By Steve Hodges, M.D.
At my pediatric urology clinic, just about every parent of a bedwetting child is convinced that “deep sleep” explains the wet sheets.
Parents tell me, “She’s such a deep sleeper that you could blast Motorhead in her room and she wouldn’t budge.”
Or, “When he’s out, he’s out — there’s no chance of waking him up.”
In many cases, the child’s pediatrician has confirmed this theory or suggested it in the first place. And when families search online, they find additional support for the idea that deep sleep causes bedwetting.
For example, under the heading “Causes of Bedwetting,” the American Academy of Pediatrics (AAP) states: “Your child is a deep sleeper and does not awaken to the signal of a full bladder.” This statement tops a list of 8 bedwetting “causes.” And in an article titled "Nocturnal Enuresis in Teens," the AAP lists among the “contributing” factors to teenage bedwetting: “a deep sleep pattern that can be part of normal adolescent development, inconsistent sleep schedule and limited hours sleeping.”
On its website, the Enuresis Treatment Center calls bedwetting “a treatable sleep disorder” and claims that “targeting treatment to changing the sleep pattern will not only end the bedwetting, it will allow the bedwetter to experience better night’s sleep.”
There are two problems with the deep-sleep theory: 1.) it makes no sense, and 2.) no evidence supports it.
Why Deep Sleep Cannot “Cause” Bedwetting
Your bedwetting child may very well be a deep sleeper, but that’s beside the point, because children with healthy bladders simply do not need to pee overnight.
Do you have other children who are lighter sleepers? Do you hear them walking down the hallway at 2 a.m. to pee? I doubt it!
It’s not as if light-sleeping kids are awakened overnight by the urge to pee, whereas deep sleepers fail to heed the signal and therefore wet the bed. No child, whether a light sleeper or a heavy sleeper, should even have the urge to pee at 2 a.m.
Because human beings typically don’t eat or drink overnight, we don’t produce enough urine to need to pee. A healthy bladder has the capacity and stability to hold the urine we do produce.
When a person — child or adult — needs to pee overnight, it’s because his or her bladder is overactive; in other words, the bladder spasms when it’s not full, often with little warning. (In extremely rare cases, the person has a medical condition, such as diabetes insipidus, that causes an overproduction of urine while sleeping, but I can’t emphasize enough how rare this is). In children, virtually all bladder overactivity is directly caused by constipation. In adults, it’s typically due to changes to bladder function that occur with age, though constipation can contribute.
When stool piles up in a child’s rectum, the rectum stretches dramatically and encroaches upon the bladder, shrinking bladder capacity substantially. Compounding the problem, the stool-stuffed rectum irritates the spinal nerves that supply the bladder, causing it behave as if it were full, even though it isn’t.
How we can we be certain constipation is what triggers bedwetting (nocturnal enuresis) in children? As I detail in The M.O.P. Book, the constipation-bedwetting connection was proven repeatedly back in the 1980s by a University of Montreal team led by Sean O’Regan, M.D.
In his studies on bedwetting children, Dr. O’Regan used the most objective measurement of constipation: anorectal manometry, a procedure that involves measuring the rectum’s response to a slowly inflated air balloon. His enuresis patients were shown to have wildly abnormal measurements: These kids’ rectums were so stretched by stool that the children could not detect balloons inflated to the size of a small tangerine. In research at my own clinic, we use X-rays to assess constipation in children. Specifically, we measure rectal diameter, and we consistently find that virtually all bedwetting patients have rectums stretched well beyond normal, usually to twice normal diameter (6 cm compared to 3 cm).
As X-rays plainly show, the child’s bladder can be practically flattened by the adjacent rectum. It's easy to see why the child can’t last all night without peeing.
OK, but why don’t these kids wake up in time to avoid an accident?
For the same reason so many bedwetting children also have daytime accidents: an overactive bladder spasms too quickly for the child to react. It’s like a hiccup: You can’t stop it. Even when fully awake, many chronically constipated kids can’t make it to the toilet in time to avoid an accident. So if a child is sleeping when the bladder hiccups, what chance does this child have of jolting awake and sprinting to the toilet? None!
The theory that deep sleep causes bedwetting conveniently overlooks the proven connection between bedwetting and daytime accidents. A significant percentage of bedwetting children also have daytime accidents. In one study of 16,000 children, about 15% of bedwetting boys ages 5 to 10 also had daytime wetting; among tweens and teens, the overall bedwetting rate was lower, but 32% of the bedwetting kids in that age group also had daytime accidents.
A Swedish study found a strong association between daytime pee accidents and bedwetting; elementary-age kids who had daytime accidents were four times as likely to wet the bed as kids who did not have daytime accidents. The link between daytime pee accidents and daytime poop accidents (which are always caused by constipation) was even stronger.
Virtually all of my patients with daytime pee or poop accidents also wet the bed. Same goes for children of the parents in my private Facebook support group. Dr. O’Regan’s patient load showed similar overlap.
What doesn’t make sense: When pediatricians tell parents their child’s bedwetting is due to deep sleep, how do they explain the very same child’s daytime accidents? Typically, they don’t. According to many parents I work with, their doctors say daytime and nighttime accidents are unrelated.
