When breastfeeding, the return of menstruation is usually around 6 to 8 months after delivery, whether by normal birth or by cesarean section, and menstruation after delivery usually does not affect the quality of milk. This is because menstruation after childbirth usually means that the ovaries resume ovulation, so with the stimulation of estrogen and progesterone in the body, the endometrial lining will be shed periodically and cause menstruation, but the estrogen in the body is not at a particularly high level at this time, so it will not lead to back milk and will not affect the quality of milk. Therefore, for women who have resumed menstruation, as long as they are breastfeeding normally and have not experienced a decrease in lactogen production due to stagnation, the amount of milk produced at this time will be exactly the same as when they did not have a period. Moreover, the quality of breast milk is not directly affected by the onset of menstruation because the formation of breast milk is not directly related to menstruation, so women can still breastfeed normally even after menstruation and can generally continue to feed their children until they are weaned naturally according to their needs. Therefore, even after menstruation, women do not need to worry about the effect of menstruation on the secretion and quality of breast milk, but just go with the flow and continue breastfeeding.