Ductus Venosus Agenesis in Fetuses: Epidemiological Data, Prenatal Findings, and Perinatal Outcomes—A Systematic Review

Background: The fetal circulatory system is characterized by the presence of physiological vascular shunts—the ductus venosus, foramen ovale, and ductus arteriosus—which enable a significant portion of blood to bypass the pulmonary circulation and partially the hepatic portal system. This mechanism ensures preferential delivery of oxygenated blood to the brain, heart, and upper body. Agenesis of the ductus venosus (ADV) is a rare vascular anomaly associated with diverse anatomical variations and clinical outcomes. Objectives: This systematic review aimed to determine the prevalence of ADV and to assess the frequency of intrahepatic and extrahepatic types. Additional objectives were to identify the most common drainage sites of the umbilical vein (UV) in extrahepatic ADV, evaluate the genetic abnormalities, congenital heart defects, and extracardiac anomalies most frequently associated with ADV, and establish the prognosis of affected fetuses. Methods: A comprehensive literature search was conducted in the PubMed, Embase, and Web of Science databases using predefined and precise inclusion criteria. Results: The overall prevalence of ADV in the general population was 0.05%. The intrahepatic and extrahepatic types occurred with comparable frequencies, accounting for 51.2% and 48.8% of cases, respectively. In extrahepatic ADV, the most common drainage site of the UV was the right atrium (48%). The most frequent genetic abnormalities were trisomy 21 (12%) and Turner syndrome (6%). Among congenital heart defects, ventricular septal defect (22.7%) and atrioventricular septal defect (8.8%) were most prevalent. Functional consequences were observed in 37.4% of fetuses with isolated ADV, most commonly cardiomegaly. Conclusions: ADV is a rare fetal vascular anomaly. With the increasing availability and utilization of prenatal diagnostic techniques, expanding knowledge of this condition and its clinical implications is essential for accurate diagnosis, management, and prognostic assessment.