Low menstrual flow can be caused by two general conditions: endometrial damage and anovulatory menstruation. Both of these conditions can cause infertility. The etiology of endometrial damage is diverse and commonly includes: endometrial inflammation, endometrial scarring and adhesions due to mechanical damage after uterine operations such as abortion, and endometrial tuberculosis. The endometrial layer is divided into a functional layer and a basal layer. During the female cycle, the functional layer undergoes proliferation, secretion and shedding under the action of hormones, while the basal layer is able to generate a new functional layer and repair the trauma of the shedding of the functional layer; this cyclic change is the key to successful embryo implantation and development. A minimum endometrial thickness of 7-8 mm at the time of follicular maturation is a prerequisite for normal embryo implantation; below 6 mm, the likelihood of pregnancy is extremely low. Uterine operations such as abortion, postpartum bleeding and curettage often cause mechanical damage to the basal layer, combined with multiple retrograde uterine infections with reproductive tract bacteria resistant to conventional antibiotic therapy; this often leads to impaired regeneration of epithelial and mesenchymal cells, impaired neovascularization, loss of endometrial activity, lack of endometrial coverage of the myometrium, endometrial fibrosis and adhesions to the anterior and posterior walls of the uterine cavity, or persistent non-regeneration of the endometrium. Regeneration. The clinical manifestations are mainly menstrual disorders, decreased menstrual flow and even amenorrhea, which eventually lead to difficulty in embryo implantation and infertility. Hysteroscopy can confirm this, and if there is organic damage to the endometrium, hysteroscopic examination and treatment are required. Normal ovulation in women is an important factor in maintaining the menstrual cycle, but there is also anovulatory menstruation, which is manifested by the absence of ovulation despite a normal menstrual cycle. To determine whether ovulation is occurring, basal body temperature, ultrasound to monitor follicle development, and hormone level monitoring are clinically indicated. If the absence of ovulation is confirmed, then ovulation promotion therapy is required. All, infertility patients who have low menstrual flow need to fully consider the above two factors and give appropriate treatment in time.