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Keywords:

  • gastroschisis;
  • prenatal diagnosis;
  • surveillance;
  • ultrasound

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

Objectives

Infants with gastroschisis have a high survival rate. However, the rate (10–15%) of intrauterine fetal death (IUFD) is considerable, and the association with fetal distress is well known. The aim of this study was to describe the outcome of fetuses with a prenatal diagnosis of gastroschisis. The impact of correct prenatal diagnosis, surveillance and signs of complicating risk factors were evaluated.

Methods

All fetuses with prenatally diagnosed gastroschisis at the National Center for Fetal Medicine from January 1988 to August 2002 were registered and prospectively evaluated with regular ultrasound examinations. From 34–36 completed gestational weeks the fetuses were monitored daily to every second day with cardiotocography (CTG).

Results

Gastroschisis was diagnosed in 64 fetuses at a mean gestational age of 19 + 2 weeks. All had normal karyotype. Associated anomalies were found in four cases (6.3%). Three pregnancies (4.7%) were terminated, all for reasons other than gastroschisis. One fetus (1.6%) died in utero. Thirteen fetuses (22%) had abnormal CTG leading to subsequent Cesarean sections. Mean gestational age at delivery was 36 + 1 weeks. Mean birth weight was 2586 g. Thirteen infants (22%) were small for gestational age (SGA). In 15 cases (25%) meconium-stained amniotic fluid was found; 14 of these had abnormal CTG and/or were SGA. Small bowel atresia was found in four infants (6.7%). Four infants died postnatally at the age of 0–9 months.

Conclusions

CTG surveillance of fetuses with gastroschisis may improve the outcome through detection of fetal distress thereby reducing the risk of IUFD. Other clinical situations of importance that are associated with gastroschisis are described and discussed. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

Gastroschisis is a defect in the abdominal wall, typically located on the right side of a normally inserted umbilical cord and with bowel protruding through the defect. The diagnosis is easily made on ultrasound examination and is possible even in the first trimester1. The accuracy of prenatal diagnosis is high and it is assumed that prenatal detection will increase as the use of routine ultrasound becomes more widespread.

There are reports of an increasing incidence of gastroschisis2–5. This increase may be multifactorial: low maternal age is well known to be associated with gastroschisis4, 6–8. Smoking9, 10 and the use of vasoactive drugs11 are other factors that have been suggested to be associated with gastroschisis. The existence of familial cases indicates a genetic factor12.

Gastroschisis is believed to be the result of a vascular compromise in the embryonic period. One hypothesis is that there is an interruption in the development of the omphalomesenteric artery13, 14. This hypothesis helps to explain the additional gastrointestinal complications associated with gastroschisis, as the proximal part of the omphalomesenteric artery becomes the superior mesenteric artery during the embryologic development. Another theory is that an abnormal involution of the right umbilical vein may cause a weakness in the abdominal wall leading to protrusion of the bowel through the weakness15.

Fetuses with gastroschisis are usually smaller than normal fetuses6, 16–18. There is no association with abnormal karyotype18–20 and the incidence of associated anomalies is low2, 21. However, associated intestinal complications such as atresia/stenosis of the bowel are present in 10–20% of cases22.

The survival rate of liveborn infants with gastroschisis is approximately 90–95%23, 24. Associated intestinal complications may influence the outcome, and therefore efforts have been made to identify fetuses with risk of bowel complications25–27. It is well known that fetuses with gastroschisis have a high risk of developing fetal distress16–18, 28 and an increased risk of intrauterine fetal death (IUFD) has been reported16, 18, 28, 29.

The aim of this study was to follow a case-series of fetuses with a prenatal diagnosis of gastroschisis. The main purpose was to identify possible risk factors for poor outcome and find out whether surveillance may be of benefit for the overall outcome. We also wanted to determine the incidence rate, detection rate and accuracy of diagnosis in our unselected population.

Methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

The study comprised all fetuses for which a prenatal diagnosis of gastroschisis was made at the National Center for Fetal Medicine (NCFM) in Trondheim, Norway. NCFM is a tertiary referral center for prenatal diagnosis and therapy for the whole of Norway and thus the sample represents a selected population. Complete anamnestic history, ultrasound findings and prenatal and postnatal development were prospectively registered and evaluated from January 1988 to August 2000. Long-term outcome of infants was determined from postnatal charts after discharge from hospital with a follow-up time until March 2003. A postnatal follow-up period of at least 6 months was required.

