Risk factors in congenital abdominal wall defects (omphalocele and gastroschisi): a study in a series of 265,858 consecutive births

Gastroschisis with Hirschsprung's disease: a therapeutic dilemma

The authors report a case of a neonate with gastroschisis, which, after repair, was further complicated by the diagnosis of Hirschsprung's disease. The authors discuss the diagnostic and management dilemmas posed by the coexistence of these two conditions for the clinician.

Teratogens inducing congenital abdominal wall defects in animal models

Congenital abdominal wall defects are common anomalies which include gastroschisis, omphalocele and umbilical cord hernia. Recent reports indicate that gastroschisis is increasing in prevalence, whereas omphalocele has remained steady, suggesting that environmental factors may play a part in their pathogenesis. The aim of this study is to review animal teratogen studies resulting in abdominal wall defects to investigate their possible causes. Each report was examined not only for the teratogens causing the defects, but also to carefully identify the defect occurring and its correlation with the known clinical anomalies. We found many discrepancies between the nomenclature used by animal teratology investigators and that used by clinicians. We were able to confirm the induction of gastroschisis by 22 teratogens, omphalocele by 9 teratogens and umbilical cord hernia by 8. There is no doubt that environmental factors may be responsible, at least in part, for all three of the clinical abdominal wall defects. Future studies should take care to appreciate the differences between these anomalies and describe them in detail, so that accurate and meaningful conclusions can be obtained.

Predicting adverse neonatal outcomes in fetuses with abdominal wall defects using prenatal risk factors

OBJECTIVE

The aim of this study was to determine whether prenatal variables can predict adverse neonatal outcomes in fetuses with abdominal wall defects.

STUDY DESIGN

A retrospective cohort study that used ultrasound and neonatal records for all cases of gastroschisis and omphalocele seen over a 16-year period. Cases with adverse neonatal outcomes were compared with noncases for multiple candidate predictive factors. Univariable and multivariable statistical methods were used to develop the prediction models, and effectiveness was evaluated using the area under the receiver operating characteristic curve.

RESULTS

Of 80 fetuses with gastroschisis, 29 (36%) had the composite adverse outcome, compared with 15 of 33 (47%) live neonates with omphalocele. Intrauterine growth restriction was the only significant variable in gastroschisis, whereas exteriorized liver was the only predictor in omphalocele. The areas under the curve for the prediction models with gastroschisis and omphalocele are 0.67 and 0.74, respectively.

CONCLUSION

Intrauterine growth restriction and exteriorization of the liver are significant predictors of adverse neonatal outcome with gastroschisis and omphalocele.

The incidence and maternal age distribution of abdominal wall defects in Norway and Arkhangelskaja Oblast in Russia

OBJECTIVES

To determine the foetal incidence of isolated anterior abdominal wall defects (gastroschisis and omphalocele) in the Arkhangelskaja Oblast (AO) in Russia and in Norway, as well as to study the maternal-age distribution of these defects.

STUDY DESIGN

A register-based incidence study.

METHODS

All registered foetuses and newborns with at least 12 weeks of gestation in the populations of AO (141,159) and Norway (293,708) were included. The data covered the period 1995-2004 in AO and 1999-2003 in Norway and were obtained from the malformation register in AO and the Medical Birth Registry of Norway.

RESULTS

The majority of the outcomes with a defect were liveborn in Norway (65%), while in AO the majority were spontaneously or medically aborted (59%). The incidence of anterior abdominal wall defects was 5.4/10,000 (95% confidence limits: +/- 1.7) in AO and 5.1/10,000 +/- 0.8) in Norway, and the ratio of omphalocele to gastroschisis was 1.2 in AO vs. 0.9 in Norway. Gastroschisis was inversely associated with maternal age in Norway.

CONCLUSIONS

Despite a difference in maternal age distribution, there was no difference in the incidence of abdominal wall defects in AO and Norway. Gastroschisis was associated with young maternal age only in Norway, and the higher incidence in maternal age groups younger than 25 warrants further studies about aetiological factors associated with young maternal age.

Rising incidence of gastroschisis and exomphalos in New Zealand

BACKGROUND

An apparent increase in the incidence of gastroschisis and exomphalos has been reported from several parts of the world. The exact mechanism of this trend is unknown. The aim of this study was to determine the regional and national trends in the incidence of gastroschisis and exomphalos in New Zealand.

MATERIAL AND METHODS

This retrospective multicenter study involved collection of data from all 4 tertiary care pediatric surgical centers in New Zealand. The incidence was calculated per 10,000 live births. Data were analyzed to determine the regional and national trends. The statistical analysis was done using linear regression model and Poisson distribution.

