Increased amount of sugar can cause increase in urination but it can be a tell tale sign of possible diabetes... or if her fluid intake is hire as well as her activity she may be flushing quicker... If the fluid intake decreases in the PM and she is less active so would her urinating... also during sleep our bodies go into sleep mode and all bodily functions slow down... have a sugar test done on her at the doctor to uliminate possible diabetes or hypoglycemia... good luck:))