Omphalocele

What is Omphalocele?

Omphalocele occurs in approximately 1 in 5000 live births. It is a rare defect of the anterior abdominal wall whereby the bowel, liver and abdominal organs are found outside of the abdomen, contained in a sac. Omphaloceles are different from gastroschisis; the herniated organs are covered by the omphalocele sac, except ruptured omphaloceles. Omphaloceles tend to occur with mothers of older age, as opposed to gastroschisis. Recurrence rate is <1% unless due to chromosomal cause.

The diagnosis can be made prenatally by ultrasound in most cases, usually in the second trimester during the anatomical survey. The amount and type of abdominal organs within the umbilical sac can be determined as well as possible rupture of the sac. Lung size can also be estimated. Serial ultrasounds will be done, especially in the third trimester to monitor the fetus closely. Serum alpha-fetoprotein (AFP) may also be an initial screening tool, as it is found to be elevated in abdominal wall defects.

Delivery of fetuses with omphalocele can be a vaginal delivery or Cesarean Section based on fetal and maternal indications. Unless there are obstetrical indications, we can await for spontaneous labor. If the liver is involved in the herniation, then delivery by Cesarean section may protect the omphalocele and avoid rupture and bleeding.

What causes Omphalocele?

Most omphaloceles are sporadic. A failure of the lateral abdominal walls infolding can cause an abnormal abdominal cavity and thus a larger omphalocele. Only a thin clear membrane, the omphalocele sac, surrounds these protruding abdominal organs. Smaller omphaloceles are due to the failure of the umbilical ring to close around the umbilical cord. This category is often associated with chromosomal abnormalities or genetic syndromes.

What is the prognosis (outcomes) for a fetus with Omphalocele?

Overall survival is 79%: the size of the omphalocele will determine greatly the outcomes for the baby after birth. Babies without associated defects generally do the best. However, those with associated anomalies (50%), such as brain, spine, heart, intestinal or renal defects, will have a poorer prognosis.  Chromosomal abnormalities and genetic syndromes also carry different outcomes for the baby. If the liver is herniated, the abdomen and lungs are usually smaller, thus affecting surgical treatment and post-natal complications. Pulmonary hypoplasia (underdevelopment of the lungs) not only can cause respiratory difficulties for the newborn, but also affects function of the heart, feeding ability and overall  growth and development.

What other tests should we consider?

  • An amniocentesis to assess for chromosomal abnormalities (50-70%) or genetic syndromes
  • A detailed ultrasound to detect other associated anomalies in the fetus (50-70%)
  • Fetal MRI to confirm ultrasound findings and evaluate for other anatomic abnormalities
  • Fetal echocardiogram to assess for cardiac anomalies

What therapy is available?

At birth, the omphalocele is wrapped with a sterile dressing. Stabilization of the baby is a priority, especially respiratory support and initial resuscitation if necessary.

Surgery can be offered after birth as a primary repair (one surgery) or staged repair (multiple surgeries). This repair of the omphalocele is done in multiple steps whereby the abdominal organs are slowly replaced back in the abdomen with the aid of a mesh before closing the defect surgically once all organs have been replaced into the abdomen. However it may also be delayed for several months depending on the overall health of the baby such as the respiratory status and growth, size of the herniation and degree of liver herniation.

A multidisciplinary team from Mount Sinai Hospital and Hospital for Sick Children will be involved in the care of your baby:

  • Pediatric surgeon
  • Maternal Fetal Medicine Specialist
  • Genetics
  • Neonatologist
  • Nursing

Where can I get more information?

The Fetal Care Center
http://www.fetalcare.org/omphalocele

UCSF Benioff Children’s Hospital
http://www.ucsfbenioffchildrens.org/conditions/omphalocele/

Children’s Hospital of Philadelphia
http://www.chop.edu/service/fetal-diagnosis-and-treatment/fetal-diagnoses/omphalocele.html

Special Pregnancy Program

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Fetal Medicine: 416-586-4800 x 7756
Fax: 416-586-3216

Maternal Medicine: 416-586-4800 x 7000
Fax: 416-586-5109

Main clinic hours: Monday to Friday, 8am to 4pm

Prenatal Diagnosis & Medical Genetics

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phone: 416-586-4800 x 4523
fax numbers:
416-586-4723 or 416-586-8384

Perinatal Mental Health

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Phone: 416-586-4800 x 8325
Fax: 416-586-8596