Period products
This page is reference information compiled from the cited sources. It is not medical advice. For any decision about health, diagnosis or care, consult a qualified professional.
What it is
Menstruation is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. It is also known as a period. Menstruation is the most visible phase of the menstrual cycle. The menstrual cycle is characterized by the rise and fall of hormones. Menstruation is triggered by falling progesterone levels and is a sign that pregnancy has not occurred. Feminine hygiene products are used to maintain hygiene during menses. The fluid discharged is called menstrual fluid, which is reddish-brown and contains blood, cervical mucus, vaginal secretions, and endometrial tissue.
Key facts
The first period, called menarche, usually begins between ages 11 and 13, but can occur as early as eight. The average age of menarche is 12 to 15 years. The typical length between periods is 21 to 45 days in young women and 21 to 35 days in adults, with a mean length often cited as 28 to 29.3 days. Bleeding typically lasts two to seven days. The average volume of menstrual fluid is 35 ml, with 10–80 ml considered typical. About half of menstrual fluid is blood. Periods stop during pregnancy and typically do not resume during the initial months of breastfeeding. Menstruation ceases after menopause, which usually occurs between 45 and 55 years of age. During their menstrual period, 38% of all women reported not being able to perform all their regular daily activities.
When to seek professional help
Professional help is associated with symptoms that interfere with normal life. This includes premenstrual syndrome (PMS) experienced by 20 to 30% of women, with 3 to 8% experiencing severe symptoms. Severe symptoms that disrupt daily activities and functioning may be diagnosed as premenstrual dysphoric disorder. Painful periods, or dysmenorrhea, are reported by many women, with 2%–28% of adults having pain severe enough to affect daily activity. Heavy menstrual bleeding, occurring monthly, can result in anemia. A lack of periods, known as amenorrhea, is when periods do not occur by age 15 or have not re-occurred in ninety days. When severe pelvic pain and bleeding suddenly occur or worsen during a cycle, this could be due to ectopic pregnancy and spontaneous abortion, which is checked by using a pregnancy test.
Source: Menstruation (CC BY-SA 4.0 (Wikipedia)), retrieved 2026-09-19.
