What causes an omphalocele?
We don't really know. Steps that normally happen in the development of the abdominal organs and muscles simply did not happen properly. It is not known to be caused by anything the mother did during pregnancy.
So how does it happen?
As a fetus is growing in the mother's uterus before birth, different organ systems are developing and maturing. Between the sixth and the tenth weeks of pregnancy, the intestines actually project into the umbilical cord as they are growing. By the eleventh week of development, the intestines should return to the abdomen.
An omphalocele occurs when the abdominal organs do not return to the abdominal cavity as they should.
Who is at risk for developing an omphalocele?
Many babies born with an omphalocele also have other abnormalities.
- Thirty percent have a genetic abnormality, most commonly Trisomy 13, Trisomy 18, Trisomy 21, Turner syndrome or triploidy.
- Some infants with omphalocele have a syndrome known as Beckwith-Wiedemann syndrome.
- More than half of babies with omphalocele have abnormalities of other organs or body parts, most commonly the spine, digestive system, heart, urinary system and limbs.
When an omphalocele is isolated (no other birth defects are present), the risk for it to happen in a future pregnancy is one percent or one in 100. There are some families that have been reported to have an omphalocele inherited as an autosomal dominant or X-linked recessive trait. In these cases, the chance for reoccurrence would be higher.
How often does an omphalocele occur?
- "Small" type omphalocele (involving protrusion of a small portion of the intestine only) - one out of every 5,000 babies
- "Large" type omphalocele (involving protrusion of the intestines, liver, and other organs) - one out of every 10,000 babies.
- More boys than girls are affected with omphalocele.
Why is an omphalocele a concern?
Since some or all of the abdominal organs are outside the body, infection is a concern, especially if the protective membrane around t gans breaks. Also, an organ may lose its blood supply if it becomes pinched or twisted. A loss of blood flow can damage the affected organ.