4 months baby need to supplement calcium, should be based on the baby’s physical condition to decide, if the baby has symptoms of calcium deficiency is the need to supplement calcium, if the baby does not have symptoms of calcium deficiency, usually do not recommend additional calcium supplement, specific analysis is as follows: 1. symptoms of calcium deficiency: such as the baby appeared hand and foot twitching, night sweating, poor sleep and other symptoms, parents can take the baby to the hospital for relevant examination, to determine whether there is a calcium deficiency, if diagnosed with calcium deficiency in babies, you can generally take calcium preparations under the guidance of the doctor for calcium supplementation. 2. No symptoms of calcium deficiency: 4 months baby is usually pure breastfeeding or formula feeding, general breast milk or formula in the calcium can meet the needs of the baby’s growth and development, the baby’s diet and sleep is good, there is no symptoms of calcium deficiency, is generally not recommended to intentionally extra calcium, usually can give the baby more sunshine to promote the absorption of calcium.