Omphalocele and gastroschisis are birth defects where the abdominal wall fails to close completely during fetal development, resulting in abdominal organs being located outside the body. While they share this trait, they are distinct conditions with different developmental origins, associated health issues, and management strategies.
Defining Characteristics
The primary differences between an omphalocele and gastroschisis are their location and the presence of a protective covering. An omphalocele is a defect at the base of the umbilical cord where the intestines, and sometimes other organs like the liver and spleen, protrude but are enclosed within a protective membranous sac.
Gastroschisis, on the other hand, presents as a hole in the abdominal wall, located to the right of an intact umbilical cord. Unlike an omphalocele, there is no protective sac. This means the intestines, and occasionally other organs, float freely in the amniotic fluid.
This direct exposure in gastroschisis can lead to inflammation and thickening of the intestinal walls, causing digestive complications after birth. In contrast, the sac in an omphalocele shields the organs, though the size of the defect itself can vary significantly from small to very large.
Associated Conditions and Risk Factors
The likelihood of other health problems differs between the two conditions. An omphalocele is frequently linked with other congenital issues, especially chromosomal abnormalities like Trisomy 13, Trisomy 18, and Down syndrome. Cardiac defects are also common, and an omphalocele can be a feature of genetic syndromes like Beckwith-Wiedemann syndrome.
Conversely, gastroschisis is less often associated with chromosomal or other major birth defects. Certain maternal risk factors are linked to the condition, including a maternal age under 20, smoking, and poor nutrition. The health concerns for infants with gastroschisis are related to the bowel itself, such as intestinal atresia, where a portion of the intestine has not developed properly.
Diagnosis and Initial Management
Both conditions are identified before birth during routine prenatal ultrasound screenings. An ultrasound reveals abdominal contents outside the body, the defect’s position relative to the umbilical cord, and the presence or absence of a covering sac. Maternal serum alpha-fetoprotein (MSAFP) levels are often elevated for both conditions but can be particularly high with gastroschisis.
After birth, the priority for an infant with gastroschisis is to protect the exposed intestines. The bowel is covered with sterile, moist dressings and placed into a protective sack or “silo.” This prevents heat and fluid loss and guards against infection and injury before surgery.
For a newborn with an omphalocele, the focus is keeping the protective sac intact and shielded from injury. The approach is less urgent than for gastroschisis. This allows time for a thorough evaluation for associated anomalies common with this condition.
Surgical Treatment and Prognosis
Surgical repair is the definitive treatment for both defects, though the timing and method can vary. The goal is to return the organs to the abdominal cavity and close the opening. For a small defect, a surgeon may perform a primary closure in a single operation shortly after birth, placing the organs back inside and suturing the muscle and skin closed.
For larger defects, a staged repair is more common. In this approach, a silicone pouch, or silo, is placed over the exposed organs. Over several days or weeks, the silo is gradually tightened, pushing the contents back into the cavity before a final surgery closes the abdominal wall.
The long-term outlook for infants with gastroschisis is favorable, with survival rates exceeding 90%. The prognosis depends on the health of the bowel, as some children may experience long-term feeding and digestion issues due to its exposure to amniotic fluid.
For an omphalocele, the prognosis is more variable, with a survival rate from 70% to 95%. The outcome depends almost entirely on the severity of associated cardiac and chromosomal abnormalities, which are the primary cause of mortality, not the abdominal defect itself.