Question
A three-month-old baby, although able to hold their head up, cannot maintain it for long and exhibits a shaking motion. Parents are worried whether this is due to calcium deficiency. Generally, at what age can an infant independently and stably hold their head up without external support?
Answer
By three months old, a baby can freely turn their head and their eyes can follow the movement to observe their surroundings. When an adult supports the baby under the armpits and hips, the baby can sit up. In a prone position, the baby can stabilize their head, with the chin and shoulders able to lift off the bed surface, supported by their upper arms. When lying alone, the baby will place their hands in front of their eyes to watch and play. When supported under the armpits to stand, the baby will take a step by lifting one leg and then the other, which is an innate reflex. By six months old…