the Teen Scene: A Balanced Look
at the Menstrual Cycle
by Marian Segal
This article is part of a series with important
health information for teenagers.
Some young women feel it coming days before they get it. Others are hardly aware
they have it. Friends who compare notes about their periods will probably find
that menstruation--the monthly shedding of the lining of the uterus, or womb-affects
each of them a little differently, both physically and emotionally.
"The menstrual cycle has its ups and downs of hormones, and different people
react differently to hormonal swings," says Lisa Rarick, M.D., a gynecologist
in FDA's Center for Drug Evaluation and Research. She explains that just before
and during menstruation, levels of the female hormones estrogen and progesterone
are low. That's when some women feel bloated, irritable or blue, or "just
crummy," she says.
"Just crummy" might mean cramps, sore breasts, backache, headache,
nausea, and feeling tired.
"A day or two after your period starts you begin to feel better. Hormone
levels go back on the upswing and you get back to what you're accustomed to during
the rest of your cycle," Rarick explains. (See "Monthly
Cramps--A Common Complaint
More than half of menstruating women have cramp-like pain during their periods.
The medical term for menstrual pain is dysmenorrhea. Cramps are usually felt
in the pelvic area and lower abdomen, but can radiate to the lower back or down
"Many girls have cramps severe enough to keep them home from school," Rarick
says. In fact, according to Danforth's Obstetrics and Gynecology, dysmenorrhea
is the most frequent cause of absenteeism from school among younger women. Rarick
says women seem to go through phases when cramps are severe, then get better
for several years, and then maybe worsen again. She adds that most women find
they have less menstrual pain after having children.
Mechanically, cramps are like labor pains. Just as the uterus contracts to open
up the cervix (neck of the uterus) and push out a baby, it contracts to expel
menstrual blood. Often, after several years of menstruating or after childbirth,
the cervical opening enlarges. The uterus doesn't have to contract as much to
discharge the menstrual flow, so there is less cramping.
Menstrual pain may also come from the bleeding process itself. When the uterine
lining separates from the wall, it releases chemicals called prostaglandins.
Prostaglandins cause blood vessels to narrow, impeding the supply of oxygen to
the uterus. Just as the pain of a heart attack comes from insufficient blood
to the muscles of the heart, too little blood to the uterine muscle might cause
the pain of menstrual cramps.
Menstrual pain can have other causes, although these are rare among teenagers.
They include tumors, fallopian tube infection, and endometriosis, a condition
in which fragments of the lining of the uterus become embedded elsewhere in the
body (see "On the Teen Scene: Endometriosis--Painful but Treatable" in
the January-February 1993 FDA Consumer).
Pain, Pain Go Away
Sometimes, simple measures are all that's needed to feel better. Cutting down
on salt might help reduce fluid buildup, and support hose may alleviate swelling
in the legs or ankles. Crawling into bed for some extra rest or sleep is one
way to deal with fatigue, and taking along a heating pad or hot water bottle
eases cramps for some. Exercising also helps reduce pain in many young women,
and may lift a blue mood as well.
Charles Debrovner, M.D., associate clinical professor of obstetrics and gynecology
at New York University School of Medicine, explains that exercising during menstruation
lessens pain because it causes release of brain chemicals called endorphins,
which are natural painkillers. He says exercise may also decrease pain by affecting
Rarick adds that exercise may also help because it increases blood flow, and
because it "just makes a lot of people feel better in general."
If symptoms interfere with work, school or sleep, the American College of Obstetricians
and Gynecologists recommends seeing a doctor, who may suggest taking one or more
medicines. Certain anti-inflammatory drugs called NSAIDs (an abbreviation for
nonsteroidal anti-inflammatory drugs) inhibit prostaglandin production, thus
easing cramps. Prescription NSAIDs include naproxen (Naprosyn, Anaprox), ibuprofen
(Motrin, IBU), indomethacin (Indocin), and mefenamic acid (Ponstel).
If needed, your doctor may prescribe stronger painkillers or diuretics, or even
oral contraceptives. One side effect of birth control pills is relief of menstrual
"Birth control pills work two ways to lessen cramps," says Rarick. "They
prevent the lining of the uterus from building up so much, so there's less bleeding.