To determine the incidence rate, prenatal detection rate and accuracy of diagnosis in our unselected population, all cases with gastroschisis from a well-defined area consisting of the city of Trondheim and eight surrounding municipalities were registered. During the time interval January 1988–December 2001, 38 924 infants were born in this area. Within this non-selected population, approximately 97% of the pregnant women had a routine fetal examination at the NCFM and were later delivered at the University Hospital of Trondheim.

The gestational age was expressed in completed weeks and days based on ultrasound measurements of the biparietal diameter (BPD) during weeks 17–20 (routine fetal examination). When no routine ultrasound had been done, the gestational age was based on the last menstrual period (LMP). Small for gestational age (SGA) was defined as a birth weight of less than mean − 2 SDs30. Deviation from mean fetal weight was estimated by measuring the BPD and the mean abdominal diameter31. To investigate the accuracy of the method of estimating fetal weight in this case-series of fetuses with gastroschisis the last weight estimation by ultrasound before birth (range, 1–14 days) was used. A difference of less than 10% between the estimated and true weight deviation was judged to be in agreement. Bowel dilatation was assessed qualitatively.

The policy in our unit was to deliver fetuses with gastroschisis by Cesarean section at 37–39 weeks. From 34–36 weeks of gestation cardiotocograms (CTGs) were performed daily or every second day, and ultrasound examinations were performed at least once a week. The examination included estimation of fetal weight, evaluation of amniotic fluid and fetal bowel appearance. Doppler measurements of the umbilical artery, and occasionally other vessels, were performed in the majority of the cases.

In eight infants the primary surgery was performed at other co-operating University Hospitals, all with pediatric surgery and neonatal intensive care units.

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

Gastroschisis was diagnosed in 64 fetuses. In 63 cases the defect was located to the right of the umbilicus while in one case the defect was extensive, reaching from the right side of the umbilicus to the left costal margin and the whole liver was exteriorized.

Forty-three women (67%) were nulliparous and 32 of them were primigravidae. The mean age was 23 (range, 16–37) years. Seventy-two percent (46/64) were 25 years or younger and 30% (19/64) were 20 years or younger. Forty-seven percent of the women reported daily smoking during pregnancy.

The diagnosis was made at mean 19 + 2 (range, 13 + 2 to 38 + 2) weeks. In 57 fetuses (89%) the diagnosis of gastroschisis was made at the routine fetal examination in the second trimester. In seven cases the diagnosis was made at an ultrasound examination for clinical reasons: two before the time of the routine fetal examination and five later, in the third trimester. In one of these cases a routine examination had not been performed. All fetuses had normal karyotype. There were 32 female fetuses and 32 male fetuses. Two fetuses were siblings.

Associated anomalies (except intestinal anomalies) were found in four cases (6.3%). Two infants had cardiac anomalies with a ventricular septal defect and tetralogy of Fallot, respectively. The other two cases had serious arthrogryposis of amyoplasia type with extensive muscular atrophy (Figure 1). Both these pregnancies were terminated. In one of the cases autopsy confirmed atrophy of the anterior horn cells and extremely underdeveloped muscles. A total of three (4.7%) pregnancies were terminated. The reason for termination of pregnancy was arthrogryposis (two cases) and weighty social reasons (one case). Karyotyping and autopsy were performed in all terminated fetuses.

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Figure 1. A female fetus with gastroschisis associated with arthrogryposis of amyoplasia type. (a) Ultrasound image showing gastroschisis and extremely underdeveloped muscles of the abdominal wall in transverse section. (b) Ultrasound image of a leg with extensive muscular atrophy. (c) The fetus after termination. All extremities had extensive muscular atrophy.

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One fetus (1.6%) died in utero at 35 + 4 weeks. The mother had moderate pre-eclampsia. She experienced severe headache, nausea and vomiting at home. On admission, the following day, fetal death was diagnosed. The mother then had proteinuria and blood pressure of 135/100. The last CTG and ultrasound examination, both with normal findings, had been performed 2 weeks prior to fetal death. The infant was delivered vaginally and the birth weight was within normal range. Autopsy confirmed no anomalies other than gastroschisis.

