Usually it is not absolute that women cannot donate blood three days before or after menstruation, but it is not recommended to donate blood. In general, before and after menstruation, most women may experience premenstrual discomfort (such as abdominal pain, gastrointestinal dysfunction), decreased immunity, menstrual irregularities and other conditions, and donating blood at this time may aggravate the clinical symptoms, and at the same time before and after menstruation to donate blood, but also need to be checked to see if it meets the requirements for blood donation. Usually, during menstruation, with the cyclic changes of the ovaries and the cyclic shedding and bleeding of the endometrium, and due to the interaction of pelvic congestion and prostaglandins before and after menstruation, most women may also experience abdominal and lumbosacral discomfort or uterine contraction pain, with gastrointestinal dysfunction, and may also experience headache or mild neurological instability. Generally under normal circumstances, pre-menstrual period if the blood donation standard, you can donate a small amount of blood, but the need to promptly replenish protein and water, but if the past before and after the menstrual period, most of the women with obvious clinical manifestations, it is not recommended to donate blood, to avoid blood donation may lead to the possibility of aggravation of the previous symptoms. In addition, it is recommended that during menstruation, women should eat a reasonable diet, strengthen nutrition, increase exercise, keep the vulva clean and dry, pay attention to warmth while ensuring sufficient rest, and then, after the menstrual period is completely over and the blood condition is back to normal, they can donate blood according to the doctor’s instructions if they are not anemic. If you have any other questions, it is recommended to consult a professional doctor for guidance.