Gastroschisis is a congenital birth defect where the abdominal wall fails to fully close early in pregnancy, resulting in the intestines being outside the body. Although the defect can appear alarming, modern medical and surgical interventions have made it a highly manageable condition. Most infants with Gastroschisis have a positive long-term prognosis.
The Nature of the Abdominal Wall Defect
Gastroschisis involves a defect in the abdominal wall, typically a small opening located next to the umbilical cord, usually to the right. Through this opening, the intestines protrude outside the infant’s body, sometimes accompanied by other organs like the stomach. This defect arises during early fetal development when the abdominal wall fails to fully form and close around the organs.
A defining characteristic of Gastroschisis is that the exposed organs are not covered by a protective membranous sac (peritoneum). This lack of covering means the fetal intestines float freely in the amniotic fluid within the womb. Prolonged exposure to the amniotic fluid irritates the bowel, causing it to become thickened, inflamed, and often leading to swelling and scarring.
Gastroschisis is distinct from Omphalocele, another abdominal wall defect. In Omphalocele, the abdominal contents protrude through the umbilical cord and are contained within a translucent protective sac. The absence of this sac is the most significant difference, and Gastroschisis is typically an isolated defect, rarely occurring with other birth defects.
Known Causes and Associated Risk Factors
The precise cause of Gastroschisis remains unknown, but current understanding points toward a combination of environmental and vascular factors rather than a purely genetic origin. One leading theory suggests the defect results from a disruption of the blood supply to the developing abdominal wall during the fourth to eighth week of gestation. This vascular incident may cause the tissue to weaken and fail to fuse correctly, creating the opening.
Another proposed mechanism is the failure of the abdominal wall to properly fold and close during embryonic development. The defect is thought to be an acquired disruption rather than a primary malformation, given its low association with other congenital anomalies. Research continues to investigate the interplay between genetic predisposition and external influences that may trigger this developmental failure.
Epidemiological studies have identified several risk factors, with the strongest association being young maternal age, particularly mothers under 20. The relative risk for mothers under 20 can be seven times higher compared to mothers aged 25 to 29. This correlation suggests that environmental factors, possibly related to the lifestyle or physiological state of younger mothers, play a role in the defect’s development.
Lifestyle factors during early pregnancy also increase the risk. Smoking cigarettes has been consistently linked to a higher incidence of Gastroschisis, sometimes showing a synergistic adverse effect when combined with low maternal body mass index (BMI). Other reported risk factors include:
- The use of alcohol.
- Specific over-the-counter medications.
- Genitourinary infections early in the pregnancy.
Diagnosis and Immediate Post-Birth Care
Gastroschisis is most often detected before birth, typically during a routine prenatal ultrasound in the second trimester (around 14 to 20 weeks gestation). The ultrasound clearly shows loops of the fetal intestine floating freely outside the abdominal cavity. Another diagnostic indicator is an elevated level of maternal serum alpha-fetoprotein (AFP), a protein that leaks from the exposed intestine into the mother’s bloodstream.
Once the diagnosis is confirmed, delivery planning involves a specialized team at a hospital with a Neonatal Intensive Care Unit (NICU). This preparation ensures experts are ready to stabilize the newborn immediately after birth. The mode of delivery (vaginal or Cesarean section) is determined by standard obstetrical indications, as the type of birth does not affect the outcome for the infant.
Upon delivery, the immediate focus is protecting the exposed bowel and managing fluid and heat loss, which can be substantial through the moist surfaces. The intestines are immediately covered with a sterile, protective material, often a plastic bag (silastic silo or bowel bag), to keep them moist and warm. Intravenous access is established quickly to administer necessary fluids and antibiotics to prevent dehydration and infection.
The newborn is typically positioned on their side, often the right side, to reduce tension on the blood vessels supplying the exposed intestine. A nasogastric tube is placed to continuously drain air and fluid, decompressing the stomach and bowel. During this stabilization phase, the infant is continuously monitored for temperature, fluid balance, and signs of infection before surgical intervention proceeds.
Surgical Repair and Recovery Expectations
The definitive treatment for Gastroschisis is surgical repair to return the abdominal contents to the body cavity and close the defect. Surgeons assess the condition of the bowel and the size of the infant’s abdominal cavity to determine the appropriate approach. The two primary methods are primary closure and staged repair.
Primary closure is performed if the abdominal cavity is large enough and the exposed bowel is not overly swollen. This allows the surgeon to gently place the organs back inside and close the defect in a single operation. This procedure is done soon after birth, often within the first day, to minimize exposure and potential damage. Preserving the umbilical cord insertion site is a priority for a more natural cosmetic appearance.
If the bowel is too swollen or the abdomen is too small to safely accommodate the organs without excessive pressure, a staged repair is utilized. In this method, a pre-formed silo (a flexible, plastic pouch) is placed over the exposed bowel and suspended above the infant. Gravity and gentle daily pressure slowly push the intestines back into the abdominal cavity over several days to a week or more.
After either type of closure, a significant recovery period in the NICU is required, often lasting several weeks to months. The intestines are often slow to begin functioning normally, a condition known as ileus. During this time, the baby receives all nutrition intravenously through a central line, known as total parenteral nutrition (TPN).
The long-term prognosis for children with Gastroschisis is generally very good, with survival rates exceeding 95 percent. However, some infants may face prolonged feeding difficulties and nutrient absorption issues due to intestinal damage. A small number may develop short bowel syndrome, requiring specialized care from a pediatric gastroenterologist to ensure proper growth and development.