15 months baby 20 minutes to urinate once, generally is not normal, consider is the urinary tract infection or urinary system development deformity and other pathological changes caused. 15 months baby, if do not pay attention to the private parts of the clean and hygiene, drinking less water and other factors lead to urinary tract infection, may cause the baby more than 20 minutes to urinate once, at the same time can be accompanied by urinary urgency, urinary pain, serious cases can appear hematuria and so on. If the baby drinks too much water or there is a developmental abnormality of the urinary system such as bladder developmental abnormality may also cause the baby to urinate once in 20 minutes. 15 months baby 20 minutes urine once may also have other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, to give targeted treatment or treatment.