Two infants were delivered vaginally and 58/60 (97%) were delivered by Cesarean section (Table 1). Elective Cesarean section was performed in 16/60 (27%) cases and 22/60 (37%) women underwent emergency Cesarean section due to spontaneous onset of labor. Emergency Cesarean section due to pathological CTG was performed in 13/60 (22%) cases; five of these women had contractions but none was in labor. The typical pathological findings of the CTG were reduced short-term variability.

Table 1. Indication, gestational age and mode of delivery (n = 60)
Mode of deliveryn%Gestational age in weeks (mean, (range))
Vaginal
 Spontaneous onset 2  332 + 4 (28 + 4 to 36 + 4)
Cesarean section
 Elective16 2737 + 4 (36 + 6 to 38 + 6)
 Fetal distress13 2236 + 4 (34 + 1 to 39 + 0)
 Spontaneous onset22 3735 + 3 (28 + 0 to 38 + 5)
 Oligohydramnios 2  335 + 6 (34 + 5 to 37 + 0)
 Pre-eclampsia 1  236 + 4
 Abnormal umbilical artery Doppler 2  336 + 1 (35 + 2 to 37 + 1)
 Suspect bowel complication 2  334 + 1 (32 + 6 to 35 + 3)
Total6010036 + 1 (28 + 0 to 39 + 0)

The mean gestational age at delivery was 36 + 1 (range, 28 + 0 to 39 + 0) weeks. Thirty-two (53%) women were delivered prematurely (before 37 completed weeks) and five (8%) were delivered before 34 weeks. The mean birth weight was 2586 (range, 940–4030) g. Thirteen infants (22%) were SGA30 (Figure 2).

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Figure 2. Birth weight and gestational age at birth in the present gastroschisis case-series.

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The mean weight deviation at birth was mean − 9% of normal infants30. In 34/58 (59%) cases the estimated fetal weight deviation31 was in agreement with the true weight deviation of the newborn, while in 19/58 (33%) cases the weight deviation was underestimated. Sixty mothers had a known LMP, and of these 45 (75%) were given an ultrasound estimate of the day of delivery later than the LMP estimate at routine ultrasound examination. Only 18 mothers had a reliable LMP date, regular cycles and no contraceptives within 6 months. In this subgroup the ultrasound estimates of the day of delivery were later than the LMP estimates in 14/18 (78%) cases.

Apgar scores at 5 min were mean 9.1 (range, 2–10). Only one infant (the case with a large abdominal wall defect and hydrops) had an Apgar score < 7 at 5 min. Levels of pH and base excess (BE) from the cord umbilical artery were obtained in 42 cases. Mean pH was 7.32 (range, 7.22–7.41) and mean BE was 0.2 (range, − 3.5–4.3) mmol/L. In fifteen cases (25%) meconium-stained amniotic fluid was noticed. Ten of these were delivered because of pathological CTG. Five of the cases with meconium-stained amniotic fluid were SGA. Three cases had abnormal Doppler velocimetry in the umbilical artery at 34 + 1 to 36 + 5 weeks. One was a SGA fetus without any other complications; in a second case the mother had pre-eclampsia. The third case also had pathological CTG, which was the indication for delivery. This infant died at 23 days of age. The weight deviations at birth of the infants with abnormal Doppler were − 23%, − 17% and − 22%, respectively. Oligohydramnios was present in three cases; one of these infants was SGA and the amniotic fluid was meconium-stained. The outcome was good in all three cases.

For the 13 infants who had pathological CTG, mean Apgar scores at 5 min were 8.8 (range, 7–10). Levels of pH and BE from the cord umbilical artery were obtained in 9/13 infants with a mean pH of 7.33 (range, 7.29–7.40) and mean BE − 0.23 (range, − 2.1–2.3). Doppler velocimetry in the umbilical artery was normal in 8/13, not performed in 4/13 and pathological in 1/13 fetuses with pathological CTG.

