Gastroschisis Fetuses Research Articles

120 Hadlock growth curves over-diagnose fetal growth restriction among fetuses with gastroschisis

Fetal growth restriction (FGR) occurs in a significant proportion of pregnancies complicated by gastroschisis, however is diagnosed based on growth percentiles for non-anomalous fetuses. Due to abdominal organ herniation, fetal abdominal circumference (AC) often measures less than expected when using Hadlock biometric measurements. This may over-diagnose FGR in these fetuses. Our objective was to evaluate 2nd and 3rd trimester biometric measurements of fetuses with gastroschisis to create growth curves specific to this anomaly. This single-center retrospective cohort study included biometric data from 413 ultrasounds of 116 fetuses with isolated gastroschisis between January 2011 and July 2020. Estimated fetal weight (EFW) was calculated by Hadlock 1984. Revised growth curves were generated using gastroschisis biometric measurements, with the 10th, 50th and 90th centiles calculated. A non-parametric model and ANOVA chi-square test were used to compare gastroschisis-specific curves to Hadlock growth curves. Five growth curves were generated for gastroschisis fetuses including EFW, biparietal diameter, head circumference, AC, and femur length (FL). EFW curves for gastroschisis fetuses were significantly different than 1984 Hadlock growth curves (p<0.001). The gastroschisis 50th percentile curve virtually overlays the Hadlock 10th percentile curve. 60% of fetuses diagnosed with FGR by Hadlock were misdiagnosed based on the gastroschisis-specific growth curve. Curves for AC and FL revealed a similar pattern, with the Hadlock 50th percentile curve just below the gastroschisis 90th percentile curve. Fetuses with gastroschisis have a growth curve that is distinctly different from that defined by Hadlock. Gastroschisis fetuses are over-diagnosed with FGR when compared to non-anomalous fetuses. Given the known risks of preterm delivery, using a gastroschisis-specific growth curve may assist in risk-stratification and potentially adjust the gestational age goal to achieve among otherwise reassuring cases of gastroschisis.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

354 Sonographic bowel findings among fetuses with gastroschisis do not predict antenatal and delivery outcomes

Among fetuses with gastroschisis, data are conflicting regarding antenatal sonographic bowel findings and postnatal outcomes. At our institution, we perform weekly ultrasounds at 32 weeks for all gastroschisis pregnancies. Our study examined the association of sonographic bowel measurements in fetal gastroschisis with antenatal and delivery outcomes. A single-institution, retrospective cohort study of 116 pregnancies complicated by gastroschisis delivered between 2011 and 2020. We reviewed ultrasounds documenting fetal bowel measurements including intra- and extra-abdominal bowel dilation, internal and external bowel wall thickness, and stomach cross-section. To evaluate the association of these measurements with antepartum and delivery outcomes, we ran logistic and linear models using generalized estimating equations to account for clustering across patients. Mean gestational age (GA) at delivery was 36.4 weeks with mean birthweight 2537g. 43% were delivered by Cesarean, with 73% undergoing induction of labor. Mean GA of NST start was 31.2 weeks, and 32% of patients had an NST abnormality that led to delivery. Several perinatal outcomes reached statistical significance, however with negligible clinical impact. Intra-abdominal bowel dilation was associated with 0.05 week decrease in delivery GA (95% CI -0.07, -0.03). Intra-abdominal bowel wall thickness was associated with a 0.22 week increase in GA of NST start (95% CI 0.07, 0.37), 0.08 week difference in GA at delivery (95% CI 0.02, 0.15), 0.26 increase in umbilical artery base deficit (95% CI 0.09, 0.43), and OR 0.83 (95% CI 0.7, 0.99) of Cesarean delivery. Extra-abdominal bowel dilation was not associated with any evaluated outcome. Extra-abdominal bowel wall thickness was associated with 0.1 increase in umbilical artery base deficit (95% CI 0.02, 0.19) and 0.05 increase in 5-min APGAR (95% CI 0.01, 0.09). In utero bowel findings for gastroschisis fetuses, while occasionally reaching statistical significance, were not associated with clinically significant differences in antenatal or delivery outcomes.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Fetal gastroschisis: Maternal and fetal methylation profile.