But these conditions are completely related. As Dr. O’Regan’s research showed, bedwetting, daytime pee accidents, and encopresis (poop accidents) have the same cause — constipation — and respond to the same treatment. When you aggressively clean out the stuffed rectum and keep it clear — for example, with a daily enema regimen, Dr. O’Regan’s preferred protocol — all three types of accidents resolve, typically in this order: first encopresis, then daytime wetting, then bedwetting.
You can reasonably say your child wets the bed and is a deep sleeper, but it’s not logical to say a child wets the bed because she’s a deep sleeper. Deep sleep cannot trigger bladder overactivity.
Now, if you, yourself, need to pee in the middle of the night — as plenty of adults over 40 do — you may wonder why you are able to wake up whereas your child is not. I don’t have a proven answer for you. It isn’t clear why adults with an overactive bladder are so much more likely to wake up than kids are. Some adults do wet the bed, but I suspect those able to avoid wet sheets experience a type of bladder overactivity that is less forceful and comes on slowly enough to let them wake up and get to the toilet. Children, by contrast, experience dynamic, abrupt bladder spasms. So, boom: wet sheets.
Even if constipation is the primary culprit, could sleep issues play any role in bedwetting?
It’s possible, though not in a way that seems intuitive. Perhaps the best study evaluating the relationship between bedwetting and sleep was conducted by researchers at the Chinese University of Hong Kong and summarized by the authors in a letter to the New England Journal of Medicine. This study found bedwetting children actually sleep less soundly than other children! The researchers monitored children’s sleep patterns overnight and concluded that compared to children who were dry, bedwetting children got less REM sleep, probably because their bladders were going haywire all night. Every child who wet the bed in this study was shown to have an overactive bladder.
The researchers did not investigate whether these children were constipated, but I would bet big money that the cause of the bladder contractions in the bedwetting group was a giant rectal clog. That was the case in my own study comparing children with daytime accidents and children who were dry.
The Chinese researchers also found that the bedwetting children had less than half the bladder capacity as the dry kids. Though they did not speculate as to why, the reason will be obvious to anyone who has looked at X-rays of children with enuresis: These kids’ bladders are so squished by the large mass of poop in the rectum that they do not have the capacity to hold urine all night long.
The vast majority of studies that have looked at sleep patterns in bedwetting children have failed to consider whether the children were constipated, so these studies are of limited value. And even when bedwetting studies do consider constipation, they “measure” constipation using subjective methods such as parent history and physician exam, rather than objective methods such as anorectal manometry and X-ray. As a result, they dramatically underestimate the actual incidence of constipation. Most folks think of "constipation" as "infrequent pooping," when, in fact, frequency of pooping doesn't tell you much, since many severely constipated children poop daily or multiple times a day. The real issue is the rectal stool pile-up due to incomplete emptying.
Ultimately, it doesn’t really matter why a child doesn’t wake up. Because if you want to fix a child’s bedwetting, that’s not the relevant question. Instead you need to ask: Why is this child’s bladder unstable?
In almost all cases, the answer will be constipation. And the most effective solution will be an enema-based regimen, such as the Modified O’Regan Protocol (M.O.P.), the version of Dr. O’Regan’s original regimen that I use in my practice. (Note that the key to success is completely emptying the rectum; in chronically clogged kids, this takes hard work, patience, and often trial and error. It’s not a matter of giving a child a few enemas, and a daily dose of Miralax doesn’t remotely do the job.)
Any bedwetting therapy that involves waking children up or teaching them to have “healthier” sleep patterns will only serve to frustrate these kids.
One family I worked with spent thousands on a bedwetting treatment center that advises parents to spray their children with cold water “to wake them out of their deep sleep.” The parents wouldn’t spray their teenage son, the mom told me, and then wondered if they failed him by “not following the program to a tee.”
Another patient of mine underwent numerous sleep tests. One doctor diagnosed him with narcolepsy. Another said no, it’s sleep apnea. Recalls his mom: “We thought, ‘OK, that’s it!’ He wore a headset for three months. It didn’t change a thing.” (While it’s true that medically diagnosed sleep apnea can cause increased urine output, this condition is rare in children and almost always caused by enlarged tonsils and adenoids in the upper airway.)
The AAP’s advice to teenagers is especially dismaying. By stating — without evidence! — that bedwetting can be caused by a “deep sleep pattern that can be part of normal adolescent development,” the academy is reinforcing the false notion that bedwetting is “normal” and therefore is preventing teens from receiving effective treatment. Getting on a more consistent sleep schedule is certainly a great thing for any teenager, but it’s not going to resolve bladder overactivity.
Bottom line: Most kids are deep sleepers. Most kids don’t wet the bed. It doesn’t matter if your child could sleep through a heavy-metal concert or a fire alarm. That still can’t explain why her bladder needs to empty overnight.
FURTHER READING:
Steve Hodges, M.D., is an associate professor of pediatric urology at Wake Forest University School of Medicine and coauthor of five books, including The M.O.P. Book: A Guide to the Only Proven Way to STOP Bedwetting and Accidents, Bedwetting and Accidents Aren't Your Fault, and Jane and the Giant Poop.