Impairment of nutrient uptake in a rabbit model of gastroschisis

Epithelial changes of congenital intestinal obstruction in a rat model

Introduction

Intestinal atresia is a rare congenital affliction that is often associated with severe bacterial infections despite adequate neonatal surgery. Previous studies have focused on enteric nervous system variations. We hypothesized that epithelial systems (ES) may also be involved in the pathophysiology of postnatal disorders.

Materials and methods

Global gene expression was measured by transcriptomic analysis in a rat model of induced intestinal atresia. The analyses then focused on genes involved in ES (enterocytes and goblet cells). Rat fetus small intestines at various stages of development (ED15, ED17, ED19, and ED21, n = 22), were used as non-operated controls and compared to the upper and lower segments of rat fetus small intestines with an induced atresia (n = 14; ligature at ED18). The pattern of gene expression was then confirmed by histochemistry, electron microscopy, and RT-qPCR.

Results

From ED15 to ED21, the expression of several genes exhibited a physiological increase of ES markers, with a significant increase at the end of gestation. The operated embryos exhibited significantly higher variations of gene expression in the proximal segment than in the distal segment in terms of absorption and the epithelial barrier. An increase in goblet cells and markers was observed in the proximal segment compared to the controls.

Conclusion

Fetal intestinal obstruction accelerates maturation in the proximal segment and disrupts the intestinal wall in the distal segment, with a decrease in the number of mucosal cells. Moreover, the epithelial cells underwent significant changes, supporting the notion that intestinal disorders involve more than the ENS.

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.

Bowel-defect disproportion in gastroschisis: does the need to extend the fascial defect predict outcome?

BACKGROUND/PURPOSE

Validated outcome prediction for gastroschisis (GS) permits early risk stratification. The aim of our study was to determine whether the need for GS defect extension: (a) correlates with bowel injury severity at birth, and (b) predicts outcome.

METHODS

A national dataset was used to study GS babies born between 2005 and 2010. The primary outcome was days of parenteral nutrition (PN). Outcomes were analyzed according to the need for fascial extension to facilitate closure or silo placement as follows: Group 1, no extension; Group 2A, extension <2 cm; Group 2B, extension >2 cm. Univariate and where appropriate, multivariate analyses were used.

RESULTS

Of 507 cases, 402 had complete defect extension data: Group 1, 297 (73%); Group 2A, 67 (17%); Group 2B, 42 (10%). Group 2B patients had higher rates of atresia, perforation and severe matting (P = 0.001) and required more days on PN compared to Group 1 (63.0 ± 100.4 vs. 39.7 ± 44.5 days: CI 1.2-45.1; P = 0.03). Multivariate analysis revealed that the presence of atresia (P = 0.01) and surgical site (P = 0.001) or bloodstream (P = 0.001) infections were predictive of prolonged PN; however, the need for fascial extension was not.

CONCLUSIONS

GS newborns who require fascial extension are more likely to have complicated GS and are at greater risk for adverse outcome, although it is not an independent predictor of the latter.

Does administering albumin to postoperative gastroschisis patients improve outcome?

OBJECTIVES

Newborns who undergo surgery for gastroschisis correction may present with oliguria, anasarca, prolonged postoperative ileus, and infection. New postoperative therapeutic procedures were tested with the objective of improving postoperative outcome.

PATIENTS AND METHODS

One hundred thirty-six newborns participated in one of two phases. Newborns in the first phase received infusions of large volumes of crystalloid solution and integral enteral formula, and newborns in the second phase received crystalloid solutions in smaller volumes, with albumin solution infusion when necessary and the late introduction of a semi-elemental diet. The studied variables were serum sodium and albumin levels, the need for albumin solution expansion, the occurrence of anasarca, the length of time on parenteral nutrition, the length of time before initiating an enteral diet and reaching a full enteral diet, orotracheal intubation time, length of hospitalization, and survival rates.

