Gastroschisis: Prenatal diagnosis and management
Fetal growth restriction is more common in fetuses with gastroschisis. In part, this is due to the abnormal size of the fetal abdominal circumference (AC). However, even when controlling for the abnormal fetal AC, fetal growth restriction is more common in fetuses with gastroschisis. Additional ultrasound findings can include oligohydramios and abnormal fetal testing.15,20
Significant variability exists in antepartum management of pregnancies complicated by fetal gastroschisis. This is due, in part, to the lack of high-quality studies that could guide uniform clinical practice.21 Given the prevalence of early ultrasound assessment in the first trimester, early diagnosis of gastroschisis is possible.
Both detailed fetal anatomical survey and fetal echocardiogram in the second trimester are indicated when gastroschisis is identified. A thorough search for additional structural abnormalities will allow for optimal patient counseling and delivery planning. Due to the low association between gastroschisis and chromosomal abnormalities, invasive testing has not been routinely advocated. However, presence of additional anomalies should prompt further consideration for invasive genetic testing. Prenatal chromosomal microarray will identify chromosomal aneuploidy, large changes in the structures of the chromosomes as well as submicroscopic abnormalities that are not detected by karyotype analysis alone. Data on the yield of microarray in isolated gastroschisis remain limited.
Given the association between gastroschisis and fetal growth restriction (25%), spontaneous preterm birth (25%), and stillbirth (5%), serial ultrasound evaluation of fetal growth is warranted.15,22 Earlier gestational age at delivery has been associated with worse perinatal outcome,15 so optimal delivery planning is critical in cases of threatened preterm labor, including consideration for steroid administration to accelerate fetal maturity.
Assessment of fetal bowel for dilation and wall thickening has been commonly advocated and performed because of the possibility of adverse outcome in the setting of extra-abdominal bowel dilation; however, a systematic review did not find significant association between dilated extra-abdominal bowel and adverse perinatal outcome.23 In contrast, intraabdominal bowel dilation has been associated with postnatal diagnosis of bowel atresia and more complicated repair.24 It is important to note that existing data conflict on the implications of both extra- and intra-abdominal bowel dilation and the association with perinatal outcome. Additional well-designed studies are needed in this area.
Antenatal testing recommendations are mainly based on expert opinion and retrospective studies, given the association of gastroschisis with stillbirth.22,25 A suggested algorithm is to begin antenatal monitoring with nonstress test and amniotic fluid volume assessment or BPP at 32–36 weeks’ gestation, with earlier initiation of testing for more complicated cases (eg, in the presence of fetal growth restriction or amniotic fluid volume abnormalities).