Breast milk is produced by stimulating the pituitary gland to secrete prolactin, which stimulates the breasts to secrete milk. There are many factors that affect breast milk, such as reduced secretion of prolactin hormone due to personal constitution, unreasonable diet structure or malnutrition, anemia, etc., which can affect milk production and lead to reduced milk, and prolonged depression, excessive stress and fatigue can also cause reduced milk. Menstruation is caused by necrosis, shedding and bleeding of the endometrium. The main component of menstruation is blood, also mixed with necrotic shed endometrium, uterine cavity and cervical secretion, the volume of menstruation is about 50ml, bleeding is very little, it has little effect on health, it will not cause anemia, nor will it cause reduction of lactation. If you are weak, have insufficient qi and blood or suffer from anemia, plus blood loss during menstruation, it may cause reduced menstruation, and you need to follow medical advice to actively treat the original disease.