RESULTS

Serum sodium levels were higher in newborns in the second phase. There was a correlation between low serum sodium levels and orotracheal intubation time; additionally, low serum albumin levels correlated with the length of time before the initiation of an oral diet and the time until a full enteral diet was reached. However, the discharge weights of newborns in the second phase were higher than in the first phase. The other studied variables, including survival rates (83.4% and 92.0%, respectively), were similar for both phases.

CONCLUSIONS

The administration of an albumin solution to newborns in the early postoperative period following gastroschisis repair increased their low serum sodium levels but did not improve the final outcome. The introduction of a semi-elemental diet promoted an increase in body weight at the time of discharge.

Evolution of critically ill patients with gastroschisis from three tertiary centers

OBJECTIVES AND INTRODUCTION: Gastroschisis is a congenital abdominal wall defect with increasing occurrence worldwide over the past 20-30 years. Our aim was to analyze the morbidity of newborns after gastroschisis closure, with emphasis on metabolic and hydroelectrolyte disturbances in patients at three tertiary university centers.

METHODS

From January 2003 to June 2009, the following patient data were collected retrospectively: (A) Background maternal and neonatal data: maternal age, prenatal diagnosis, type of delivery, Apgar scores, birth weight, gestational age and sex; (B) Surgical modalities: primary or staged closure; and (C) Hospital course: levels of serum sodium and levels of serum albumin in the two first postoperative days, number of ventilation days, other postoperative variables and survival. Statistical analyses were used to examine the associations between some variables.

RESULTS

163 newborns were included in the study. Primary closure of the abdominal defect was performed in 111 cases (68.1%). The mean serum sodium level was 127.4 ± 6.7 mEq/L, and the mean serum albumin level was 2.35 ± 0.5 g/dL. Among the correlations between variables, it was verified that hyponatremia and hypoalbuminemia correlated with the number of days on the ventilator but not with the number of days on total parenteral nutrition (TPN); mortality rate correlated with infection. The final survival rate was 85.9%.

CONCLUSION

In newborns with gastroschisis, more aggressive attention to hyponatremia and hypoalbuminemia would improve the outcome.

Elevated amniotic fluid amino acid levels in fetuses with gastroschisis

Our objective was to measure maternal plasma and amniotic fluid amino acid concentrations in pregnant women diagnosed as having fetuses with gastroschisis in the second trimester of pregnancy. Twenty-one pregnant women who had fetuses with gastroschisis detected by ultrasonography (gastroschisis group) in the second trimester and 32 women who had abnormal triple screenings indicating an increased risk for Down syndrome but had healthy fetuses (control group) were enrolled in the study. Amniotic fluid was obtained by amniocentesis, and maternal plasma samples were taken simultaneously. The chromosomal analysis of the study and control groups was normal. Levels of free amino acids and non-essential amino acids were measured in plasma and amniotic fluid samples using EZ:fast kits (EZ:fast GC/FID free (physiological) amino acid kit) by gas chromatography (Focus GC AI 3000 Thermo Finnigan analyzer). The mean levels of essential amino acids (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine) and non-essential amino acids (alanine, glycine, proline, and tyrosine) in amniotic fluid were found to be significantly higher in fetuses with gastroschisis than in the control group (P < 0.05). A significant positive correlation between maternal plasma and amniotic fluid concentrations of essential and nonessential amino acids was found only in the gastroschisis group (P < 0.05). The detection of significantly higher amino acid concentrations in the amniotic fluid of fetuses with a gastroschisis defect than in healthy fetuses suggests the occurrence of amino acid malabsorption or of amino acid leakage from the fetus into amniotic fluid.

Impact of corticosteroid on intestinal injury in a gastroschisis rat model: morphometric analysis

BACKGROUND/PURPOSE

The goal in the treatment of gastroschisis is to prevent intestinal injury. Corticosteroids are known by their effects at the inflammatory response and by the improvement on the intestinal maturity. The authors evaluated the effects of maternal corticosteroid administration on the intestines of rats that underwent fetal gastroschisis.

