Vaginal bleeding on the 40th day after delivery is considered to be incomplete uterine regeneration, and it is necessary to review the ultrasound to see the situation of uterine regeneration. If there is fluid in the uterine cavity or a small amount of residual fluid, suggesting that the uterine regeneration is incomplete, and it is necessary to take motherwort or use uterosuppressant to promote uterine regeneration. If the residual fluid is much, the bleeding exceeds the amount of menstruation, and the bleeding time is long, it is necessary to give a purging of uterus to stop the bleeding. If there is no abnormality in the ultrasound examination, and the bleeding is not much and there is no foul odor, it can be left untreated, pay attention to hygiene, keep the vulva clean and dry, change the underwear diligently, don’t be overworked but need to have appropriate activities, which will help the body to recover after delivery. If the amount of bleeding is similar to the amount of menstruation, it may also be the return of menstruation. Most breastfeeding mothers resume menstruation 4-6 months after delivery, and there are also those who resume menstruation after the first full month of life, and those who are not breastfeeding mothers resume menstruation a little earlier than those who are breastfeeding mothers.