The estimated prevalence of encopresis in four-year-olds is between one and three percent. The disorder is thought to be more common in males than females, by a factor of 6 to 1.

The six-week period after pregnancy is called the postpartum stage. During this time, women are at increased risk of being constipated. Multiple studies estimate the prevalence of constipation to be around 25% during the first 3 months. Constipation can cause discomfort for women, as they are still recovering from the delivery process especially if they have had a perineal tear or underwent an episiotomy. Risk factors that increase the risk of constipation in this population include:

- Damage to the levator ani muscles (pelvic floor muscles) during childbirth

- Forceps-assisted delivery

- Lengthy second stage of labor

- Delivering a large child

- Hemorrhoids

Hemorrhoids are common in pregnancy and also may get exacerbated when constipated. Anything that can cause pain with stooling (hemorrhoids, perineal tear, episiotomy) can lead to constipation because patients may withhold from having a bowel movement so as to avoid pain.

The pelvic floor muscles play an important role in helping pass a bowel movement. Injury to those muscles by some of the above risk factors (examples- delivering a large child, lengthy second stage of labor, forceps delivery) can result in constipation. Women sometimes get enemas during labor that can also alter bowel movements in the days after having given birth. However, there is insufficient evidence to make conclusions about the effectiveness and safety of laxatives in this group of people.

Encopresis is commonly caused by constipation, by reflexive withholding of stool, by various physiological, psychological, or neurological disorders, or from surgery (a somewhat rare occurrence).

The colon normally removes excess water from feces. If the feces or stool remains in the colon too long due to conditioned withholding or incidental constipation, so much water is removed that the stool becomes hard, and becomes painful for the child to expel in an ordinary bowel movement. A vicious cycle can develop, where the child may avoid moving his/her bowels in order to avoid the "expected" painful toilet episode. This cycle can result in so deeply conditioning the holding response that the rectal anal inhibitory response (RAIR) or anismus results. The RAIR has been shown to occur even under anesthesia and when voluntary control is lost. The hardened stool continues to build up and stretches the colon or rectum to the point where the normal sensations associated with impending bowel movements do not occur. Eventually, softer stool leaks around the blockage and cannot be withheld by the anus, resulting in soiling. The child typically has no control over these leakage accidents, and may not be able to feel that they have occurred or are about to occur due to the loss of sensation in the rectum and the RAIR. Strong emotional reactions typically result from failed and repeated attempts to control this highly aversive bodily product. These reactions then in turn may complicate conventional treatments using stool softeners, sitting demands, and behavioral strategies.

The onset of encopresis is most often benign. The usual onset is associated with toilet training, demands that the child sit for long periods of time, and intense negative parental reactions to feces. Beginning school or preschool is another major environmental trigger with shared bathrooms. Feuding parents, siblings, moving, and divorce can also inhibit toileting behaviors and promote constipation. An initiating cause may become less relevant as chronic stimuli predominate.

Reducing opiate-based medication (when possible, tolerable, and safe; prescription medication changes should be done under the supervision of a physician), and adequate intake of liquids (water) and dietary fiber and daily exercise.

Approximately 3% of children have constipation, with girls and boys being equally affected. With constipation accounting for approximately 5% of general pediatrician visits and 25% of pediatric gastroenterologist visits, the symptom carries a significant financial impact upon the healthcare system. While it is difficult to assess an exact age at which constipation most commonly arises, children frequently suffer from constipation in conjunction with life-changes. Examples include: toilet training, starting or transferring to a new school, and changes in diet. Especially in infants, changes in formula or transitioning from breast milk to formula can cause constipation. Fortunately, the majority of constipation cases are not tied to a medical disease, and treatment can be focused on simply relieving the symptoms.

Liquid stool is more difficult to control than formed, solid stool. Hence, FI can be exacerbated by diarrhea. Some consider diarrhea to be the most common aggravating factor. Orlistat is an anti-obesity (weight loss) drug that blocks the absorption of fats. This may give side effects of FI, diarrhea and steatorrhea.

