INTRODUCTION — Gastroschisis is a full-thickness paraumbilical abdominal wall defect usually associated with evisceration of bowel (picture 1) and sometimes other abdominal organs.
This topic will discuss issues related to prenatal diagnosis and management of pregnancies with fetal gastroschisis. The other major fetal abdominal wall defect, omphalocele, occurs at the umbilicus and is reviewed separately. (See "Omphalocele: Prenatal diagnosis and pregnancy management".)
CLINICAL SIGNIFICANCE — Bowel herniation may lead to a variety of intestinal abnormalities because the mesenteric blood supply can become compromised and because the bowel wall can become inflamed from prolonged exposure to amniotic fluid (see 'Associated anomalies and findings' below). In addition to intestinal abnormalities, other common potential sequelae of gastroschisis include growth restriction (30 to 60 percent of cases), spontaneous preterm birth (30 to 50 percent), and fetal demise (3 to 6 percent) [1-8].
The mechanisms causing these adverse outcomes are unclear. Growth deficiency may be due to undernutrition from loss of protein and fluid across the exposed bowel [9]; however, abnormal Doppler measurements, which are indicative of placental insufficiency, have been observed in a minority of cases [10,11]. The increased risk of fetal demise may be related to placental insufficiency, cord compression, undernutrition, other undefined factors, or a combination of factors.
After birth, the newborn requires special care because of the exposed bowel. The defect must be closed, which can be difficult if it is large and other abdominal organs are also herniated; however, the prognosis is generally very good. (See 'Neonate' below.)
PATHOGENESIS — Several hypotheses have been proposed to explain the pathogenesis of gastroschisis; all involve defective formation or disruption of the body wall in the embryonic period, with subsequent herniation of bowel [12]. Major hypotheses include:
●Failure of mesoderm to form in the body wall
●Rupture of the amnion around the umbilical ring
●Abnormal involution of the right umbilical vein leading to weakening of the body wall
●Disruption of the right vitelline artery with subsequent body wall damage
Gene polymorphisms that interact with environmental factors, such as smoking, may play a role in pathogenesis [13]. The maternal immune response to new fetal antigens of paternal origin may also play a role [14]. There is no high-quality evidence that any drug causes gastroschisis, but a possible association has been reported for aspirin [15], ibuprofen [16], and vasoconstrictive agents (eg, pseudoephedrine) [17]. Use of acetaminophen in the first trimester has been reported both to lower the risk of gastroschisis [18] and to increase the risk [19].
The prevalence of gastroschisis appears to be higher in areas where agricultural chemical levels in surface water are high and when conception occurs in the spring, the time when agricultural chemicals (eg, atrazine) are commonly applied [20-26]. The possible role of these chemicals in the pathogenesis of gastroschisis requires further study as an association with adverse birth outcomes has not been reported consistently [27,28].
Gastroschisis has not been associated with maternal deficiency of any micronutrient or macronutrient [29].
PREVALENCE AND EPIDEMIOLOGY — Gastroschisis and omphalocele are the most common fetal abdominal wall defects: the prevalence of each is approximately 3 to 4 per 10,000 live births plus fetal deaths/stillbirths/pregnancy terminations [1,30,31], although one contemporary study reported slightly lower rates for omphalocele (2 per 10,000 live births) [31]. The incidence of gastroschisis is similar in male and female fetuses [32-34], higher in singleton than in twin gestations [35], and higher in offspring of non-Hispanic White mothers than non-Hispanic Black mothers [36].
Studies worldwide have consistently reported that young pregnant people (ie, under 20 years of age) have a severalfold higher rate of offspring with gastroschisis than the general obstetric population [1,37-40]. This is likely related to lifestyle factors that are more common in young people (eg, cigarette smoking, use of recreational drugs, alcohol consumption, low body mass index, increased frequency of genitourinary infection) [16,37,41-46].
Both resource-rich and resource-limited countries reported an increasing prevalence of gastroschisis until the past decade [33,47-49], when prevalence started to fall [50]. In the United States, from 1997 to 2008, the prevalence of gastroschisis increased from 2.9 to 6.4 per 1000 infants and then by 2018 decreased to 3.3 per 1000 infants [50]. Mothers <20 years old had the highest rate of gastroschisis and the largest recent decrease in prevalence (from 20.8 to 13.1 per 1000 infants from 2008 to 2018).
