Bleeding again half a month after menstruation may be caused by pregnancy-related abnormal bleeding, ovulation bleeding, menopausal menstrual disorders, luteal insufficiency, polycystic ovary syndrome and other diseases. 1. Pregnancy-related regular bleeding: in non-menopausal women, if there is abnormal bleeding, first of all, we should exclude pregnancy-related abnormal bleeding, such as preeclampsia, fetal eclampsia, ectopic pregnancy and so on. 2. Ovulation bleeding: half a month after menstruation may be in the ovulation stage of women, the body’s estrogen level briefly declines, and there is a small amount of endometrial stripping, which may cause a small amount of vaginal bleeding half a month after menstruation. 3. Menstrual disorders during menopause: When women enter menopause, the ovarian function declines, and the level of hormones in the body decreases, which may cause menstrual cycle disorders and bleeding half a month after menstruation. 4. Luteal insufficiency: women with luteal insufficiency have insufficient secretion of progesterone in their bodies, which leads to insufficient secretion of endometrium, resulting in ovulatory dyskinesia and frequent menstruation. 5. Polycystic ovary syndrome: in patients with polycystic ovary syndrome, the endometrium lacks regular stripping, and the inner wall of the uterus may bleed, and there will be bleeding after half a month of menstruation. The causes of bleeding after half a month of menstruation are more varied and should be determined by examination in the hospital.