Symptoms of Menstrual pains

What causes menstrual cramps?

Each month, the inner lining of the uterus (the endometrium) normally 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 is eventually shed as the menstrual flow and is 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 labor.

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 bleeding, 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.