Why does type 1 diabetes cause bedwetting?

When blood glucose is high, the kidneys may not reabsorb all of the glucose filtered from the blood. Glucose remaining in urine draws water with it, increasing urine volume and thirst. A full bladder during sleep can lead to bedwetting. Bedwetting is a common presentation of Type 1 Diabetes, but bedwetting also has other causes, especially in children.

New bedwetting after a child has been dry at night, particularly with marked thirst, frequent daytime urination, tiredness or weight change, deserves timely clinical assessment. The same applies to new bedwetting in an adult.

Contact a clinician promptly for new or worsening bedwetting alongside thirst or frequent urination. A simple blood glucose or urine assessment may be part of the evaluation. If type 1 diabetes is already diagnosed, follow the sick-day and glucose-management plan provided by your diabetes team.

Do not punish a child for bedwetting. Protect bedding, encourage regular daytime drinks, and share the timing and pattern of wet nights with the clinician. Restricting fluids can increase dehydration risk when glucose is high.

Get emergency care for vomiting, stomach pain, deep or rapid breathing, unusual sleepiness, confusion, fruity-smelling breath, or inability to keep fluids down. These can occur with a serious complication of high blood glucose and need urgent treatment.

Ask whether glucose or urine testing is needed, whether the symptoms fit the current diabetes plan, how to respond during illness, and which warning signs require emergency care.