Intra-abdominal dilatation of the bowel was noted in five cases. All had obstruction of the bowel. Two infants had multiple jejuno-ileal atresias. The other three had a single jejunal atresia, jejunal stenosis and volvulus, respectively. In all cases an obstruction was suspected prenatally. The case with a single jejunal atresia experienced in utero perforation of the bowel. This was suspected at ultrasound examination 5 weeks before birth and the diagnosis was verified at birth. In 56 cases reliable information about which intra-abdominal organs were exteriorized through the abdominal wall defect at birth was obtained (Table 2). The gonads were exteriorized in 50% (13/26) of the female fetuses.

Table 2. Viscera and organs (or part of) exteriorized before surgery
OrganFemale (n = 26)Male (n = 30)Total (n = 56)
n%n%n%
Liver   3 10 3  5
Spleen   1  3 1  2
Stomach17 6513 4330 54
Duodenum18 6918 6036 64
Small intestine261003010056100
Large intestine2610026 8752 93
Urinary bladder 6 23 2  7 8 14
Gonads (ovaries, testes)13 50 2  715 27

Primary closure of the abdominal wall defect was performed in 54/59 (92%) cases. In five (8%) cases staged closure with application of a silo32 and final closure of the abdominal wall after 5–10 (mean, 7.2) days was performed. Of the five cases with a staged closure, 2/5 infants were SGA and 2/5 infants died. In total, 4/60 infants (6.7%) had atresia of the bowel, all jejuno-ileal. All four had primary closure of the abdominal wall. Two infants with multiple atresias subsequently had elective delayed primary anastomosis for correction of the atresias after approximately 1 month. The reason for deferring correction of the atresias was the presence of massive peel initially (Figure 3b). At the second-look operation the peel had resolved almost completely in both cases. One of the infants with a single atresia in the jejunum also had a colonic stenosis. In addition, three other infants had stenosis of the bowel. The stenoses were situated in the jejunum, ileum and ileo-cecal junction, respectively. An overview of total surgery procedures is given in Table 3. Fourteen infants (24%) had re-surgery due to signs of gastrointestinal obstruction after closure. One of the two infants who were delivered vaginally had a 3-cm fresh perforation at the greater curvature of the stomach. The defect was closed at the primary surgery and there were no further complications.

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Figure 3. Appearance of bowel postnatally in two infants with gastroschisis. (a) Normal appearance and (b) bowel with massive ‘peel’ in an infant with multiple atresias of the bowel.

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Table 3. Surgery in infants with gastroschisis (n = 59)
Surgical proceduren%
Primary closure5492.0
Additional surgery at primary closure
 Bowel resection due to atresia (one ileal, one jejunal) 23.4
 Appendectomy 711.9
 Orchiopexy 23.4
 Closure of gastric defect 11.7
Staged closure58.0
 Planned second operation (due to multiple atresias) 23.4
Total59100
Surgery for obstruction after closure1424.0
 Stenosis 46.8
 Adhesions 813.6
 Inguinal hernia 11.7
 Infection 11.7

In all, 4/60 (6.7%) liveborn infants died (Table 4). The fetus with the extensive abdominal wall defect developed hydrops with hydrothorax and was delivered vaginally after spontaneous onset of labor at 28 + 4 gestational weeks. The infant died within 30 min. One infant died of sudden infant death syndrome at 1 month of age. Two infants had gastrointestinal complications and died. Both had a staged silo closure initially. In one case the primary operation was complicated by a perforation of the bowel when the surgeon tried to undo peel. Sepsis and kidney failure occurred and the infant died at 23 days of age. The other infant had severe bowel dysmotility hindering adequate enteral nutrition; it died of end-stage liver failure due to long-term total parenteral nutrition at 9 months of age. These two infants never achieved full oral feeding. The total outcome in terms of mortality is shown in Table 5. Full oral feeding was achieved for 57 infants at mean 30.9 (range, 7–260; median, 20) days. The length of hospital stay was mean 40.3 (range, 11–309; median 29) days.

Table 4. Clinical data for postnatal deaths (n = 4)
Age at deathBirth weight (g)Weight deviation (%)Gestational age at birth (weeks)CTG abnormalDoppler abnormalAtresia/stenosis of bowelStaged closure/siloComments
  1. CTG, cardiotocography; SIDS, sudden infant death syndrome.

