In women, the menstrual cycle includes several phases. The very first of these is called the follicular phase, since in the indicated period in the follicles oocytes mature in the follicles. Then this phase passes into the ovulatory, and after it - into the luteal phase .
Duration of Phase
The onset of the follicular phase is the first day of menstruation, that is, when the woman noticed the discharge. Its duration is determined by the period of full maturation of one dominant follicle. Sometimes there are two or more, but such cases are quite rare. The follicular phase is completed by ovulation. The duration of it can be different. Often the duration of this phase of the female cycle determines the delay in menstruation. For example, in cases where the follicle matures very slowly or does not ripen at all (thus the phase of the yellow body is characterized by predominant constancy).
The main factor that influences the duration of a given physiological process is the time required for the body to reach the maximum amount of estrogens in the blood. Such estrogens as estriol and estrone are irreplaceable in the female body. They are involved in stimulating the secretion of cervical mucus - an environment that is extremely necessary for nutrition and movement of spermatozoa. Normally, in the end of the follicular phase, this mucus is similar in consistence to the egg raw protein - the same slippery, elastic and transparent. If this mucus is not, the spermatozoa, unfortunately, will die. Estrogens also contribute to a sharp release of luteinizing hormone. In two to four days after this, ovulation occurs itself. It is on this sharp surge of hormones that most of the tests that help to determine the ovulatory peak are based. Estrogens promote the growth and regeneration of the endometrium, preparing the uterus for the action of progesterones. In addition, they reduce body temperature.
Completion of the follicular phase means that the level in the estrogen follicle has reached the threshold, and it is ruptured, which leads to ovulation. In general, it is believed that the follicular phase of the cycle is the preparation of the female organism for probable conception.
Disorders and dysfunctions
The duration of the follicular phase may change in some cases. If the follicle ripens faster than normal, then the follicular phase is shortened. In this case, there are no other abnormalities, since the short follicular phase in most cases does not affect ovulation and the subsequent possible pregnancy.
The reverse situation develops when the duration of this phase increases. The follicle thus ripens for a long time, and sometimes does not mature at all. This makes ovulation impossible. The reasons for the absence of ovulation in women can be:
- pregnancy;
- lactation;
- abolition or intake of hormone-containing drugs;
- adolescence;
- menopause;
- hormonal failure .
A variety of diseases, sudden climate change, travel, professional sports, stress, obesity or weight loss can also have a temporary effect on the duration of the follicular phase, causing it to be deficient or protracted.
If a woman does not have a pregnancy, then after ovulation and luteal phase, lasting from 10 to 12 days, the formed yellow body stops its activity. The level of progesterone, estrogen decreases sharply, which provokes the synthesis of prostaglandins. The uterus begins to contract, spasms are seen in the vessels. These phenomena are accompanied by the rejection of two outer layers of the endometrium. And then again begins the next follicular phase, indicating the onset of a new menstrual cycle.