This may occur when there is a large mass of feces in the rectum (fecal loading), which may become hardened (fecal impaction). Liquid stool elements are able to pass around the obstruction, leading to incontinence. Megarectum (enlarged rectal volume) and rectal hyposensitivity are associated with overflow incontinence. Hospitalized patients and care home residents may develop FI via this mechanism, possibly a result of lack of mobility, reduced alertness, constipating effect of medication and/or dehydration.

There are many possible causes; for example, physical inactivity, not eating enough (particularly of fiber), and not drinking enough water. Medications such as opioid pain relievers (suboxone, methadone, codeine, oxycodone, hydrocodone, etc.) and certain sedatives that reduce intestinal movement may cause fecal matter to become too large, hard and/or dry to expel. Specific diseases or conditions, such as irritable bowel syndrome, neurological disorders, diabetes, and autoimmune diseases such as amyloidosis, celiac disease, lupus, and scleroderma can cause constipation. Hypothyroidism can cause chronic constipation because of sluggish, slower, or weaker colon contractions. Iron supplements or increased blood calcium levels are also potential causes. Spinal cord injury is a common cause.

Manual removal of a fecal impaction is often required with obese patients in traction, after a barium enema, and in poorly hydrated older adults.

Several definitions have been offered:

- "Absence of normal relaxation of pelvic floor muscles during defecation, resulting in rectal outlet obstruction".

- "Malfunction (a focal dystonia) of the external anal sphincter and puborectalis muscle during defecation".

- "[...] failure of [the external anal sphincter and puborectalis] muscle[s] to relax, resulting in maintenance of the anorectal angle and the difficulty with initiating and completing bowel movements".

- "[...] failure of relaxation (or paradoxic contraction) of the puborectalis muscle sling during defaecation, attempted defaecation or straining."

Anismus is classified as a functional defecation disorder. It is also a type of rectal outlet obstruction (a functional outlet obstruction). Where anismus causes constipation, it is an example of functional constipation. Some authors describe an "obstructed defecation syndrome", of which anismus is a cause.

The Rome classification subdivides functional defecation disorders into 3 types, however the symptoms the patient experiences are identical.

- Type I: paradoxical contraction of the pelvic floor muscles during attempted defecation

- Type II: inadequate propulsive forces during attempted defecation (inadequate defecatory propulsion)

- Type III: impaired relaxation with adequate propulsion

It can be seen from the above classification that many of the terms that have been used interchangeably with anismus are inappropriately specific and neglect the concept of impaired propulsion. Similarly, some of the definitions that have been offered are also too restrictive.

Anal warts are irregular, verrucous lesions caused by human papilloma virus. Anal warts are usually transmitted by unprotected, anoreceptive intercourse. Anal warts may be asymptomatic, or may cause rectal discharge, anal wetness, rectal bleeding, and pruritus ani. Lesions can also occur within the anal canal, where they are more likely to create symptoms.

Proctitis is inflammation of the anal canal and the distal of the rectum.

Proctitis has many causes, such as infections or intercourse.

Tuberculosis proctitis can create a mucous discharge.

Oesophageal diseases include a spectrum of disorders affecting the oesophagus. The most common condition of the oesophagus in Western countries is gastroesophageal reflux disease, which in chronic forms is thought to result in changes to the epithelium of the oesophagus, known as Barrett's oesophagus.

Acute disease might include infections such as oesophagitis, trauma caused ingestion of corrosive substances, or rupture of veins such as oesophageal varices, Boerhaave syndrome or Mallory-Weiss tears. Chronic diseases might include congenital diseases such as Zenker's diverticulum and esophageal webbing, and oesophageal motility disorders including the nutcracker oesophagus, achalasia, diffuse oesophageal spasm, and oesophageal stricture.

Oesophageal disease may result in a sore throat, throwing up blood, difficulty swallowing or vomiting. Chronic or congenital diseases might be investigated using barium swallows, endoscopy and biopsy, whereas acute diseases such as reflux may be investigated and diagnosed based on symptoms and a medical history alone.

Most girls can stay dry at night by age six and most boys stay dry by age seven. Boys are three times more likely to wet the bed than girls.

Doctors frequently consider bedwetting as a self-limiting problem, since most children will outgrow it. Children 5 to 9 years old have a spontaneous cure rate of 14% per year. Adolescents 10 to 18 years old have a spontaneous cure rate of 16% per year.