30 min16001828 + 4NoNoNoNo surgeryHydrops, atypical defect
1 month2240− 2036 + 0YesNoNoNoSIDS
9 months2100− 2335 + 5NoNoNoYes 
23 days1875− 2234 + 1YesYesNoYes 
Table 5. Outcome of fetuses with gastroschisis (n = 64)
Outcomen%
Termination of pregnancy 34.7
Intrauterine fetal death 11.5
Postnatal death 46.3
Alive5687.5
Total64100

At follow-up over a period of 6–180 months, all the 56 surviving infants (29 male and 27 female infants) had a life without any significant gastrointestinal problems. A few had experienced transient problems with lactose intolerance. Late surgery was performed on 13 occasions during the follow-up period (Table 6). The mental development was normal, though one child had Tourette's syndrome. Concerning the two infants with associated anomalies; the infant with a ventricular septal defect had spontaneous closure of the defect and the infant with tetralogy of Fallot had heart surgery at 9 months and an uneventful development afterwards.

Table 6. Late surgery in infants with gastroschisis during the follow-up period (n = 56)
Surgical proceduren%
  • *

    Male infants.

Inguinal hernia47.1
Ventral hernia35.4
Fundoplication23.6
Orchiopexy*23.6
Scrotal hernia*11.8
Hydrocele*11.8

In the unselected population of Trondheim, 17 cases of gastroschisis were found among 38 924 infants born during the time period January 1988–December 2001. This gives an incidence of 1/2290. All 17 cases were detected prenatally (100% detection rate). Fifteen cases (88%) were detected at the routine fetal examination at 17–20 weeks while 2/17 were detected by ultrasound on clinical indication; one prior to the routine examination and one later in pregnancy. There were no false-positive cases.

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

Pregnancies with fetal gastroschisis should be considered high-risk pregnancies. In this case-series of 64 prenatally diagnosed instances of gastroschisis we found a high risk of fetal distress as 13/60 (22%) fetuses had pathological CTG leading to Cesarean section before the onset of labor. Several authors have addressed the increased risk of fetal distress16, 17, 28 and the increased risk of IUFD16, 18, 28. The rate of IUFD among fetuses with gastroschisis has been reported to be 10–15%6, 7, 16, 28. In the present study only one case (1.6%) of IUFD was noted. Although it is impossible to prove that the surveillance with CTG decreased the mortality rate, one may speculate whether the rate of IUFD might have been higher if the cases of fetal distress had not been identified. The typical CTG pathology with reduced variability has also been reported in previous studies33, 34. Our study confirms the suggestion that antenatal surveillance will decrease perinatal mortality in pregnancies complicated by gastroschisis16. In one study28 the introduction of regular CTG monitoring from 32 weeks' gestation increased the ability to detect fetal distress two-fold. The increased detection of fetal distress, with subsequent obstetric intervention, led to a reduction of adverse neurological outcome from 21% to 6%. Our study supports the value of CTG monitoring during the last weeks of pregnancy in cases with gastroschisis and confirms the findings of Burge and Ade-Ajayi28 who introduced regular CTG monitoring. In the case of IUFD in our study, the mother had moderate pre-eclampsia, which may have been the cause of fetal death. This particular case did not, for reasons unknown, follow our normal surveillance program.

The incidence of gastroschisis has been increasing in recent decades2, 3, 35. In Norway the birth prevalence of gastroschisis increased from 1.3/10 000 in the period 1967–1989 to 3.2/10 000 in 19985. The present study with its total prevalence of 4.4/10 000 is in line with these previous reports; the higher prevalence may be partly explained by improved diagnosis and inclusion of all prenatal cases. The findings from previous studies4, 6–8, 36, namely that young mothers have a higher risk of having a fetus with gastroschisis, was confirmed in the present study with a mean maternal age of 23 years and 19/64 (30%) women aged 20 years or younger. The mean maternal age of all pregnant women in Norway in the year 2000 was 29 years37. The reason for young mothers having an increased risk, as well as the increasing incidence of gastroschisis generally, is still unknown. Infection has been suggested as one underlying cause38. Smoking has been identified as a risk factor by some authors9, 10 but not by others4. In the present study, 47% of the mothers were smokers compared with 21% smokers in a national survey during 1994–199539. Familial cases of gastroschisis exist12 and two siblings were affected in our study.