The purpose of this study was to describe the genomic deoxyribonucleic acid (DNA) methylation profile in fetuses with gastroschisis, determine whether the profile was inherited, and investigate any possible correlations with maternal risk factors. Genome-wide DNA methylation analysis of 96 blood samples was performed using the Illumina Human Methylation 850K BeadChip. The blood samples were collected as follows: 32 from the umbilical cord of fetuses with gastroschisis, 32 from their respective mothers, 16 from the umbilical cord of fetuses without malformation, and 16 from their respective mothers. The differential DNA methylation analysis showed a significant difference between the groups. The enrichment analysis resulted in 12 sites related to T-cell activation (p=0.0128). The sites with different methylation status contained 10 genes, three of which were related to the beta-2-microglobulin gene. The methylation profile observed in the fetuses with gastroschisis was not inherited from the mothers. In addition, there was no association between maternal urinary tract infection, smoking, and alcohol use and different methylated sites. We established the methylation profile of gastroschisis fetuses, which differs from that of normal fetuses. The profile was not inherited and did not correlate with maternal risk factors.

Fetal abdominal wall defects in an Australian tertiary setting: contemporary characteristics, ultrasound accuracy, and outcome

Purpose In this study, we aimed to comprehensively evaluate risk factors, ultrasound estimation of fetal weight, prenatal management, and pregnancy outcomes of gastroschisis and omphalocele at a metropolitan Australian hospital. Material and methods This was a retrospective single-center cohort study from 2006 to 2014 at a tertiary hospital with colocated neonatal surgical facilities. Demographic, pregnancy, ultrasound, birth and neonatal data were compared between gastroschisis and omphalocele. Correlation between routine (Hadlock 1 &2) and specific (Siemer) estimated fetal weight (EFW) estimation formulae with birth weight (BW) was made for those 50 gastroschisis cases with ≥2 third trimester scans and last scan ≤2 weeks prior to birth. Results There were 126 abdominal wall defects: 83 gastroschisis and 43 omphalocele. Consistent with international literature, the average maternal age was lower for gastroschisis and rates of smoking higher, while there were more intrauterine deaths and pregnancy terminations in omphalocele. Gastroschisis mothers were more likely living outside Sydney, had more infections in pregnancy and were followed with a larger number of antenatal visits, with a shorter period from the last visit to birth. In omphalocele pregnancies, amniocentesis was more likely performed, with more abnormal results than in gastroschisis fetuses. All EFW formulae had a good correlation between Z score for the last US and actual BW (ICC 0.693–0.815), with Hadlock 2 being the best. Siemer formula had the best correlation from first to the last scan. Gastroschisis newborns were born earlier (36.8 versus 38.2 wks p = .001), with smaller birthweight (2.52 versus 3.03 kg, p < .001), a longer request of intensive care (central line, parenteral nutrition, intubation) and second surgery, along with more multisystem complications (average 1.5 versus 0.7, p = .004) and a longer hospital stay (58.8 versus 36.8 d, p < .001). Conclusion Demographic, antenatal, and pregnancy outcome data for abdominal wall defects correlated well with the international literature. Hadlock 1–2 gave the most consistent EFW estimate, with all formulae showing good correlation.

Gestational Outcomes of Pregnancies with Prenatally Detected Gastroschisis and Omphalocele

Objective: To evaluate and compare the outcomes of pregnancies with prenatally detected gastroschisis and omphalocele. Materials and Methods: We retrospectively evaluated prenatally detected gastroschisis and omphalocele cases. Cases were compared in terms of maternal demographic and clinical characteristics as well as pregnancy and neonatal outcomes. Results: This study consisted of 17 gastroschisis and 30 omphalocele cases. Only one case with gastroschisis was terminated due to additional severe limb deformities. Seventeen out of 30 cases of omphalocele were terminated for various reasons (56.7%). All patients with gastroschisis had surgical repair, while 8 out of 13 omphalocele cases had surgery. One patient with an omphalocele died after surgery due to sepsis. Six cases of gastroschisis also died in the neonatal period due to various reasons (6/16, 37.5%). Conclusion: Additional genetic disorders are more frequent in those with omphalocele cases, and they are more frequently terminated during gestation that the gastroschisis fetuses.

