The menstrual cycle of more than 37 days is considered abnormal, which may be caused by polycystic ovary syndrome, early onset ovarian insufficiency and other diseases. Usually, women’s menstrual cycle is 21~35 days, menstrual cycle more than 37 days is an abnormal phenomenon, patients need to pay attention to it, and this phenomenon is considered to be caused by polycystic ovary syndrome, early onset ovarian insufficiency and other diseases. The exact cause of polycystic ovary syndrome is not clear, and it is considered to be caused by a combination of environmental and genetic factors. Acne, menstrual abnormalities, and infertility usually occur in adolescent and childbearing patients, while menstrual abnormalities may manifest as scanty menstruation, decreased menstrual flow, or amenorrhea. The etiology of early onset ovarian insufficiency is complex and is mostly related to factors such as medical injury, autoimmune diseases, chromosomal abnormalities and genetic diseases. Patients often experience scanty or frequent menstruation, or amenorrhea, and some patients may also suffer from sudden fractures. It is recommended that if a woman’s menstrual cycle exceeds 37 days, she should consult a doctor in time for relevant examinations and take targeted treatment according to the doctor’s instructions.