Definition: An area of uniform strong echogenicity of the fetal intestinal canal with an echogenic intensity equal to or greater than that of the surrounding skeletal echo. Methods: Scan with a 5MHz probe. When intestinal echo enhancement is considered, turn down the gain of the instrument and carefully compare it with the surrounding skeletal echoes to reduce false positives. Intestinal echo enhancement can be classified as focal or multifocal. Compared with the surrounding skeletal echo, its echo intensity can be classified into 3 levels: level 1 is weaker than the skeletal echo; level 2 is equal to the surrounding skeletal echo; and level 3: greater than the surrounding skeletal echo. Relationship with fetal haploid abnormalities: those with enhanced intestinal echogenicity have an increased risk of trisomy 13, 18, 21 and sex chromosome abnormalities. In fetuses at 13-28 gestational weeks, the detection rate of enhanced intestinal canal echo is 0.6-2.4%. Echo enhancement of the intestinal canal alone is found in 9% of fetuses with haploid abnormalities. The risk of cystic fibrosis, congenital infection, intra-amniotic hemorrhage, congenital intestinal malformation and other perinatal complications such as intrauterine growth retardation is increased in fetuses with enhanced intestinal echogenicity, with the incidence of cystic fibrosis being approximately 2%. The most common cause of enhanced gut echo is fetal infection (cytomegalovirus, herpes virus, microcytic virus, rubella virus, varicella virus, and toxoplasmosis virus). The next most common causes are intra-amniotic hemorrhage (often due to amniotic intervention or placental rupture) and congenital intestinal malformations, especially upper gastrointestinal malformations. Fetal ascites and dilatation of the intestinal canal are often seen with echogenic enhancement of the intestinal canal. The fetal intestinal canal should be examined for other anatomical structures, growth, placental position and fetal chromosomes, and fetal DNA should be checked when available.