In Norway all mothers are offered one routine ultrasound examination at 17–20 gestational weeks. Additional ultrasound examinations are only made on clinical indications. A maternal serum-screening program is not available. The detection rate of gastroschisis in the non-selected population was 100% and the accuracy of the diagnosis was 100%. This shows that it is possible to make the diagnosis in most cases when a thorough fetal examination is performed routinely. Usually the diagnosis of gastroschisis is simple but in some cases differentiating gastroschisis from amniotic rupture sequence can be difficult. In the literature gastroschisis has often been presented together with other abdominal wall defects, most commonly omphalocele. Sometimes there is also an intermingling of the diagnoses of gastroschisis and amniotic rupture sequence as well as limb-body-wall complex. Left-sided gastroschisis has been reported40 and it is important to be aware of the existence of rare atypical cases of gastroschisis41. In our study group there was one case with an extensive defect; this fetus developed hydrops and the infant died. The infant was scrutinized for other possible diagnoses but the final diagnosis was the descriptive diagnosis of an epigastric gastroschisis. We believe that these large defects are not comparable to the typical gastroschisis and probably have a high risk for poor outcome. But also in typical cases of gastroschisis, organs other than bowel may be present extra-abdominally42, 43. In the present study this was particularly common among girls whose gonads and urinary bladder were commonly involved. The involvement of gonads may affect future fertility44 and caution should be taken during surgery. The association of undescended testes and gastroschisis has been discussed and conservative management with later orchiopexy, if necessary, has been recommended45. The type of herniated organs may even complicate the immediate postnatal management, especially if the stomach is herniated with risk of aspiration46.

The rate of 6.3% (4/64) of associated anomalies (except intestinal anomalies) is in agreement with other studies2, 18, 21, 28. The association of gastroschisis and arthrogryposis of the amyoplasia type has been described previously with a frequency of 3–5%47, 48. It has been suggested48 that the limb anomalies seen in amyoplasia are due to vascular compromise that leads to hypotension in the developing spinal cord at a critical time, during which the anterior horn cells are susceptible to insult. This leads to failure of maturation or death of the developing anterior horn cells. In the same study, amyoplasia in association with bowel atresia was also noted. Hall et al.49 presented an association between amyoplasia and twinning; thus supporting the theory of a vascular compromise. Gastroschisis is also thought to be due to a vascular compromise13–15. We found two cases (3.1%) with arthrogryposes of the amyoplasia type. Both cases had extensive muscular atrophy and autopsy confirmed the degeneration of anterior horn cells in one case.

The findings of normal karyotype in all cases in our study is in agreement with the findings of other authors18–20, however many authors2, 6, 7 report single cases of abnormal karyotype in fetuses with gastroschisis. This may reflect different age populations, intermingling of diagnoses or lack of study power to detect a slightly increased risk. Even though gastroschisis does not appear to be associated with abnormal karyotype we offer karyotyping after thorough counseling.

The rate of termination of pregnancy (4.7%) was low compared to other studies6, 50. None of the pregnancies was terminated solely because of gastroschisis. A total of 61/64 (95%) of the women decided to continue their pregnancy. Based on 6–180 months of follow-up, 56/61 (92%) fetuses had a good outcome. Such information is of prognostic importance. We believe that thorough counseling by a multidisciplinary perinatal team may encourage women to continue a pregnancy with gastroschisis.

It has been shown that infants with gastroschisis are smaller than normal infants6, 16–18, 51. We found similar results with 13 (22%) SGA infants. The estimated and the true weight deviation were in agreement in 59% of cases. This indicates that traditional methods of weight estimation may be used. This has also been noted in a previous study in which Fries et al.51 concluded that postnatal outcome in gastroschisis was not poorer for fetuses who were SGA. Other authors have found that low birth weight was associated with an increased risk of septic complications23, and that Cesarean section for fetal distress was associated with a lower fetal weight17. In our study 1/4 infants who died was SGA.