RESULTS

The incidence of gastroschisis has increased from 2.96 per 10,000 live births to 5.16 per 10,000 live births between 1996 and 2004. During the same period, the incidence of exomphalos has increased from 0.69 per 10,000 live births to 3.27 per 10,000 live births. Gastroschisis was observed more in younger mothers, whereas exomphalos was associated with older mothers.

CONCLUSION

The incidence of gastroschisis and exomphalos is increasing in New Zealand, which is consistent with worldwide trends in showing the increasing incidence of anterior abdominal wall defects.

Parental age as a risk factor for isolated congenital malformations in a Polish population

Currently available data on the relationship between the prevalence of isolated congenital malformations and parental age are inconsistent and frequently divergent. We utilised the data from the Polish Registry of Congenital Malformations (PRCM) to accurately assess the interplay between maternal and paternal age in the risk of isolated non-syndromic congenital malformations. Out of 902 452 livebirths we studied 8683 children aged 0-2 years registered in the PRCM. Logistic regression was used to simultaneously adjust the risk estimates for maternal and paternal age. Our data indicated that paternal and maternal age were independently associated with several congenital malformations. Based on our data, young maternal and paternal ages were independently associated with gastroschisis. In addition, young maternal age, but not young paternal age, carried a higher risk of neural tube defects. Advanced maternal and paternal ages were both independently associated with congenital heart defects. Moreover, there was a positive association between advanced paternal age and hypospadias, cleft palate, and cleft lip (with or without cleft palate). No significant relationships between parental age and the following congenital malformations were detected: microcephaly, hydrocephaly, oesophageal atresia, atresia or stenosis of small and/or large intestine, ano-rectal atresia or stenosis, renal agenesis or hypoplasia, cystic kidney disease, congenital hydronephrosis, diaphragmatic hernia and omphalocele.

Scheduled preterm delivery for gastroschisis improves postoperative outcome

There are some evidence to suggest that careful antenatal monitoring, scheduled preterm delivery and immediate abdominal wall closure may reduce gastroschisis morbidity. We hypothesised that the advantages of a scheduled preterm delivery balance possible complications related to prematurity. A retrospective study was performed including all cases of gastroschisis born between 1990 and 2004 (n = 69). Cases were categorised in two groups. Group 1 contained gastroschisis cases born between 1990 and 1997. Group 2 contained cases occurring since 1997, when a new management pathway for gastroschisis was established: weekly evaluation of the foetal gut by ultrasound (>28 weeks), corticosteroids, and delivery by scheduled caesarean section at 35 weeks (before if evidence of bowel compromise was present). The primary endpoints of this study were the initiation of oral feeding and the number of re-operation for intestinal obstruction. There was a significantly faster initiation of oral feeding (P < 0.0001), however, duration of parenteral nutrition (34 vs. 38 days) and hospital discharge (53 vs. 58.5 days) was not reduced. There was no complication due to prematurity in group 2. Postoperative outcome was improved with less need for muscular stretching or prosthetic patch and less re-operation for intestinal obstruction (P < 0.05). Scheduled and elective preterm delivery facilitates surgical procedure and shortens the time to first feeding. A delivery at 35 weeks (preferring vaginal delivery) seems to be a good compromise between risks related to prematurity and complications related to intestinal peel.

Increasing prevalence of gastroschisis: population-based study in California

OBJECTIVE

To evaluate time trend of gastroschisis and examine the epidemiological risk factors for gastroschisis.

STUDY DESIGN

This population-based study analyzed the active surveillance data from the California Birth Defects Monitoring Program from 1987 to 2003.

RESULTS

The overall birth prevalence of gastroschisis was 2.6 cases per 10,000 births (908 cases in >3.5 million births). In the adjusted analysis, by using the age of 25 to 29 years as the reference, mothers aged 12 to 15 years had a 4.2-times greater birth prevalence (95% CI, 2.5-7.0), and fathers aged 16 to 19 years and 20 to 24 years had 1.6- and 1.5-times greater birth prevalence (95% CI, 1.1-2.1 and 1.2-1.8), respectively. Compared with non-Hispanic whites and US-born Hispanic, both foreign-born Hispanics and blacks had adjusted prevalence ratio of 0.6 (95% CI, 0.5-0.7 and 0.4-0.9, respectively). In addition, nulliparity was also associated with gastroschisis. Independent of maternal age, paternal age, and maternal ethnicity, the birth prevalence increased 3.2-fold (95% CI, 2.3-4.3) during the 17-year study period.

