During menstruation, some women experience painful menstrual cramps, called dysmenorrhea. These cramps result from the uterus contracting. The Center for Young Women's Health explains that two types of dysmenorrhea exist: primary dysmenorrhea and secondary dysmenorrhea. With primary dysmenorrhea, the most common type, women have cramps that begin one to two days before menstruation. These cramps continue on for two to four days. Women can have pain in their lower back, lower abdomen or both. With secondary dysmenorrhea, the cramps result from a medical condition, such as pelvic inflammatory disease (PID) or endometriosis.
The MayoClinic.com describes the menstrual cramps as “dull, throbbing or cramping pain.” This pain can spread down from the lower abdomen to the lower back to the thighs. Women can have other symptoms in addition to the pain. For example, they may feel dizzy during the cramps. Some women may have nausea and vomit. Other accompanying symptoms include sweating and loose stools.
A new study published in the journal PAIN notes that the reason why some women have menstrual cramp pain may be due to brain changes. HealthDay News reports that the study in Taiwan included 32 young women with moderate to severe menstrual cramp pain and 32 young women without much menstrual cramp pain. The researchers used optimized voxel-based morphometry, a type of brain scan, to look for any changes in the brain. They found that women who had the moderate to severe menstrual cramp pain had abnormalities in the gray matter, a type of brain tissue. The gray matter contains the cell bodies, in comparison to the white matter that has the nerve fibers. The researchers note that these abnormalities existed even when women were currently not having pain.
In the gray matter of the women with the moderate to severe menstrual cramp pain, the researchers found that some parts had an increased volume while other parts had a decreased volume. HealthDay News notes that the functions of the areas with decreased volume are thought to be the regulation of emotions, pain processing and higher-level sensory processing; the functions of the areas with increased volume are thought to be endocrine function regulation and pain modulation.
The researchers point out that the findings on menstrual cramp pain and brain changes suggest a correlation with chronic pain conditions. For example, the brain may become very sensitive to pain after several periods of pain, which could make menstrual pain even worse. But as the researchers note, the exact effect that the changes in the brain have on the experience of pain is unknown.