Several months of the baby can use the waist stool, need to be judged according to the baby’s developmental status, can not be generalized. If all the development of the baby is normal, generally in the baby 4 months can use the waist stool, but if the baby develops later, need to be in about 6 months before you can use the waist stool. At present, Chinese babies in 0-4 months, most of the supine state, the baby’s waist and cervical vertebrae are in the developmental stage, about 4 months baby’s head can be erected, the baby can be held vertically, at this time the baby can use the waist stool. However, it should be noted that 4 months of the baby, its cervical spine is not fully developed, if sitting for too long, can cause deformation of the cervical spine, scoliosis, so when using the lumbar stool to the baby, avoid letting it sit for a long time. In addition, some lumbar stool will make the baby’s legs improper posture, may cause hip dislocation, parents need to pay attention to prevention.