Approximate bedwetting rates are:

- Age 5: 20%

- Age 6: 10–15%

- Age 7: 7%

- Age 10: 5%

- Age 15: 1–2%

- Age 18–64: 0.5–1%

As can be seen from the numbers above, a portion of bedwetting children will not outgrow the problem. Adult rates of bedwetting show little change due to spontaneous cure. Persons who are still enuretic at age 18 are likely to deal with bedwetting throughout their lives.

Studies of bedwetting in adults have found varying rates. The most quoted study in this area was done in the Netherlands. It found a 0.5% rate for 18- to 64-year-olds. A Hong Kong study, however, found a much higher rate. The Hong Kong researchers found a bedwetting rate of 2.3% in 16- to 40-year-olds.

The pathophysiology of the condition results from neuronal plasticity associated with bladder afferents and motor neurons innervating the external urethral sphincter. People with this condition generally experience daytime and night time wetting, urinary retention, and often have a history of urinary tract and bladder infections. Constipation and encopresis are often associated with this condition.

Gastric diseases refer to diseases affecting the stomach. Inflammation of the stomach by infection from any cause is called gastritis, and when including other parts of the gastrointestinal tract called gastroenteritis. When gastritis persists in a chronic state, it is associated with several diseases, including atrophic gastritis, pyloric stenosis, and gastric cancer. Another common condition is gastric ulceration, peptic ulcers. Ulceration erodes the gastric mucosa, which protects the tissue of the stomach from the stomach acids. Peptic ulcers are most commonly caused by a bacterial "Helicobacter pylori" infection.

As well as peptic ulcers, vomiting blood may result from abnormal arteries or veins that have ruptured, including Dieulafoy's lesion and Gastric antral vascular ectasia. Congenital disorders of the stomach include pernicious anaemia, in which a targeted immune response against parietal cells results in an inability to absorb vitamin B12. Other common symptoms that stomach disease might cause include indigestion or dyspepsia, vomiting, and in chronic disease, digestive problems leading to forms of malnutrition. In addition to routine tests, an endoscopy might be used to examine or take a biopsy from the stomach.

Botulinum A toxin is a valuable alternative for patients who do not want surgical methods.

The aetiology of NE is not fully understood, although there are three common causes: excessive urine volume, poor sleep arousal, and bladder contractions. Differentiation of cause is mainly based on patient history and fluid charts completed by the parent or carer to inform management options.

The following list summarizes bedwetting's known causes and risk factors. Enuretic patients frequently have more than one cause or risk factor from the items listed below.

Most cases of bedwetting are PNE-type, which has two related most common causes

- Neurological-developmental delay This is the most common cause of bedwetting. Most bedwetting children are simply delayed in developing the ability to stay dry and have no other developmental issues. Studies suggest that bedwetting may be due to a nervous system that is slow to process the feeling of a full bladder.

- Genetics Bedwetting has a strong genetic component. Children whose parents were not enuretic have only a 15% incidence of bedwetting. When one or both parents were bedwetters, the rates jump to 44% and 77% respectively. Genetic research shows that bedwetting is associated with the genes on chromosomes 13q and 12q (possibly 5 and 22 also).

These first two items are the most common factors in bedwetting, but current medical technology offers no easy testing for either cause. There is no test to prove that bedwetting is only a developmental delay, and genetic testing offers little or no benefit.

As a result, other conditions should be ruled out. The following causes are less common, but are easier to prove and more clearly treated:

- Alcohol consumption Drinking alcohol increases urine production, inhibits anti-diuretic hormone production, decreases awareness, increases drowsiness and causes impulsive decisions.

- Anti-diuretic hormone (ADH) Anti-diuretic hormone regulates urine production by increasing water reabsorption in the kidney. Both insufficient production of ADH, or insufficient response to ADH, leads to an overproduction of urine, often beyond the capacity of a child's bladder. The body normally increases ADH levels at night, signalling the kidneys to produce less urine. The diurnal change may not be seen until about age 10. In some bed wetting children this increase in ADH production does not occur, while other children may produce an increased amount of ADH but their response is insufficient.