CONCLUSIONS

The birth prevalence of gastroschisis continues to increase in California, and young, nulliparous women are at the greatest risk of having a child with gastroschisis.

Structural birth defects associated with omphalocele and gastroschisis, Hawaii, 1986-2001

There is limited information on the specific structural birth defects associated with the abdominal wall defects (AWD) omphalocele and gastroschisis, particularly which defects occur with the AWD at greater than expected rates (rates among all infants and fetuses with birth defects other than the AWD). Using data from a population-based birth defects registry in Hawaii, this study calculated the rates for 48 specific structural birth defects among the AWD and compared these rates to the expected rates. There were 60 cases of omphalocele, 96 cases of gastroschisis, and 12,161 infants and fetuses with structural birth defects excluding the AWD among deliveries during 1986-2001. For omphalocele, higher than expected rates were found for 23 (47.9%) of the defects. These involved defects of a variety of organ systems. For gastroschisis, higher than expected rates were found for 8 (16.7%) of the defects, mainly neural tube defects (NTD) and specific defects of the orofacial and gastrointestinal system and the genital and urinary system. Both omphalocele and gastroschisis had elevated rates for NTD, intestinal atresia/stenosis, malrotation of intestines, obstructive genitourinary defects and limb reduction deformities. Certain specific structural birth defects occurred more often than expected with the AWD. The associated birth defects tended to vary between omphalocele and gastroschisis, although there were a few similarities. Due to the small number of cases, further research involving larger amounts of data are warranted.

Prenatal diagnosis of a fetal abdominal eventration: a rare congenital abdominal wall defect

We report a case of abdominal eventration associated with cystic fibrosis, diagnosed by mid-trimester ultrasonography. The defect concerned the abdominal muscles and their aponevrotic sheath, but respected the skin. There was no associated malformation. The outcome was favorable after surgery, and the infant is well at the age of 6 months.

Outcome of antenatally diagnosed abdominal wall defects

OBJECTIVE

To examine the natural history and detailed outcome of antenatally diagnosed abdominal wall defects.

METHODS

This was a retrospective review of the antenatal reports, pediatric surgery records and subsequent follow-up information of all cases of omphalocele and gastroschisis diagnosed in a 10-year period in our tertiary referral center.

RESULTS

There were 109 cases of abdominal wall defects, including omphalocele in 67 cases and gastroschisis in 42 cases. Of the 67 cases of omphalocele there were 26 (39%) with chromosomal abnormalities and 22 (33%) underwent termination of pregnancy, mainly for associated structural abnormalities. Of the ongoing 19 cases there were five (26%) in-utero deaths, 12 (63%) survivors and two (11%) neonatal deaths, both associated with prematurity. Excluding chromosomal abnormalities, the survival rate in isolated omphalocele was 7/16 (44%) whilst it was 5/25 (20%) in those with associated abnormalities. Gastroschisis was isolated in 40 (95%) cases. Among these 40 isolated cases there were two (5%) terminations. Of the 38 ongoing cases, there were two (5%) in-utero deaths, and 36 (95%) live births. Four of the 36 liveborn infants (11%) died in the postoperative period owing to complications of small bowel atresia.

CONCLUSIONS

Although only 18% of infants with antenatally diagnosed omphalocele were alive in the neonatal period, postoperative morbidity was low. The majority (90%) of fetuses with antenatally diagnosed gastroschisis survived to delivery, but the mortality in affected newborns was 11%.

Increasing prevalence of gastroschisis in Europe 1980-2002: a phenomenon restricted to younger mothers?

Gastroschisis is an abdominal wall defect more prevalent in offspring of young mothers. It is known to be increasing in prevalence despite the general decrease in the proportion of births to young European women. We investigated whether the increase in prevalence was restricted to the high-risk younger mothers. We analysed 936 cases of gastroschisis from 25 population-based registries in 15 European countries, 1980-2002. We fitted a Bayesian Hierarchical Model which allowed us to estimate trend, to estimate which registries were significantly different from the common distribution, and to adjust simultaneously for maternal age, time (in grouped years) and the random variation between registries. The maternal age-standardised prevalence (standardised to the year 2000 European maternal age structure) increased almost fourfold from 0.54 [95% Credible Interval (CrI) 0.37, 0.75] per 10,000 births in 1980-84 to 2.12 [95% CrI 1.85, 2.40] per 10,000 births in 2000-02. The relative risk of gastroschisis for mothers <20 years of age in 1995-2002 was 7.0 [95% CrI 5.6, 8.7]. There were geographical differences within Europe, with higher rates of gastroschisis in the UK, and lower rates in Italy after adjusting for maternal age. After standardising for regional variation, our results showed that the increase in risk over time was the same for mothers of all ages--the increase for mothers <20 years was 3.96-fold compared with an increase of 3.95-fold for mothers in the other age groups. These findings indicate that the phenomenon of increasing gastroschisis prevalence is not restricted to younger mothers only.

