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Key Points
Isolated abdominal wall defect to right of normally inserted umbilical cord.
Associated with young maternal age and maternal smoking.
Associated with growth restriction and abnormalities of amniotic fluid.
The efficacy of amnioexchange is under investigation.
Increased incidence of intrauterine fetal demise in the third trimester.
Intestinal atresia can complicate 10% to 15% of cases.
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Gastroschisis (Greek for belly cleft) is a full-thickness defect in the abdominal wall that occurs secondary to incomplete closure of the lateral folds during the 6th week of gestation (Moore and Stokes, 1953; Moore and Persaud, 1993). At birth, the eviscerated bowel characteristically has a thick edematous appearance described by Moore as a “peel” (Figure 63-1). The peel involves the serosa and is composed of fibrin and collagen. The peel in gastroschisis is thought to be caused by an inflammatory reaction as a result of exposure to amniotic fluid, combined with constriction at the abdominal wall defect (Amoury and Holder, 1977; Klein et al., 1983; Tibboel et al., 1986a, b; Amoury et al., 1988; Langer et al., 1990; Moore, 1992). Duhamel (1963) theorized that gastroschisis originates from a discrete teratogenic insult that results in an isolated defect in differentiation of the somatopleural mesenchyme. Others argue that gastroschisis is due to an in utero rupture of an umbilical cord hernia after completion of the infold in the anterior abdominal wall, but before complete closure of the umbilical ring (Shaw, 1975). In at least some cases, in utero rupture of a hernia of the cord that resulted in gastroschisis supports the argument for this being a cause (Glick et al., 1985). DeVries (1980) suggested that gastroschisis could be caused by a congenital weakness on the right side of the umbilical cord. From an umbilical cord hernia, premature atrophy or abnormal persistence of the right umbilical vein could predispose to disruption of the somatopleura at its junction with the body stalk. Because gastrointestinal defects such as atresia associated with gastroschisis are caused by vascular disruptions, Hoyme et al. (1983) suggested that gastroschisis may be caused by disruption of the right omphalomesenteric artery, which connects the yolk sac with the dorsal aorta. The fact that gastroschisis almost always occurs to the right of the umbilical ring is consistent with these latter theories (Torfs et al., 1990).
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As second trimester maternal serum-α-fetoprotein (MSAFP) screening has become incorporated into routine prenatal care, more cases of gastroschisis are being detected prenatally. This is due to the association between elevated MSAFP levels and ventral abdominal wall defects (McKeown et al., 1953; Brock et al., 1979; Redford et al., 1985; Stiller et al., 1990; Killam ...