Specific signs of calcium deficiency in babies: I. Irritability, often unexplained crying, not easy to fall asleep, even if sleep is easy to be awakened. Two, sweating more. Third, hair is thinning, there are hair loss circles in the occipital area, and hair loss may occur at the back of the head. 4. Teething is later than children of the same age. V. Sluggishness, less expression, and lagging behind in movement and language than children at the same stage. Sixth, the forehead protrudes and forms a square skull. It often compresses the lungs to make the baby poorly ventilated and prone to bronchitis and pneumonia. Severe calcium deficiency may lead to impaired bone mineralization and rickets.