Gastroschisis: Prenatal diagnosis and management
There is no single delivery management algorithm, and due to the association of gastroschisis with stillbirth, earlier delivery has been advocated.26 A retrospective cohort study that included 860 cases of gastroschisis from a reference population of more than 2 million singleton pregnancies found that risk of stillbirth may be minimized with delivery as early as 37 weeks’ gestation.22 In settings of normal fetal growth and fetal testing, the delivery plan can be made on a case-by-case basis, but due to the increased risk of stillbirth with advancing gestational age, fetuses with gastroschisis should undergo delivery planning by 39 weeks’ gestation. Although newer literature may support elective delivery planning prior to 39 weeks’ gestation, this is not currently standard of care and delivery prior to 39 weeks should be reserved for obstetrical indication.
The recommended mode of delivery is vaginal, with cesarean delivery reserved for obstetrical indication as there is no evidence that cesarean delivery improves the outcome in uncompromised gastroschisis. Use of this obstetrical management algorithm is increasing, as seen in a recent population-based study that showed a rate of attempted vaginal delivery of 59.7% in 2005 and 68.8% in 2013.27
Due to the exposed fetal bowel, the neonate is at risk for insensible losses of fluid and heat (Figure 4). Upon delivery, the neonate should be placed in a sterile plastic bag up to the level of the chest and handed to waiting pediatricians for assessment. The neonate should be placed on its side to avoid kinking the bowel while awaiting pediatric surgery assessment. A nasogastric tube generally is placed to decompress the stomach and intravenous access is obtained.28 One preferred method of closure for uncomplicated gastroschisis is placement of a Silastic spring-loaded silo (Figure 5).29 The defects are reduced in 1–3 days and bioclosure with umbilical cord may be used (Figure 6). If complications are suspected, exploration in the operating room is required. Approximately 17% of cases are complex due to the presence of additional gastrointestinal pathologies, and will likely require exploratory and corrective surgery prior to placement of the silo.18 Herniated bowel can also be reduced with a staged closure, if needed. The most common postnatal complications are overcoming poor mucosal function and hypoperistalsis of the fetal bowel. The neonatal mortality rate ranges from 2% to 17%, with higher rates for complex cases.15,18
Gastroschisis is a result of a full-thickness paraumbilical defect that allows herniation of free-floating fetal bowel into the amniotic cavity. Incidence of this birth defect is increasing worldwide and young maternal age at the time of pregnancy is a significant risk factor for the condition. Fetal gastroschisis is rarely associated with aneuploidy and is commonly isolated. Nearly all cases are associated with elevated MSAFP and the defect is readily diagnosed on ultrasound. Affected fetuses are at increased risk for growth restriction, preterm birth, and stillbirth. Approximately 10% of cases are associated with intestinal atresia requiring more extensive postnatal management and intervention. The atresia may or may not be diagnosed prior to birth. Recommended mode of delivery is vaginal with cesarean delivery reserved for usual obstetrical indications.