EP14.06: Correlation of 3D fractional limb volumes with birthweight in fetuses with gastroschisis

Estimated fetal weight (EFW) calculations in fetuses with gastroschisis is inherently inaccurate due to the abdominal wall defect and often yield small fetal size. The objective of this study is to compare the accuracy of 3D fractional limb volumes, specifically, thigh and arm volume percentiles versus EFW percentiles in predicting the birth weight percentiles in infants with gastroschisis to develop a more accurate birth weight calculation and improve outcome predictions. With IRB approval, a retrospective chart review of 21 fetuses with gastroschisis form October 2015 - November 2016 at a single institution was performed. Statistical analysis was performed and p<0.05 was considered statistically significant. Utilising Spearman's Rho Correlation, various correlation tests were run between the following: arm volume percentile, thigh volume percentile, and EFW percentile versus birth weight percentiles. There is a statistically significant correlation between arm volume percentile and birth weight percentile. There was no statistical significant correlation between thigh volume percentile, EFW percentile, and birth weight percentile. The main limitation of the study is a small sample size (21 patients). Our results show the possibility of further utilisation of arm volume percentiles for predicting birth weight percentiles in infants with gastroschisis. The results also showed that the current practice of utilising ultrasound measurements of EFW percentile, as well as the proposed thigh volume percentiles, have limited application in determining birth weight percentile in infants with gastroschisis. These results express the need for further research to determine a more accurate prenatal approach to aid in prediction of birth weight in gastroschisis fetuses. EP14.06: Table 1. Results

Fetal Growth Pattern and Prediction of Low Birth Weight in Gastroschisis

Objectives: To examine growth patterns and predictions of low birth weight in gastroschisis fetuses. Methods: This is a retrospective study of isolated fetal gastroschisis before week 24. Ultrasound fetal biometric parameters - head circumference (HC), abdominal circumference (AC), femur length, HC/AC ratio and estimated fetal weight (EFW) - were plotted against normal growth charts. The percentage difference in mean values between normal and gastroschisis fetuses was determined. The growth deficit for each ultrasound parameter was calculated for the fetuses with 1 examination in each designated period (period I: weeks 20-25⁺⁶; period II: weeks 26-31⁺⁶; period III: from week 32 until term). For low birth weight prediction, measurements below the 10th percentile in periods I and II were tested. Results: Seventy pregnancies were examined. For all fetal parameters, the mean measurements were lower in fetuses with gastroschisis (p < 0.005). The EFW revealed an increased growth deficit between the periods (p = 0.030). HC was predictive of low birth weight in period II (OR = 6.07; sensitivity = 70.8%; specificity = 71.4%). Conclusions: Fetuses with gastroschisis present a reduced growth pattern, and it appears that no growth recovery occurs after the growth restriction has been established. Between week 26 and week 31⁺⁶, an HC measurement below the 10th percentile is associated with an increased risk of low birth weight.