- Attention deficit hyperactivity disorder (ADHD) Children with ADHD are 2.7 times more likely to have bedwetting issues.

- Caffeine Caffeine increases urine production.

- Constipation Chronic constipation can cause bed wetting. When the bowels are full, it can put pressure on the bladder. Often such children defecate normally, yet they retain a significant mass of material in the bowel which causes bed wetting.

- Infection/disease Infections and disease are more strongly connected with and with daytime wetting. Less than 5% of all bedwetting cases are caused by infection or disease, the most common of which is a urinary tract infection.

- More severe neurological-developmental issues Patients with intellectual disabilities have a higher rate of bedwetting problems. One study of seven-year-olds showed that "handicapped and intellectually disabled children" had a bedwetting rate almost three times higher than "non-handicapped children" (26.6% vs. 9.5%, respectively).

- Physical abnormalities Less than 10% of enuretics have urinary tract abnormalities, such as a smaller than normal bladder. Current data does support increased bladder tone in some enuretics, which functionally would decrease bladder capacity.

- Psychological Psychological issues (e.g., death in the family, sexual abuse, extreme bullying) are established as a cause of (a return to bedwetting), but are very rarely a cause of PNE-type bedwetting. Bedwetting can also be a symptom of a pediatric neuropsychological disorder called PANDAS. When enuresis is caused by a psychological or neuropsychological disorder, the bedwetting is considered a "symptom" of the disorder. Enuresis has a psychological diagnosis code (see previous section), but it is not considered a psychological condition itself. (See section on psychological/social impact, below)

- Sleep apnea Sleep apnea stemming from an upper airway obstruction has been associated with bedwetting. Snoring and enlarged tonsils or adenoids are a sign of potential sleep apnea problems.

- Sleepwalking Sleepwalking can lead to bedwetting. During sleepwalking, the sleepwalker may think he/she is in another room. When the sleepwalker urinates during a sleepwalking episode, he/she usually thinks they are in the bathroom, and therefore urinate where they think the toilet should be. Cases of this have included opening a closet and urinating in it; urinating on the sofa and simply urinating in the middle of the room.

- Stress Stress is not a cause of "primary" nocturnal enuresis (PNE), but is well established as a cause of returning to bedwetting (). Researchers studying children who have yet to stay dry find "no relationship to social background, life stresses, family constellation, or number of residencies." On the other hand, stress is a cause of people who return to wetting the bed. Researchers find that moving to a new town, parent conflict or divorce, arrival of a new baby, or loss of a loved one or pet can cause insecurity, contributing to returning bedwetting.

- Type 1 Diabetes Mellitus Nocturnal enuresis could be the presenting symptom of type 1 diabetes mellitus, classically associated with polyuria, polydipsia, and polyphagia; weight loss, lethargy, and diaper candidiasis may also be present in those with new-onset disease.

There are a number of factors that could potentially contribute to the development of feeding and eating disorders of infancy or early childhood. These factors include:

- Physiological – a chemical imbalance effecting the child's appetite could cause a feeding or eating disorder.

- Developmental – developmental abnormalities in oral-sensory, oral-motor, and swallowing can impact the child's eating ability and elicit a feeding or eating disorder.

- Environmental – simple issues such as inconsistent meal times can cause a feeding or eating disorder. Giving the child food that they are not developmentally acquired for can also cause these disorders. Family dysfunction and sociocultural issues could also play a role in feeding or eating disorders.

- Relational – when the child is not securely attached to the mother, it can cause feeding interactions to become disturbed or unnatural. Other factors, such as parental emotional unavailability and parental eating disorders, can cause feeding and eating disorders in their children.

- Psychological and behavioral – these factors include one involving the child's temperament. Characteristics such as being anxious, impulsive, distracted, or strong-willed personality types are ones that could affect the child's eating and cause a disorder. The individual could have learned to reject food due to a traumatic experience such as choking or being force fed.

Since feeding and eating disorders in children can cause dangerous risks to the child, it is important to seek treatment as soon as possible. Cognitive behavioral therapy can be incredibly beneficial to children with feeding or eating disorders. Family therapy is usually encouraged in order to keep all members involved in nourishing the child.