones (estradiol, progesterone, testosterone) are tested.
Follicular phase – uterine mucosa
The beginning of the follicular phase is the first day of your period. During menstruation, and thus also at the beginning of the follicular phase, the thickened uterine mucosa exfoliates. It becomes very thin and is thinnest during the entire menstrual cycle. Over time, the mucosa becomes thicker again and the body prepares for a potential pregnancy.
Follicular phase – follicular development
An ovarian follicle also develops during the follicular phase. The follicles that mature in the ovaries begin to produce estrogen, which causes the lining of the womb to thicken.
At the same time, a sperm-friendly environment is created. The cervical mucus becomes more stretchy, making it easier for sperm to reach the egg.
As a result of the release of estrogens into the blood and pituitary gland, the level of follicle stimulating hormone also decreases. The larger the ovarian follicles, the more estrogens that inhibit FSH secretion.
About the 6th day of the cycle, the dominant follicle appears, i.e. the follicle with the most estrogen. Follicle stimulating hormone levels decline. There is an egg in the follicle that will be released during ovulation. Before ovulation, the amount of estrogen in the follicle suddenly rises rapidly.
The follicular phase ends when the luteinizing hormone luteinizing hormone, or lutropin, reaches its peak.