MATERNAL LABORATORY MARKERS — An increased possibility of gastroschisis, as well as other fetal anomalies, should be considered in pregnancies with an elevated maternal serum alpha-fetoprotein (MSAFP) level as almost all cases of gastroschisis are associated with this finding [51-53]. In three series of gastroschisis cases, the median MSAFP level ranged from 4.4 to 9.4 multiples of the median (MoMs) [52-54]. By comparison, the MSAFP in pregnancies with open spina bifida and anencephaly are, on average, 4 and 8 MoMs, respectively [55].
An elevated MSAFP is an indication for thorough ultrasonographic examination of the fetus for anatomic abnormalities. (See "Neural tube defects: Overview of prenatal screening, evaluation, and pregnancy management", section on 'Alpha-fetoprotein'.)
PRENATAL DIAGNOSIS — Most cases can be detected by the end of the first trimester (11 to 14 weeks) and certainly in the second trimester. Prenatal detection rates are over 90 percent [55] as a result of routine second-trimester ultrasound screening for fetal anomalies, maternal serum alpha-fetoprotein (MSAFP) assessment performed in some screening protocols for open neural tube defects, and MSAFP assessment performed as part of second-trimester Down syndrome screening panels (eg, integrated test, quadruple test) [56].
Ultrasound findings — On ultrasound examination, gastroschisis appears as a relatively small (typically 2 to 5 cm) paraumbilical abdominal wall defect, usually to the right of the midline, with visceral herniation. The umbilical cord insertion site is adjacent to and separate from the defect and should be normal. Usually, the intestine is the only herniated organ, but the liver and stomach may also herniate; other intra-abdominal organs rarely pass through the defect. The stomach is usually malpositioned, even when intra-abdominal. The intestinal mass lacks a covering membrane and floats freely in the amniotic fluid. Sonographic findings of gastroschisis are illustrated by the following diagnostic images: gray-scale (image 1A-B), color Doppler (image 2), three-dimensional ultrasound (image 3).
The exteriorized bowel appears cauliflower-like because fluid between adjacent bowel loops results in acoustic interfaces at both near and far bowel walls. Visualization of the bowel is enhanced by the highly echogenic bowel wall edema and inflammation that may occur in addition to the dilated lumen created by multiple volvuli in the free-floating loops. Late in pregnancy, the eviscerated bowel often appears thickened, matted, and mildly dilated due to chronic exposure to amniotic fluid. The stomach and intra-abdominal loops of bowel also may become dilated due to obstruction [57].
Role of magnetic resonance imaging — Whether magnetic resonance imaging (MRI) provides additional benefit in the prenatal evaluation and management of gastroschisis is an ongoing area of investigation. The benefit of routine MRI after ultrasound is unproven, but selective use may be informative for counseling in complicated cases when ultrasound imaging is limited by severe maternal obesity or oligohydramnios.
In a study that used MRI to calculate the volume ratio between eventrated organ volume and intraabdominal volume (E/I ratio) to predict surgical treatment in 22 cases of gastroschisis at 19 to 34 weeks, an E/I ratio of ≥0.27 correctly predicted silo bag treatment in about 90 percent of cases and E/I ratio of <0.27 correctly predicted primary closure in about 67 percent of cases [58]. Prenatal management was not altered based on the MRI, but the information helped in prenatal counseling regarding the likely need for postnatal silo bag treatment versus primary closure. Another study also concluded that prenatal MRI did not alter pregnancy management; however, MRI allowed for more precise counseling on additional complications related to the fetal bowel and the likelihood of postnatal intestinal complications in fetuses with intraabdominal bowel dilatation [59]. Given these findings, we recommend not routinely performing fetal MRI in cases of gastroschisis, particularly in fetuses with well-defined anatomy by ultrasound, except in the context of research studies.
Associated anomalies and findings — Once gastroschisis is identified on prenatal ultrasound, the first priority is determining whether it is isolated (related anomalies of the intestinal tract may be present) or nonisolated (associated with unrelated structural anomalies in other organ systems, which may occur when the etiology is an underlying syndrome or other genetic abnormality).
