The previous period of 7 days now 9 days may be luteal atrophy, pelvic inflammatory disease, endometritis, as well as cervical polyps and other causes. 1. Luteal insufficiency: the cause of luteal insufficiency is still unclear, and it is considered to be related to follicular growth disorder and poor development of follicle itself. Patients will show prolonged menstrual period, excessive menstruation, frequent menstruation, infertility, etc. Therefore, patients will have a period of 7 days in the past and now have a period of 9 days. 2. Pelvic inflammatory disease: Pelvic inflammatory disease is mainly caused by Chlamydia trachomatis, Neisseria gonorrhea, Staphylococcus aureus and other pathogens. Patients will have lower abdominal pain, prolonged menstrual period, increased menstrual flow and other manifestations, so the patient will appear before the period of 7 days now 9 days of menstrual period symptoms. 3. Endometritis: endometritis is considered to be caused by endometrial trauma, mycoplasma or chlamydia infection and other factors. Patients will have prolonged menstrual period, increased menstrual flow, lower abdominal pain and other manifestations, so that the patient will have a previous period of 7 days now 9 days of menstrual period. 4. Other: Women who used to have 7 days of menstruation and now have 9 days of menstruation are also considered to be caused by cervical polyps, uterine fibroids, chronic anemia and other diseases. It is recommended that female patients with symptoms of 7 days of menstruation and now 9 days of menstruation need to consult a doctor in time, and the doctor will take appropriate measures for the cause of the treatment.