What is the reason why a child's head is always hanging down?

Patient's question:

My child has been tilting his head down intermittently (2-3 times each time) recently while sitting. Is it possible that my child is lacking something? Thank you

Doctor's answer:

According to your description, it is likely caused by calcium deficiency. It is recommended to have a blood test for trace elements at the hospital and undergo a comprehensive check-up in the pediatric department. Once diagnosed in this situation, it is generally advisable to start rehabilitation training and comprehensive treatment for the baby as early as possible. Please monitor the changes in your child's condition. If you have time, it is beneficial to take the baby out for more sun exposure. I wonder how the baby's other development is going?