1ST CITY CLINICAL HOSPITAL

This article discusses such a concept as the “menstrual cycle”. What is considered normal and what is a deviation from the norm.

What is the menstrual cycle?

The menstrual cycle is a specific time interval: from the first day of menstruation to the beginning of the next menstruation. Regardless of the individual duration of menstruation, the first day is precisely the first day of bleeding.

What is the normal length of the menstrual cycle?

The length of the menstrual cycle is not the same. Variations are possible from 21 to 35 days. For most women, 28-29 days pass from the first to the first day of the menstrual cycle. If over the course of two to three months the time intervals for the onset of menstruation vary - sometimes after 20 days, sometimes after 30 days - this is regarded as a lack of regularity in the menstrual cycle. The difference in the duration of the menstrual cycle, as a rule, concerns the period before ovulation (follicular phase). For most women, 12-16 days pass from ovulation to the start of menstruation (luteal phase).

1st phase of the menstrual cycle

At the beginning of the cycle, the pituitary gland, a gland located at the base of the brain, produces follicle-stimulating hormone (FSH), which promotes the maturation of several follicles in the ovary and the production of estrogens. As the follicles develop, one of them becomes “dominant” and the egg matures in it. Rising levels of estrogen promote the growth of the uterine lining (endometrium), where a fertilized egg will be implanted if pregnancy occurs. Also, high levels of estrogen stimulate the production of mucus in the cervix, which promotes the movement of sperm through the cervical canal.

Ovulation.

Estrogen levels rise steadily towards the middle of the menstrual cycle. The pituitary gland releases luteinizing hormone (LH), which leads to the rupture of the dominant follicle and the release of a mature egg. This process is called ovulation. Many people believe that ovulation occurs on day 14, but this is an average. The day of ovulation may vary slightly from cycle to cycle. Some women may experience pain during ovulation. In most cases, ovulation occurs without any signs.

Phase 2 of the menstrual cycle.

After ovulation, a “corpus luteum” is formed in the ovary at the site of the ruptured follicle, and the hormone progesterone begins to be produced. Progesterone promotes the maturation of the lining of the uterus (endometrium) for implantation of a fertilized egg. During this phase of the menstrual cycle, there may be symptoms of drowsiness, irritability, bloating, and tenderness of the mammary glands (premenstrual syndrome). If fertilization does not occur, the egg dies.

By the end of the menstrual cycle, the “yellow body” decreases in size, the amount of hormones (estrogens and progesterone) decreases, the endometrium begins to shed, and spotting appears. This represents the beginning of your period and the beginning of the next menstrual cycle.

If fertilization occurs, the egg moves through the fallopian tube into the uterine cavity, where it is implanted into the uterine mucosa and further develops. As a rule, this occurs 7-10 days after fertilization. During this period, the hormone human chorionic gonadotropin (hCG) begins to be produced.

Methods for determining ovulation

1. Ultrasound monitoring

2. Ovulation test strips

There are other methods for determining ovulation that can be used as additional methods (to ultrasound and hormonal monitoring).

1. Basal temperature. The method can be used independently at home. Based on the hyperthermic action of progesterone, i.e. when measuring the temperature in the rectum, there is an increase in temperature by 0.5-0.6 C in the second phase of the menstrual cycle.
2. The nature of cervical (cervical) mucus. This method is based on changing the nature of cervical mucus under the influence of estrogens.
3. The “fern” method. The work of microscopes for determining ovulation is based on this method. This method, like the previous one, is based on changing the nature of saliva and cervical mucus under the influence of estrogens.
4. Symptom “Pupil” By the time of ovulation, the cervix begins to change. In its normal state it is hard and the cervical canal is closed. At the moment of ovulation, the cervical canal opens slightly and when examined by a gynecologist, mucus is visualized in the speculum, which looks like a “pupil.” This sign is assessed by a doctor during examination.

These methods are not recommended for diagnosing menstrual disorders and prescribing hormonal medications. This requires more modern types of diagnostics. Not recommended for use to prevent pregnancy.

Prepared by: obstetrician-gynecologist (head of department) of the emergency department (obstetric and gynecological departments Roslik I. N.