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Children Toilet Trained Before Age 2 Have Triple the Risk of Wetting Problems

For years in my pediatric urology practice I noticed a pattern: My patients with the most severe wetting problems were toilet trained as toddlers.

Some of these kids were pushed to use the toilet by overeager parents, but others seemed to lead the way. I’d hear from parents: “I don’t get it — she basically trained herself at 18 months and never had an accident. Now she’s 3 and wetting her pants every day in preschool.”

Virtually of these children were severely constipated, as X-rays in my clinic confirmed; based on their parents’ reports, most of these kids also were in the habit of holding pee.

I was seeing so many early-trained patients that I developed a theory: Toddlers — capable as they may be of using the toilet — simply do not have the judgment to respond to their bodies’ urges in a timely manner.

Compared to children who trained later, my theory went, toddlers are far more likely to delay peeing and pooping. As a result, they’re more prone to dysfunctional toileting.

Well, I am pleased to report that I now have solid research that supports my theory. The journal Research and Reports in Urology has published a study conducted in my clinic at Wake Forest Baptist Health titled “The association of age of toilet training and dysfunctional voiding.” Our key finding: children toilet trained before age 2 have triple the risk of developing daytime wetting problems down the road.

What’s more: In our study, the children trained as toddlers had triple the risk of constipation. In fact, virtually all of study subjects who had wetting problems also were constipated.

This is no coincidence. It is well documented that constipation is the main cause of enuresis (wetting). When stool piles up in the rectum, it forms a hard lump that presses against the bladder, shrinking its capacity and irritating the nerves that feed it. Holding pee exacerbates the problem by thickening and further irritating the bladder.

Our study is the first to consider daytime wetting and constipation status along with age of toilet training, and it confirms what I’ve been telling parents for years: Toilet training a toddler is risky business. Of course, not every child trained as a toddler will later develop problems, but in my study, 60 percent of the subjects trained before age 2 did present with accidents.

Bottom line: Parents who train their children early — to meet preschool deadlines, to save money, to save landfills from diapers, or because they think toddlers are easier to train or because other cultures train early — should know there can be serious repercussions.

I hope our findings will encourage parents to delay toilet training their children, to temper their expectations of toddlers, and to have more patience when children have toileting accidents. “Failed toilet training” is one of the leading triggers of child abuse, according to the Child Abuse Prevention Center. Every week brings more news reports of toddlers killed by parents out of frustration over toilet training. Often the reason toilet training “failed” is that the children were trained at too young an age.

I also hope our findings will encourage preschools to ease up on deadlines requiring children to be potty trained by age 3. These deadlines often prompt parents to train their toddlers extra early so that the children will be completely trained and accident-free by the time school starts. Unfortunately, preschools fail to realize early training can backfire, and they end up blaming parents and children for accidents.

The most prominent case of this blame was when 3-year-old Zoe Rosso of Arlington, Virginia — who later became my patient — was kicked out of preschool for having “too many” potty accidents. Her accidents were caused by severe constipation that had gone unrecognized.

Our research found that children toilet trained before age 2 had triple the risk of the later developing wetting problems. This is because toddlers are more prone to holding their poop. This infographic illustrates how constipation directly causes accidents.

How We Conducted Our Study

Our study involved 112 children ages 3 to 10. About half of these kids came to our urology department for dysfunctional voiding. We compared these kids with a second group of children who had no history of dysfunctional voiding and who had visited a general pediatric clinic or pediatric emergency room for entirely different reasons, ranging from ear infections to broken bones.

Using a questionnaire, we asked parents in both groups what age their child had begun toilet training and whether the child had dysfunctional voiding issues.

Then we grouped patients into three categories based on age potty training was initiated: “early” (before age 2), “normal” (between 2 and 3) and “late” (after age 3). Our sample included 38 early trainers, 64 normal trainers, and 10 late trainers.

Sixty percent of the early trainers had daytime wetting. Crunching the numbers, this translated to a 3.37 times increased risk of daytime wetness as compared to group trained between ages 2 and 3.

The early trainers also were three times more likely to complain of constipation than the normal trainers.

Does Potty Training “Late” Increase Risk of Problems?

So you may be wondering: What did we learn about the kids who potty trained after age 3?

As early training comes back into fashion, I often hear from parents: “I want to train my child before he starts pushing back and it becomes a struggle.” There’s this notion floating around that if you wait too long to teach a child to use the toilet, you’ll end up with a “potty refuser.”

In our study, the sample of “late” trainers was small — we had 10 kids who trained after age 3 — but the results completely jibe with what I see daily in my practice. Of the 10 late trainers, seven had wetting problems, and all seven were constipated. The three late trainers who did not have wetting problems were not constipated.

In no way do these results suggest that late training causes problems. The reason late trainers so commonly have wetting problems is that they were already constipated when their parents started training them. When a 3 ½-year-old has no interest in pooping on the toilet or seems afraid of it, it’s almost always because pooping hurts.

Training a constipated child is terribly difficult — with some kids, impossible. Parents whose 3- or 4-year-olds have trouble training are often blamed for waiting too long, but our data suggest waiting isn’t the problem; it’s the constipation.

What’s The Right Age to Toilet Train?

I hope folks won’t read our study and jump to the conclusion that there’s a “magic window” for toilet training between ages 2 and 3. It’ just that children trained before age 2 are at the highest risk for developing problems. Based on my experience and my research, I believe that most children under 3 haven’t developed the capacity to respond to their bodies’ urges to pee and poop in a judicious manner.

I personally would not recommend toilet training a 2 1/2-year-old, and I believe that preschools that require toilet training by age 3 are doing families a great disservice. Based on my experience and my research, I have waited until after age 3 to initiate training with my own kids. My "It’s No Accident" co-author, Suzanne Schlosberg, toilet trained her boys at 24 months; she talks about the repercussions in a video titled “How I Screwed Up (Royally) By Potty Training My Twins Too Soon.”

I understand that, for multiple reasons, many parents will potty train children under age 3, and I think the most important point to glean from our study is that constipation status — rather than age — is the critical factor that will influence whether a child develops wetting problems.

No matter what age you introduce your children to the toilet, make sure your child is ready — that is, interested and not constipated — and is leading the way. And once the child gets the hang of using the toilet, remain vigilant about monitoring for signs of constipation and make sure your child pees every two to three hours.

If every parent did all that, I’m certain my clinic would be a lot less crowded.

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