What is the reason for my aunt's low blood

Menstruation blood is endometrial exfoliation bleeding, menstrual blood less reasons there are many kinds. Endometrium without progesterone conversion, no ovulation, there may be less menstrual volume. Abnormal uterine development, less endometrial shedding, hysteroscopic uterine surgery, curettage, curettage, induced abortion, salpingography, tubal catheterization and other uterine operations caused by endometrial damage, tuberculosis infection caused by endometrial damage will cause menstrual volume reduction phenomenon. Excessive diet, life pressure, mood irritability, reproductive system diseases caused by endocrine disorders, and then make estrogen decline, so that the endometrium thinning, but also may reduce menstrual volume.