Related gastrointestinal anomalies and problems (eg, malrotation, atresia, stenosis, perforation, necrosis, volvulus) occur in up to 25 percent of cases [60-62] and may be due to vascular disruption caused by herniated bowel. Disruption of the superior mesenteric artery, for example, may lead to volvulus or to "apple peel" jejunal-ileal lesions. Meckel's diverticulum and gallbladder atresia also occur but are less common. Bladder herniation has been reported in 6 percent of cases (image 4) and may cause bowel or urinary tract dilation. A rare type of complex gastroschisis has been termed "closed," "closing," or "vanishing" gastroschisis [63-67]. In these cases, the defect closes around the viscera, which can cause intestinal atresia and ischemia or midgut infarction resulting in short bowel syndrome.
Most cases have no extraintestinal abnormalities.
●In a study of pooled data from 24 international congenital anomaly registries including over 3300 cases of gastroschisis, approximately 85 percent were isolated, defined in the study as gastroschisis alone or associated with only one or more of the following anomalies: any intestinal defect, any deformation (eg, clubfoot and hip dysplasia, except arthrogryposis), any minor or mild defect (eg, patent ductus arteriosus, patent foramen ovale, unspecified atrial septal defect, hydronephrosis, or enlarged pelvis) [49]. The other 15 percent of gastroschisis cases were associated with a chromosomal syndrome (mostly trisomy 18, 13, or 21, or sex chromosome aneuploidy), other syndrome, or multiple congenital anomalies (one or more major defects unrelated to gastroschisis).
●A study using a prospectively collected database including nearly 4700 infants with gastroschisis discharged from 348 neonatal intensive care units in North America reported associated anomalies in 8 percent and cardiac anomalies in 1 percent [2].
●Others have reported associated anomalies in as many as one-third of cases [68].
The discordancy among these studies may be due to ascertainment bias [3,49,60,69,70].
Oligohydramnios is the most common amniotic fluid abnormality, but polyhydramnios may occur, particularly in fetuses with reduced bowel motility or obstruction.
Differential diagnosis — Omphalocele is the major disorder to consider in differential diagnosis. The membranous sac helps to distinguish omphalocele from gastroschisis; however, membranes occasionally rupture in utero, in which case, other features (liver location, cord vessels, cord insertion site) need to be evaluated to make the correct diagnosis [2,68,71].
●Omphalocele is often associated with an extracorporeal liver, while the liver is typically intracorporeal in gastroschisis.
●The cord insertion site is into the umbilical sac in omphalocele and paraumbilical onto an otherwise intact abdominal wall in gastroschisis.
●If the omphalocele sac ruptures, the cord vessels traverse the amniotic remnant and enter the abdomen in the suprapubic region.
●Omphalocele is associated with a higher rate of associated defects than gastroschisis (80 versus 32 percent in one large study [68] and 35 versus 8 percent in another large study [2]).
Other major abdominal wall defects in differential diagnosis (ectopia cordis, limb-body wall complex, cloacal exstrophy, and urachal cyst) are rare (prevalence of each is less than 1 in 100,000 births). Omphalocele and body-stalk defects are connected to the cord, ectopia cordis develops above and bladder exstrophy below the cord insertion, and gastroschisis is paraumbilical (table 1).
COUNSELING — Patients are informed about the causes of gastroschisis and the prenatal and postnatal implications of the anomaly and any other anomalies that have been identified on ultrasound. Issues regarding pregnancy and pediatric care are also reviewed. This information can help them make the decision to continue or terminate the pregnancy, prepare for the birth of an affected child, and consider transfer to a center with prenatal, delivery, and/or neonatal care commensurate with maternal and/or neonatal needs, if appropriate. In addition to their obstetric provider, consultation with a multidisciplinary team, including a maternal-fetal medicine specialist, pediatric surgeon, and neonatologist is useful. (See 'Pregnancy management' below and 'Neonate' below.)
Parents should be counseled that after birth, other anomalies involving or outside of the intestinal tract may be detected. Postnatally, pediatric surgeons categorize gastroschisis as "simple" or "complex" based on the absence or presence of related intestinal abnormalities, but this distinction is often not possible to discern prenatally. (See 'Prognosis' below.)
PREGNANCY MANAGEMENT
Fetal genetic studies — The purpose of fetal genetic testing is to obtain information that has prognostic significance and thus can impact parental decision-making with respect to continuing the pregnancy, pregnancy/delivery management, and management of the newborn. The prevalence of chromosomal abnormalities in fetuses with isolated gastroschisis is not increased above that in the baseline population; therefore, this anatomic finding alone is not a strong indication to pursue invasive diagnostic fetal genetic testing (assuming ruptured omphalocele sac has been excluded) [72], but many patients will opt for noninvasive genetic screening (eg, cell-free DNA) if not already performed as part of Down syndrome screening.
