Why not a menstrual clot

The menstrual cycle

A woman is sexually mature between around 12 and 55 years of age. H. she can get pregnant. The sexual maturity is shown by the regular ovulation (Ovulation) and associated Menstruation (Menstrual bleeding, menstrual bleeding, withdrawal bleeding, period, menses, "days"). Since the bleeding recurs every month, it is also referred to as Menstrual cycle (mensis = month). The first menstrual bleeding in a young girl is called Menarche refers to and usually begins between the ages of 11 and 13. The woman's last menstrual period is called menopause and means the end of fertility. The basis of the menstrual cycle is a sophisticated interplay of the female sex hormones estrogen and progesterone, the concentrations of which rise and fall again cyclically. Under the influence of estrogen, on the one hand in the ovaries, on the other hand also from the maturing one Follicles (Follicle) is formed, the lining of the uterus prepares itself for a fertilized egg to implant. The mucous membrane thickens as its cells multiply and stores nutrients. It is built up and grows from about 2 mm to a thickness of 10–12 mm. Once the estrogen concentration has reached a certain level, it causes the release of luteinizing hormone (LH). This in turn ensures that ovulation takes place. The egg cell is picked up by the funnel-shaped opening of the fallopian tube and begins its migration through the fallopian tube to the uterus. The remainder of the follicle left in the ovary becomes the Corpus luteum. It produces the hormone progesterone, too Luteal hormone called. Under its influence, the built-up uterine lining is preserved. However, if the egg cell is not fertilized, the corpus luteum regresses and, at the same time, the secretion of progesterone is reduced. If the progesterone concentration in the blood falls below a certain value, the built-up mucous membrane cannot be preserved. About two weeks after ovulation, the upper layers of the lining of the uterus peel off and bleeding occurs. Since the decreased hormone concentration triggers the bleeding, it is often referred to as withdrawal bleeding. The first day of bleeding is defined as the first day of your cycle.

Course and duration of the cycle

Menstrual bleeding usually lasts 3–7 days. The duration, strength and course of menstruation can be different for every woman. During menstruation, an average of 65 ml of menstrual fluid is excreted, most of it in the first two days. To make it easier for the lining of the uterus to detach, the uterus often contracts at the beginning of menstruation. For women, this can range from slight pulling to severe, cramp-like abdominal pain. Together with the blood, even the smallest pieces of tissue that belong to the lining of the uterus and are not a cause for concern are excreted. Smaller blood clots are also normal for the first few days of your menstrual period.

Simultaneously with the bleeding, a new follicle matures in the ovary, the estrogen concentration increases day by day, and the uterine lining prepares again for the implantation of a fertilized egg. This phase in the menstrual cycle is called Build-up phase (Proliferation phase). It ends between the 12th and 15th day of the cycle (Mid-cycle) with ovulation. At this point, the mucous membrane is maximally built up again and is preserved as long as the corpus luteum is still producing progesterone. These Secretion phase (Luteal phase) ends after the 28th day of the cycle with the start of the next bleeding. The secretion phase after ovulation, in which the corpus luteum regresses if fertilization fails, always lasts 14 days. In contrast, the first half of the cycle - that is, the period of menstrual bleeding and the renewed build-up of the mucous membrane - can be of different lengths and varies between 11 and 21 days. Accordingly, a full menstrual cycle lasts between 25 and 35 days, an average of 28 days.

The main hormonal changes in the menstrual cycle. If the egg is fertilized and implanted, the corpus luteum does not die, but continues to grow as the production of progesterone increases. The beta-HCG (human chorionic gonadotropin) hormone is produced by the cells of the placenta when pregnancy occurs. In the pregnancy test, the HCG hormone is detected in the urine.
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Noticeable changes in the cycle

The regular rise and fall of the hormone level in the blood is of course also noticeable in other ways than just during the menstrual period. It can be that at the time of ovulation and in the second half of the cycle, due to the influence of estrogen, more water is stored and the breast becomes tense. As a result of the action of progesterone, the body temperature rises by about 0.5 ° C 1–2 days after ovulation and remains elevated for the entire second half of the cycle. Mood swings due to the sudden drop in hormone levels are just as common in the days leading up to menstruation as food cravings or dull hair.

Another cyclical change concerns the Cervical mucus (Cervical mucus). The mucus plug, which normally closes the cervix and thus prevents both germs and sperm from entering the uterus, liquefies shortly before ovulation and is excreted through the vagina. At the same time, the cervix opens a little, making it easier for the sperm to get into the uterus. The woman notices the mucus emerging from the vagina as early as the 10th or 11th day, the maximum is reached on the 15th day. At this point, the slime also changes color and consistency. It becomes transparent and can be pulled apart several centimeters between two fingers ("spinnability").

Determination of the current cycle phase

The changes in the sex hormones estrogen and progesterone within the different cycle phases are noticeable for the woman on the one hand, and on the other hand they can be seen by the doctor with the help of the hormonal functional diagnostics (Vaginal cytology) check and document. The function of progesterone z. B. shows up in changed cells of the vaginal wall.

For the examination, the doctor moves a cotton swab along the wall of the vaginal vault. He unrolls the smear material on a slide and looks at it under the microscope. Vaginal cytology can determine relatively precisely which phase of the cycle the woman is currently in. The measurement of the morning body temperature (basal temperature method) and the assessment of the cervical mucus (cervical mucus method) also help determine the cycle phase and thus the hormone function.


Dr. med. Astrid Waskowiak, Dr. med. Arne Schäffler in: Gesundheit heute, edited by Dr. med. Arne Schäffler. Trias, Stuttgart, 3rd edition (2014). Revision and update: Dr. med. Sonja Kempinski | last changed on at 16:30