There are more reasons why menstruation comes back in the middle of menstruation, which may be caused by bleeding during ovulation, or by diseases such as uterine fibroids and cervicitis. 1. Ovulation bleeding: women who are ovulating may experience bleeding due to fluctuations in estrogen levels, usually no special treatment is needed and most of them will recover on their own. 2. Uterine fibroids: Uterine fibroids are caused by heredity, stem cell dysfunction and other factors. Patients will have symptoms such as irregular vaginal bleeding during non-menstrual period, increased menstrual flow, dysmenorrhea, etc., which will lead to the phenomenon that patients will have menstruation again in the middle of menstruation. 3. Cervicitis: Cervicitis is caused by pathogen infection, and patients mainly manifest abnormal vaginal bleeding, increased leukorrhea, and painful intercourse. There may be other reasons for patients to have menstruation in the middle of menstruation, and it is recommended that patients should consult a doctor in a timely manner to find out the cause of the disease and follow the doctor’s instructions for treatment.