Menstruation that clears in two days is not amenorrhea, it belongs to the category of shortened menstrual period. Amenorrhea is divided into primary amenorrhea and secondary amenorrhea. There are two types of primary amenorrhea, one refers to the age of more than 16 years old, the secondary sexual characteristics have already developed, but the menstruation has not yet come, the other refers to the age of more than 14 years old, the secondary sexual characteristics have not yet developed; secondary amenorrhea is defined as the establishment of the normal menstrual cycle, menstruation stops for 6 months, or according to the calculation of their own menstrual cycle stops for three cycles Secondary amenorrhea is defined as the cessation of menstruation for 6 months after the establishment of a normal menstrual cycle or for 3 cycles according to one’s menstrual cycle. Two days of menstruation is not the absence of menstruation, but only a shortening of the menstrual period, so it does not belong to the category of amenorrhea. If your period clears in two days, you should consult your clinician for diagnosis and treatment.