Babies dream crying is common in the following situations: 1. When babies are in excessive excitement or crying before going to sleep, the cerebral cortex does not calm down immediately after going to sleep, resulting in the phenomenon of dream crying. This is why it is important to keep the baby in a warm and quiet environment before going to sleep. 2. Lack of sleep, irregular sleep or sleeping in a noisy and unfamiliar environment can easily lead to dream crying. 3. Vitamin D deficiency rickets. When babies have hypocalcemia present, they will have night terrors, night crying and excessive sweating, which will gradually improve after being given vitamin D and calcium supplements.