Enteric Nervous System Impairment in Gastroschisis

After surgical repair of gastroschisis, most neonates exhibit severe intestinal dysmotility. We hypothesized that impaired development of the enteric nervous system or interstitial cells of Cajal (ICC) network contributes to impaired intestinal motility in gastroschisis. We evaluated this hypothesis in a rat model of gastroschisis. Gastroschisis was created surgically in rat fetuses on gestational day 18, under general anesthesia, and small bowel was harvested on day 22. Intestinal weight-to-length (IW/L) ratio, and small-bowel wall thickness were assessed. Specimens were processed for hematoxylin-eosin staining or immunohistochemistry with specific markers for neuronal cells (Hoxb5), glial cells (GFAP, S100), and ICCs (c-kit). Myenteric plexus maturation was assessed morphologically and compared with sham and control fetuses. Stage of development of the myenteric plexus was graded from 1 (mature) to 3 (very immature) comparatively with specimens from E16 to E22 control fetuses. Compared with sham-operated or control fetuses, gastroschisis was associated with increases in mean intestinal weight/intestinal length (IW/L) ratio, and mean thicknesses of the total, muscular, and submucosal layers of the small-bowel wall. The myenteric plexus were present in the small bowel from fetuses with gastroschisis, however all exhibited abnormal myenteric plexus maturation. Thus, of the gastroschisis fetuses, 55% had an aspect similar to the immature myenteric plexus of E19-E20 fetuses and 45% to the very immature mesenteric plexus observed in E16-E18 fetuses. When compared with sham and control groups, ICCs were less abundant in eviscerated small bowel in the gastroschisis group and often exhibited weak c-kit staining or an abnormally round shape without branches. Hoxb5, a marker for enteric neuroblasts and neuronal precursors, was expressed similarly in myenteric plexuses in all groups. S100 or GFAP staining showed the presence of glial cells within the myenteric plexuses in all groups. The S100 expression level was similar in all groups. In contrast, the GFAP expression level was higher in the gastroschisis group than in the sham and control groups. Our results suggest that delayed maturation of the enteric nervous system combined with impaired ICC network development may largely explain the intestinal dysmotility seen in neonates with gastroschisis.

Clinical Presentation of Children With Gastroschisis and Small for Gestational Age

Gastroschisis (GS) is defined as a full-thickness paraumbilical abdominal wall defect associated with evisceration of fetal abdominal organ. Although the concomitant nongastrointestinal anomalies and aneuploidy are rarely presented, fetal growth restriction is common. The aim of this study is to compare the primary and secondary outcomes of GS between infants small for gestational age (SGA) and those appropriate for gestational age as well as term and late preterm infants. Chart records of neonates born with gestational age at or more than 34 weeks were reviewed. All babies received repair procedure immediately after birth. SGA was defined as birth weight for gestational age below the 10th percentile. The primary outcomes were the length of hospital stay, duration of total parental nutrition used, and the surgical complications. The secondary outcome was the percentile of body weight at 6 months old. There were 21 babies diagnosed with GS from January 1990 to January 2010 at Kaohsiung Chang Gung Memorial Hospital. Four (19%) babies expired soon after operation. Nine (53%) of the 17 surviving babies had SGA. Length of hospital stay, surgical complications, and the percentile of body weight at 6 months old were significantly poorer for the SGA compared with appropriate for gestational age group (p = 0.005, 0.050, and 0.035). Furthermore, preterm neonates in SGA group had lower Apgar scores at 1 minute and 5 minutes than did term neonates (p = 0.045 and 0.031). SGA commonly occurred in GS cases and it was associated with longer hospital stay, more operative complications, and less body weight gain. Our conclusion may provide informative data to parents of GS fetuses during prenatal consultation, and reminds us that long-term follow-up of these cases could be necessary.

Gastroschisis in Mice Lacking Aortic Carboxypeptidase-Like Protein Is Associated With a Defect in Neuromuscular Development of the Eviscerated Intestine

