Dysmenorrhea is the medical term for painful menstrual periods. Many women feel some pain or discomfort on the first day or two of their periods, but usually the pain subsides once the flow is established. However, at some time in their lives about 50 percent of women experience menstrual pain severe enough to interfere with their normal activities, and 10 percent have cramps that keep them home from work or school one to three days a month.
Menstrual pain can begin a day or two before your period or it may start just as the flow begins. It can vary from mild discomfort that responds to common painkillers to pain that keeps you in bed because even walking around is too uncomfortable. Sometimes menstrual pain feels like sharp cramps in the lower abdomen and sometimes like a dull ache, which may or may not spread to the lower back or upper thighs. Some women also have headaches, nausea, diarrhea, or dizziness. A few vomit or faint.
Primary dysmenorrhea, which I call ordinary garden-variety dysmenorrhea, is the kind for which physicians can find no underlying physical cause. You are perfectly healthy, but you have cramps. In general, primary dysmenorrhea afflicts younger women. Secondary dysmenorrhea is menstrual pain caused by a known medical condition (for example, endometriosis or fibroids) and is more likely to be a problem for older women.
Menstrual pain, which may begin in the midteen years, becomes more common during the mid-20s and then decreases. Unless there is some medical cause, women who have had comfortable periods in the past do not ordinarily begin having cramps in their 30s, though some women continue to have cramps if they have had them before.
Obese women (those at least 20 percent overweight) are more likely to have menstrual cramps than thin women. Athletes are less likely to get them than other women, and highly trained, very thin athletes may stop getting menstrual periods altogether. Women who have regular periods are more apt to have cramps than women who do not. Women with longer periods are more likely to get cramps than women whose periods last fewer than three days.
Most girls just starting to have periods have no cramps at all because they are not yet ovulating. Prostaglandins, hormone-like chemicals that are responsible for ordinary cramps, are not produced until after ovulation begins — usually a year or so after periods start. If you are a teenager and have started getting cramps after a couple of years of comfortable menstrual periods, chances are that you have just begun to ovulate. It is unlikely, though possible, that you have endometriosis or fibroids or some other condition that is causing cramps. If you are worried, talk to your doctor.