Because the risk of a chromosomal abnormality is higher when extraintestinal structural abnormalities are identified on ultrasound, we suggest genetic amniocentesis in these cases [49]. Microarray molecular testing rather than G-banding has been recommended whenever fetal structural anomalies are detected on prenatal ultrasound examination [73], but the additional value in cases of gastroschisis has not been studied extensively [74]. (See "Prenatal genetic evaluation of the fetus with anomalies or soft markers".)
Fetal monitoring — There is little consensus regarding the best approach to monitoring the fetus in these pregnancies due to a lack of high-quality evidence to guide clinical practice [34,75].
Assessment of fetal growth and amniotic fluid volume — Assessment of fetal growth is typically performed starting at 24 weeks and repeated every 3 to 4 weeks [75]. Growth restriction in fetuses with abdominal wall defects is predictive of an increased risk of adverse neonatal outcome in some studies [4,10] and may be associated with an increased risk of fetal demise [6,76]. (See 'Antepartum fetal surveillance' below.)
Amniotic fluid volume (AFV) abnormalities frequently occur. Oligohydramnios may be related to fetal growth restriction and is a risk factor for cord compression and its sequelae. Polyhydramnios is less common but an important finding because it is often caused by bowel atresia and it is predictive of severe bowel complications in the neonatal period [77]. (See "Oligohydramnios: Etiology, diagnosis, and management in singleton gestations" and "Polyhydramnios: Etiology, diagnosis, and management in singleton gestations".)
We use a standard formula for estimating fetal weight, which was validated in one large study [78]. Because the most commonly used formulas for estimating fetal weight, such as the Hadlock formula, rely heavily on the measurement of abdominal circumference, formulas involving abdominal circumference tend to underestimate the weight of these fetuses [79]. Siemer and colleagues developed a specific formula for estimating fetal weight in fetuses with abdominal wall defects using the biparietal diameter, occipitofrontal diameter, and femur length measurements [80]. This formula appears to estimate fetal weight in these fetuses more accurately than formulas using abdominal circumference and is used by some clinicians [80-82].
Assessment of fetal bowel — We perform serial targeted sonographic evaluations of the stomach and bowel (both intra- and extra-abdominal) to look for substantial dilation (generally >25 mm) or acute changes, such as thickening and edema, at the time of fetal growth scans, which we obtain every 3 to 4 weeks starting after the anatomic survey. Some others advocate for bowel assessment every 2 weeks after 32 weeks of gestation. If we observe these bowel changes before 34 weeks, we administer a course of antenatal corticosteroids to enhance fetal maturation in the event that preterm delivery becomes indicated, but we do not deliver solely on the basis of bowel wall thickening or dilation.
Gastric dilation, bowel dilation, and bowel wall thickening have been considered poor prognostic signs by several investigators [83-88], but others have not found the presence of these findings sufficiently predictive to influence clinical management [4,89-98]. For this reason, approximately 50 percent of maternal-fetal medicine specialists do not measure bowel wall thickness at all, and the remainder measure it weekly to monthly [75]. A 2009 systematic review including data from 10 observational studies (273 patients) concluded that there was no strong evidence that fetuses with isolated gastroschisis and antenatal bowel dilation greater than 10 mm or greater than 18 mm were at increased risk of intrauterine death, postnatal bowel resection, length of time to oral feeds, or length of time hospitalized [99]. However, the small number of adverse events in these studies precluded making a definite conclusion about the significance of prenatal bowel dilation in fetuses with gastroschisis.
For fetuses with substantial bowel dilation, we begin weekly antepartum fetal surveillance promptly rather than waiting until 32 weeks, which is our routine for otherwise uncomplicated gastroschisis (see 'Antepartum fetal surveillance' below). There is evidence that extra-abdominal small bowel dilation >25 mm is associated with short-term prenatal complications, including nonreassuring fetal testing and fetal death [87]. In one small series, the three fetuses with external bowel diameters of 27 to 28 mm had these adverse outcomes, while 11 fetuses with diameters of 5 to 24.5 mm did not [87]. Adverse prenatal sequelae may be related to umbilical cord compression by the dilated bowel or severe uteroplacental insufficiency. Other series have observed that intra-abdominal dilation was predictive of bowel obstruction [100-102] and associated with increased neonatal morbidity when multiple, but not single, loops of bowel were dilated [88]. But data are far from definitive; the threshold for dilation predictive of adverse outcome varies among studies, and some studies have not observed adverse effects from either intra-abdominal or extra-abdominal bowel dilation [103,104].
