The baby sleeps at night with a stuffy nose, but during the day it is normal, which may be caused by allergies, adenoid hypertrophy or colds and other reasons. 1. Allergy: If there are suspected allergens in the sleeping environment, such as bed sheets, clothes, quilts, etc., it may lead to allergies in children, which may cause symptoms of nasal congestion, but because the air is circulating during the day, the concentration of allergens in the air decreases, and at night, because the windows and doors are tightly closed, the air quality is not good, which may cause the phenomenon of nasal congestion at night. 2. Adenoid hypertrophy: children will have adenoid development, and abnormal hypertrophy of the adenoids, due to the position of the reason at night when sleeping, will make the symptoms of nasal congestion further aggravated, but also accompanied by snoring at the same time. 3. Colds: viral colds lead to nasal mucosa congestion, edema, there will be a nose without air, during the day because of the role of gravity, the influence of body position, secretions can be discharged. At night when you sleep, the nasal secretion will be relatively too much, so the symptoms of non-ventilation will be aggravated. If your baby’s nose is out of breath at night and gets better during the day, it is recommended that you go to the hospital in time to find out the cause of the problem and treat the symptoms.