A contemporary assessment of fetal intra-abdominal umbilical vein (FIUV) varix and obstetrical outcomes in pregnancy

Fetal intra-abdominal umbilical vein varix (FIUVV) is associated with concurrent structural anomalies, aneuploidy, and poor obstetrical outcomes such as growth restriction and demise. Management recommendations for FIUVV, however, are based on low level of evidence and vary drastically. Our clinic performs serial growth ultrasounds and additional antenatal surveillance in the third trimester in pregnancies with FIUVV, however whether this close surveillance impacts fetal outcomes remains unknown. In this study, we sought to characterize the natural progression and identify associated obstetrical outcomes. We identified a cohort of 105 pregnancies with FIUVV, which is the largest cohort to date of published cohort. The most common diagnosis time was 32 gestational weeks. There were more pregnancies complicated by LGA and polyhydramnios than FGR and oligohydramnios. Approximately 20% have other structural anomalies, most common for cardiac and genitourinary. There were no differences in fetal growth or amniotic fluid level abnormalities between fetuses with isolated FIUVV or with associated structural anomalies. We had no cases of varix thrombosis or intrauterine fetal demise. The outcomes for FIUVV appear to be favorable. We conclude that presence of FIUVV alone should not be an indication for performing serial growth scans and antenatal surveillance.