Menstrual cramps are pains in the abdominal (belly) and pelvic areas that are experienced
by a woman as a result of her menstrual period. Menstrual cramps are not the same as the
discomfort felt during premenstrual syndrome (PMS), although the symptoms of both
disorders can sometimes be experienced as a continual process. Many women suffer from
both PMS and menstrual cramps.
Menstrual cramps can range from mild to quite severe. Mild menstrual cramps may be
barely noticeable and of short duration - sometimes felt just as a sense of light heaviness in
the belly. Severe menstrual cramps can be so painful that they interfere with a woman's
regular activities for several days.
How common are menstrual cramps?
Menstrual cramps of some degree affect more than an estimated 50% of women, and
among these, up to 15% would describe their menstrual cramps as severe. Surveys of
adolescent girls show that over 90% of girls report having menstrual cramps.
What is dysmenorrhea?
The medical term for menstrual cramps is dysmenorrhea. There are two types of
dysmenorrhea, primary and secondary.
In primary dysmenorrhea, there is no underlying gynecologic problem causing the pain. This
type of cramping may begin within six months to a year following menarche (the beginning of
menstruation), the time when a girl starts having menstrual periods. Menstrual cramps
typically do not begin until ovulatory menstrual cycles (when an egg is released from the
ovaries) occur, and actual menstrual bleeding usually begins before the onset of ovulation.
Therefore, an adolescent girl may not experience dysmenorrhea until months to years
following the onset of menstruation.
In secondary dysmenorrhea, some underlying abnormal condition (usually involving a
woman's reproductive system) contributes to the menstrual pain. Secondary dysmenorrhea
may be evident at menarche but, more often, the condition develops later.
What causes menstrual cramps?
Each month, the inner lining of the uterus (the endometrium) builds up in preparation for a
possible pregnancy. After ovulation, if the egg is not fertilized by a sperm, no pregnancy will
result and the current lining of the uterus is no longer needed. The woman's estrogen and
progesterone hormone levels decline, and the lining of the uterus becomes swollen and
dies. It is then shed and will be replaced by a new lining in the next monthly cycle.
When the old uterine lining begins to break down, molecular compounds called
prostaglandins are released. These compounds cause the muscles of the uterus to
contract. When the uterine muscles contract, they constrict the blood supply
(vasoconstriction) to the endometrium. This contraction blocks the delivery of oxygen to the
tissue of the endometrium which, in turn, breaks down and dies. After the death of this
tissue, the uterine contractions literally squeeze the old endometrial tissue through the cervix
and out of the body by way of the vagina. Other substances known as leukotrienes, which are
chemicals that play a role in the inflammatory response, are also elevated at this time and
may be related to the development of menstrual cramps.
Why are some cramps so painful?
Menstrual cramps are caused by the uterine contractions that occur in response to
prostaglandins and other chemicals. The cramping sensation is intensified when clots or
pieces of bloody tissue from the lining of the uterus pass through the cervix, especially if a
woman's cervical canal is narrow.
The difference between menstrual cramps that are more painful and those that are less
painful may be related to a woman's prostaglandin levels. Women with menstrual cramps
have elevated levels of prostaglandins in the endometrium (uterine lining) when compared
with women who do not experience cramps. Menstrual cramps are very similar to those a
pregnant woman experiences when she is given prostaglandin as a medication to induce
Can menstrual cramps be measured?
Yes. Menstrual cramps can be scientifically demonstrated by measuring the pressure within
the uterus and the number and frequency of uterine contractions. During a normal
menstrual period, the average woman has contractions of a low pressure (50-80 mm Hg),
which last 15-30 seconds at a frequency of 1-4 contractions every 10 minutes. When a
woman has menstrual cramps, her contractions are of a higher pressure (they may exceed
400 mm Hg), last longer than 90 seconds, and often occur less than 15 seconds apart.
What other factors influence menstrual cramps?
As mentioned above, an unusually narrow cervical canal tends to increase menstrual
cramps. Another anatomical factor thought to contribute to menstrual cramps is a
backwards tilting of the uterus (a retroverted uterus).
Lack of exercise is now recognized to contribute to painful menstrual cramps.
It has long been thought that psychological factors also play a role. For example, it is widely
accepted that emotional stress can increase the discomfort of menstrual cramps.
What are the symptoms of menstrual cramps?
Menstrual cramps are pains that begin in the lower abdomen and pelvis. The discomfort
can extend to the lower back or legs. The cramps can be a quite painful or simply a dull
ache. They can be periodic or continual.
Menstrual cramps usually start shortly before the menstrual period, peak within 24 hours
after the onset of the pains, and subside again after a day or two.
Menstrual cramps may be accompanied by a headache and/or nausea, which can lead,
although infrequently, to the point of vomiting. Menstrual cramps can also be accompanied
by either constipation or diarrhea because the prostaglandins which cause smooth
muscles to contract are found in both the uterus and intestinal tract. Some women
experience an urge to urinate more frequently.
How are menstrual cramps diagnosed?
The diagnosis of menstrual cramps is usually made by the woman herself and reflects her
individual perception of pain. Once a woman has experienced menstrual cramps, usually
with the adolescent onset of her menses (monthly menstrual flow), she becomes well
aware of the typical symptoms (by Melissa Conrad Stöppler and William C. Shiel Jr).
Discover effective treatment for menstrual cramps and natural remedies used for cramps on next pages.