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.

Menstrual Cycle Facts

Girls often ask about the menstrual cycle. They want to know what will happen when their period begins.

Menstrual Cramps
During menstruation, the muscles of the uterus contract (tighten) to help the body get rid of the surface of the endometrium. This can be uncomfortable for some girls and women. This pain is often called cramps. Cramps can be made to feel better with moderate exercise, a warm bath or a heating pad. Over-the-counter pain medications such as ibuprofen or naproxen will usually help. Menstrual cramps that are not relieved by over-the-counter medicines should be evaluated by a health care provider.

Pre-Menstrual Syndrome (PMS)
PMS is a group of physical and emotional signs (symptoms) that some girls and women have before menstruation begins each month. Common symptoms include: tenderness of the breast, head aches, fatigue, bloating, weight gain, moodiness, sadness, being irritable and angry, and cravings for sweet and salty foods.
Exercise, good nutrition and getting enough sleep can help some girls and women feel better.

Sanitary Pads
It is used to absorb the menstrual fluid as it leaves the body. Sanitary pads absorb the flow from outside the body and are worn inside the underwear. It is important to change pads several times a day. Tampons absorb the flow from inside the vagina, as it leaves the uterus. It is important to wear the lowest absorbency needed and change them regularly, at least every four to six hours.

Toxic Shock Syndrome (TSS)
TSS is a rare condition caused by toxins released by bacteria called Staphylococcus aureus that can be present in the vagina during menstrual cycles. Using tampons can increase the risk for TSS, especially if they are not changed every four to six hours. In addition, men and children and women who are not menstruating can also develop TSS because the bacteria can enter the body in different places. It is important to use the lowest absorbency tampon that is right for a female's flow. It is also important to change the tampon every four to six hours. Switching between using pads and tampons (for example, using a pad during the night) may also lower the risk of toxic shock syndrome.

What Happens During Menstruation?

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.

Menstrual Cycle Truths

Some bad information about menstruation is out there. Your kids may have heard things that are NOT true! As a parent, you can share the truth with them.

True:

• Girls who have never had sex can certainly use tampons.
• Using a tampon does not cause loss of virginity.
• Tampons cannot get lost inside the body.
• Cold water will not stop the menstrual flow.
• Girls can bathe when menstruating.
• Girls can exercise during their period.
• Girls can eat or drink hot things during their period.

Last revised: May 28, 2008

Source: U.S. Department of Health and Human Services

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