Five-month-old babies do not urinate all night long most of the normal phenomenon, a small number of may be related to pathological factors, such as fever. 1. Normal phenomenon: usually, the baby in 3 months will gradually form a regular work and rest time, the urinary system is also gradually mature. If there is no other adverse reaction, may be due to increased urination during the day or night eating and drinking relatively little, resulting in the body does not have enough liquid volume, or most of the water in the baby’s body will be evaporated along with the skin surface, there is not enough urine, appeared throughout the night does not urinate. 2. abnormal phenomenon: five months of the baby all night without peeing may also be caused by pathological factors, such as fever, liver and kidney function abnormalities, etc., and may also be accompanied by poor mental health and limb swelling and other symptoms of discomfort. If the baby has symptoms of discomfort, you need to take the baby to the hospital in time, under the guidance of the doctor, the relevant examination, through the results of the examination, to take targeted treatment.