Menstruation that stops after two days may be related to ovulation bleeding, preeclampsia, endocrine disorders or gynecological diseases. 1. Ovulatory bleeding: If the bleeding is about half a month after the last menstrual period, the bleeding at this time is more likely to be ovulatory bleeding and not the real menstrual period. 2. Pre-eclampsia: Women who have had sex should first take a pregnancy test or check the blood HCG (human chorionic gonadotropin) to determine whether they are pregnant or not, and pre-eclampsia will have the symptom of vaginal bleeding. 3. Endocrine disorders: If a woman is usually under stress, emotionally disturbed, and has irregular work and diet, it will lead to endocrine disorders, which will reduce the amount of menstruation. 4. Gynecological diseases: Gynecological diseases such as pelvic inflammatory disease, endometritis, endometriosis, uterine adhesions, etc., will affect the shedding of the uterine lining during menstruation, which may lead to shortened menstrual flow. There are many other possible causes for shortened menstrual periods, so it is recommended to consult a doctor in time for a clear diagnosis by a medical professional in order to rule out abnormalities, and actively treat the problem if necessary.