One of the main causes is suggested to be excessive and repetitive straining during defecation. Other causes include weakness of the pelvic floor muscles (secondary to age related neuropathic degeneration or traumatic injury during pregnancy and labor.

A 2008 study found that over 85% of women having a vaginal birth sustain some form of perineal trauma, and 60-70% receive stitches. A retrospective study of 8,603 vaginal deliveries in 1994 found a third degree tear had been clinically diagnosed in only 50 women (0.6%). However, when the same authors used anal endosonography in a consecutive group of 202 deliveries, there was evidence of third degree tears in 35% of first-time mothers and 44% of mothers with previous children. These numbers are confirmed by other researchers in 1999.

A study by the Agency for Healthcare Research and Quality (AHRQ) found that in 2011, first- and second-degree perineal tear was the most common complicating condition for vaginal deliveries in the U.S. among women covered by either private insurance or Medicaid.

Second-degree perineal laceration rates were higher for women covered by private insurance than for women covered by Medicaid.

Surgical treatments may be used to treat the condition, and include retro-rectal levatorplasty, post-anal repair, retro-anal levator plate myorrhaphy.

Several techniques are used to reduce the risk of tearing, but with little evidence for efficacy. Antenatal digital perineal massage is often advocated, and may reduce the risk of trauma only in nulliparous women. ‘Hands on’ techniques employed by midwives, in which the foetal head is guided through the vagina at a controlled rate have been widely advocated, but their efficacy is unclear. Waterbirth and labouring in water are popular for several reasons, and it has been suggested that by softening the perineum they might reduce the rate of tearing. However, this effect has never been clearly demonstrated.

One review stated that the most common causes of disruption to the defecation cycle are associated with pregnancy and childbirth, gynaecological descent or neurogenic disturbances of the brain-bowel axis. Patients with obstructed defecation appear to have impaired pelvic floor function.

Specific causes include:

- Anismus and pelvic floor dysfunction

- Rectocele

- "Rectal invagination" (likely refers to rectal intussusception)

- Internal anal sphincter hypertonia

- Anal stenosis

- Fecal impaction

- Rectal or anal cancer

- Descending perineum syndrome

Obstructed defecation has many causes, so the management in any individual case is specific to the cause of the symptom. For rectal internal intususception treatment is surgical, either STARR or rectopexy. For rectocele STARR or mesh implantation. For anismus/ pelvic floor dessynergia: biofeedback exercise.

Post-void dribbling or post-micturition dribbling is the where urine remaining in the urethra after voiding the bladder slowly leaks out after urination. A common and usually benign complaint, it may be a symptom of urethral diverticulum, prostatitis and other medical problems.

Men who experience dribbling, especially after prostate cancer surgery, will choose to wear incontinence pads to stay dry. Also known as guards for men, these incontinence pads conform to the male body. Some of the most popular male guards are from Tena, Depends, and Prevail. Simple ways to prevent dribbling include: strengthening pelvic muscles with Kegel exercises, changing position while urinating, or pressing on the perineum to evacuate the remaining urine from the urethra. Sitting down while urinating is also shown to alleviate complaints: a meta-analysis on the effects of voiding position in elderly males with benign prostate hyperplasia found an improvement of urologic parameters in this position, while in healthy males no such influence was found.

In dogs, perineal hernia usually is found on the right side. Most cases are in older intact (not neutered) male dogs (93 percent in one study). Breeds that may be at risk include Welsh Corgis, Boxers, Australian Kelpies, Boston Terriers, Collies, Dachshunds, Old English Sheepdogs, and Pekingese. Perineal hernias are rare in female dogs and uncommon in cats.

Dogs with benign prostatic hyperplasia have been found to have increased relaxin levels and suspected subsequent weakening of the pelvic diaphragm. In cats, perineal hernias are seen most commonly following perineal urethrostomy surgery or secondary to megacolon. Medical treatment consists of treatment of the underlying disease, enemas, and stool softeners. Because only about 20 percent of cases treated medically are free of symptoms, surgery is often necessary. Recurrence is common with or without surgery.

Several surgeries have been described for perineal hernias in dogs. The current standard involves transposition of the internal obturator muscle. This technique has a lower recurrence and complication rate than traditional hernia repair. A new technique uses porcine small intestinal submucosa as a biomaterial to help repair the defect. This is can also be done in combination with internal obturator muscle transposition, especially when that muscle is weak.

