1, Primary amenorrhea: never had a period. 2, Premature ovarian failure: those who had normal menstruation before the age of 40; 3, Ovarian insensitivity syndrome: also known as ovarian resistance syndrome, with follicles, basically normal ovarian size, low estrogen, and amenorrhea; 4, Ovarian hypoplasia: mostly primary amenorrhea, including gonadal hypoplasia (XX or XY), infantile uterus, and striped ovaries; 5, Primordial uterus: also known as trace uterus, mostly non-functional, and primary amenorrhea 6, infantile uterus: or uterine hypoplasia, scanty menstruation, or amenorrhea; cycle therapy more menstrual. 7, menstrual cycle refers to the time between the second menstruation; menstrual period refers to the duration of each menstruation; 8, basic endocrine: the examination time is the best for the 3rd-5th day of menstruation, including basic ultrasound examination. The first day of menstruation refers to the number of days from the time of menstruation, never the number of days after menstruation is clean.