This means less prostaglandin production and blood vessel narrowing because there's
less lining to separate, and fewer contractions because there's less tissue to
In 1984, FDA approved ibuprofen in over-the-counter (OTC) strengths to be sold
without a prescription. It's the active ingredient in medicines such as Advil,
Nuprin and Motrin IB. In 1994, the agency approved naproxen for OTC marketing
in lower doses than the prescription strength. OTC naproxen is sold under the
brand name Aleve.
Like NSAIDs, aspirin also suppresses prostaglandins, but it's often not as effective
as other NSAIDs for menstrual pain. Aspirin should never be used by children
or teenagers who have chickenpox or flu symptoms before checking with a doctor.
This is because Reye syndrome, a rare but sometimes deadly illness, may develop
in children and teenagers who have taken aspirin or products that contain it
while they were sick with chickenpox or flu.
Several OTC products, such as Midol and Pamprin, are specifically formulated
for menstrual symptoms. Read the labels of these medicines before you buy them,
because different formulations often contain different ingredients or strengths
of ingredients. For example, Teen Formula Midol contains acetaminophen for pain
and pamabrom (a mild diuretic) for fluid retention. Pamprin contains acetaminophen,
pamabrom and pyrilamine maleate (an antihistamine) for tension and irritability.
Cramp Relief Formula Midol IB contains as its sole ingredient ibuprofen. Manufacturers
may change their products' ingredients from time to time, so it's a good idea
to check the label each time you buy the product.
Plain acetaminophen products like Tylenol, Datril, and Aspirin-Free Anacin also
may help menstrual pain. It takes time for pain relievers to work, so it's best
to take them before the pain gets bad and continue for one or two days, as needed.
Some 20 to 40 percent of menstruating women have PMS, or premenstrual syndrome.
Starting anywhere from mid-cycle to a few days before menstruation begins, women
with PMS may have one or all of a virtual laundry list of physical and emotional
symptoms. They include breast swelling and tenderness, fluid retention, increased
thirst or appetite, craving for sweets and salty foods, headaches, anxiety, restlessness,
irritability, depression, hostility, and loss of self confidence. Experts say
PMS doesn't usually affect teenagers, though. It increases with age and is more
prevalent in the 30s and 40s.
From Menarche to Menopause
In the United States, the average age of menarche--a girl's first period-is 12
years, although it's normal to start as early as 10 or as late as 16. Menopause--when
periods stop-usually occurs around age 50, although that, too, can vary by several
years. Except perhaps for the first two years of menstruation-and barring pregnancy,
nursing, and certain illnesses or other problems-the reproductive cycle repeats
with predictable regularity every month.
Exercise, diet and stress can delay the onset of menstruation, Rarick says, or
alter cycles once they've been established.
"Gymnasts, ballerinas and others who exercise strenuously can sometimes
delay the onset of their periods, so you might not be surprised to find a 16-
or 17-year-old in that group who hasn't started menstruating," she says. "Some
experts believe the connection between exercise and amenorrhea [the absence of
menstrual periods] is related to body fat content, because fat affects estrogen.
Young women who are very thin from malnourishment may not start menstruating
until they gain weight, with a certain portion of that weight being fat. So,
girls who exercise a lot-who are all bone and muscle with no fat-may delay their
Similarly, young women with severe eating disorders such as anorexia or bulimia
often do not menstruate. (See "On the Teen Scene: Eating Disorders Require
Medical Attention" in the March 1992 FDA Consumer).
The American College of Obstetricians and Gynecologists recommends that a girl
see her doctor if she hasn't started menstruating by age 16, or if by age 13
or 14 she hasn't begun to develop breasts or pubic and underarm hair.
Just Like Clockwork?
Many young women have very irregular periods the first couple years of menstruating--even
skipping some months, until, as Rarick says, "the system is well-tuned."
In addition, she says, young women don't always ovulate every month when they
first get their periods. She adds that there's no sure way for a young woman
to know which month she is ovulating and which she is not. So, from the time
her periods begin, a young woman should assume she can get pregnant each and
every month, even if her periods are irregular.
Eventually, periods become regular, but even when they do, a missed or late period
once a year--especially at a stressful time--is considered normal, according
Also, just as strenuous exercise and eating disorders can delay the onset of
menstruation, they can also cause previously regular menstrual cycles to become
irregular or stop completely.