In humans, a major cause of perineal hernia is perineal surgery without adequate reconstruction. In some cases, particularly surgeries to remove the coccyx and distal sacrum, adequate reconstruction is very difficult to achieve. The posterior perineum is a preferred point of access for surgery in the pelvic cavity, particularly in the presacral space. Surgeries here include repair of rectal prolapse and anterior meningocele, radical perineal prostatectomy, removal of tumors including sacrococcygeal teratoma, and coccygectomy. Perineal hernia is a common complication of coccygectomy in adults, but not in infants and children (see coccygectomy).

The standard surgical technique for repair of perineal hernia uses a prosthetic mesh, but this technique has a high rate of failure due to insufficient anchoring. Promising new techniques to reduce the rate of failure include an orthopedic anchoring system, a gluteus maximus muscle flap, an acellular human dermis graft, and an acellular pig collagen graft.

Even with successful surgery, patients may have long-term problems with:

- incontinence, where serious usually treated with some form of continent urinary diversion such as the Mitrofanoff

- depression and psycho-social complications

- sexual dysfunction

Imperforate anus has an estimated incidence of 1 in 5000 births. It affects boys and girls with similar frequency. However, imperforate anus will present as the low version 90% of the time in females and 50% of the time in males.

Imperforate anus is an occasional complication of sacrococcygeal teratoma.

With a high lesion, many children have problems controlling bowel function and most also become constipated. With a low lesion, children generally have good bowel control, but they may still become constipated.

For children who have a poor outcome for continence and constipation from the initial surgery, further surgery to better establish the angle between the anus and the rectum may improve continence and, for those with a large rectum, surgery to remove that dilated segment may significantly improve the bowel control for the patient. An antegrade enema mechanism can be established by joining the appendix to the skin (Malone stoma); however, establishing more normal anatomy is the priority.

When an infant is born with PSH, the most difficult management decision has often been the sex assignment, since genitalia with this degree of ambiguity do not resemble either sex very well with respect to looks or function. Many infants with PPHS have been assigned and raised as female despite presence of testes and XY chromosomes.

Nearly all parents of infants with PPSH are offered surgical reconstruction, to either further masculinize or feminize the external genitalia.

Treatment with testosterone postnatally does not close the urethra or change the malformation, but in some cases may enlarge the penis slightly.

The main treatment for isolated epispadias is a comprehensive surgical repair of the genito-urinary area usually during the first 7 years of life, including reconstruction of the urethra, closure of the penile shaft and mobilisation of the corpora. The most popular and successful technique is known as the modified Cantwell-Ransley approach. In recent decades however increasing success has been achieved with the complete penile disassembly technique despite its association with greater and more serious risk of damage.

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.

The prognosis for non-ischemic cases of SBO is good with mortality rates of 3–5%, while prognosis for SBO with ischemia is fair with mortality rates as high as 30%.

Cases of SBO related to cancer are more complicated and require additional intervention to address the malignancy, recurrence, and metastasis, and thus are associated with poorer prognosis.

All cases of abdominal surgical intervention are associated with increased risk of future small-bowel obstructions. Statistics from U.S. healthcare report 18.1% re-admittance rate within 30 days for patients who undergo SBO surgery. More than 90% of patients also form adhesions after major abdominal surgery.

Common consequences of these adhesions include small-bowel obstruction, chronic abdominal pain, pelvic pain, and infertility.

It is considered a form of 5-alpha-reductase deficiency involving SRD5A2.

A 2014 meta-analysis of three small trials evaluating probiotics showed a slight improvement in management of chronic idiopathic constipation, but well-designed studies are necessary to know the true efficacy of probiotics in treating this condition.

Children with functional constipation often claim to lack the sensation of the urge to defecate, and may be conditioned to avoid doing so due to a previous painful experience. One retrospective study showed that these children did indeed have the urge to defecate using colonic manometry, and suggested behavioral modification as a treatment for functional constipation.