Mice lacking aortic carboxypeptidase-like protein (ACLP) exhibit a gastroschisis (GS) like abdominal wall defect. The objectives of this study were to evaluate the pathophysiological features of GS in ACLP mice and to characterize the neuromuscular development of the eviscerated intestine (EI). ACLP mice were created by heterozygous mating from previously generated mice with targeted disruption of ACLP. Specimens were processed for H&E, and immunohistochemistry for smooth muscle cells [SMC, alpha-smooth muscle actin (alpha-SMA) antibody], interstitial cells of Cajal (ICC, c-kit-antibody), neural crest cells (NCC, Hox-b5-antibody), and enteric neurons (EN, PGP9.5-, alpha-internexin, and synaptophysin antibody). From 47 fetuses genotyped, 13 (27.7%) were wild type, 20 (42.5%) were heterozygous, and 14 (29.8%) were ACLP homozygous. In GS mice, expression of c-kit, Hox-b5, PGP-9.5, alpha-internexin, and synaptophysin were almost completely absent and only faint alpha-SMA expression was seen in the EI. In contrast, c-kit, Hox-b5, PGP9.5, alpha-internexin, synaptophysin, and alpha-SMA expression in intra-abdominal intestine in GS fetuses was the same as control intestine. The defect observed in ACLP mice closely resembles GS. Absence of ICC, NCC, EN, and immature differentiation of SMC supports an associated defect in neuromuscular development that is restricted to the EI.

Inflammatory response in a rat model of gastroschisis is associated with an increase of NF-kappaB

Babies with gastroschisis have high morbidity, which is associated with inflammatory bowel injury caused by exposure to amniotic fluid. The objective of this study was to identify components of the inflammatory response in the intestine and liver in an experimental model of gastroschisis in rats. The model was surgically created at 18.5 days of gestation. The fetuses were exposed through a hysterotomy and an incision at the right of the umbilicus was made, exposing the fetal bowel. Then, the fetus was placed back into the uterus until term. The bowel in this model had macro- and microscopic characteristics similar to those observed in gastroschisis. The study was conducted on three groups of 20 fetuses each: gastroschisis, control, and sham fetuses. Fetal body, intestine and liver weights and intestine length were measured. IL-1beta, IL-6, IL-10, TNF-alpha, IFN-gamma and NF-kappaB levels were assessed by ELISA. Data were analyzed statistically by ANOVA followed by the Tukey post-test. Gastroschisis fetuses had a decreased intestine length (means +/- SD, 125 +/- 25 vs 216 +/- 13.9; P < 0.005) and increased intestine weight (0.29 +/- 0.05 vs 0.24 +/- 0.04; P < 0.005). Intestine length correlated with liver weight only in gastroschisis fetuses (Pearson's correlation coefficient, r = 0.518, P = 0.019). There were no significant differences in the concentrations of IL-1beta, TNF-alpha or IFN-gamma in the intestine, whereas the concentration of NF-kappaB was increased in both the intestine and liver of fetuses with gastroschisis. These results show that the inflammatory response in the liver and intestine of the rat model of gastroschisis is accompanied by an increase in the amount of NF-kappaB in the intestine and liver.

Maturity of the Myenteric Plexus Is Decreased in the Gastroschisis Rat Model

Background: Amniotic fluid (AF) and its components, such as fetal urine and meconium, may lead to intestinal alterations in gastroschisis, which cause immaturity of the myenteric plexus and consequent intestinal hypomotility and malabsorption. In this study we identified morphological and histological alterations of the intestine and the myenteric plexus with two different times of exposure to AF. Methods: The experimental gastroschisis was achieved at two different gestational ages, on day 18.5 (E18.5) and day 19.5 (E19.5) of gestation, in fetal rats which were divided into 3 subgroups: control, sham and gastroschisis. We measured fetal body weight (BW), intestinal weight (IW) and intestinal length (IL). The layers of intestinal wall and myenteric plexus were evaluated by hematoxylin and eosin staining (HE staining) and immunofluorescence (α-internexin), respectively. Results: BW was not significantly different among the control, sham and gastroschisis groups at both ages. IW and IL were larger and shorter, respectively, in the gastroschisis fetuses (p < 0.001) at both ages. Intestinal diameters and wall layers presented significant differences among control, sham and gastroschisis fetuses at both ages (p < 0.001), but the time of exposure to AF compromised the serous membrane, D-II (diameter II, p < 0.001) and IL (p = 0.001). α-Internexin presented more intensive immunoreactivity in gastroschisis fetuses at E18.5. Conclusions: In gastroschisis, the longer the time of exposure to AF, the more severe bowel impairment will be, especially with regard to IL and the serous layer, and the more immature the myenteric plexus will be.

