Breast milk contains less calcium, and babies who are breastfed are prone to calcium deficiency. If your baby has obvious symptoms of calcium deficiency from breast milk, such as restless sleep, easy to wake up and crying at night, you should focus on the following points: 1. You should supplement your baby with vitamin AD and vitamin D3 at the same time. because vitamin D helps your baby absorb calcium from the intestine, if vitamin D is lacking, calcium cannot be effectively absorbed and will cause calcium deficiency. 2. properly choose the right calcium supplement for your baby The baby’s taste is different, some may like to eat calcium lactate, some like to eat calcium acetate, and some like to eat liquid calcium. 3, should ensure that the baby has a certain amount of time outdoors every day, more sunshine. 4, the diet can also be appropriate to add calcium-rich supplementary food.