Pain in the lower back after childbirth can be caused by ligamentous laxity during pregnancy or by anesthesia of the lumbosacral region during delivery. It may also be caused by poor rest after delivery. During pregnancy, the placenta secretes relaxin, which causes the ligaments to relax, so it may lead to the relaxation of the ligaments in the joints and the pain in the lower back. If a woman has a cesarean section to terminate her pregnancy, she may also have back pain after the operation due to local anesthesia in her lower back. At the same time, women need to breastfeed and stay up late after giving birth, so this often leads to poor rest and causes obvious lumbar pain after delivery, so women are often advised to rest in bed and avoid staying up late after delivery. As long as the postpartum lumbar pain is not particularly obvious, you can usually use hot towels to apply hot compresses, while trying to rest in bed, so that it can slowly return to normal. If the pain is unbearable or there are symptoms of pressure, you need to go to the orthopedic department in time, and if necessary, perform an MRI examination to understand whether there are organic lesions.