The mechanism of becoming SGA in fetuses with gastroschisis is not known. It has been suggested51 that transmural loss of substances, particularly proteins, may cause a nutritional drain from the fetus. The findings of lower serum protein concentrations and higher amniotic fluid total protein and α-fetoprotein levels in fetuses with gastroschisis52 support this theory. It has also been proposed52 that the loss of proteins may cause hypovolemia and cardiovascular compromise, which may contribute to the increased risk of fetal distress and IUFD. One might speculate whether the drainage of nutrients through the bowel during fetal life leading to growth restriction is an indicator of bad bowel function with increased risk of motility disturbances postnatally. Dixon et al.53 hypothesized that atresia protects the fetus against growth restriction. However, two infants with atresia of the bowel in the present study were SGA. Our study suggests that placental insufficiency is a minor problem in these fetuses, since only one of the SGA fetuses had pathological Doppler velocimetry of the umbilical artery. However, it may still be useful to perform Doppler velocimetry examinations to discriminate the individual problem for each fetus. The fact that 75% of the women had their estimated date of delivery postponed at routine fetal examination suggests that these fetuses are smaller already in the second trimester, since postponement is usually the case in 60% of cases in a non-selected population54. This indicates that the increase in BPD is slightly impaired in gastroschisis fetuses compared to normal fetuses.

It is important to survey fetuses with gastroschisis by monitoring the fetal bowel. Sustained intra-abdominal dilatation of the bowel (Figure 4b) was noted in five cases, all with obstruction of the bowel. These findings support the hypothesis that intra-abdominal dilatation of bowel may be correlated with bowel obstruction. However, obstruction of the bowel was, in our study, not associated with poor outcome. This confirms findings reported in previous studies22, 55, 56. Nevertheless, intra-abdominal dilatation may be associated with increased risk of closed gastroschisis57, 58. In closed gastroschisis there is a significant progressive narrowing of the abdominal wall defect around the prolapsed gut. This may lead to mid-gut infarction and vanishing bowel ending in short bowel syndrome, which may be a life-threatening condition. It should be borne in mind that it may be difficult to discriminate between a relatively harmless bowel obstruction and an obstruction caused by a closure with possible fatal consequences. An increasing intra-abdominal dilatation in the third trimester, especially if the dilatation is newly developed, may be a warning sign for the development of closed gastroschisis. A combination of dilated intra- and extra-abdominal bowel (Figure 4) was observed in the cases of multiple atresias. However, a sole dilatation of the extra-abdominal bowel was not a consistent finding in this study, which is in agreement with others59. Conversely, the ultrasonographic description of both the intra- and extra-abdominal bowel, concerning both dilatation and wall thickening, at the final examination before birth was in agreement with the postnatal appearance. A recent study60 found no correlation between either extra-abdominal bowel dilatation or bowel wall thickness and adverse neonatal outcome. However, the same study60 found a correlation between polyhydramnios and bowel complications. In our study we had no cases of polyhydramnios. A sudden decrease in bowel dilatation may raise the suspicion of perforation of the bowel61. Doppler measurements of the superior mesenteric artery have, to date, not added any prognostic information concerning neonatal outcome62. The infant in our study who had severe bowel dysmotility, and who finally died of end-stage liver failure, had no signs at all of bowel compromise on ultrasound examination in utero.

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Figure 4. Ultrasound images of dilatation of bowel. (a) Extra-abdominal and (b) intra-abdominal dilatation. The infant had gastroschisis associated with multiple atresias in the jejuno-ileal area.

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The underlying cause of development of peel and edema may be multifactorial but the concentration of meconium63, 64 may play a role. The findings of elevated levels of interleukin-6, interleukin-8 and acute inflammatory exudate in the amniotic fluid65, 66 contribute to the understanding and may partly explain the high frequency of early spontaneous onset of labor. Amnion infusion has been suggested67 to reduce the inflammatory response. The presence of massive peel at birth in cases with suspected atresia may benefit from delayed primary anastomosis56 as was performed in our two cases with multiple atresias. In the present study four infants (6.7%) had atresia of the bowel and another three (5%) had stenosis. All atresias were jejuno-ileal. Most studies have reported an incidence of associated intestinal atresia of 10–20%53, 55, 56, 68 and the majority were of the jejuno-ileal type22. The further development of the infants who underwent surgery for atresia or stenosis of the bowel was uneventful.

