Menstruation
and the Menstrual Cycle
article syndicated from NWHIC
November 2002
What is menstruation?
What is the menstrual cycle?
What happens during the menstrual cycle?
What is a typical menstrual period like?
What kinds of problems do women have with
their periods?
At what age does a girl get her first period?
How long does a woman have periods?
When should I see a health care provider
about my period?
How often should I change my pad/tampon?
What is menstruation?
Menstruation is a woman's monthly bleeding. It is also called menses,
menstrual period, or period. When a woman has her period, she is menstruating.
The menstrual blood is partly blood and partly tissue from the inside of the uterus (womb).
It flows from the uterus through the small opening in the cervix, and
passes out of the body through the vagina. Most menstrual periods last
from three to five days.
What is the menstrual cycle?
Menstruation is part of the menstrual cycle, which helps a woman's body prepare
for the possibility of pregnancy each month. A cycle starts on the first day
of a period. The average menstrual cycle is 28 days long. However, a cycle can
range anywhere from 23 days to 35 days.
The parts of the body involved in the menstrual cycle include the brain, pituitary
gland, uterus and cervix, ovaries, fallopian tubes, and vagina. Body
chemicals called hormones rise and fall during the month and make the
menstrual cycle happen. The ovaries make two important female hormones, estrogen and progesterone.
Other hormones involved in the menstrual cycle include follicle-stimulating
hormone (FSH) and luteinizing hormone (LH), made by the pituitary
gland.
What
happens during the menstrual cycle?
In
the first half of the menstrual cycle, levels of estrogen
rise and make the lining of the uterus grow and thicken.
In response to follicle-stimulating hormone, an egg (ovum)
in one of the ovaries starts to mature. At about day 14
of a typical 28-day cycle, in response to a surge of luteinizing
hormone, the egg leaves the ovary. This
is called ovulation.
In
the second half of the menstrual cycle, the egg begins
to travel through the fallopian tube to the uterus. Progesterone
levels rise and help prepare the uterine lining for pregnancy.
If the egg becomes fertilized by a sperm cell and attaches
itself to the uterine wall, the woman becomes pregnant.
If the egg is not fertilized, it either dissolves or is
absorbed into the body. If pregnancy does not occur, estrogen
and progesterone levels drop, and the thickened lining
of the uterus
is shed during the menstrual period.
In
the illustration below, an egg has left an ovary after
ovulation and is on its way through a fallopian tube to
the uterus.

Image
Source: U.S. Food and Drug Administration
What is a typical
menstrual period like?
During the menstrual period, the thickened uterine lining and extra blood are
shed through the vaginal canal. A woman's period may not be the same every
month, and it may not be the same as other women's periods. Periods can be
light, moderate, or heavy, and the length of the period also varies. While
most menstrual periods last from three to five days, anywhere from two to seven
days is considered normal. For the first few years after menstruation begins,
periods may be very irregular. They may also become irregular in women approaching menopause.
Sometimes birth control pills are prescribed to help with irregular periods
or other problems with the menstrual cycle.
Sanitary pads or tampons, which are made of cotton or another absorbent material,
are worn to absorb the blood flow. Sanitary pads are placed inside the panties;
tampons are inserted into the vagina.
What
kinds of problems do women have with their
periods?
Women
can have various kinds of problems with
their periods, including pain, heavy bleeding,
and skipped periods.
-
Amenorrhea -
the lack of a menstrual period. This
term is used to describe the absence
of a period in young women who haven't
started menstruating by age 16, or
the absence of a period in women
who used to have a regular period.
Causes of amenorrhea include pregnancy,
breastfeeding, and extreme weight
loss caused by serious illness, eating
disorders, excessive exercising,
or stress. Hormonal problems (involving
the pituitary, thyroid, ovary, or
adrenal glands) or problems with
the reproductive organs may be involved.
-
Dysmenorrhea -
painful periods, including severe
menstrual cramps. In younger women,
there is often no known disease or
condition associated with the pain.
A hormone called prostaglandin is
responsible for the symptoms. Some
pain medicines available over the
counter, such as ibuprofen, can help
with these symptoms. Sometimes a
disease or condition, such as uterine
fibroids or endometriosis,
causes the pain. Treatment depends
on what is causing the problem and
how severe it is.
-
Abnormal
uterine bleeding-vaginal bleeding
that is different from normal menstrual
periods. It includes very heavy bleeding
or unusually long periods (also called menorrhagia),
periods too close together, and bleeding
between periods. In adolescents and
women approaching menopause, hormone
imbalance problems often cause menorrhagia
along with irregular cycles. Sometimes
this is called dysfunctional uterine
bleeding (DUB). Other causes of abnormal
bleeding include uterine fibroids
and polyps. Treatment for abnormal
bleeding depends on the cause.
At
what age does a girl get her first
period?
Menarche is another name for the beginning
of menstruation. In the United States, the average
age a girl starts menstruating is 12. However, this
does not mean that all girls start at the same age.
A girl can begin menstruating anytime between the ages
of 8 and 16. Menstruation will not occur until all
parts of a girl's reproductive system have matured
and are working together.
How long does a woman have
periods?
Women usually continue having periods until menopause. Menopause occurs around
the age of 51, on average. Menopause means that a woman is no longer ovulating
(producing eggs) and therefore can no longer become pregnant. Like menstruation,
menopause can vary from woman to woman and may take several years to occur.
Some women have early menopause because of surgery or other treatment, illness,
or other reasons.
When
should I see a health care provider about
my period?
You
should consult your health care provider
for the following:
-
If
you have not started menstruating
by the age of 16.
-
If
your period has suddenly stopped.
-
If
you are bleeding for more days than
usual.
-
If
you are bleeding excessively.
-
If
you suddenly feel sick after using
tampons.
-
If
you bleed between periods (more than
just a few drops).
-
If
you have severe pain during your
period.
How
often should I change my pad/tampon?
Sanitary
napkins (pads) should be changed as often
as necessary, before the pad is soaked
with menstrual flow. Each woman decides
for herself what is comfortable. Tampons
should be changed often (at least every
4-8 hours). Make sure that you use the
lowest absorbency of tampon needed for
your flow. For example, do not use super
absorbency on the lightest day of your
period. This can put you at risk for toxic
shock syndrome (TSS). TSS is a rare
but potentially deadly disease. Women under
30, especially teenagers, are at a higher
risk for TSS. Using any kind of tampon
- cotton or rayon of any absorbency - puts
a woman at greater risk for TSS than using
menstrual pads. The risk of TSS can be
lessened or avoided by not using tampons,
or by alternating between tampons and pads
during your period.
The
Food and Drug Administration (FDA) recommends
the following tips to help avoid tampon
problems:
-
Follow
package directions for insertion.
-
Choose
the lowest absorbency for your flow.
-
Change
your tampon at least every 4 to 8
hours.
-
Consider
alternating pads with tampons.
-
Know
the warning signs of toxic shock
syndrome (see below).
-
Don't
use tampons between periods.
If
you experience any of the following symptoms
while you are menstruating and using
tampons, you should contact your health
care provider immediately:
article
syndicated from National
Women's Health Information Center (NWHIC):
http://www.4woman.gov/faq/menstru.htm