To investigate the normal ultrasound images of the fetal umbilical portal venous system (UPVS) and the ultrasound diagnostic characteristics of abnormal shunt.

The ultrasound image features of the normal UPVS in 85 fetuses were analzyed from January 2018 to December 2020, and the data of 26 cases of abnormal shunts of the fetal UPVS were collected to analyze the prenatal ultrasound images and complications.

There were three types of connection between the main portal vein and the portal sinus in the normal fetal UPVS: T-shaped connection in 60 cases, X-shaped in 11, and H-shaped in 14 cases. There were 26 cases of abnormal shunts of the fetal UPVS in the study: umbilical-systemic shunts (USS) in 6 cases, including 4 cases with the umbilical vein flowing into the right atrium, 1 case with the umbilical vein flowing into the inferior vena cava, and 1 case with the umbilical vein flowing into the hepatic vein. There was no ductus venosus in all the six cases. Three cases were associated with other malformations, and three cases with cardiac enlargement. Ductus venosus-systemic shunts (DVSS) occurred in four cases. The position of the ductus venosus (DV) flowing into the inferior vena cava moved down in two cases. The DV flew into the right atrium through the coronary sinus in one case. The DV flew into the right hepatic vein in one case. Two cases were associated with other malformations. Intrahepatic portal-systemic shunts (IHPSS) occurred in 16 cases, included 1 case of type Ⅰ, 6 cases of type Ⅱ, 3 case of type Ⅲ, and 6 cases of type Ⅳ. Among them, 4 cases were combined with fetal growth restriction (FGR), 2 were complicated with cardiac malformations, and 2 were combined with single umbilical artery.

Knowing the normal ultrasound images of the UPVS is helpful to find and diagnose abnormal shunt. Each type of abnormal shunt of the UPVS has different ultrasonic image features. Evaluating the development of intrahepatic portal venous system, cardiac function, and other malformations is helpful for clinical consultation and treatment.