Omphalocele is a rare congenital birth defect where a baby’s abdominal organs develop outside the body, at the base of the umbilical cord. These organs, which can include the intestines, liver, or stomach, are contained within a thin, transparent sac.
Understanding Omphalocele
Omphalocele arises from an interruption in early fetal development. Normally, during the sixth to eleventh week of gestation, a baby’s intestines temporarily bulge into the umbilical cord, then retract into the abdominal cavity. An omphalocele forms when this natural process does not occur, leaving abdominal contents outside the body.
The organs that protrude, such as the bowel, liver, and sometimes the spleen or stomach, are enclosed within a protective sac composed of peritoneum and amniotic membrane. The size of the defect can vary significantly. A small omphalocele, often called a cord hernia, involves only a small portion of the intestine, typically less than 5 centimeters in diameter.
A large or “giant” omphalocele involves a more substantial protrusion, frequently including most of the liver and other abdominal organs, generally 5 centimeters or more. The abdominal cavity itself may also be smaller than usual because it did not fully expand to accommodate the developing organs internally.
Diagnosis and Associated Conditions
Omphalocele is most commonly detected before birth through prenatal ultrasound scans, typically around 20 weeks of pregnancy. While it can be seen as early as 12 to 14 weeks, a later scan often provides clearer details about the defect’s extent and organs involved. After birth, a physical examination confirms the diagnosis.
Omphalocele frequently occurs alongside other congenital anomalies, with more than half of affected infants having additional health concerns. These associated conditions can include heart defects and chromosomal abnormalities like Trisomy 13, Trisomy 18, and Trisomy 21 (Down syndrome).
Certain genetic syndromes, such as Beckwith-Wiedemann syndrome and Pentalogy of Cantrell, are also associated with omphalocele. Due to this frequent association, a comprehensive diagnostic process includes screening for these other conditions. This may involve fetal echocardiograms to assess the heart or amniocentesis to check for chromosomal or genetic anomalies. Identifying these co-occurring conditions is important for medical management and prognosis.
Treatment and Long-Term Outlook
Surgical repair is the primary treatment for omphalocele, with the approach determined by the defect’s size and the baby’s overall health. For smaller omphaloceles, a primary repair is performed soon after birth, gently placing organs back into the abdominal cavity and closing the opening. The sac covering the organs is typically removed.
Larger or “giant” omphaloceles often require a staged repair. This approach is used when the abdominal cavity is too small to accommodate all the organs immediately or if the baby’s condition requires a more gradual process. In a staged repair, a surgical pouch, often called a “silo,” is placed around the exposed organs and attached to the abdominal wall. Over several days or weeks, the silo is progressively tightened, gradually pushing the organs back into the abdomen. In some cases, a “paint and wait” technique is used for very large defects, allowing skin to grow over the sac before surgical closure is attempted later.
Babies with omphalocele require specialized neonatal care, particularly for respiratory support. The abdominal cavity’s smaller size can lead to underdeveloped lungs, potentially requiring ventilator assistance. Nutritional management is also important, often involving intravenous feeding (total parenteral nutrition) until the digestive system functions adequately. The long-term outlook for infants with omphalocele varies widely. Outcomes depend significantly on the size of the defect and the presence and severity of any associated birth anomalies. Infants with isolated omphalocele generally have a higher survival rate compared to those with multiple co-occurring conditions.
Omphalocele Versus Gastroschisis
Omphalocele is sometimes confused with gastroschisis, as both are abdominal wall defects where organs protrude. However, distinct differences exist. In omphalocele, the abdominal organs protrude through an opening at the base of the umbilical cord and are covered by a thin, transparent sac. This sac provides a protective barrier for the exposed organs.
Conversely, in gastroschisis, the abdominal organs protrude through an opening located next to the umbilical cord, typically to its right. A distinguishing feature of gastroschisis is the absence of a protective sac, meaning the organs are directly exposed to amniotic fluid during pregnancy. This exposure can lead to inflammation and damage to the intestines.
Omphalocele is more frequently linked with other birth defects, including chromosomal abnormalities and various syndromes. Gastroschisis, on the other hand, is usually an isolated defect, though it can still be associated with intestinal issues such as malrotation or atresia.