[Prenatal care and postnatal outcome for fetuses with laparoschisis]

OBJECTIVES

To assess the relevance and the quality of gastroschisis's care in a mid level referral centre.

METHOD

A retrospective analysis was performed for infants diagnosed or born with gastroschisis between 1992 and 2003 at the Citadelle hospital, Department of Obstetrics and Gynaecology, University of Liège.

RESULTS

Twenty-four cases of gastroschisis were identified. For 22 of them (92%) antenatal sonographic diagnosis was performed at a mean gestational age of 23 weeks. Antenatal diagnosis did not allow to identify additional malformation or chromosomal anomaly. Postnatal diagnosis allows to identify 3 infants with minor cardiac anomalies without functional consequence and one X fragile syndrome. One pregnancy was electively terminated at 24 weeks and one late intrauterine death was reported at 35 weeks. Bowel atresia, stenosis or ischemia were present at birth for 8 cases (33%). Out of 24 cases 22 were live born. 10 infants out of 22 (45%) underwent uncomplicated primary surgical repair. Three infants out of 22 (14%) underwent delayed closure without complications. Nine infants out 22 (41%) underwent multiple surgery (2 to 6). In this group all had postnatal complications, some with multisystem complications, including 3 deaths, 6 with infectious complications, 5 with gastrointestinal complications and 2 with genitourinary or haematological complications. Hospital stay range from 19 to 378 days (median, 51 days). Length of stay and time to full enteral feeding were longer if oligohydramnios or sonographic signs of intestinal damage were found. Among infants born before 35 weeks, only those with intestinal damage at birth had length of stay or time to full enteral feeding longer. Out of 22 live born infants 19 survived (86%) after one year. Survival rate without handicap due to gastroschisis is 84%.

CONCLUSION

Sonographic examination is a valid method for prenatal diagnosis and surveillance. Our survival rate agrees with recent data in the literature. It has to be noticed that hospital stay is lengthy and complications are frequent. The most important prognostic factor is the condition of the bowel at birth and there is no antenatal means to predict severe damage.

Manitoba Oculotrichoanal (MOTA) syndrome: report of eight new cases

The Manitoba Oculotrichoanal (MOTA) syndrome was initially described by Marles et al. [1992; Am J Med Genet 42: 793-799] in Aboriginal patients of the Island Lake region of Northern Manitoba. Characteristic findings in affected patients included unilateral upper eyelid coloboma or cryptophthalmus with ipsilateral aberrant anterior hairline pattern and anal anomalies. We describe here seven new patients of the same extended kindred of Cree/Ojibway ethnicity of the Island Lake region and an eighth patient of Caucasian Dutch parents with clinical findings consistent with the diagnosis of MOTA syndrome. Two of the patients have bilateral, instead of unilateral, abnormal anterior hairline patterns. Omphalocele, a feature previously not identified, is present in three of them. The most consistent features appear to be hypertelorism and a broad or notched tip of the nose. Due to the obvious clinical overlap with Fraser syndrome, FRAS1 gene was screened in two of the affected and no mutation was found [Slavotinek et al., submitted].

Chromosomal Abnormalities Associated With Omphalocele

Fetuses with omphalocele have an increased risk for chromosomal abnormalities. The risk varies with maternal age, gestational age at diagnosis, association with umbilical cord cysts, complexity of associated anomalies, and the contents of omphalocele. There is considerable evidence that genetics contributes to the etiology of omphalocele. This article provides an overview of chromosomal abnormalities associated with omphalocele and a comprehensive review of associated full aneuploidy such as trisomy 18, trisomy 13, triploidy, trisomy 21, 45,X, 47,XXY, and 47,XXX, partial aneuploidy such as dup (3q), dup (11p), inv (11), dup (1q), del (1q), dup (4q), dup (5p), dup (6q), del (9p), dup (15q), dup(17q), Pallister-Killian syndrome with mosaic tetrasomy 12p and Miller-Dieker lissencephaly syndrome with deletion of 17p13.3, and uniparental disomy (UPD) such as UPD 11 and UPD 14. Omphalocele is a prominent marker for chromosomal abnormalities. Perinatal identification of omphalocele should alert chromosomal abnormalities and familial unbalanced translocations, and prompt thorough cytogenetic investigations and genetic counseling.

