Overproduction of urine at night
Sleeping at night is very important. For this reason, the body produces more of the hormone that concentrates the urine at night, so we don’t need to wake up to urinate. Normally, this nocturnal increase in hormone develops around the age of 5 to 6 (for some, it happens later). In children, if the hormone level is too low at night, it can result in bedwetting.
This hormone is called vasopressin and it is also known as ADH (anti-diuretic hormone). Anti-diuretic means it reduces urine production.
When vasopressin reduces urine production, the urine that is produced becomes more concentrated. This is why urine is darker in the morning than it is during the rest of the day. If you do not produce enough vasopressin at night, the urine becomes diluted and there is not enough room in the bladder.
This overproduction of urine at night is also called nocturnal polyuria. You then have to get out of bed to urinate. You can download and fill in the fluids diary from this website, to find out if you have too great a production of urine at night.
Your doctor will discuss treatment options for nocturnal polyuria with you - he may decide to prescribe a tablet for you.