Menstrual and ovarian cycle

Apr 15, 2012 , Lucia Hlavatá

menstruacni-a-ovarialni-cyklus-vynechani-menstruace.jpg - kopie
menstruacni-a-ovarialni-cyklus-vynechani-menstruace.jpg - kopie
Menstrual and ovarian cycle occurs in reproductive organs of every woman, they are cyclical changes in ovaries and in uterine mucosa. Every woman should know their menstrual and ovarian cycle, in the case of a missing menstruation, which can have different causes. Missing menstruation can mean pregnancy, but also various diseases.

Menstrual and ovarian cycle

Cyclical changes occur in the reproductive organs of every woman, caused by fluctuating levels of FSH (follicle-stimulating hormone) and LH (luteinizing hormone). These changes involve the ovaries and the mucous layer of the uterus and are referred to as a menstrual and ovarian cycle. They repeat approximately every 28 days. These cycles are closely dependent, because hormones produced by ovaries directly influence the uterine mucous layer.

Ovaries and uterus

The ovaries are a female reproductive organs located in the pelvis on both sides of the uterus. They are reproductive glands, which produce female reproductive cells, the eggs, as well as sex hormones, estrogens and gestagens. Much like the uterus, ovaries arfe a necessary organ for continuation of the species. The uterus is also one of the female reproductive organs. It is located between the ovaries inside the pelvis, where it is fixed by strong uterine ligaments. Its insides are covered by uterine mucosa, which undergoes changes important for the correct nesting of a fertilized egg, its development and growth. Uterus is connected to the ovaries by fallopian tubes, through which the eggs travel to the uterus and in which the eventual fertilization occurs.

Ovarian cycle

The ovarian cycle involves the changes in ovaries. Every woman is born with a set amount of eggs. This amount decreases with age, only around 400-450 of them become full-fledged, mature eggs, known as Graaf follicles. During the first phase of an ovarian cycle, the follicular phase, a randomly selected egg grows due to the influence of FSH (follicle-stimulating hormone) and etrogens are produced at a high rate. At the end of this phase the levels of LH (luteinizing hormone) also increase, helping to mature the egg and release it from the ovary, in a process known as ovulation. Ovulation begins approximately the 14th day of the ovarian cycle. The released egg travels through the fallopian tubes to the uterus, where it can be fertilized. After ovulation begins the second phase, the luteal phase, during which a corpus luteum is created out of the remnants of the released egg. The corpus luteum starts producing large quantities of female reproductive hormones, namely progesteron, which prepares the uterus for eventual pregnancy. Should the egg not be fertilized, hormone levels sharply drop and the egg is washed away from the body together with menstrual blood.

Menstrual cycle

During the menstrual cycle the thickness of the uterine mucous layer changes based on hormonal levels and ovarian cycle. Menstrual phase, or menstrual bleeding lasts for 5 days on average. The mucous layer detached and is washed out together with the unfertilized egg and cca. 20-80 ml of blood. In the next phase, the proliferation phase, which lasts from the 5th day to the 14th of the menstrual cycle, the mucous layer is renewed and regrown under the influence of estrogens. The following phase is the secretory phase, during which the uterus prepares for accepting a fertilized egg, being influenced by progesterone produced by corpus luteum. If the egg is not fertilized, hormonal levels drop and another menstrual bleeding follows.

Absence of menstruation

The first menstruation or menarche usually occurs between the 11th -14th year of life and end around the 50th year, when the woman enters menopause. A 25-35 days menstrual cycle is considered normal. Lack of or skipped menstruation is known as amenorrhea and can have a variety of causes. If menstruation hasn't occurred until 16th year, the issue may be a developmental defect in the reproductive organs are or a genetic defect. If menstruation occurs, but occurs irregularly or not at all, it can be a hormonal problem. These tend to be caused by psychological stimuli such as psychical overexertion, unfavorable life situation or changing environment. An extreme weight loss or physical exertion can also be a reason for missing menstruation. Menstrual cycle is also influenced by pathological processes on reproductive organs, such as inflammations, tumors, but also injuries. A common reason here is the polycystic ovary syndrome. The polycystic ovary syndrome is one of the most common causes of infertility in women. It is manifested by lack of ovulation. Eggs are not released from follicles, they clump together, forming cysts, small cavities filled with fluid. The result is missing or extremely irregular menstrual cycle, together with other issues, such as diabetes, obesity, increased body hair or acne.

Another possible cause of missing menstruation are hormonal disbalances, such as a high level of male sex hormones or prolactine, which is increased in breastfeeding mothers. Women using hormonal contraceptives can also delay their menstruation on purpose by avoiding the gap when taking pills. Lack of menstruation is of course normal during pregnancy. Some psychoactive or blood pressure lowering drugs can cause amenorrhea as well.

Premenstrual syndrome

Premenstrual syndrome or PMS is a group of symptoms afflicting a part of the female population several days before menstruation. Premenstrual syndrome is tied to hormonal changes during the menstrual cycle. A lack of vitamin B6, calcium, magnesium, stress, lack of exercise and too much caffeine can worsen PMS. Premenstrual syndrome has these symptoms: flatulence, sensitive breasts, aches, stomach pains and cramps, back pains, acne, lack of energy, tiredness and increased appetite. PMS can influence your mood as well. You may suffer from sadness, irritability, anxiousness, lack of focus or changes in sexual drive. Treatment of PMS lies in resting and relieving leading symptoms, using painkillers for example. It is important to have a balanced diet, a sufficient intake of fluids, enough exercise and to avoid alcohol and smoking.


It is important for every woman to know her menstrual and ovarian cycle for finding her fertile and infertile day, whether for planning pregnancy or avoiding it. It is also important to know the length of your cycle, and visit your doctor in case of a longer delay, as he is the only one who can determine the cause and offer the course of treatment for adjusting your menstrual cycle.

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