Calcium deficiency in four month old babies may have symptoms such as increased neurologic reactivity such as irritability, muscle weakness, skeletal abnormalities, and convulsions. 1. Increased neural reactivity: four-month-old babies with calcium deficiency usually have symptoms such as irritability, insomnia, night terrors, excessive sweating and formation of occipital baldness. 2. Muscle weakness: decreased muscle tone, muscle joint laxity, weakness, etc. are also some of the symptoms of calcium deficiency in four-month-old babies. 3. Skeletal abnormalities: four-month-old babies with calcium deficiency may also have symptoms such as square skull. 4. convulsions: four month old babies with calcium deficiency may also have convulsions, hand and foot twitching and other symptoms if the deficiency is severe. Calcium deficiency in four-month-old babies may also have other symptoms. If you suspect that your baby is suffering from calcium deficiency, it is recommended that you go to the hospital in time for early and regular treatment.