Menstruation

Menstruation begins during puberty and is commonly called a period. This is the time when females shed bloody fluid from their uterus as part of the menstruation cycle. For the first couple of years periods will probably not be regular. This is because hormone levels are still changing in the body and ovulation may not be occurring every month. After that, periods usually are more regular - they usually come at about the same time each month.

The first menstrual period is called "menarche." The average age of menarche in the United States is 12 ½ years. This means that from menarche until menopause - when a woman can no longer menstruate - pregnancy is possible.

Each month, the ovary releases an egg cell. It travels down the fallopian tube towards the uterus. The uterus has been getting ready for an embryo by thickening the uterus lining (endometrium).

If the egg cell is fertilized by a male's sperm cell, it happens in the fallopian tube. Then, during the next three days, the new embryo travels the remaining distance down the fallopian tube, enters the uterus, and attaches to the lining of the uterus. This lining protects and feeds it as the fetus develops.

If the egg is not fertilized or if the egg does not attach to the lining of the uterus, then menstruation begins and the endometrial lining sheds its surface layer and it leaves the body as a bloody fluid. It usually takes three to seven days to completely shed. This is the menstrual period. The uterus is a muscle that can "contract" or "cramp" as the menstrual fluid leaves the body. Over-the-counter medication can help relieve menstrual pain.

Sanitary products absorb the menstrual fluid as it leaves the body. The two types of sanitary products are sanitary pads and tampons. Sanitary pads absorb from the outside of the body. Tampons absorb from inside the vagina.

The entire menstrual process or cycle takes about 28 days. However, some women have cycles that last as many as 34 days or as few as 19 days. The menstruation, or bleeding, usually lasts from about three to seven days.

Menstrual fluid does not have an unpleasant odor. But bacteria can grow when menstrual fluid comes into contact with the air. This can cause an odor. So it is very important to bathe regularly during menstruation.

For more information, visit Menstrual Cycle Phases and Menstrual Cycle Facts.

Last revised: April 21, 2008