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

By Steve Hodges, M.D.

For years in my pediatric urology practice I noticed a pattern: Many of my patients with the most severe enuresis (bedwetting or daytime wetting) were toilet trained as toddlers.

Though some of these kids were pushed to use the toilet by overeager parents, it seemed that others led 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 though 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.

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 down the road. What’s more: In our study, the children trained as toddlers had triple the risk of constipation.

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 mass 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 under age 2 will later develop problems, but in my study, 60 percent of the subjects trained before 24 months did present with accidents.

Bottom line: Parents who train their children early — to meet preschool potty 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.

One prominent example 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.

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 potty problems 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.

Based on parent reports, early trainers also were three times more likely to have constipation than the children who had trained between ages 2 and 3.

Does Potty Training “Late” Increase Risk of Problems?

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 — only 10 kids had trained after age 3 — but the results jibe with what I see 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.

These results do not 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, so they have learned to avoid it.

Training a constipated child is terribly difficult, if not 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.

If your child does have a history of constipation or if you are just now discovering it, make sure you resolve the constipation before starting toilet training. I explain how to do this in The Pre-M.O.P. Plan: How to Resolve Constipation in Babies and Toddlers and Overcome Potty-Training Struggles. The book offers guidance for toilet training a child with a history of 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.

In general, I don't 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 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. The Pre-M.O.P. Plan includes charts that can help you monitor your child's constipation status.

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