Sudden turning of reddish color of evil discharge on the 25th day of the month is the occurrence of bleeding, which may be related to poor uterine regression, retained placenta or fetal membranes, puerperal infection and other causes. 1. Poor uterine regeneration: If a pregnant woman has poor uterine contractions after delivery, late postpartum hemorrhage may occur. 2. Retained placenta or fetal membranes: If there is retained placenta or fetal membranes in the uterine cavity of a pregnant woman, it may also cause poor uterine contraction and the discharge will turn into blood on the 25th day of the month. 3. Puerperal infection: Because of the lower immunity of women after delivery, endometritis and other inflammatory diseases are likely to occur, which can lead to the situation of the 25th day of the month, the bad dew turns into blood again. It is recommended that pregnant women pay attention to rest after delivery, pay attention to perineal hygiene, and it is best to prohibit sexual intercourse for one and a half months.