Calcium deficiency in 2-month-old babies may firstly be caused by physiological factors such as insufficient exposure to sunlight and insufficient calcium intake by the body, which need no treatment. Secondly, it may also be caused by vitamin D deficiency rickets and other diseases, need to take medication. 1. Physiological factors: 2-month-old babies with prolonged insufficient light will affect the endogenous vitamin D production, in addition to the lack of calcium in breast milk or inadequate nutritional intake of infants can also lead to calcium deficiency. These are physiological factors caused by calcium deficiency, can not be treated, but usually appropriate to the baby sun, breastfeeding mothers need to appropriate calcium supplement. 2. Vitamin D deficiency rickets: 2 months baby calcium deficiency may also be caused by vitamin D deficiency rickets, it is recommended that you can apply vitamin D to your baby under the guidance of a doctor, if necessary, you can give your baby oral calcium gluconate, calcium carbonate and other calcium supplements as prescribed by the doctor. 2 months baby calcium deficiency may also be pseudo-hypoparathyroidism, hypomagnesemia, taking anticonvulsants or glucocorticoids and other drugs. If it is physiological factors caused by 2 months baby calcium deficiency without treatment, for disease factors of calcium deficiency, need to take the baby to the doctor in time, clear the cause of the disease and follow the doctor’s instructions.