The main reasons for babies practicing lifting their heads to one side include insufficient neck strength, habitual head deviation and congenital cervical inclination. 1. Insufficient neck strength: When babies first practice lifting their heads, their neck strength is insufficient, and they do not have enough control over the direction of lifting their heads and cannot precisely control the movement of their necks, which is why babies practice lifting their heads to one side. This situation is common in babies within three months. 2. Habitual head deviation: If the baby is accidentally placed in the head side position by the parents during early sleep and is not corrected in time, the baby may develop the habit of head deviation to one side. When practicing lifting the head, it will be habitually tilted to one side. 3. Congenital Diagonal Neck: Commonly known as Crooked Neck Disease, the common causes of this disease include intrauterine developmental disorders, ischemia, and birth injuries. The baby’s head is always tilted to the affected side due to the hardening and shortening of the neck muscles on one side. If your baby is practicing lifting his/her head to one side and this condition does not improve, you should take your baby to the hospital for treatment.