Whether a fetal GI malformation can be detected by 4D ultrasound is determined by the type of fetal GI malformation, and its severity. Generally, 4D ultrasound can detect problems such as congenital megacolon and widening of the intestinal canal. In addition to direct observation by ultrasound, digestive tract abnormalities can also be indirectly determined by other ultrasound indicators, for example, when the fetus has digestive atresia, it is often accompanied by excessive amniotic fluid, so when the ultrasound examination suggests excessive amniotic fluid, attention should be paid to exclude the possibility of digestive tract abnormalities. The fetal MRI is also a means to assess whether the fetus has digestive tract anomalies. If the fetal digestive tract anomalies are mild, the 4D ultrasound examination may not necessarily detect them.