METHODS

A Correia-Pinto-modified gastroschisis rat model was used. Two groups were assessed: the control group (group 1) and the dexamethasone group (group 2). Each group was composed of control and sham fetuses, and fetuses with gastroschisis. Fetal body weight, intestinal weight, intestinal length, and protein were assessed. Histologic analysis involved measures of intestinal loop diameter, total intestinal wall, mucosa and submucosa, both circular and longitudinal muscle layers, and serosal thicknesses. Differences between groups and subgroups were tested by the analysis of variance method with a significant P value less than .05.

RESULTS

Dexamethasone decreased in all the morphometric data except in the intestinal length. Dexamethasone increased the intestinal protein content in fetuses with gastroschisis, and control and sham fetuses. In both groups, all histologic parameters were increased in fetuses with gastroschisis (P < .0001).

CONCLUSIONS

Dexamethasone caused a substantial decrease in intestinal weight in GFs, increased the intestinal protein content, and it may be useful in decreasing the intestinal damage of gastroschisis.

A multicenter, randomized, double-blind, placebo-controlled trial of the prokinetic agent erythromycin in the postoperative recovery of infants with gastroschisis

BACKGROUND/PURPOSE

The recovery of gut function after repair of gastroschisis is frequently prolonged, and these infants are prone to complications associated with parenteral nutrition. This trial was designed to investigate the effect of the prokinetic agent, erythromycin, on the attainment of full enteral feeding in infants after primary repair of uncomplicated gastroschisis.

METHODS

A multicenter, randomized, double-blind, placebo-controlled trial was used to investigate the effect of enteral erythromycin (3 mg/kg/dose 4 times daily) compared with placebo on the attainment of full enteral feeding tolerance after primary repair of uncomplicated gastroschisis. Eleven neonatal surgical units in the United Kingdom participated in the study. The primary end-point was the time taken to achieve continuous enteral feeding at 150 mL/kg/24 hours sustained for 48 hours.

RESULTS

Of 70 eligible infants, 62 were recruited and randomly divided. There were 30 patients in group I (placebo) and 32 in group II (erythromycin). The groups were comparable in terms of mean gestational age, mean birth weight, extent of evisceration, and degree of intestinal peel. There was no statistically significant difference between the 2 groups in the time taken to achieve full enteral feeding (27.2 v 28.7 days; P =.75). Similarly, no significant differences were found in the incidence of catheter-related sepsis, duration of parenteral nutrition, or time to discharge between the 2 groups.

CONCLUSIONS

Enterally administered erythromycin at a dose of 3 mg/kg 4 times daily conferred no advantage in the time taken to achieve full enteral feeding after primary repair of uncomplicated 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 mNcm2; 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.

Prenatal management of gastroschisis: the place of the amnioexchange procedure

Gastroschisis is a malformation of the anterior abdominal wall that consists of a right paraumbilical defect with bowel loops bathed in the amniotic fluid. The survival rate is now greater than 90% and the prognosis relies mainly on morbidity attributable to bowel dysfunction. Recent research has examined gastrointestinal waste present in amniotic fluid that induces bowel toxicity and an inflammatory process. The amnioexchange procedure (changing the amniotic fluid regularly) involves a new therapeutic approach: reducing bowel injuries in the fetuses. This article shows that there is an inflammatory reaction in human gastroschisis and in the authors' model, and that the clinical and biological data plead for the practice of amnioexchange in human beings. A randomized, controlled study is now needed.

Morphology and mucosal biochemistry of gastroschisis intestine in urine-free amniotic fluid

BACKGROUND/PURPOSE

The aim of this study was to determine the role of urine exposure in gastroschisis on the pathologic and biochemical aspects.