Aminiotic Fluid and Intrauterine Growth Restriction in a Gastroschisis Fetal Rat Model

Fetuses with digestive anomalies such as gastroschisis may present intrauterine growth restriction (IUGR) and shortened intestines. Objective: The aim of this study was to assess the influence caused by amniotic fluid (AF) in intestinal length and somatic growth in an experimental gastroschisis fetal model at two distinct gestational ages. Material and Method: Fetal rats were operated according to Correia-Pinto on 2 different days of gestation: day 18.5 (group I) and day 19.5 (group II). Each group was divided into three sub-groups: fetuses with gastroschisis (G), control (C) and sham(S). Body measurements and histological analysis were done. Result: Body measurement analysis showed: average body weight (g) in group I was G = 5.32, C = 5.68, S = 5.86; group II was G = 5.32, C = 5.80, S = 5.66. Average intestine weight (g) in group I was G = 0.283, C = 0.238, S = 0.231; group II was G = 0.272, C = 0.231, S = 0.233. Average intestine length (mm) in group I was G = 125, C = 216, S = 209; group II was G = 148, C = 226, S = 226. Histological analysis showed a decrease in the number and size of the intestinal microvillae and a light edema of serosa. Conclusion: Gastroschisis had a direct correlation with IUGR and the time of exposure of the fetuses to AF had no influence on body weight in gastroschisis fetuses but did interfere with intestinal length.

Gastroschisis in the rat model is associated with a delayed maturation of intestinal pacemaker cells and smooth muscle cells

Background A pacemaker system is required for peristalsis generation. The interstitial cells of Cajal (ICC) are considered the intestinal pacemaker, and are identified by expression of the c- kit gene—encoded protein. Gastroschisis is characterized by a severe gastrointestinal dysmotility in newborns. In spite of this clinical picture, few studies have focused on smooth muscle cells (SMC) morphology and none on ICC. Therefore, their morphology has been studied in fetuses at term in the rat model of gastroschisis. Methods At 18.5 day’s gestation (E18.5), 10 rat fetuses were killed, 10 underwent surgical creation of gastroschisis, and 10 underwent manipulation only. The small intestine of the latter 2 groups was harvested at E21.5. Specimens were processed for H&E, c- kit and actin (alpha smooth muscle antibody [α-SMA]) immunohistochemistry, and trasmission electron microscopy (TEM). Results In the controls, SMC were c- kit+ and α-SMA+, with labeling intensity increasing by age. At E21.5, some cells around the Auerbach’s plexus were more intensely c- kit+, and differentiating ICC were seen under TEM at this level. Gastroschisis fetuses had no c- kit+ cells referable to ICC. In the more damaged loops, SMC were very faintly c- kit+ and α-SMA+. Under TEM, there were few differentiated SMC and no presumptive ICC. In the less-damaged loops, SMC were faintly c- kit+ and α-SMA+ and had ultrastructural features intermediate between those of E18.5 and E21.5 controls; ICC were very immature. Conclusions ICC and SMC differentiation is delayed in gastroschisis with the most damaged loops showing the most incomplete picture. These findings might help in understanding the delayed onset of peristalsis and the variable time-course of the recover seen in babies affected by gastroschisis.