Antepartum fetal surveillance — The precise timing, choice of test, and frequency of testing is arbitrary. A survey of maternal-fetal medicine specialists reported that 68 percent began antenatal testing at 32 weeks, another 12 percent began at 28 weeks, and 8 percent began at 34 weeks [75]. Nonstress tests (NSTs) with/without amniotic fluid indexes or biophysical profile scores (BPPs) were generally performed weekly.
●Uncomplicated cases – In the absence of growth restriction, oligohydramnios, or other complications warranting close fetal surveillance (eg, substantial bowel dilation, preeclampsia), we suggest weekly NST and/or a BPP beginning at 32 weeks of gestation for all fetuses with gastroschisis. This is because these pregnancies may be associated with an increased risk for fetal demise late in the third trimester (pooled prevalence 4.48 per 100 gastroschisis pregnancies overall, 95% CI 3.48-5.76 [6]) [6,76,105]. Fetal surveillance is increased to twice weekly after 36 weeks. Although fetal heart rate (FHR) abnormalities are common in these pregnancies, the value of antepartum fetal surveillance is supported by only low-quality data [106-110].
●Gastroschisis with substantial bowel dilation – If substantial bowel dilation is detected, we begin weekly antepartum fetal testing upon diagnosis rather than waiting until 32 weeks, as discussed above. (See 'Assessment of fetal bowel' above.)
●Gastroschisis with growth restriction – If growth restriction diagnosed, fetal monitoring and timing of delivery is the same as that for nonanomalous fetuses with growth restriction attributed to placental insufficiency. (See "Fetal growth restriction: Pregnancy management and outcome".)
In utero intervention — Various in utero interventions have shown promising results in animal studies, but none have demonstrated a benefit in investigational studies in humans [111].
Delivery — Ideally, delivery should occur in a facility with appropriate resources for caring for these neonates as the body of evidence suggests inborn newborns have better outcomes than those who require transfer after birth for treatment [112]. Coordinating delivery at a tertiary care center provides optimal conditions for the neonate [113].
Timing — The decision on timing of delivery is based on a combination of factors, including gestational age (probability of fetal lung maturity), ultrasound findings (fetal growth profile, AFV, appearance of fetal bowel), and fetal testing results (NST, BPP, umbilical cord Doppler if fetal growth restriction is present). We suggest consultation with a maternal-fetal medicine specialist, neonatologist, and pediatric surgeon before delivery to discuss patient-specific factors in the timing of delivery. We do not consider bowel dilation alone an indication for preterm birth if fetal growth, AFV, and fetal testing (BPP, NST) remain reassuring. In the authors' practices, delivery of fetuses with gastroschisis, normal growth, normal AFV, and reassuring fetal testing is scheduled for 38+0 weeks of gestation. Delivery before 38+0 weeks is performed for standard obstetric indications. It should be noted that the mean gestational age at spontaneous labor in pregnancies complicated by gastroschisis is in the 36th week of gestation [7,114,115]. This should be considered if patients are planning to relocate to deliver at a facility capable of performing postnatal surgical repair.
We believe available data support this approach, which avoids the morbidity of preterm birth, minimizes the risk of gastroschisis related neonatal morbidity (eg, sepsis, bowel damage [necrosis, atresia, perforation, adhesion]), and eliminates any possibility of stillbirth at term (39 to 40 weeks) [110,116,117]. One contributor to this topic (LWH) does not intervene until the 39th week of gestation in the absence of growth restriction if twice-weekly fetal surveillance (BPP, NST) is reassuring and the bowel is not significantly dilated, but delivers earlier if bowel dilation >25 mm develops after 37 weeks of gestation. A survey of maternal-fetal medicine specialists reported 43 percent performed delivery at 37 weeks and 29 percent at 39 weeks if gastroschisis was stable; 6 percent recommended delivery prior to 37 weeks [75]. A decision analysis suggested delivery at 38 to 39 weeks for fetuses with gastroschisis, growth restriction, and normal umbilical artery Dopplers, but emphasized that there are unique details for each case so timing should be individualized using shared multidisciplinary decision-making [118].