The incidence of meconium-stained amniotic fluid was high (25%), but still lower than in previous studies18, 53. It has been discussed whether the discoloration of the amniotic fluid is sometimes caused by bile-stained vomit53. However, the lower incidence in this study and existence of thick, green amniotic fluid in several cases support that it was true meconium. We also found an association between pathologic CTG and meconium-stained amniotic fluid. Despite this association, all infants who were delivered by Cesarean section because of pathologic CTG had, at 5 min, Apgar scores of 7 or higher and normal BE. It may be that they were delivered in due time. One may also speculate whether factors other than hypoxia (e.g. fluid and protein loss, pressure on the bowel) may contribute to the development of pathologic CTG.

The impact of time and mode of delivery in fetuses with gastroschisis has been widely discussed42, 69–73. One of the infants in this study who was accidentally vaginally delivered had a perforation of the stomach. The perforation probably arose during delivery; damage to the viscera during vaginal delivery has also been found in previous studies21, 74. In a literature survey by Salvesen38 similar mortality rates were found irrespective of mode of delivery. However, no information was available concerning morbidity and several of the cases in the Cesarean section groups had been in labor, and the indications for Cesarean section varied. The advantages of preterm, prelabor Cesarean section have been suggested69 but are questioned by other authors75. In a center that advocates a trial of labor, the Cesarean section rate for fetuses with gastroschisis reached 37%17 with fetal distress as the major indication. An even higher Cesarean section rate (51%) was noted in another study76 where the major indication was also fetal distress. With this background and until further evidence concerning morbidity is available, our center intends to retain its policy of delivery by Cesarean section.

The proportion of infants (24%) who had subsequent surgery for suspected intestinal obstruction following closure of the abdominal wall defect was high. However, in most cases no obvious obstruction was found. It is likely that some of these cases did not have an obstruction but a motility disturbance. The time to full oral feeding and the length of hospital stay did not differ from other studies20. The majority of the infants (92%) had primary closure of the abdominal wall. A staged closure has been suggested to increase the morbidity76. In this study 2/5 infants with a staged closure died. However, it may be the condition of the infant that is associated with both poor outcome and the need for staged closure and not the method of closure per se.

Gastro-esophageal reflux has been suggested to be a common problem in gastroschisis patients77. We found that 2/56 infants were operated on for reflux. This is in agreement with previous reports78, which found that the incidence did not exceed that of healthy children.

All surviving 56 infants had a life without any significant gastrointestinal problems. All had normal mental development, though one infant had Tourette's syndrome. Not much has been published concerning morbidity and quality of life in adult patients with previous gastroschisis. However, a recent report44 found that the majority of adult patients had a quality of life not different from the general population.

In conclusion, our study demonstrated that close CTG surveillance of fetuses with gastroschisis may improve the outcome through detection of fetal distress and thereby reducing the risk of IUFD. We found no obvious risk factors for poor postnatal outcome. A fetal intra-abdominal bowel dilatation was associated with bowel obstruction after birth. However, intestinal atresia and/or stenosis did not affect the outcome. A thorough ultrasound examination, searching for anomalies other than gastroschisis, should be performed. The rate of associated anomalies is low but still two-fold compared to normal fetuses. The main anomalies found were arthrogryposes and cardiac anomalies. Gastroschisis was not associated with abnormal karyotype in this study but karyotyping may still be indicated until future large series prove otherwise. Regular ultrasound examinations, every 2–3 weeks, up to approximately 32 gestational weeks, should be performed. The examination may include estimation of fetal growth and Doppler measurements of the umbilical artery and of other vessels as indicated. Evaluation of fetal bowel and amniotic fluid should be performed. From approximately 33 weeks of gestation we recommend daily CTG recordings and ultrasound examination at least once a week. From this time, delivery should be considered if sustained, increasing intra-abdominal dilatation is observed, especially if the dilatation is newly developed in the third trimester. In utero transport and elective delivery at 36 weeks of gestation in a unit with specialized pediatric surgery and neonatal intensive care is recommended. To optimize the benefit of giving birth in a highly prepared and specialized neonatal environment, our center will continue to deliver by Cesarean section.

Acknowledgements

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

Mrs Nancy Lea Eik-Nes revised the manuscript.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References