Meckel's diverticulum: the most common congenital bowel anomaly
Written and medically reviewed by Bahir Hadi, specialist in surgery, PhD
Published: 10 November 2026
Meckel's Diverticulum: The Most Common Congenital Anomaly of the Intestine
Meckel's diverticulum is a small pouch on the small intestine that most people who have it never discover. It is a remnant from fetal life when a channel between the intestine and the umbilical cord should have completely closed. When it doesn't close correctly, the pouch remains as a stump-shaped side branch on the lower part of the small intestine, typically 60-90 cm before the junction with the large intestine.
It is the most common congenital malformation of the gastrointestinal tract. Approximately 2 percent of the population has a Meckel's diverticulum, but only a small proportion experience symptoms. It is often remembered by the classic "rule of 2s": 2 percent of the population, 2 feet from the ileocecal valve, 2 inches long, 2 types of mucosa, 2:1 male predominance, and most often causes symptoms before 2 years of age.
What are the symptoms?
Most people experience no symptoms. When Meckel's diverticulum does cause symptoms, it is typically one of three conditions:
Bleeding: The most common symptomatic presentation in children. This is because about half of diverticula contain ectopic gastric mucosa, which produces acid. The acid erodes the adjacent intestinal wall, causing bleeding. Classically, this presents as painless reddish-blue or dark red stools (described as "currant jelly" or raspberry-red) in a young child. In adults, iron deficiency anaemia or acute intestinal bleeding of unknown origin may be observed.
Inflammation (diverticulitis): Resembles appendicitis with pain in the right side of the abdomen, nausea, vomiting, and fever. Many cases of "unexpectedly normal appendix" during surgery turn out to be Meckel's diverticulitis.
Obstruction: The diverticulum can twist or act as a leading point for an intussusception (telescoping of the bowel). This causes acute bowel obstruction with colicky pain, vomiting, and bloating. In children, it is a common cause of intussusception.
Rarer complications include perforation, fistulas to the umbilicus, and the development of a tumour in the diverticulum in adults (most often carcinoid).
Why does it happen?
During fetal life, a channel (the omphalomesenteric duct) connects the intestine to the yolk sac via the umbilical cord. Normally, it closes between the 5th and 7th week of gestation. If it remains partially or completely open, the result can be:
- Meckel's diverticulum (the most common)
- A fibrous band between the intestine and the umbilicus
- A cyst
- A completely open fistula to the umbilicus (rare)
Approximately half of diverticula contain a patch of "misplaced" mucosa, most often gastric mucosa, and less commonly pancreatic tissue. This ectopic mucosa is responsible for most bleeding episodes.
How is the diagnosis made?
The diagnosis is notoriously difficult.
- Meckel's scan (technetium-99m pertechnetate scan) is the most specific investigation in children. It binds to gastric mucosa and thus lights up both in the stomach and in a Meckel's diverticulum if it contains ectopic mucosa. Sensitivity is high in children but lower in adults.
- CT scans and MR enterography can show inflammation or obstruction in acute presentations.
- Capsule endoscopy and balloon enteroscopy are used in adults with unexplained small bowel bleeding.
- Diagnostic laparoscopy often proves decisive, both for acute abdominal pain and for persistent unexplained bleeding.
In adults, the diagnosis is often only made during surgery for acute abdominal conditions.
Treatment
Symptomatic Meckel's diverticulum should be removed. The procedure can be performed laparoscopically or openly and consists of either a simple diverticulectomy or a short bowel resection depending on the circumstances. The results are good with a low complication rate.
Incidental finding in adults: There is not full consensus here. Most guidelines recommend removal only with specific risk factors:
- Age under 50 years
- Male gender
- Diverticulum longer than 2 cm
- Narrow neck of the diverticulum
- Palpable thickening suggesting ectopic mucosa
Without these features, it is reasonable to leave an incidentally discovered diverticulum alone.
In children with an incidental finding, many paediatric surgeons choose to remove the diverticulum because the remaining lifetime risk of complications is higher than in adults. There is no full consensus, however, and the decision depends on the child's condition and the operation already being performed.
After surgery, the prognosis is excellent. Recurrence of symptoms is usually due to another cause.
When should you seek medical attention?
Call 112 for heavy continuing bleeding, fainting, cold clammy skin or reduced consciousness.
Contact the acute medical helpline (1813 in the Capital Region of Denmark, otherwise your local out-of-hours doctor) straight away and ask for urgent hospital assessment for:
- Painless rectal bleeding in a child
- Dark or black stools without another known cause
- Acute severe abdominal pain on the right side, especially with fever and vomiting
- Signs of bowel obstruction: severe vomiting, bloated abdomen, absence of stool and flatus
Contact your GP for unexplained iron deficiency anaemia in adults after normal colonoscopy and gastroscopy.
Frequently Asked Questions
Is it dangerous to have a Meckel's diverticulum? For most people, no. Only a small percentage experience symptoms, and surgery is effective.
What is the lifetime risk of complications? In asymptomatic adults, the lifetime risk of developing symptoms is approximately 4-6 percent, and it decreases with age. Therefore, we do not recommend prophylactic removal in all cases.
Can Meckel's diverticulum be seen on a standard colonoscopy? No. It is located on the small intestine and cannot be reached with a colonoscope. Capsule endoscopy or balloon enteroscopy are options.
Is it hereditary? No. It is a random developmental error with no familial clustering.
Can one get Meckel's diverticulitis after having the appendix removed? Yes. Even after appendectomy, Meckel's diverticulitis can cause the same type of symptoms as appendicitis.
About the figures on this page: incidence, complication, recurrence and survival figures for rare diseases come from international series at specialist centres with relatively few patients, often across different time periods and using different definitions. The figures therefore vary between series and cannot be transferred directly to the individual patient.
Sources
- Sagar J, Kumar V, Shah DK. Meckel's diverticulum: a systematic review. J R Soc Med. 2006;99(10):501-505. PubMed
- Lindeman RJ, Søreide K. The many faces of Meckel's diverticulum: update on management in incidental and symptomatic patients. Curr Gastroenterol Rep. 2020;22(1):3.
- Sundhed.dk. Meckels divertikel (lægehåndbogen).
- Park JJ, Wolff BG, Tollefson MK, et al. Meckel diverticulum: the Mayo Clinic experience with 1476 patients (1950-2002). Ann Surg. 2005;241(3):529-533. PubMed
This article provides general information and does not replace a medical consultation. Contact your GP if you experience symptoms.