The pain and discomfort that comes with a woman's menstrual period is called menstrual cramps. The cramping is experienced in the abdomen, back and legs. Cramps are not the same thing as premenstrual syndrome (PMS) though many women who have cramps also have PMS and vice versa.
In some women, cramps are very mild and may almost be unnoticeable. They also may not last very long. Mild cramps tend to be felt as a sort of heaviness in the abdominal region.
Severe cramping is a different story and in some cases may be so painful that a woman is sidelined from work and household duties for several days in a row.
Some women always have cramps with their periods while others never experience them ever. The general opinion is that half of all menstruating women experience mild to severe cramps. Of the women who do have cramps, 15% of them say they have severe cramps. Some surveys of teenagers found that over 90% of the girls said they get cramps.
Dysmenorrhea is the medical term for menstrual cramps. There are two types of dysmenorrhea: primary and secondary.
In primary dysmenorrhea, the cramps are not linked to any apparent gynecological issue. A young woman may start having primary dysmenorrhea from 6 months to a year after having her first period, known as the menarche. Up until this time, a girl may not have ovulated, yet. The cramps start up after ovulation begins.
Secondary dysmenorrhea can often be traced back to a real gynecological condition that causes this type of menstrual pain. It may be that a girl has secondary dysmenorrhea from the time of her first period, but it is more usual for the cramps to begin at a later point.
The menstrual period is an event that recurs in response to the non-fertilization of a woman's egg, which means that pregnancy has not taken place during a woman's fertile period. Period blood consists of matter that was not used to support a pregnancy, such as the lining of the uterus (endometrium) which had become thicker as it prepared for a pregnancy that did not happen. As the endometrium deteriorates and is shed, chemicals called prostaglandins are excreted.
Prostaglandins cause contractions of the uterine muscles. As these muscles contract, the blood that flows to and from the uterine lining becomes constricted. The endometrial tissue becomes deprived of oxygen which causes its decomposition and death. The contractions then help to push the deadened tissue out of the uterus, through the cervix, and on out through the vagina.
While all of this is going on, other chemicals known as leukotrienes are present in high amounts. Leukotrienes play a crucial part in inflammation. Experts believe that these high levels of leukotrienes play some part in causing menstrual cramps, too.