Raising awareness for<unk>  as a global issue: World Menstrual Hygiene Day celebration in India<unk>  (also known as a period and many other colloquial terms) is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The menstrual cycle is characterized by the rise and fall of hormones.<unk>  is triggered by falling progesterone levels and is a sign that pregnancy has not occurred. The first period, a point in time known as menarche, usually begins between the ages of 12 and 15.<unk>  starting as young as 8 years would still be considered normal. The average age of the first period is generally later in the developing world, and earlier in the developed world. The typical length of time between the first day of one period and the first day of the next is 21 to 45 days in young women. In adults, the range is between 21 and 31 days with the average being 28 days. Bleeding usually lasts around 2 to 7 days. Periods stop during pregnancy and typically do not resume during the initial months of breastfeeding.<unk>  stops occurring after menopause, which usually occurs between 45 and 55 years of age. Up to 80% of women do not experience problems sufficient to disrupt daily functioning either during<unk>  or in the days leading up to<unk> . Symptoms in advance of<unk>  that do interfere with normal life are called premenstrual syndrome (PMS). Some 20 to 30% of women experience PMS, with 3 to 8% experiencing severe symptoms. These include acne, tender breasts, bloating, feeling tired, irritability, and mood changes. Other symptoms some women experience include painful periods and heavy bleeding during<unk>  and abnormal bleeding at any time during the menstrual cycle. A lack of periods, known as amenorrhea, is when periods do not occur by age 15 or have not re-occurred in 90 days.
Menstruation
Menarche
Vibroejaculation
Electroejaculation
Menstrual leave
Menopause
Anejaculation
Lactational amenorrhea