Aim: To investigate the types, associated anomalies and postnatal outcomes of fetal hepatic venous system (HVS) variants by ultrasound in China.
Material and methods: A large-scale and prospective investigation of HVS variants for low-risk singleton pregnant women was performed in three academic tertiary referral care centers in China. Ultrasound imaging wasused for the identification and follow-up of anatomical variants. Follow-up was conducted once every four weeks prenatally and every two months postnatally, mainly concerned on the adverse events that may appear.
Results: There were 20848 cases with anatomical variants of fetal HVS identified from 46179 candidates during the study period. Following the anatomical position of variants occurring, four main divisions were present: main portal vein variants (17.9%), intrahepatic portal vein variants (21.30%), intrahepatic persistent right umbilical vein (0.27%) and hepatic vein variants (5.67%). In the fetal period, the pregnancy of all cases was normally continued, except that the pregnancy of two cases, which were associated with multiple anomalies and were terminated by their parents. After birth, approximately 99.47% of the cases with isolated variants orbeing associated no clinic significant anomalies were normally alive. Approximately 0.50% cases were associated with simple ventricular septum defect or tetralogy of Fallot and further treatment was needed.
Conclusion: The anatomical variants of fetal HVS may appear as numerical, morphological or positional variants of MPV, intrahepatic PV branches, intrahepatic PRUV and HVs. The majority of cases are isolated or their associated anomalies are not clinically significant and have normal lifeafter birth.