Making the diagnosis
Omphaloceles can be diagnosed via prenatal ultrasonography as early as 11 to 14 weeks’ gestation.26 They are classified based on size, location, and contents of the sac.26,27 A small omphalocele is defined as a defect less than 5 cm with a sac that may contain a few loops of intestines (FIGURE 3).27 A giant omphalocele is a defect with more than 75% of the liver contained in the sac.29
Location can be epigastric, umbilical, or hypogastric, and both small and giant omphaloceles may have ruptured membranes that will result in exposure of the contained viscera.27 Omphaloceles are associated with such structural anomalies as cardiac, gastrointestinal, genitourinary, diaphragmatic, and neural tube defects. We do not routinely perform magnetic resonance imaging (MRI) for evaluation of omphaloceles, but MRI may be used to help predict postnatal outcomes in the case of giant omphaloceles.26
Management
Our standard practice is to use the initial ultrasonography imaging to evaluate the size and contents of defect, measure the nuchal translucency, and evaluate for additional abnormalities. As in cases of gastroschisis, serial ultrasonography monitoring of the fetus is required to assess the size and quality of the herniated intestine, amount of amniotic fluid, and fetal growth. We typically evaluate the fetus at around 16 weeks and then again at around 20 weeks. In the absence of fetal growth restriction, we recommend serial growth ultrasonography every 3 to 4 weeks starting at 28 weeks and biophysical profiles and nonstress testing weekly starting at 32 weeks. Additionally, we routinely obtain a fetal echocardiogram to rule out cardiac structural abnormalities.
Delivery considerations. Fetuses that do not undergo spontaneous abortion or medical termination of pregnancy often are born at term.26 We recommend expectant management until spontaneous labor, another indication for delivery arises, or at least 39 weeks’ estimated gestational age. There are no evidence-based guidelines for the optimal mode of delivery in fetuses with omphalocele, although we recommend cesarean delivery for fetuses with large defects to avoid postnatal sac rupture and liver damage. Preterm induction of labor is not indicated as infants born preterm have about a 50% mortality rate.26,27
Children born with isolated omphalocele typically have a good prognosis, with an estimated survival rate of 50% to 90%.32,33 However, compared to gastroschisis, omphaloceles are often associated with other anomalies.32,33
Management of omphaloceles depends on the size of the defect. In our institution, our generalist obstetricians manage the standard prenatal care with the addition of increased fetal surveillance and testing, interdisciplinary patient counseling with maternal-fetal medicine, pediatric surgeons, and neonatologists for delivery planning, and delivery is performed at our tertiary care center.
Neonate management. Small omphaloceles are amenable to primary early fascial closure.26-30 However, attempted primary closure of giant omphaloceles carries significant risks, including abdominal compartment syndrome and postoperative herniation.29,30 Instead, several options exist for staged surgical closure, in which there are multiple operations prior to final fascial closure, as well as nonoperative delayed closure for management of giant omphaloceles.29,30
Conservative management of giant omphaloceles has certain benefits, such as earlier first feeds, decreased risk of abdominal compartment syndrome, and lower risk of infection.30 Ruptured omphaloceles can be repaired through primary repair, employment of a synthetic or biologic mesh fascial bridge, or silo placement with delayed closure.28
Body-stalk anomaly: Multiple defects and poor prognosis
Also known as limb body wall complex, body-stalk anomaly is a rare malformation that has a reported prevalence of approximately 0.12 cases per 10,000 births (both live and stillbirths).34 Body-stalk anomaly is characterized by multiple defects, including severe kyphosis or scoliosis, a short or absent umbilical cord, and a large anterior abdominal wall defect.34-36 This malformation is almost entirely incompatible with life, resulting in abortion or stillbirth.35 Survival is extremely rare and limited to case reports.
While the exact etiology of body-stalk anomaly is unknown, 3 possible causes have been hypothesized: early amnion rupture, vascular compromise, and embryonic dysgenesis.37-40
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