月经是指胞宫周期性出血的生理现象,又称为月事、月水、月信等。女子一般在14岁左右,月经即开始来潮,到49岁左右则自行闭止,历时约35年左右。此期间除去妊娠及哺乳期以外,通常是一个月来潮一次,信而有期,因而称为月经。月经应该有正常的周期、经期、经量、经色和经质。月经的周期及经期均从经血来潮第一天算起,两次月经相隔时间为周期,一般为28天,偶而提前或延后时间不超过7天者仍可视为 Menstruation refers to the physiological phenomenon of cyclical bleeding in the uterus, also known as the moon, moon water, letters and so on. Women generally about 14 years old, menstrual cramps began to 49-year-old is on its own, which lasted about 35 years. During this period except pregnancy and lactation outside, usually a monthly cramps, the letter and the period, which is called menstruation. Menstruation should have a normal cycle, menstruation, by volume, color and quality. Menstrual cycle and menstrual period are from the first day of menstrual cramps, menstrual interval between two menstrual cycle, usually 28 days, occasionally in advance or delay of not more than 7 days can still be considered as