Fetal gastrointestinal motility in a rabbit model of gastroschisis

Purpose Gastrointestinal (GI) dysmotility occurs frequently in full-term infants with gastroschisis (GS). Although controversial, preterm delivery of infants with GS has been advocated to prevent the development of GI dysmotility, and understanding the etiology of gestational-related bowel injury may lead to prenatal therapies. Using a fetal rabbit model, the authors assessed in vivo and in vitro GI motility in preterm GS fetuses. Methods On gestation day 24 (term, 31), surgery was performed in maternal rabbits and GS induced in fetuses, whereas control fetuses underwent sham procedures. On gestation day 29, both groups of fetuses received ultrasound-guided intragastric injection of fluorescein and colored microspheres. Two hours after injection, fetuses were delivered by cesarean section and stomach and small intestine harvested intact. “GI motility” was calculated as the distance traveled by fluorescein divided by total length. In vitro studies of fetal gastric muscle strips contractility responses to bethanechol, a cholinergic agonist, were assessed in an organ bath system. Data were analyzed as paired and unpaired t tests and expressed as means ± SEM. Results GS reduced fetal body weight and intestinal length compared with controls (28.4 ± 1.4 v. 33.5 ± 1.5 g, 36.9 ± 1.8 v. 25.9 ± 1.2 cm; P < .05, respectively). Fetuses with GS showed markedly reduced in vivo GI motility (51.4 ± 2.9 v 24.8 ± 2.7%; P < .05) and in vitro gastric contractile tension (769 ± 53 v 396 ± 26 mNcm 2; P < .05). Conclusions GI exposure to amniotic fluid reduces intestinal motility and gastric contractility functions in the preterm rabbit fetus. The results suggest that GS-associated impairment of GI neuromuscular functions occurs in utero, before term, and may be responsive to manipulation of amniotic fluid content or other therapeutic interventions.

Impairment of nutrient uptake in a rabbit model of gastroschisis

Infants with gastroschisis (GS) commonly require total parenteral nutrition and prolonged hospitalization because of intestinal dysfunction resulting from dysmotility and/or malabsorption. To investigate prepartum small intestinal (SI) nutrient absorption in GS, a fetal rabbit model was surgically created on gestational day 24 (term, 31 to 33 days) in 11 time-mated New Zealand White does in each left ovarian-end fetus. Each right ovarian-end fetus served as a control (C) and was manipulated only. All does, 10 of 11 GS fetuses (91%), and 8 of 11 C fetuses (73%) survived to gestational day 30. GS fetuses had significantly reduced total body weights, SI weights, and SI lengths compared with C fetuses. Using the everted mucosal sleeve technique, the uptakes of an amino acid (proline) and a sugar (glucose) were determined. The uptakes of proline per milligram SI, proline per centimeter SI, and glucose per milligram SI were significantly impaired in GS fetuses compared with C fetuses ( P < .04 by Student's paired t test). The uptake of glucose per centimeter SI was also reduced in GS fetuses, but not significantly. Uptake capacities (a measure of the entire SI's ability to absorb a given nutrient) were significantly reduced in GS fetuses compared with C fetuses (proline, 2,670 ± 612 nmol/min/entire SI v 6,842 ± 399 nmol/min/entire SI, P < .008 by Student's paired t test; glucose, 402 ± 69 nmol/min/entire SI v 950 ± 103, P < .008 by Student's paired t test).

An improved model of experimental gastroschisis in fetal rabbits

Previous animal models of gastroschisis have been associated with high mortality and variable degrees of intestinal evisceration. Using current fetal surgical techniques, an improved model of gastroschisis in fetal rabbits was developed. Twenty-eight time-mated New Zealand white rabbits underwent hysterotomies and fetal exposure on gestational day 25 (33-day gestation). Control fetuses (C) underwent fetal manipulation only. Gastroschisis fetuses (GS) had creation of right midabdominal wall defects. Twenty-five of 28 does (89%), 9 of 13 C fetuses (69%), and 18 of 22 GS fetuses (82%) survived. At the time of cesarean delivery 5 days later, GS fetuses had significantly lower body weights, intestinal lengths, and mucosa/submucosa height ratios (a measure of bowel wall edema), and significantly greater intestinal densities when compared with C fetuses ( P < .05, t test). This study demonstrates that (1) gastroschisis abdominal wall defects can be created in fetal rabbits with high survival rates; (2) experimental gastroschisis is associated with a profound decrease in fetal weight; and (3) eviscerated intestine is heavier, shorter, and thickened compared with normal control intestine, mimicking the clinical situation.