Calcium deficiency in 3-month-old babies may show symptoms such as early waking, sweating, irritability, etc. In severe cases, it may also manifest as tics and low immunity. 1. Usually, when 3-month-old babies lack calcium at an early stage, sleep is often affected, with symptoms such as night terrors, early awakening, not easy to fall asleep, and crying after waking up. The baby’s mood will also be affected to some extent, mostly in the form of crying, irritable and abrasive, disobedient and so on. 2. The baby will also appear excessive sweating phenomenon, if affected by the mood and sweat, can also appear sleep shaking head and wipe the pillow, and can even develop into pillow baldness. 3. If the baby suffers from severe calcium deficiency, he or she may suffer from tics, delayed tooth eruption, and late learning to stand and walk. Some babies may also develop rotundity, chicken chest, hunchback and muscle weakness. At the same time, the baby’s immunity will also be reduced, prone to upper respiratory tract infections, diarrhea, fever and so on. Parents are advised to pay more attention to the calcium supplementation of their 3-month-old babies and take good care of their babies to avoid the above symptoms of calcium deficiency.