Gastroschisis and associated defects: An international study

Our objective was to evaluate the frequency and type of malformations associated with gastroschisis in a large pool of international data, to identify malformation patterns, and to evaluate the role of maternal age in non-isolated cases. Case-by-case information from 24 registries, all members of the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR), were evaluated. After the exclusion of other abdominal wall defects cases were classified as: (a) isolated; (b) recognizable syndrome, chromosomal or not; (c) multiple congenital anomalies (MCA). Our results showed that out of 3,322 total cases 469 non-isolated cases were registered (14.1%): 41 chromosomal syndromes, 24 other syndromes, and 404 MCA. Among MCA four groups of anomalies were most frequent: CNS (4.5%), cardio-vascular (2.5%), limb (2.2%), and kidney anomalies (1.9%). No similar patterns emerged except two patterns resembling limb-body wall complex and OEIS. In both of them the gastroschisis could be however misclassified. Chromosomal trisomies and possibly non-syndromic MCA are associated with an older maternal age more than isolated cases. On consideration of our data and the most valid studies published in the literature, the best estimate of the proportion of gastroschisis associated with major unrelated defects is about 10%, with a few cases associated to recognizable syndromes. Recognized syndromes with gastroschisis seem to be so exceptional that the well documented and validated cases are worth being published as interesting case report. An appropriate case definition in etiological studies should include only isolated gastroschisis after an appropriate definition of isolated and non-isolated cases and a thorough case-by-case review.

The National Children's Study: a 21-year prospective study of 100,000 American children

Prospective, multiyear epidemiologic studies have proven to be highly effective in discovering preventable risk factors for chronic disease. Investigations such as the Framingham Heart Study have produced blueprints for disease prevention and saved millions of lives and billions of dollars. To discover preventable environmental risk factors for disease in children, the US Congress directed the National Institute of Child Health and Human Development, through the Children's Health Act of 2000, to conduct the National Children's Study. The National Children's Study is hypothesis-driven and will seek information on environmental risks and individual susceptibility factors for asthma, birth defects, dyslexia, attention-deficit/hyperactivity disorder, autism, schizophrenia, and obesity, as well as for adverse birth outcomes. It will be conducted in a nationally representative, prospective cohort of 100,000 US-born children. Children will be followed from conception to 21 years of age. Environmental exposures (chemical, physical, biological, and psychosocial) will be assessed repeatedly during pregnancy and throughout childhood in children's homes, schools, and communities. Chemical assays will be performed by the Centers for Disease Control and Prevention, and banks of biological and environmental samples will be established for future analyses. Genetic material will be collected on each mother and child and banked to permit study of gene-environment interactions. Recruitment is scheduled to begin in 2007 at 7 Vanguard Sites and will extend to 105 sites across the United States. The National Children's Study will generate multiple satellite studies that explore methodologic issues, etiologic questions, and potential interventions. It will provide training for the next generation of researchers and practitioners in environmental pediatrics and will link to planned and ongoing prospective birth cohort studies in other nations. Data from the National Children's Study will guide development of a comprehensive blueprint for disease prevention in children.

Caring for the newborn with an omphalocele

An omphalocele, a ventral defect of the umbilical ring resulting in herniation of the abdominal viscera, is one of the most common congenital abdominal wall defects seen in the newborn. Omphaloceles occur in 1 in 3000 to 10,000 live births. Associated malformations such as chromosomal, cardiac, or genitourinary abnormalities are common. Postnatal management includes protection of the herniated viscera, maintenance of fluids and electrolytes, prevention of hypothermia, gastric decompression, prevention of sepsis, and maintenance of cardiorespiratory stability. A primary or staged closure approach may be used to repair the defect. Some giant omphaloceles require a skin flap or nonoperative management approach, hoxvever. Immediate postoperative complications, usually related to significant changes in intra-abdominal pressures, include compromise of interior venous blood return and hemodynamic and respiratory instability due to diaphragmaric elevation. Complications occur more frequently with giant defects. Potential short-term complications include necrotizing enterocolitis, prolonged ileus, and respiratory distress. Long-term complications include parenteral nutrition dependence, gastroesophageal reflux, parenteral nutrition-related liver disease, feeding intolerance, and neurodevelopmental delay. Overall, advances in surgical therapies and nursing care have improved outcomes for infants with omphaloceles; survival rates for those with isolated omphaloceles are reported at 75 to 95 percent. Infants with associated anomalies and giant omphaloceles have the poorest outcomes.

