If your child wets the bed and the alarm hasn’t worked, there is a high chance constipation is part of the picture — even if you have never noticed any bowel difficulty. This is one of the most common and most overlooked drivers of treatment failure in childhood enuresis, and it is unique in that it can sabotage every other treatment until it is addressed.
Why constipation causes bedwetting
The bladder and the rectum sit beside each other in the small space of the pelvis. When stool builds up in the rectum — even when a child is having a bowel movement most days — it presses on the back wall of the bladder, reducing the bladder’s effective capacity, irritating the bladder muscle, and causing the kind of involuntary contractions that lead to wetting (both daytime and at night).
Crucially, the child often has no idea this is happening. Many constipated children pass a stool every day, but a hard or incomplete one — and the rectum stays loaded.
Why parents miss it
- Daily bowel movements can mask underlying constipation if the stool is hard or incomplete
- Children rarely complain — chronic constipation becomes their normal
- Older children become private about toileting, so parents lose visibility on what is happening
- Soiling (encopresis) can look like poor toileting but is often overflow around impacted stool
Signs constipation may be involved in your child’s bedwetting
- Stools are large, hard, lumpy, or look like rabbit droppings
- Pain or straining when passing stool
- Bowel movements less often than every other day
- Soiling or skid-marks in underwear
- Daytime wetting or urinary urgency alongside the bedwetting
- Tummy aches that come and go without obvious cause
- Reduced appetite
- The bedwetting alarm has been used correctly for 6+ weeks with little or no progress
What to do
If you suspect constipation, the recommended first step is to see your GP. UK NICE guidance is clear that childhood constipation is treated with disimpaction (often using a course of polyethylene glycol — Movicol Paediatric in the UK) followed by a maintenance dose, typically continued for several months. This is not a brief course of treatment. Many families stop too early because the immediate problem looks resolved, only for the cycle to restart.
Alongside medication, the daily essentials matter:
- Plenty of fluids during the day (water, not squash)
- Regular fibre — fruit, vegetables, wholegrains
- Daily physical activity
- A reliable post-meal toileting routine, sitting on the toilet for 5 minutes after breakfast and dinner with feet supported
- Reducing pressure or punishment around toileting (anxiety worsens constipation)
How this fits into bedwetting treatment
If significant constipation is present, we usually treat it before — or alongside — the bedwetting alarm. Trying to use the alarm with an underlying chronic constipation almost always disappoints both child and family. Once the constipation is properly treated, alarm treatment typically produces the expected results.
This is one of the reasons our preliminary free questionnaire asks specifically about bowel habits. It is also why a thorough assessment always covers the bowel as well as the bladder.
For more depth
For more on the bigger picture, see our central guide: How to Stop Bedwetting — A Step-by-Step Guide. To explore why a previous alarm attempt may have stalled, read Bedwetting alarm not working — what to do.
This article is for general information. It does not replace clinical advice for your child. If you suspect your child has significant constipation, please see your GP.