An omphalocele is a birth defect known as a ventral wall defect, which involves the abdominal (belly) area of the fetus. Omphalocele causes the abdominal organs to herniate (protrude) into the base of the umbilical cord. The diagnosis of omphalocele is usually made by ultrasound, in many cases following an elevated second trimester maternal serum alpha-fetoprotein test.
With omphalocele, the size of the herniation can vary from small (containing only a portion of the small intestine) to very large (containing most of the abdominal organs). A ”giant omphalocele"
is seen in approximately 1 in 10,000 births and occurs when the majority of the liver protrudes into the umbilical cord. Herniation of the fetal liver is frequently associated with a small abdominal size and pulmonary hypoplasia (small lungs), two factors that can complicate the postnatal (after delivery) course.
Fetuses with omphalocele are at an increased risk for other birth defects, such as cardiac or neural tube defects, intestinal malrotation and anomalies involving the urinary system. Those with small omphaloceles, which occur in 1 out of 5,000 births, are also at an increased risk for chromosome anomalies, such as trisomy 18. Therefore, amniocentesis or another means of fetal karyotyping is often recommended. In addition, omphalocele can be a part of several syndromes such as Beckwith-Wiedeman syndrome or Pentalogy of Cantrell. The prognosis largely depends upon the size of the herniation and the presence or absence of other birth defects.
Prognosis is based on proper evaluation conducted on families coming to the Center for Fetal Diagnosis and Treatment. Our comprehensive one-day evaluation includes a detailed level II ultrasound, a fetal echocardiogram (a specialized ultrasound of the fetal heart) and an ultrafast fetal MRI. Following the evaluation, a pediatric surgeon and an obstetrician will meet with the family to review and discuss the omphalocele prognosis, options and postnatal management.
Omphalocele treatment options:
Delivery at a tertiary center might be indicated so that a multidisciplinary team can immediately evaluate and stabilize the baby. With all cases of omphalocele treatment, the goal is to return the herniated abdominal organs back into the abdomen after the baby is delivered.
The size of the herniation determines the mode of delivery as well as the postnatal treatment of omphalocele, while the degree of liver involvement determines the level and type of omphalocele treatment. If the omphalocele is small and does not involve the liver, a vaginal delivery might be possible. After birth, the exposed organs are returned to the abdominal cavity and the herniation is closed via surgery. During and after surgery, the baby might be on a ventilator for several days to aid breathing.
A giant omphalocele usually requires a Cesarean delivery to avoid membrane rupture and liver trauma. The exposed organs are covered with a protective wrap, and the organs gradually return to the abdominal cavity with the aid of gravity. In some cases, a staged surgical repair might be required. Once the organs are returned to the abdomen, the omphalocele is closed surgically. During this time, the baby will also be on a ventilator. Surgery to close the abdominal wall defect may be postponed some six to 12 months to allow the abdominal cavity to enlarge as the baby grows. Possible complications during this time include respiratory compromise, infection and feeding intolerance.
Babies undergoing omphalocele treatment receive initial feedings intravenously while the bowels recover. Once bowel function returns, as evidenced by a successful bowel movement, feedings via a naso-gastric (NG) tube are slowly initiated while IV feeds continue. Pumping and freezing of breast milk is encouraged for NG feeds, if tolerated by the infant. Alternatively, a special alimental formula can also be given. NG feeds are gradually increased, as tolerated, and oral feedings are slowly introduced. As this is a gradual process, infants might experience occasional setbacks, including need for bowel rest or additional surgery.
When the infant can tolerate full feedings via oral and NG feeds and demonstrates adequate weight gain, he or she is ready to go home. Prior to discharge, teaching of special feeding techniques or other specialized care will be provided to parents by the nursing staff. The length of stay in the hospital varies from infant to infant, depending on the above outlined factors.