Characteristics and outcome of 90 cases of fetal omphalocele

OBJECTIVE

The aim of this study was to describe the outcome of a case series of fetuses with omphalocele.

METHODS

Ninety fetuses with omphalocele at the National Center for Fetal Medicine (NCFM) between January 1985 and January 2004 were followed from the time of prenatal diagnosis. Follow-up times ranged from 6 months to 17 years. Omphaloceles were subdivided into epigastric, central and hypogastric types based on their location on the abdominal wall.

RESULTS

There were 58 central and 32 epigastric omphaloceles. Abnormal karyotype was found in 40/58 (69%) of the central and in 4/32 (12.5%) of the epigastric omphaloceles. Trisomy 18 was the most frequent abnormality associated with omphalocele. Among the fetuses with normal karyotype, 89% of the central and 71% of the epigastric cases had other anomalies. 38 (66%) of the fetuses with central omphalocele were terminated and 12 (21%) died during pregnancy or after delivery. 11 (34%) of the fetuses with epigastric omphalocele were terminated and eight (25%) died during pregnancy or after delivery. Of the 90 cases followed from the time of diagnosis there were 21 (23%) survivals. Of eight survivals with central omphalocele, only two were considered healthy while six had other anomalies and/or substantially impaired development. Of 13 survivals with epigastric omphalocele, six were considered healthy and seven had other anomalies and/or substantial impairment.

CONCLUSIONS

Fetal central and epigastric omphaloceles may be different entities: central omphaloceles are more strongly associated with abnormal karyotype (69%) than are epigastric omphaloceles (12.5%). The outcome of fetuses with omphalocele is poor irrespective of the type of omphalocele, with only eight of the 90 (9%) being alive and healthy at present. The results emphasize the importance of identifying both those fetuses with a potentially good prognosis and favorable outcome and those which are likely to have a fatal outcome.

Folate-related genes and omphalocele

Women who take folic acid in the periconceptional period greatly reduce their chances of having a child with a neural tube defect (NTD). Using multivitamins may also reduce the risk of having a child with an omphalocele. In this study, we tested single nucleotide polymorphisms in folate-related enzyme genes for association with omphalocele. Polymorphisms in methylenetetrahydrofolate reductase (MTHFR), methylenetetrahydrofolate dehydrogenase (MTHFD1), the reduced folate carrier (SLC19A1), and transcobalamin II (TCN2) were examined in 25 children with euploid omphalocele and 59 matched controls. Omphalocele cases were significantly more likely to carry the T allele of MTHFR 677C-->T, a known risk factor for NTDs (odds ratio 3.50, 95% confidence interval 1.07-11.47, P=0.035). The MTHFD1 R653Q, SLC19A1 R27H, and TCN2 P259R polymorphisms showed no significant association with omphalocele. In this small study, the thermolabile variant of MTHFR, 677C-->T, was associated with an increased risk for omphalocele. This variant causes reduced enzyme activity, thus suggesting a mechanism by which multivitamins with folic acid might prevent omphalocele. Additional investigation is required.

Mutations in PITX2 may contribute to cases of omphalocele and VATER-like syndromes

Omphalocele is a congenital anomaly with substantial morbidity. Rieger syndrome, an autosomal dominant disorder, is characterized by craniofacial abnormalities and abdominal wall defects. PITX2 mutations are etiologic in >40% of cases of Rieger syndrome. We demonstrate that the birth prevalence of omphalocele is significantly higher in Rieger syndrome than in the general population, with omphaloceles found in 0.03% in the Iowa newborn population and 4.3% of patients with Rieger syndrome. Our objective was to screen coding and conserved non-coding regions of PITX2 for mutations in 209 patients with omphalocele. We identified remarkable evolutionarily conserved regions by comparing the 3'UTR of Pitx2 in 13 vertebrate and 3 invertebrate species. No mutations changing the amino acid sequence were found within the omphalocele population. In one case of omphalocele with VATER-like additional anomalies, a three nucleotide deletion was found in the 3'UTR. This deletion was not seen in 1,186 controls. Also in the 3'UTR, we identified a single nucleotide polymorphism at a highly conserved residue. Our findings suggest additional studies of PITX2 conserved regions will be valuable. We also screened the omphalocele cases for mutations in exon 5 of the gene FLNA. Mutations in FLNA have been shown to cause a broad range of congenital malformations, including otopalatodigital syndrome type 2 in which a missense mutation occurring in exon 5 of FLNA results in omphalocele as part of the phenotype. We did not find any mutations in exon 5 of FLNA in 179 omphalocele cases studied.