Segal is a member of FDA's public affairs staff.
absence of menstrual periods
or discomfort during menstruation
tubes: two slender tubes-one
on either side of the uterus--that
carry the egg (ovum) from the
ovary to the uterus
young woman's first period
or discomfort during ovulation
female reproductive organs--one
on either side of the uterus--that
contain the eggs, or ova, and make
of an egg from the ovary
chemical made by the body that
causes the muscle of the uterus
to contract, often causing cramps
(womb): the female organ
in which a fertilized egg grows
and develops into a baby
is just one part of the menstrual
cycle, in which a woman's body
prepares for pregnancy each month.
A cycle is counted from the first
day of one period to the first
day of the next. An average cycle
is 28 days, but anywhere from
23 to 35 days is normal.
and progesterone levels are very low at the beginning
of the cycle. During menstruation, levels of estrogen,
made by the ovaries, start to rise and make the
lining of the uterus grow and thicken. In the meantime,
an egg (ovum) in one of the ovaries starts to mature.
It is encased in a sac called the Graafian follicle,
which continues to produce estrogen as the egg
about day 14 of a typical 28-day cycle, the sac
bursts and the egg leaves the ovary, traveling
through one of the fallopian tubes to the uterus.
The release of the egg from the ovary is called
ovulation. Some women know when they're ovulating,
because at mid-cycle they have some pain--typically
a dull ache on either side of the lower abdomen
lasting a few hours. The medical word for this
is mittelschmerz, from the German, meaning middle
pain. Some women also have very light bleeding,
or spotting, during ovulation.
the egg is expelled, the sac--now called a corpus
luteum--remains in the ovary, where it starts producing
mainly progesterone. The rising levels of both
estrogen and progesterone help build up the uterine
lining to prepare for pregnancy.
few days before, during and after ovulation are
a woman's "fertile period"-the time when
she can become pregnant. Because the length of
menstrual cycles vary, many woman ovulate earlier
or later than day 14. It's even possible for a
woman to ovulate while she still has her period
if that month's cycle is very short. (Stress and
other things can sometimes cause a cycle to be
shorter or longer.) If a woman has sex with a man
during this time and conception occurs (his sperm
fertilizes the egg), she becomes pregnant.
fertilized egg attaches to the uterus, and the
corpus luteum makes all the progesterone needed
to keep it implanted and growing until a placenta
(an organ connecting the fetus to the mother) develops.
The placenta then makes hormones and provides nourishment
from the mother to the baby.
an egg is not fertilized that month and the woman
doesn't get pregnant, the corpus luteum stops making
hormones and gets reabsorbed in the ovary. Hormone
levels drop again, the lining of the uterus breaks
down, menstruation begins, and the cycle repeats.
the illustration below, an egg has left an ovary
after ovulation and is on its way through a fallopian
tube to the uterus.
What's Normal, What's Not
menstrual periods last from three
to five days, but anywhere from
two to seven days is normal.
The amount of blood flow varies,
too, but for most women, bleeding
starts out light at first, followed
by heavier flow for a day or
two and then another light day
or two. 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
amount of bleeding varies from
woman to woman because everybody's
body has a different way of building
up the lining of the uterus," says
Lisa Rarick, M.D. "A lighter
flow or heavier flow doesn't mean
you can't get pregnant as easily
or you're never going to get pregnant,
or that your periods will always
stay the same way. But if you're
bleeding excessively-soaking one
or more tampons or pads an hour-you
should see a doctor to see if there's
a gynecologist with FDA's Center
for Drug Evaluation and Research,
says teenagers often are concerned
if they expel blood clots during
their periods. She says this is
not dangerous; they are clumps
of pooled blood in the vagina.
Sometimes, instead of flowing freely,
blood drains from the uterus and
stays in the vagina until there's
a change in position--say, from
sitting to standing.
who use tampons should be aware
of toxic shock syndrome, or TSS,
a rare but serious-and sometimes
fatal-disease that's been associated
with tampon use. Tampon packages
carry information about TSS on
the box or inside. Because TSS
mostly affects 15- to 19-year-olds,
it's especially important for teenagers
to know what signs to look for.
If you develop the following symptoms
while menstruating, remove the
tampon and get medical help right
fainting, or near fainting
when standing up
rash that looks like a sunburn.
more on toxic shock syndrome,
see "On the Teen Scene:
TSS-Reducing the Risk" in
the October 1991 FDA Consumer.
syndicated from U.S.
Food and Drug Administration:
FDA Consumer Magazine - December 1993
Publication No. (FDA) 94-1215