METHODS

The intestines of fetal rabbits with gastroschisis (group G), gastroschisis and urethral ligation (group GL), and normal controls (group C) were studied by measuring weigh and length, intestinal diameter and wall thickness, and thickness of each intestinal layer. Number and length of villi and villi edema were evaluated. Total protein and DNA were measured in intestinal homogenate. Lactase activity and alkaline phosphatase activity were analyzed in isolated microvilli membranes.

RESULTS

Intestinal length, diameter, and wall thickness were significantly different in groups G and GL compared with C but not between groups G and GL. The same was true for the thickness of the internal muscular and serosa, villi length, and villi edema. Serosal reaction was milder in group GL than in group G, and absent in C. Total protein, lactase activity, and alkaline phosphatase activity were also significantly different in G and GL compared with C but not between G and GL.

CONCLUSIONS

Urine in amniotic fluid causes an increased serosal reaction but does not account for the mucosal enzyme dysfunction.

Fetal protein loss in gastroschisis as an explanation of associated morbidity

OBJECTIVE

Our purpose was to examine whether protein deficiency in utero develops in fetuses with gastroschisis.

STUDY DESIGN

Twelve infants with prenatally diagnosed gastroschisis were compared with 29 control infants without gastroschisis and 2 infants with exomphalos who were delivered between 35 and 42 weeks of gestation. The groups were compared for birth weight, cord serum total protein and amniotic fluid total protein, and alpha-fetoprotein concentrations. The amniotic fluid samples were collected when the amniotic membranes were ruptured either during cesarean delivery or at artificial rupture of the membranes, and umbilical cord blood was obtained after delivery.

RESULTS

In the 10 cases of gastroschisis in which cord serum total protein was measured, the median concentration was 51 g/L (range, 43-61 g/L) and was significantly lower than the median level of 62 g/L (range, 47-78 g/L) in the control group (P <.001). In the 8 cases of gastroschisis in which amniotic fluid total protein and alpha-fetoprotein concentrations were measured, the respective median levels were 5.1 g/L (range, 4.3-18.4 g/L) and 5.0 g/L (range, 2.4-13.2 g/L), which were significantly higher than the median levels of 2.0 g/L (range, 0.5-5.4 g/L) and 0.8 g/L (range, 0.5-1.7 g/L) in the control group (P <.0001). The ratio of amniotic fluid to cord serum total protein was significantly higher than that in the cases of exomphalos and in the control group (P <.001). The median birth weight in the neonates with gastroschisis was 2400 g (range, 1192-3155 g) and was significantly lower than the median value of 3535 g (range, 2520-4680 g) in the control group (P <.0001).

CONCLUSIONS

Fetuses with gastroschisis have protein loss that could partly explain associated morbidity. However, whether this is a major contributor to poor fetal outcome remains to be shown.

Partial bladder outlet obstruction in the fetal rabbit

PURPOSE

We developed and tested an animal model of bladder dysfunction due to posterior urethral valves using partial outlet obstruction of the fetal rabbit bladder.

MATERIALS AND METHODS

Partial bladder outlet obstruction of fetal rabbit bladders was created on day 23 of gestation. Of the litter of 8 to 10 fetuses half was obstructed and the remainder served as controls. The doe and fetuses were sacrificed on day 30 of gestation (full term 31 to 32 days) and the fetal bladders were removed. Bladders that had doubled in weight from the average bladder weight of the control littermates were deemed sufficiently obstructed. Hematoxylin and eosin staining was performed and bladder strip response to 32 Hz. field stimulation, 200 microM. bethanechol and 200 mM. potassium chloride was measured.