Congenital Abdominal Wall Defects: An Update

OBJECTIVE

To review published peer-reviewed literature regarding abdominal wall defects including gastroschisis and omphalocele.

METHODS

Review of published peer-reviewed literature using Med Line 1985-2003 and textbooks.

RESULTS

Gastroschisis and omphalocele literature is reviewed using pathology, incidence and epidemiology, prenatal evaluation, pregnancy and delivery management, postnatal outcome and fetal therapy.

CONCLUSION

Gastroschisis and omphalocele are common abdominal wall defects and have significant morbidity and mortality.

Fetal Omphalocele Detected Early in Pregnancy: Associated Anomalies and Outcomes

PURPOSE

To detect omphalocele and associated anomalies at ultrasonography (US) early in pregnancy and to describe the outcomes in fetuses with isolated and nonisolated omphalocele.

MATERIAL AND METHODS

Fetal endovaginal US was performed in 43,896 pregnant women at 12-16 weeks gestation. The women found to have fetal omphalocele were offered an amniocentesis to determine the fetal karyotype. For parents who decided to continue the pregnancy, repeat targeted transabdominal fetal US was performed at 20-24 weeks gestation. Additional follow-up US examinations performed until delivery were recommended. Postnatal pediatric examinations were performed in all of these fetuses. For the pregnancies in which no anomaly was detected at early US, the women were advised to undergo repeat US at about 24 weeks gestation for the detection of late-manifesting fetal anomalies. For pregnancies in which the baby was not delivered at the authors' affiliated hospital, the woman, her obstetrician, and her pediatrician were asked to inform the authors of any detected anomaly.

RESULTS

Omphalocele was visualized at US in 38 fetuses, who were categorized into two groups. One group consisted of 22 (58%) fetuses with associated structural anomalies. According to the karyotype determined for 18 of these fetuses, 11 of them also had chromosomal anomalies. The pregnancy was terminated at the parents' request in 19 of these 22 cases. There were two cases of missed abortion, and a small omphalocele in one fetus disappeared at 21 weeks gestation. The second group consisted of 16 (42%) fetuses with a normal karyotype and an omphalocele as an isolated US finding. In eight of these fetuses, the omphalocele disappeared at 20-24 weeks gestation and no defect was seen at delivery. In six other fetuses, omphalocele was identified at delivery. There was one case each of missed abortion and pregnancy termination. There were no false-negative diagnoses of omphalocele.

CONCLUSION

Isolated omphalocele diagnosed during the early stages of gestation typically has a good prognosis. In cases of a small defect, the anomaly may disappear later in the pregnancy.

Isolated Gastroschisis in Successive Siblings: A Case Report and Review of the Literature

BACKGROUND

Although gastroschisis occurring in siblings is rare, a number of cases have been reported. A variety of inheritance patterns and embryologic explanations have previously been suggested. Young maternal age appears to be a consistent risk factor.

CASE

At age 17 years, Melanie (pseudonym) presented at 36 weeks' gestation and delivered a boy affected by gastroschisis. This condition had not been noted at a 13-week prenatal ultrasound. At age 18 years, Melanie delivered a second son with gastroschisis. There was no history of gastroschisis or other congenital anomaly in either parent's family. Melanie denied the use of alcohol, cigarettes, street drugs, and medications. She has since delivered 2 healthy children.

CONCLUSION

There is a need for preconception counselling for women who have experienced a pregnancy complicated by gastroschisis, to discuss the low but possible risk of recurrence. Early ultrasound may allow for detection or reassurance.

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.

Surveillance and outcome of fetuses with gastroschisis

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.

Omphalocele in trisomy 3q: further delineation of phenotype

We report a case of a patient with omphalocele, dysmorphic features, and mild developmental delay associated with a chromosomal aberration. Chromosome studies showed that the propositus carries a maternally derived unbalanced translocation der(4)t(3;4)(q27.3;q32.3), resulting in trisomy for region 3q27.3-->qter and monosomy for 4q32.3-->qter. Because the association between dup3q and omphalocele has been reported in several cases, we analyzed the data on 93 previously reported patients with partial trisomy of the long arm of chromosome 3 and compared the clinical features between the cases. The imbalance of chromosome 3 in the patient was further defined by fluorescence in situ hybridization (FISH) studies using bacterial artificial chromosome (BAC) clones. BAC clone RP11-171N2 was identified as a breakpoint-spanning clone in the patient and his mother. Based on our comparative analysis, we have delineated that the smallest region of overlap (SRO) associated with omphalocele is from BAC 171N2 to 3qter. We hypothesize that the SRO contains a gene(s) important in normal abdominal wall development and is of potential interest for further investigation.

