You can go to the hospital for a postpartum checkup 40 days after delivery. Generally speaking, 42 days after delivery belongs to the puerperium period, and the body needs a recovery time after delivery, most of the body and uterus can return to non-pregnancy in about 42 days after delivery. Clinically, it is recommended to go to the hospital for a postpartum checkup 42 days after delivery, but there is no specific time limit. Pelvic ultrasound is mainly done on the 40th day after delivery to find out the recovery of the uterus and the double adnexa, and whether there is any fluid or residue, etc. If there is a lateral cut, it is necessary to see how the wound recovers. It is also necessary to do routine tests such as blood routine, urine routine, measurement of blood pressure, blood sugar, weight and other routine tests. In addition, women who have had a cesarean section should also look at the healing of the abdominal incision and the recovery of the uterine scar.