Postpartum brown discharge after menstruation may be related to abnormal luteal function, ovulation bleeding, taking certain drugs, blood diseases and other factors. 1. Abnormal luteal function: Due to the dysfunction of the hypothalamic-pituitary-ovarian axis after delivery, although the corpus luteum is well developed, the luteal mechanism is out of order, and the endometrium is shed irregularly, which is manifested as prolonged menstrual period, heavy bleeding and brown discharge after menstruation. 2. Ovulation bleeding: After delivery, in the middle of two regular menstrual periods, i.e. ovulation, due to a short drop in estrogen level caused by ovulation, the endometrium of some women loses the support of estrogen, and the endometrium sheds, causing regular vaginal bleeding, which is called ovulation bleeding. 3. Other factors: such as taking certain drugs, blood diseases or other traumatic factors can also lead to brown discharge after postpartum menstruation. Therefore, it is recommended to go to the local regular hospital for consultation and examination to clarify the cause of the disease and then follow the doctor’s instructions for treatment.