A malfunctioning bladder sphincter, leading to retrograde ejaculation, may be a result either of:

- Autonomic nervous system dysfunction. (Dysautonomia)

- Operation on the prostate. It is a common complication of transurethral resection of the prostate, a procedure in which prostate tissue is removed, slice by slice, through a resectoscope passed along the urethra.

It can also be caused by a retroperitoneal lymph node dissection for testicular cancer if nerve pathways to the bladder sphincter are damaged, with the resulting retrograde ejaculation being either temporary or permanent. Modern nerve-sparing techniques seek to reduce this risk; however, it may also occur as the result of Green Light Laser prostate surgery.

Surgery on the bladder neck accounted for about ten percent of the cases of retrograde ejaculation or anejaculation reported in a literature review.

Retrograde ejaculation is a common side effect of medications, such as tamsulosin, that are used to relax the muscles of the urinary tract, treating conditions such as benign prostatic hyperplasia. By relaxing the bladder sphincter muscle, the likelihood of retrograde ejaculation is increased.

The medications that mostly cause it are antidepressant and antipsychotic medication, as well as NRIs such as atomoxetine; patients experiencing this phenomenon tend to quit the medications.

Retrograde ejaculation can also be a complication of diabetes, especially in cases of diabetics with long term poor blood sugar control. This is due to neuropathy of the bladder sphincter. Post-pubertal males (aged 17 to 20 years) who experience repeated episodes of retrograde ejaculation are often diagnosed with urethral stricture disease shortly after the initial complaint arises. It is currently not known whether a congenital malformation of the bulbous urethra is responsible, or if pressure applied to the base of the penis or perineum immediately preceding ejaculatory inevitability may have inadvertently damaged the urethra. This damage is most often seen within 0.5 cm of the ejaculatory duct (usually distal to the duct).

Retrograde ejaculation can also result from pinching closed the urethral opening, to avoid creating a mess upon ejaculation (known as "Hughes' technique").

Retrograde ejaculation occurs when semen, which would, in most cases, be ejaculated via the urethra, is redirected to the urinary bladder. Normally, the sphincter of the bladder contracts before ejaculation forcing the semen to exit via the urethra, the path of least resistance. When the bladder sphincter does not function properly, retrograde ejaculation may occur. It can also be induced deliberately by a male as a primitive form of male birth control (known as "coitus saxonicus") or as part of certain alternative medicine practices.

Odynorgasmia, or painful ejaculation, is a physical syndrome described by pain or burning sensation of the urethra or perineum during or following ejaculation. Causes include infections associated with urethritis, prostatitis, epididymitis, as well as use of anti-depressants.

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.

Fetal and neonatal bowel obstructions are often caused by an intestinal atresia, where there is a narrowing or absence of a part of the intestine. These atresias are often discovered before birth via an ultrasound, and treated with using laparotomy after birth. If the area affected is small, then the surgeon may be able to remove the damaged portion and join the intestine back together. In instances where the narrowing is longer, or the area is damaged and cannot be used for a period of time, a temporary stoma may be placed.

Chronic idiopathic constipation is similar to constipation-predominant irritable bowel syndrome (IBS-C); however, people with CIC do not have other symptoms of IBS, such as abdominal pain. Diagnosing CIC can be difficult as other syndromes must be ruled out as there is no physiological cause for CIC. Doctors will typically look for other symptoms, such as blood in stool, weight loss, low blood count, or other symptoms.

To be considered functional constipation, symptoms must be present at least a fourth of the time.

Possible causes are:

- Anismus

- Descending perineum syndrome

- Other inability or unwillingness to control the external anal sphincter, which normally is under voluntary control

- A poor diet

- An unwillingness to defecate

- Nervous reactions, including prolonged and/or chronic stress and anxiety, that close the internal anal sphincter, a muscle that is not under voluntary control

- Deeper psychosomatic disorders which sometimes affect digestion and the absorption of water in the colon

There is also possibility of presentation with other comorbid symptoms such as headache, especially in children.

Saddle anesthesia is a loss of sensation (anesthesia) restricted to the area of the buttocks, perineum and inner surfaces of the thighs.

It is frequently associated with the spine-related injury cauda equina syndrome. It is also seen in conus medullaris, the difference is that it is symmetrical in conus medullaris and asymmetric in cauda equina.It may also occur as a temporary side-effect of a sacral extra-dural injection: