Calcium deficiency in 4-week-old girls is manifested as follows: 1. Changes in sleep, the child may have insubstantial sleep, difficulty in falling asleep, easy to wake up after sleep, easy to cry after sleep, etc. Also, the child may have obvious night sweats after sleep and itchy head after sleep due to night sweats, etc. 2. In mild cases, parents should rub the leg with their hands and adjust the diet containing calcium to relieve the pain. In severe cases, the child will often have pain, and if there is no significant improvement after massage, medication is required. 3. When there is a significant calcium deficiency, the child will form skeletal deformities, such as X-leg or O-leg, and will have a significant chicken chest.