After 40 days postpartum, you should first go to the hospital to do ultrasound to see the size of the uterus and the condition of the uterine cavity, because in this case you have to exclude the placenta or fetal membrane residue. If ultrasound is done and there is placenta or membranes residue, and there is more stuff you need to do the operation to clear the uterus, if the residue is less, you can take some medicine to invigorate the blood and let them expel. If ultrasound is done and there is no residue, but the uterus is relatively large, you can treat with contractions under the doctor’s guidance to strengthen the contraction of the uterus.