It is also normal for a 4-month-old baby not to be able to roll over, in which case it needs to be observed in conjunction with the baby’s other gross motor development. Generally speaking, the development of the baby’s big movements follow the law of two lifting, four turning, six will sit, seven rolling, eight crawling, week will walk. 4 months of the baby if the baby is not trained or the baby’s development is too fast, the height is too high, the weight is too fat and so on, relatively speaking the baby is relatively bulky, will not roll over is also normal. If the baby’s head is steady when lying on the bed or steady when held vertically, in this case, slowly train the baby to turn over. First, adults should let him lie on his back in the prone position. Secondly, when lying down, the adult should use one palm to help the baby slowly turn over to the opposite side, so that the baby is conscious of turning over, and slowly training can be. Usually, if the baby still can’t roll over after 5 months or 6 months, this kind of baby needs to go to the pediatric developmental department to rule out the backwardness of macromotor development.