First-year mortality rates for selected birth defects, Hawaii, 1986-1999

Birth defects have been the leading cause of infant death in the United States for over the last decade. However, there is little population-based data on the first-year mortality rates for many specific birth defects and the factors that may affect these mortality rates. This investigation examined the first-year mortality rates for 54 selected birth defects of various organ systems in Hawaii during 1986-1999 using data from a population-based birth defects registry and evaluated the impact of the presence of chromosomal abnormalities and other structural birth defects and the year of delivery on the mortality rates. Mortality rates varied widely by defect, being highest for anencephaly (100%), trisomy 13 (82%), and trisomy 18 (74%), while no first-year deaths were reported for glaucoma, bladder exstrophy, and persistent cloaca. The majority (36 of 54 or 67%) of the birth defects had a mortality rate of less than 25%. Among the 51 structural birth defects, 38 (75%) had higher first-year mortality rate for cases with chromosomal abnormalities and 42 (82%) had higher first-year mortality rates for cases with other major structural birth defects. The mortality rate among 1986-1992 deliveries was higher than the mortality rate among 1993-1999 deliveries for 37 (69%) of the 54 birth defects. This study indicates that first-year mortality rates vary widely by type of birth defect, although the mortality rate for the majority of birth defects is relatively low. The presence of a chromosomal abnormality or other structural birth defect increases the mortality rate, and mortality rates for the majority of birth defects have declined in Hawaii during the study period.

Preformed silos in the management of gastroschisis: new progress with an old idea

Outcomes for infants with gastroschisis have paralleled advances made in neonatal intensive care and the use of parenteral nutrition. Mortality rates approaching 100% a half century ago are now closer to 2% to 8%. Further reduction in morbidity has been the focus of many studies during the past decade. Efforts have been made to identify factors associated with the development of gastroschisis and to evaluate the mode, timing, and location of delivery on the outcome of these infants. The effect of the mode and timing of definitive surgical repair has received attention by more recent reports of newer approaches, including the use of a preformed silo to provide coverage for the exposed viscera and allow a gradual reduction into the abdominal cavity.

Absorbable mesh and skin flaps or grafts in the management of ruptured giant omphalocele

PURPOSE

The authors report the use of absorbable mesh closure with subsequent skin graft or skin flap coverage for giant ruptured omphalocele.

METHODS

Retrospective review of a single surgeon's experience was conducted from 1996 through 2001.

RESULTS

Four infants were identified presenting an average of 4 weeks prematurely. All patients had an initial attempt at silo reduction but had either infection or respiratory compromise. The silo was removed, and the defect was covered with polyglycan mesh followed by subsequent skin coverage. In 2 patients, final coverage was obtained using skin flaps, whereas in 2 patients, split-thickness skin grafts were required. All patients were noted to have a distinct narrow chest contour with evidence of pulmonary hypoplasia. Three patients had respiratory failure requiring tracheostomy and prolonged ventilation. Two children were decannulated after one and 2 years, respectively; the third child is booked for decannulation at age 12 months. Although these children have required multiple reoperations, they are all presently doing well with an average of 4 years of follow-up.

CONCLUSIONS

Patients with giant omphalocele have associated pulmonary hypoplasia, which limits the ability to reduce the abdominal contents. Absorbable mesh coverage followed by split-thickness skin graft or skin flap coverage provides a viable biological coverage and minimizes ongoing pulmonary morbidity. The authors recommend a minimally aggressive attempt at sac reduction in the initial treatment of giant omphalocele and, if necessary, the use of absorbable mesh as a staged coverage with subsequent split-thickness skin grafting to minimize the pulmonary effects of the abdominal operation.

Study of placenta of children born with congenital malformations

The malformations in this study were observed in a series of 279,642 consecutive births of known outcome registered in our Registry of congenital anomalies. For each case, more than 50 factors included in the registration forms were studied. One of the factors studied was the placenta. For each malformed child, a control was chosen. Cases with maternal known factors impairing placenta function, i.e. vasculopathy and diabetes, were excluded. In each category of malformations studied, the malformed children were divided into isolated and non-isolated (multiple malformed) cases. The weight of placenta of isolated cases was not lower than the weight of placenta of the controls. In contrast, the weight of placenta of the cases with non-isolated malformations was lower than the weight of placenta of the controls and of the isolated cases, for all categories of malformations but gastroschisis and omphalocele. The mean weights at birth of the cases with multiple malformations were also lower than those of the controls. The human placenta discounts a principal functional part, the maternal blood in the intervillous space. Congenital malformations may interact with this function.