Introduction 

Toilet training is recognised as an important milestone in child development. It involves a complex interaction of neurological, muscular and behavioural mechanisms, and data indicates that the age of attainment has gradually increased over time. For example, in a study of more than 1000 children in the 1950s, the mean age at completion of daytime toilet training was 28.5 months, and >97% had achieved this milestone by 36 months of age (Brazelton, 1962). A study of 266 children during the mid-1980s found a mean age of completion of toilet training between 25 and 27 months of age (Seim, 1989). However, a later study suggests that only 40–60% of children are completing training by 36 months of age (Blum et al, 2004). 
 

Why is toilet training happening later? 

So why is this happening and why are children being toilet trained much later? Possible reasons include increased maternal employment, socioeconomic changes, and prolonged use of disposable nappies. 
 

Type of nappy 

One of the main differences between children toilet trained in the 1950s and 1960s and children toilet trained in later years is the type of nappy used. Before the introduction of disposable nappies children wore cloth nappies. Managing cloth nappies made a lot of work for the parents – first soaking, then rinsing, then washing/boiling and then drying. This process may have provided some motivation for the parents to get the toilet training over and done with as soon as possible. 
 
Using cloth nappies allowed parents to more readily tell when their child had urinated or defecated. They also made it easier to tell when the child had gone longer between voids, indicating that the child was able to remain dry for longer periods, which often prompted the parents to start to potty train.
 
The terry towelling squares used at the time were not fully absorbent, so after passing urine the child would feel wet, raising awareness and providing some sensory feedback. This, combined with the expectation that most children should be toilet trained by the time they were 2 years old, may be some of the reasons why children were trained much earlier.
 
A small study by Simon and Thompson (2006) found that switching from disposable nappies to cotton pants improved continence in 2 out of 5 toddlers. This aligns with a study by Tarbox et al (2004) and suggests that changing from nappies to cloth pants can be a simple, effective part of toilet training for some children. 
 

Signs of ‘readiness’ 

A key factor in the delayed initiation of toilet training may be that parents are often told to wait for signs of ‘readiness’ before toilet training is introduced, such as the child’s ability to pull their pants up and down, or be able to indicate when they were wet. However, a literature review by Kaerts et al (2012) concluded that there was neither consensus nor any evidence-based research that identifies which or how many readiness signs should be present to suggest that toilet training should be started. This lack of consensus and a reliance on waiting for the child to ‘be ready’ appears to be one of the main reasons why toilet training is now often delayed. 
 
Many parents are also told to look for any ‘urination elimination signals’, such as the child showing some apparent discomfort or touching their nappy, as an indication their child has some awareness of passing urine and is therefore ready to start toilet training. However, the prolonged use of disposable nappies is associated with a reduced display of these urination elimination signals, leading to a further delay in starting toilet training (Xu et al, 2021; Bladt et al, 2025).
 
A study by Amir and Karim (2023) also concluded that prolonged use of disposable nappies may impede a child's preparedness for toilet training. Their results reported an odd ratio calculation which showed that toddlers who use disposable nappies are 26 more times at risk of being unprepared for toilet training compared to toddlers who are not using disposable nappies. They suggested that because disposable nappies are highly absorbent and keep the top surface dry, children often have trouble recognising when they have urinated. This can lead to delays in learning how to recognise the urge to urinate, making it harder for the child to develop conscious control over their bladder and ultimately affecting the success of toilet training.

In 2023 there was an awareness from some like-minded healthcare professionals regarding a lack of consensus around the best approach to toilet training and the overall impact of delayed training. This resulted in the production of national best practice consensus guidelines regarding toilet training (Rogers and Richardson, 2023). This document was based on earlier work by Rogers and Enoch (2020) who reported on their early intervention toilet skill development programme which led to children with Down syndrome being successfully toilet trained at an appropriate age.
 
In 2025 Kindred Squared carried out a school readiness survey and found that 26% of children starting reception were not toilet trained (up from 24% in 2023 and 2024), rising to 36% in the north-east. Even though 86% of parents acknowledged that toilet training is mainly their responsibility, a remarkable 22% did not think a child needs to be toilet trained by the time they start reception (Kindred Squared, 2026). As a result, in December 2025 Kindred Squared, along with a range of early years organisations, published a potty-training guide with the key recommendation that children should be out of nappies between the ages of 18–30 months old (Starting Reception, 2025).
 
Delayed toilet training and the unnecessary prolonged use of disposable nappies can therefore have considerable consequences, potentially affecting not just the child and family, as a result of its association with ongoing bladder problems and incontinence, but with wider impacts on the environment. Disposable nappies represent about 4% of solid waste and are the third highest number of single consumer items in landfills which are discarded after a single use (Ntekpe et al, 2020). Disposable nappies place a great burden on landfill sites and can have a health-related impact on the environment (Ntekpe et al, 2020).
 
van Nunen et al (2015) explored parents’ perspectives on toilet training and discovered that most parents were unaware of the possible negative effects of delayed toilet training. The researchers concluded that parents need better information regarding these possible negative outcomes.
 

