When ultrasonography reveals a fetal abdominal wall defect
Although these fetal defects are rare, be alert to their potential presence when early ultrasonography indicates structural abnormalities. Here, surveillance, planning, and appropriate patient counseling are reviewed.
Making the diagnosis
Body-stalk anomaly typically can be diagnosed by 10 to 14 weeks’ gestation via ultrasonography.34-41 We currently follow the diagnostic criteria proposed by Van Allen and colleagues, which requires 2 of the following 3 anomalies34:
- exencephaly/encephalocele with facial clefts
- thoraco- and/or abdominoschisis (midline defect)
- limb defect.
Additional ultrasonographic findings can include the identification of evisceration of the abdominal contents, a short umbilical cord, and increased nuchal thickness.36,42 During the second and third trimesters, oligohydramnios may be seen.2
Management
Body-stalk anomaly is considered a fatal condition without specific therapeutic interventions. Maternal risks include an increased risk of preterm labor and gestational hypertension.35 Research on body-stalk anomaly has not shown any correlation with patients’ age, fetal sex, or abnormal karyotype, and the reported risk of recurrence for this anomaly is very low.42,43 Early diagnosis therefore is essential to provide families with information and counseling. Given the poor fetal prognosis, increased maternal risk, and low recurrence rates, mothers can be advised toward elective termination of pregnancy.
Should a patient desire expectant management, care can be provided by generalist obstetricians or care can be transferred to maternal-fetal medicine, with the addition of increased fetal surveillance and testing, interdisciplinary patient counseling with maternal-fetal medicine, pediatric surgeons, and neonatologists for delivery planning; delivery should be performed at a tertiary care center.
Pentalogy of Cantrell: Very rare, with variable prognosis
Pentalogy of Cantrell is characterized by a collection of defects in the midline abdominal wall, lower sternum, anterior diaphragm, diaphragmatic pericardium, and some manifestation of intra-cardiac defect.44 It is thought to arise early in gestation due to abnormal differentiation, migration, and fusion of the embryonic mesoderm.44 The condition is rare, with an incidence of about 1 in 5.5 million live births.45
Making the diagnosis
The diagnosis of pentalogy of Cantrell can be made via prenatal ultrasonography as early as the first trimester, although it is diagnosed more commonly in the second trimester.46 Three-dimensional ultrasonography and fetal MRI have been used to confirm the diagnosis.47
Management
Typically, corrective operations are performed during the neonatal period, and cases of successful staged and one-stage operations have been reported.48 Surgical treatment is determined based on the complexity of the condition and the presence of coexistent heart defects.49,50 However, very few patients survive surgical repair; mortality rates are estimated at around 50% to 60%, with high postsurgical morbidity risks for those who do survive.45
Prognosis varies depending on the type and severity of the associated malformations and intracardiac anomalies.46 Patients with partial ectopia cordis and incomplete presentation may have more favorable outcomes, but for patients with severe ectopia cordis, the survival rate is only 5% to 10%.47
Depending on the severity of the defects, mothers can be advised toward elective termination of pregnancy. In our institution, prenatal care usually is transferred to the maternal-fetal medicine service, and delivery is planned at our tertiary care institution.
OEIS complex comprises abdominal, pelvic, and spinal defects
Omphalocele-exstrophy-imperforate anus-spinal defects (OEIS) complex is a congenital malformation syndrome characterized by the combination of midline abdominal and pelvic defects (including omphalocele, exstrophy of the cloaca, and imperforate anus) and spinal defects.51 The condition’s etiology is unknown but is thought to be multifactorial.51-53 It is a rare condition, with an incidence of around 1 in 200,000 to 400,000 pregnancies.52
Making the diagnosis
Prenatal diagnosis of OEIS complex can be made as early as the first trimester via ultrasonographic identification of an infraumbilical abdominal wall defect with protruding mass, absent bladder, and spinal defects.52 When OEIS complex is suspected, fetal MRI can play a critical role in the diagnosis.
Management
As OEIS complex is rare, there are no evidence-based guidelines for optimal mode and timing of delivery. Cases are individualized based on their specific pathology, and we recommend cesarean delivery for fetuses with large defects to avoid postnatal sac rupture and liver damage.
The prognosis for infants with OEIS complex depends on the spectrum and severity of the structural defects.52,53 The many surgeries involved in the repair of OEIS have potential complications, such as urogenital and gastrointestinal dysfunction.52,53 Advances in medical and surgical treatment have resulted in improved survival and quality of life, and survival rates for OEIS complex are now close to 100%.53 While many OEIS patients live with a permanent colostomy, improvements in management mean that more patients are now candidates for gastrointestinal pull-through procedures, which allow for natural bowel control and a higher degree of bowel cleanliness.53
Prenatal care, patient counseling, and delivery planning should be individualized based on the defects present and determined in a multidisciplinary discussion with maternal-fetal medicine, neonatology, and pediatric surgery as necessary. In our institution, prenatal care usually is transferred to the maternal-fetal medicine service, and delivery is planned at our tertiary care institution.
Multidisciplinary team strategy is essential
Based on our experience, when faced with an anterior AWD in utero, prenatal imaging, genetic testing, increased fetal surveillance, and a multidisciplinary team approach improves outcomes. We must emphasize that careful patient counseling is paramount in our practice. ●
Acknowledgement: The authors would like to thank Ashley Tran, BS, for her assistance in the literature review and drafting of this article.
- Patients with fetuses with anterior wall defects should be referred to a maternal-fetal medicine specialist for co-management and advanced fetal imaging.
- The American College of Obstetricians and Gynecologists recommends microarray for all major fetal structural abnormalities, with the qualifier that karyotype can be offered if a specific aneuploidy is suspected based on the abnormality or prior genetic screening tests.
- If confirmatory testing is performed (amniocentesis or chorionic villus sampling), the sample should undergo karyotyping, chromosomal microarray, and if indicated, testing for Beckwith-Wiedemann syndrome. If the patient declines confirmatory sampling, performing cell-free DNA screening to rule out aneuploidy is recommended.
- Fetal echocardiography is recommended.
- Fetal magnetic resonance imaging should be considered in complex cases.
- Management should be individualized based on the type and severity of defect(s).
- Delivery timing and method should be individualized based on the defect(s) and determined in a multidisciplinary discussion with maternal-fetal medicine, neonatology, pediatric surgery, and pediatric cardiology, as necessary.
- The most common fetal abdominal wall defect is omphalocele, followed by gastroschisis.
- Maternal serum α-fetoprotein is usually elevated in all of the disorders.