RESULTS

Average body weight did not differ between the control and obstructed fetuses, indicating that surgery did not hinder fetal development. Hematoxylin and eosin staining confirmed smooth muscle cell hypertrophy and increased connective tissue in the obstructed bladders. Obstructed bladder strips responded significantly less to field stimulation, and significantly more to bethanechol and potassium chloride (mean plus or minus standard deviation 5.18 +/- 1.52, 6.29 +/- 1.3 and 10.15 +/- 2.18 x force per/100 mg. tissue, respectively)than control bladder strips (9.0 +/- 1.19, 3.5 +/- 0.46 and 6.16 +/- 1.33 x force per/100 mg. tissue, respectively) suggesting that denervation supersensitivity may have resulted from obstruction.

CONCLUSIONS

Partial outlet obstruction of the fetal rabbit bladder results in bladder hypertrophy and dysfunction but these changes are markedly different from those in the adult rabbit. Since rabbit fetal development is delayed compared to human fetal development, this model can be used to assess the consequences of posterior urethral valves.

Enterocytic gene expression is altered in experimental gastroschisis

Gastroschisis is a congenital anomaly in which exposure of the intestines to amniotic fluid throughout fetal life results in nutrient malabsorption. To begin to understand the molecular basis underlying epithelial changes in this condition, we investigated enterocytic gene expression during fetal development. Gastroschisis was surgically created at 24 days gestation (term = 31 days) in fetal rabbits; sham-operated and unoperated fetuses served as controls. Bowel was harvested at 28 and 31 days gestation. Cellular lactase expression was detected using immunohistochemistry, and apolipoprotein A-I and cellular retinol binding protein II (CRBPII) mRNA levels were quantitated using Northern blot analysis. Despite absence of gross histological changes in the mucosa, lactase protein expression and apolipoprotein A-I and CRBPII mRNA expression were decreased in intestine from gastroschisis compared to sham-operated animals. Expression of GAPDH (a housekeeping gene) increased over the same period, suggesting that the changes in enterocytic absorptive gene expression associated with gastroschisis were relatively specific. In conclusion, a decrease in expression of a variety of genes involved in nutrient absorption and trafficking within the enterocyte may contribute to the absorptive defects seen in this gastroschisis.

Are babies with gastroschisis small for gestational age?

A large proportion of babies with gastroschisis (GS) have low birth weights. It is not clear, however, whether only certain subgroups or the whole population of babies with GS have low birth weights. The aim of this study was to ascertain if the birth weights of babies with GS are significantly lower than those of the general population and to determine if the birth weights of babies with GS from two different populations were significantly different. From 1969 to 1995, 44 babies with GS were treated at Auckland Children's Hospital, New Zealand. From 1980 to 1993, 69 babies were treated at Birmingham Children's Hospital, England. For each group, the mean birth weight relative to the mean birth weight for gestation (WtStdev) was significantly different from zero (Auckland = -0.806, Birmingham = -0.762, P < 0.001, one-sample analysis). The mean WtStdev scores from each centre were not significantly different from each other. Our data demonstrate that the birth weights of babies with GS are significantly lower than those of the general population and are similar in different populations. These findings support the notion that a normally functioning intestinal tract is essential for normal fetal growth.

Effect of intraamniotic dexamethasone administration on intestinal absorption in a rabbit gastroschisis model

Infants with gastroschisis experience delayed intestinal motility and absorption for several weeks after birth. This intestinal dysfunction is believed to occur primarily in the third trimester and to be largely caused by the prolonged exposure of the intestine to amniotic fluid. Previous studies have shown that prenatal steroid administration will enhance mucosal disaccharidase activity and nutrient uptake. The present study evaluates the effects of dexamethasone on intestinal function in a rabbit fetal gastroschisis model. Thirty-four fetuses from 10 New Zealand white rabbits were divided into three groups: (1) gastroschisis group (GSC, n = 10), gastroschisis was created on gestational day (GD) 24 (term = 31 to 33 days); (2) dexamethasone group (GSD, n = 10), after the creation of gastroschisis, a small osmotic pump was placed into the rabbit doe for dexamethasone infusion into the fetal amniotic cavity for 7 days (0.2 microgram/g/d); (3) normal group (NF, n = 10), unoperated littermates from the GSC group. There were no maternal deaths, and fetal survival rate was 85%. The fetal small intestinal disaccharidase enzyme, lactase (UE/g protein), was markedly decreased in GSC fetuses. It was increased 70% in the GSD group but lower than in normal fetuses (GSC = 10.0 +/- 1.6; GSD = 17.3 +/- 1.6 [GSD versus GSC, P < .05]; NF = 48.0 +/- 6.7). Maltase activity in the GSD group was significantly increased (GSC = 7.2 +/- 1.1; GSD = 13.9 +/- 1.8 [GSD versus GSC, P < .05]; NF = 12.2 +/- 1.3).(ABSTRACT TRUNCATED AT 250 WORDS)

