Three days of dysmenorrhea is an abnormal sign. Normally, women do not have dysmenorrhea, so for women who experience dysmenorrhea, whether it is one day, two days or three days, it is an abnormal sign. In general, when a woman has dysmenorrhea for three days, it is best to have an ultrasound to determine whether it is primary or secondary dysmenorrhea. In most women with primary dysmenorrhea, the pain is usually 1-2 days and rarely lasts for three days, while in women with secondary dysmenorrhea, the pain is often more than three days, for example, in women with adenomyosis, the pain may be present throughout the menstrual period.