Menstruation is an important physiological phenomenon in women of reproductive age.
Menstruation
Menstruation refers to the periodic shedding and bleeding of the endometrial lining, which occurs in response to cyclical changes in the ovaries. The onset of regular menstruation is a key indicator of reproductive maturity. The first occurrence of menstruation is called menarche. Menarche typically occurs between the ages of 13 and 14, though it may begin as early as age 11 or as late as age 15. Clinical attention is required if menstruation has not begun by the age of 15 in order to investigate potential underlying causes. The timing of menarche is primarily influenced by genetic factors, although other factors such as nutrition and body weight also play significant roles. There has been a recent trend toward an earlier onset of menarche.
Characteristics of Menstrual Blood
Menstrual blood has a dark red color and consists not only of blood but also fragments of the endometrium, cervical mucus, and exfoliated vaginal epithelial cells. It contains prostaglandins and a significant amount of fibrinolysin derived from the endometrium. Due to the fibrinolytic action of fibrinolysin on fibrinogen, menstrual blood does not normally clot. However, in cases of heavy or rapid bleeding, blood clots may be present.
Clinical Manifestations of Normal Menstruation
Normal menstruation is characterized by periodicity and self-limitation. The first day of bleeding marks the beginning of the menstrual cycle. The interval between the first day of two consecutive menstrual periods is referred to as the menstrual cycle, which typically ranges from 21 to 35 days, with an average of 28 days. The duration of each period of bleeding is called the menstrual period, which usually lasts 2 to 8 days, with an average of 4 to 6 days. Menstrual volume refers to the total amount of blood lost during a single menstrual cycle, with a normal range of 20 to 60 ml. A volume exceeding 80 ml is considered heavy menstrual bleeding.
In general, menstruation is not accompanied by unusual symptoms. However, some women may experience discomfort such as a sensation of heaviness in the lower abdomen and lower back, or uterine cramps, due to pelvic congestion and the effects of prostaglandins during menstruation. Gastrointestinal symptoms such as diarrhea may also occur due to functional disturbances. A small number of individuals may experience headaches or mild symptoms of nervous system instability. Severe dysmenorrhea requires medical evaluation to provide pain relief and to exclude underlying pathological conditions.