The menstrual cycle is a periodic physiological process in the female body that regulates reproductive function. It lasts an average of 28 days (21 to 35 days is a variant of the norm) and includes several phases controlled by hormonal changes. The menstrual cycle prepares the body for possible fertilization and pregnancy.

The main phases of the cycle are follicular, ovulatory and luteal. In the follicular phase (the first 10-14 days), under the influence of estrogens, the dominant follicle matures in the ovaries, and the uterine mucosa (endometrium) begins to thicken. In the ovulatory phase, which usually occurs on the 12th-16th day of the cycle, the mature follicle ruptures, and the egg is released into the fallopian tube, where fertilization can occur. The luteal phase (14 days) is accompanied by an increase in progesterone levels, which prepares the uterus for embryo implantation. If fertilization does not occur, the level of hormones decreases, and menstruation begins – rejection of the endometrium with bleeding.

Menstrual irregularities can be caused by stress, hormonal imbalances, chronic diseases, nutrient deficiencies, or physical overload. A regular menstrual cycle is an indicator of a healthy reproductive system, so if it fails, it is recommended to consult a gynecologist for diagnosis and correction of possible disorders.