Etiology of intestinal damage in gastroschisis. III: Morphometric analysis of the smooth muscle and submucosa

The response of intestinal smooth muscle to injury may explain some of the motility derangement observed in infants with gastroschisis. An experimental model of gastroschisis was created and a detailed analysis of the intestinal muscle layer was undertaken to study this response. An abdominal wall defect and evisceration of the bowel were carried out in fetal lambs at 80 days' gestation (full term, 145 days), with delivery at 100 days or 135 days. Smooth muscle cell size and number were determined by detailed morphometric analysis, proliferative rate was determined using proliferating cell nuclear antigen staining, and collagen content was determined by morphometry after Verhoeff van Gieson staining. Compared with controls, there was a significant increase in cell number (hyperplasia) in the gastroschisis animals at 100 days and an increase in size (hypertrophy) at 135 days. The proliferation rate of smooth muscle was significantly lower and the submucosal collagen thickness was significantly greater in the gastroschisis animals during both periods. These data suggest that gastroschisis is characterised by initial hyperplasia, with subsequent diminution in smooth muscle proliferation. The hypertrophy may reflect a response to injury in which cell growth instead of proliferation occurs. The persistent elevation in collagen throughout gestation in animals with gastroschisis may be a reflection of this hyperplastic response in the smooth muscle cells and an important factor in the bowel-wall thickening. This deranged pattern of growth may lead to the clinical problems observed in human infants with this disease.

Effect of maternal ethanol intake on fetal rabbit gastrointestinal development

Maternal ingestion of alcohol is believed to be one factor that greatly influences the development of intrauterine growth retardation (IUGR) and postnatal growth failure. The present study was undertaken to determine whether maternally ingested alcohol adversely affects fetal growth and intestinal mucosal function. Five time-mated New Zealand white rabbit does were given ethanol intravenously (ETH group) (30% vol/vol; 1.0 g/kg/d) on gestational days (GD) 15 through 29 (term, 31 days). Two other rabbits received the same dose of ethanol. Maternal, fetal, and amniotic fluid alcohol levels were measured on GD 24. Four control rabbits (SH group) received normal saline (25 mL, intravenously). At term, the animals were delivered by cesarean section and killed. Seventeen of the 42 ETH fetuses survived the study period (43%); all 24 SH fetuses survived. On GD 24, within 60 minutes after maternal ethanol infusion, the fetal blood alcohol concentration (BAC) increased to 153 +/- 1.97 mg/dL (v maternal, 179 +/- 1.75 mg/dL); the amniotic ethanol level increased to 46 +/- 1.32 mg/dL. Birth weight was lower in the ETH group (46.88 +/- 2.21 g) than in the SH group (55.78 +/- 1.80 g) (P < .01). Disaccharidase activity, an indicator of intestinal mucosal function, showed that lactase activity (per milligram of protein) was significantly lower in ETH fetuses (2.60 x 10(-2) +/- 0.22 UE/mg) than in SH fetuses (3.50 x 10(-2) +/- 0.25 UE/mg) (P = .01); maltase activity and protein content were not affected significantly. This report provides the first description of the adverse effects of maternal alcohol ingestion on the small intestinal mucosal function of the fetal rabbit.