Delivery as early as 33 weeks of gestation has been suggested based on reports of an increased risk of fetal demise in the third trimester [4,76,119,120] and a possible increase in risk of inflammatory bowel changes from ongoing exposure to amniotic fluid. Not only is there no evidence that planned preterm birth decreases the need for silo closure, the time until enteral feeding can begin, or other gastrointestinal problems [110,121,122], but most contemporary studies of pregnancies complicated by gastroschisis have found that preterm birth is the most important predictor of adverse outcome [114,123,124], especially if performed before 34 weeks [125]. Thus, we believe preterm birth to reduce the risk of fetal demise or improve neonatal outcome is unwarranted if fetal growth, AFV, and fetal testing (BPP, NST) are normal [110].
Route — Although high-quality evidence is not available, we recommend reserving cesarean birth for usual obstetric indications. Labor and rupture of membranes have not been proven to adversely affect outcome, and there is no evidence that cesarean birth improves outcome in uncomplicated gastroschisis [8,126-129]. In meta-analyses of observational studies evaluating the effect of mode of delivery in fetuses with abdominal wall defects (gastroschisis or omphalocele), cesarean birth was not associated with improvement in any neonatal outcome (mortality, rate of primary fascial repair, neonatal sepsis, necrotizing enterocolitis, secondary repair, short-gut syndrome, time until enteral feeding, length of hospital stay) [130,131].
Some pediatric surgeons recommend cesarean birth for gastroschisis with liver involvement, especially when there is marked liver herniation, because of the theoretic risk of dystocia and trauma. This is a relatively rare finding and may represent omphalocele complicated by rupture of the surrounding amnio-peritoneal membrane. The delivery route in these rare cases should be individualized based on patient specific factors.
If there is liver herniation, then limb-body wall defect or severe amniotic band syndrome should be ruled out because cesarean birth would not be indicated in cases considered lethal.
Intrapartum fetal heart rate — Some, but not all, studies report a high frequency of nonreassuring FHR tracings and amniotic fluid staining (meconium or bile [132]) leading to cesarean birth [7,48]. FHR abnormalities could be due to cord compression related to oligohydramnios or fetal hypovolemia related to chronic loss of protein and water across the exposed bowel. There are no studies on the use of intrapartum amnioinfusion in these cases. We do not perform it because of concerns of injuring bowel and lack of demonstrable benefit.
NEONATE
Clinical findings — The characteristic clinical finding in newborns is a full-thickness paraumbilical abdominal wall defect, often associated with evisceration of bowel (picture 1). It is usually located to the right of the umbilical cord insertion site and tends to be <4 cm in diameter [133,134]. There is no covering membrane. Inflammation and fibrosis from chronic exposure to amniotic fluid result in thickening and matting of the intestines, decreased bowel motility, and possibly luminal obstruction [133]. Although amnioexchange procedures reduced the inflammatory process in animal studies, a randomized trial in humans did not find beneficial effects on pregnancy outcome or complications [135].
Delivery room care — Neonatal fluid losses are 2.5 times that of a healthy newborn in the first 24 hours of life [136]. The neonate is at risk for insensible heat and fluid losses from exposure of the eviscerated bowel. In addition, third space fluid deficits from sequestration of intestinal fluid can be significant.
The initial approach to management of these newborns includes [136,137]:
●Wrapping the bowel with sterile saline dressings covered with plastic wrap. This preserves body heat, minimizes insensible fluid loss, and protects the bowel. In some centers, the neonate is immediately placed into a plastic bag covering its lower half to maximize temperature control and hydration while allowing access to initial visual examination.
●Inserting an orogastric tube to decompress the stomach.
●Placement of peripheral intravenous access to provide fluids and broad-spectrum antibiotics that cover maternal vaginal flora (eg, ampicillin and gentamicin). The maintenance fluid requirement is increased two- to threefold because of losses from the exposed bowel.
●Ensuring a patent airway.
●Keeping the neonate in a thermoneutral environment.
●Providing respiratory support, if required.
Although breastfeeding or other oral feeding is not possible until after the gastroschisis has been repaired, mothers are encouraged to pump and store breast milk for future use [138].
