Three-month-old babies urinate less considerations related to drinking less water, hot weather, but also may be the emergence of urinary tract obstruction, glomerulonephritis and other diseases. 1. Drinking less water, if the three-month-old baby usually drink less water, the lack of water in the body, may lead to urinary symptoms. 2. Hot weather, if the weather is hot, sweating more, the body loses more water, may also appear urine symptoms. 3. Urinary obstruction, if there is a urinary obstruction, the urine discharge is affected, may lead to this situation. 4. Glomerulonephritis, some babies have glomerulonephritis after kidney function is abnormal, metabolism is slowed down, may lead to decreased urine output. Three months baby urine, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.