Menstruation begins at puberty and is commonly known as the rule. This occurs when women secrete a bloody fluid from the uterus as part of the menstrual cycle. During the first two years, the rules probably are not regular. This occurs because the body’s hormone levels are still changing and ovulation may not occur every month. After that, the rules usually are more regular (usually occur at about the same time each month).

The first menstrual period is called “menarche” or “menarche”. In the United States the average age of menarche is 12 years. This means that from menarche to menopause, when women can no longer menstruate, it may result in pregnancy.

Every month, the woman’s ovary releases an egg or cell. It travels down the fallopian tube to the uterus. The uterus and has been preparing to receive an embryo, so that the uterine lining (endometrium) has increased in thickness.

If the egg is fertilized by the male sperm, this occurs in the fallopian tube. Then for the next three days the new embryo travels the rest of the way down the fallopian tube, enters the uterus and attaches to the uterine wall. The uterine lining protects and nourishes the fetus as it develops.

If the egg is not fertilized, or if it does not adhere to the walls of the uterus, then starts the menstruation and endometrial lining sheds its surface layer and leaves the body as blood flow. Normally, the ejection of these tissues lasts three to seven days. This is menstruation. The uterus is a muscle that can “shrink” or “cramp” when menstrual fluid leaves the body. There are counter medications to relieve menstrual cramps.

Medical devices absorb menstrual fluid as it exits the body. The two types of medical devices are towels and tampons. Sanitary towels absorb menstrual fluid as it exits the body. The buffers absorb the fluid inside the vagina.

The menstrual process or cycle lasts 28 days. However, some women have cycles that last up to 34 days or short courses of 19 days. Menstruation or bleeding usually lasts 3-7 days.

Menstrual fluid has no odor. But when the menstrual fluid contact with the air causes the bacteria to grow. This can cause odor, so it is very important to bathe regularly during menstruation.