Synopsis of surgical management — Primary closure, when feasible, is performed within a few hours of birth [139]. In the operating room, the bowel is decompressed by aspirating stomach contents and evacuating the large bowel through the rectum. The size of the defect is increased 1 to 2 cm to minimize trauma to the bowel during reduction. The abdominal wall is manually stretched, and the bowel is replaced, taking care to avoid creating intra-abdominal pressure that is too high [136,140]. Primary closure is successful in 70 percent of cases.
If primary closure is not feasible because of thickened, distended intestinal loops and a small abdominal domain, a staged closure with a silastic silo can be used as in omphalocele cases. A preformed silo with a spring-loaded ring can be placed at the bedside to cover the herniated intestine quickly without suturing [141]. Some surgeons perform silo placement with staged closure in all gastroschisis cases as some data suggest that outcomes are equivalent to primary closure [142].
A sutureless closure that stretches the umbilical cord across the defect without fascial suturing is a promising management approach [143], but data are limited [144,145].
Prolonged postoperative dysmotility is a common problem and interferes with enteral feeding. Studies in animal models suggest that dysmotility is due to delayed maturation of the enteric nervous system [146,147], possibly as a result of prolonged exposure to amniotic fluid [148].
Prognosis — Gastroschisis has the most favorable prognosis of the abdominal wall defects because most cases are not complicated by concomitant nongastrointestinal anomalies or aneuploidy [149]. The overall survival rate for liveborns with gastroschisis was 97.8 percent in a prospective study of 4420 neonates born at 175 North American centers [8]. Sepsis, which occurred in 8.6 percent of the cohort, was the only significant independent predictor of mortality in this study. In global studies, access to quality neonatal surgical care, which is less available in low- and middle-income countries, is another important prognostic factor (survival to hospital discharge in low-, middle-, and high-income countries: 10, 68, and 98.6 percent, respectively) [150].
Gastroschisis in neonates can be categorized as "simple" or "complex" based on the absence or presence of intestinal atresia, stenosis, perforation, necrosis, malrotation, or volvulus, but this distinction is often not possible to discern prenatally [62]. Up to 25 percent of cases are complex, and these neonates have significantly more gastrointestinal, respiratory, and infectious disease complications in the neonatal period [151]. In a meta-analysis of studies that compared the outcome of complex versus simple gastroschisis, complex gastroschisis was associated with higher risks of in-hospital mortality (risk ratio [RR] 5.4, 95% CI 2.4-12), short bowel syndrome (RR 12, 95% CI 6.3-22.8), bowel obstruction (RR 2.2, 95% CI 1.4-3.6), necrotizing enterocolitis (RR 1.97, 95% CI 1.1-3.7), and parenteral nutrition and tube feedings on discharge (RR 11.2, 95% CI 3.8-33.2 and 2.8, 95% CI 1.5-5.5, respectively), but the rates of primary abdominal closure and silo bag placement were similar for both groups [151]. The postsurgical course for these infants can be lengthy (in one study: mean 53 days, range 8 to 307 days [97]).
Long-term outcomes are generally satisfactory. A study assessing neurodevelopment at 5 to 17 years of age reported overall intellectual abilities were within a normal range [152]. Survivors are prone to the typical problems related to intestinal adhesions [153,154]. Although a minority of children have short-bowel syndrome, many can eventually discontinue parenteral nutrition [155-157]. Lastly, many patients are bothered by their lack of an umbilicus [153]; these individuals can consider umbilical reconstruction surgery.
RECURRENCE RISK — There is an increased risk of recurrence in families with a child with gastroschisis, which suggests that genetic factors play a role in causation. A systematic review of 11 population-based studies (862 probands) reported a 5.7 percent risk of gastroschisis in other family members, 3 percent adjusted for probands and 4.3 percent in subsequent siblings [158]. However, nongenetic factors are also important, which suggests a multifactorial inheritance pattern.
SUMMARY AND RECOMMENDATIONS
●Prenatal diagnosis
•Clinical manifestations and diagnosis – Gastroschisis is a full-thickness paraumbilical abdominal wall defect, usually on the right and associated with evisceration of fetal bowel. There is no covering membrane. (See 'Clinical findings' above.)
Prenatal diagnosis is based on sonographic visualization of a paraumbilical abdominal wall defect, usually to the right of the midline, with visceral herniation (image 1A-B). The adjacent umbilical cord insertion site is normal. The herniated intestines lack a covering sac and float freely in the amniotic fluid. The combination of ultrasound examination and MSAFP screening detects at least 90 percent of cases. (See 'Prenatal diagnosis' above.)
