Omphalocele

Definitions & Key takeaways

An omphalocele is an abdominal wall birth defect in which the intestines, liver, and occasionally other organs remain outside of the abdomen in a sac, as a result of a defect in the development of the muscles of the abdominal wall. The sac, which is formed from an outpouching of the peritoneum, protrudes in the midline through the umbilicus.

Omphalocele shouldn't be confused with another condition called gastroschisis, which also involves the herniation of abdominal contents out of the abdominal cavity. Unlike in omphalocele, herniated bowels in gastroschisis lack a peritoneal layer covering.

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Introduction0:00–0:23

With an omphalocele, omphalo- refers to the naval, also known as the bellybutton—or more formally the umbilicus—which is the attachment site of the umbilical cord, and -cele relates to hernia or swelling.
Omphalocele, therefore, is when some of the bowels herniate out into the umbilical cord. During the fourth week of fetal development, the embryo starts to change shape from a flat, three-layer disc to something more shaped like a cylinder, a process called embryonic folding.

Embryology0:23–1:16

In the horizontal plane, the two lateral folds eventually come together and close off at the midline, except for at the umbilicus, where the umbilical cord connects the fetus to the placenta.
This folding allows for the formation of the gut within the abdominal cavity. During around the sixth week of development, the liver and intestines grow really quickly, and because the abdominal cavity’s still pretty small, there’s limited space, which causes the midgut to herniate through the umbilical ring into the umbilical cord, and this happens normally.
At about week 10, though, the abdominal cavity typically has grown enough to allow the midgut to come back from the umbilical cord.

Pathology1:16–2:12

With omphalocele, the midgut—along with potentially other organs from the abdominal cavity—fail to return back to the abdominal cavity, and therefore stay in the umbilical cord all the way through fetal development and even after birth.
Now, since the intestines and potentially other organs aren’t meant to be in the umbilical cord, there can be complications like the abdominal cavity not growing to its normal size, as well as pinched blood vessels and loss of blood flow to an organ.
So with an omphalocele, after birth the abdominal organs protrude out of the body, but are contained within the umbilical cord, meaning the organs are sealed by a peritoneal layer.
In contrast, a related defect called gastroschisis involves the abdominal contents herniating out of the abdominal cavity as well, but it happens through a separate hole in the abdomen, so in this case the intestines are not covered by a peritoneal layer.

Causes and risk factors2:12–2:47

Although the cause of omphalocele is ultimately unknown, it’s likely a result of both genetic and environmental factors.
Some cases of omphalocele are due to underlying genetic disorders like Trisomy 13, Trisomy 18, Trisomy 21—also known as Down syndrome—and Beckwith-Wiedemann syndrome.
Also, certain factors have been found to increase the risk of a woman having a baby with omphalocele, like consumption of alcohol and tobacco during the pregnancy, use of certain medications like SSRIs, as well as obesity.

Diagnosis2:47–3:03

Diagnosis can be done before birth, or prenatally, through detailed fetal ultrasound, or lab tests, screening for increased maternal serum alpha-fetoprotein levels.
If not detected prenatally, omphaloceles are obvious right at birth. Treatment involves surgery following birth, in which the intestines and organs need to be placed back in the abdominal cavity and the defect repaired.

Treatment3:03–3:20

If the omphalocele’s large, then the organs might have to be slowly moved back into the abdominal cavity over a period of time.

Review3:20–3:52

Alright, as a quick recap, omphalocele is when the intestines, and potentially other organs, fail to return to the abdominal cavity from the umbilical cord, allowing them to protrude outside the belly but inside the umbilical cord.
In contrast to gastroschisis, the abdominal contents are covered by a layer of peritoneum. Thanks for watching, you can help support us by donating on patreon, or subscribing to our channel, or telling your friends about us on social media.