The reason why a one-month-old baby cries may be due to improper feeding, lack of calcium or uncomfortable environment, etc., which needs to be analyzed specifically. 1. Improper feeding: one-month-old babies may not be able to feed parents, feeding too much milk leads to indigestion and thus abdominal pain and bloating, resulting in the baby crying. Need to promptly adjust the way of feeding, reduce the burden on the baby’s gastrointestinal tract. 2. Calcium deficiency: If the baby is not supplemented with vitamin D in time after birth, it may lead to calcium deficiency in the baby’s body. When the lack of calcium may cause increased nerve excitability, resulting in the baby crying. 3. uncomfortable environment: the baby crying may be because the indoor temperature is too low, too high, the child’s body symptoms, or the child due to wet urine and so on lead to wear uncomfortable and crying. There are many other reasons why a month old baby cries, if it continues to be unrelieved, you need to consult a doctor in time to check the specific causes and take targeted treatment and therapy.