Maternal serum alpha-fetoprotein (MSAFP) is elevated in virtually all pregnancies with gastroschisis. (See 'Prenatal diagnosis' above.)
•Isolated versus nonisolated – Prenatally, gastroschisis is classified as isolated (related anomalies of the intestinal tract may be present) or nonisolated (associated with unrelated structural anomalies in other organ systems, which may occur when the etiology is an underlying syndrome or other genetic abnormality).
Most cases (approximately 85 percent) are isolated. Among fetuses with isolated gastroschisis, additional gastrointestinal problems (eg, intestinal atresia, stenosis, perforation, necrosis, malrotation, volvulus) are present in up to 25 percent of cases. (See 'Associated anomalies and findings' above.)
•Frequency of chromosomal abnormalities – The prevalence of chromosomal abnormalities in fetuses with isolated gastroschisis is not increased above that in the baseline population; thus, this anatomic finding alone is not a strong indication to pursue invasive diagnostic fetal genetic testing, but many patients will opt for noninvasive genetic screening (eg, cell-free DNA). Because the risk is higher when extraintestinal structural abnormalities are identified on ultrasound, we suggest genetic amniocentesis in these cases. (See 'Fetal genetic studies' above.)
●Pathogenesis – The pathogenesis of gastroschisis is unknown. All theories involve defective formation or disruption of the body wall in the embryonic period, with subsequent herniation of bowel. (See 'Pathogenesis' above.)
●Epidemiology – There is an inverse association between maternal age and incidence of fetal gastroschisis, with the highest prevalence in the White population and births to mothers under age 20 years. (See 'Prevalence and epidemiology' above.)
●Antepartum management
•Complications – Pregnancy complications include increased risk of fetal growth restriction, fetal demise, spontaneous preterm birth, and bowel thickening and dilation. (See 'Fetal monitoring' above.)
•Ultrasound surveillance – We obtain serial ultrasound examinations to follow fetal growth and amniotic fluid volume (AFV) at two- to four-week intervals since these fetuses are at risk of growth impairment and amniotic fluid abnormalities. We also obtain targeted views of the intra- and extra-abdominal bowel to look for substantial dilation (>25 mm), thickening, or edema. If such changes are observed prior to 34 weeks, we administer a course of antenatal corticosteroids to enhance fetal maturation should preterm birth become indicated, but we do not intervene solely on the basis of bowel wall thickening or dilation. (See 'Fetal monitoring' above.)
•Fetal monitoring – Given the increased risk of fetal demise late in pregnancy, we suggest antepartum fetal surveillance (nonstress test, biophysical profile) (Grade 2C). (See 'Fetal monitoring' above.)
●Delivery site, timing, and route – Ideally, delivery should occur in a facility with appropriate resources for caring for these neonates. In the absence of standard obstetric indications for abdominal delivery, we suggest a trial of labor rather than scheduled cesarean birth for most patients (Grade 2C). Cesarean birth is reasonable if the liver is significantly herniated because of the theoretic risk of dystocia and trauma. In the authors' practices, delivery of fetuses with gastroschisis, normal growth, normal AFV, and reassuring fetal testing is scheduled for 38+0 weeks of gestation; with earlier delivery for standard obstetric indications. This minimizes neonatal morbidity and mortality and avoids the possibility of term (39 to 40 weeks) stillbirth; however, there is no consensus on the optimum timing of delivery of these pregnancies. (See 'Delivery' above.)
●Newborn management – In the delivery room, the bowel is wrapped with sterile saline dressings covered with plastic wrap to preserve heat and minimize insensible fluid loss. In some centers, the neonate is immediately placed into a plastic bag covering its lower half to maximize temperature control and hydration while allowing access to initial visual examination. In addition, an orogastric tube is placed to decompress the stomach, peripheral intravenous lines are inserted, and the airway is stabilized. (See 'Neonate' above.)
●Pediatric outcome – Overall survival is over 90 percent. Gastroschisis in neonates can be categorized as "simple" or "complex" based on the absence or presence of intestinal atresia, stenosis, perforation, necrosis, malrotation, or volvulus, but this distinction is often not possible to discern prenatally. Up to 25 percent of cases are complex, and these neonates have significantly more gastrointestinal, respiratory, and infectious disease complications in the neonatal period. (See 'Prognosis' above.)
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