Development of bladder control 

Studies have shown that, before achieving bladder control, infants and young children often have dyscoordination during voiding with incomplete bladder emptying and residual urine left in the bladder (Jansson et al, 2000; Sillén et al, 2000). 
 
Jansson et al (2005) conducted a long-term study of healthy Swedish children, monitoring urination patterns from 3 months to 6 years old. Interrupted voiding and incomplete bladder emptying were seen as signs of dyscoordination. These symptoms continued at varying degrees until bladder control developed. On completion of toilet training, any residual urine resolved and most children were able to fully empty their bladders.
 

As bladder control develops, bladder capacity grows and coordination between the bladder and sphincter improves, which enhances the bladder’s ability to empty to completion (Duong et al, 2010). However, if there is a delay in toilet training then this leads to an increase in the age at which bladder control is achieved. This results in the period of dyscoordination between bladder and sphincter being prolonged, potentially putting the child at risk of developing bladder problems going forward.
 
Yu et al (2023) reported that long-term use of disposable nappies increases the risk of urinary tract infections (UTIs). They carried out an epidemiological survey in mainland China which involved sending out anonymous questionnaires to families attending various nurseries and kindergartens. Just over 11,000 completed questionnaires were returned with a prevalence rate of extended use of disposable nappies of 4.17%. Within this group almost 40% of the children had symptoms of an UTI. Urinary stasis can lead to UTIs and it was proposed that this may result from infrequent urination or incomplete bladder emptying, both of which are associated with delayed bladder control.
 

Delayed toilet training and lower urinary tract symptoms

A study by Barone et al (2009) researched the toilet training history of children aged 4–12 years who attended a clinic with urge incontinence. They reviewed the case history of 58 affected children and compared them to a control group of children without any urge symptoms. Cases and controls were matched for various factors including age, gender and race. They found that those children with urge incontinence had initiation of toilet training later than controls, and this difference was statistically significant. The mean age of initiation of toilet training was 31.7 months compared to 28.7 months in the control group (P=0.02). The recommendation was that toilet training should not be postponed, as initiating training after 32 months correlates with an increased incidence of urge incontinence.
 
Joinson et al (2009) also investigated the association between the age of initiation of toilet training and the development of daytime bladder control. The study was based on more than 8000 children, aged 4.5–9 years, from a UK birth cohort – The Avon Longitudinal Study of Parents and Children. The main aim of the study was to examine whether initiation of toilet training after 24 months was associated with an increased incidence of daytime wetting in school-age children. They found that initiation of toilet training after 24 months was associated with a higher incidence of daytime wetting, delayed acquisition of daytime bladder control, or relapse in daytime wetting, compared with children whose toilet training was initiated between 15 and 24 months.
 
Li et al (2020a) carried out a systematic review and meta-analysis to investigate the association between age at initiation of toilet training and the risks of lower urinary tract dysfunction. The review included 10 eligible papers with a total of 14 121 subjects. Their preliminary findings were that early initiation of toilet training (before 24 months) was more beneficial than late toilet training. They reported that incidences of lower urinary tract dysfunction such as day-time wetting and enuresis (bedwetting) were increased in children who introduced training later.
 
Another study by Li et al (2020b) identified a significant association between children diagnosed with enuresis after the age of 5 years and the later cessation of daytime disposable nappy use compared to the control group.
 

Delayed toilet training and bowel control 

Delayed toilet training in toddlers can result in postponed bowel control, constipation and soiling (Amir and Karim, 2023). Refusing to open their bowels on a potty or toilet (stool toileting refusal) is a phenomenon often associated with toilet training and stool-related issues. Initially described by Taubman (1997), the prevalence was reported as 22%. His research further indicated that children who underwent toilet training at a later age faced an increased risk of stool toileting refusal, exhibited behaviours such as hiding during defecation, and experienced frequent constipation.
 

Conclusions 

Delaying toilet training has been shown to negatively impact on the child’s overall health and wellbeing as well as having a potential impact on the wider community. The incidence of lower urinary tract dysfunction, such as urge, overactive bladder, and day-time wetting, as well as bowel problems and constipation, is reported to be higher when toilet training has occurred late.
 
Delayed toilet training is often associated with parents waiting for some signs of ‘readiness’ before starting training. However, there is no evidence-based consensus regarding what and how many signs the parents need to look for. Disposable nappies have been shown to reduce a child’s awareness of bladder signals and recognition of when they have voided. With no clear signs from the child when they have passed urine or that they are feeling wet, parents are further unsure about when to start, resulting in them often citing that their child is ‘not ready’ as a reason for delaying toilet training. 
 
Healthcare professionals need to give parents guidance regarding the best time to start toilet training, including the early introduction of the potty and toilet. Sitting on the potty should become a routine part of a toddler’s day with the aim of helping raise awareness and understanding, with more formal toilet training commencing no later than between the ages of 18–24 months.