Supplementary Material for: Fetal Extrahepatic Porto systemic Venous Shunts: prenatal diagnosis management and therapy: 21 years of evolving insights.

Abstract
Introduction
Fetal extrahepatic portosystemic Venous Shunt (FEPSVS) are vascular malformations that divert placental and bowel blood from the liver into the systemic circulation. When uncorrected, it can lead to severe pathologic consequences after birth.
Objective
To report our method of prenatal diagnosis, the developing insight regarding prenatal counseling, and postnatal treatment.
Method
Retrospective review of fetuses diagnosed with FEPSVS, classified into Abernethy type I or II based on the absence or existence of intrahepatic portal venous system (IHPVS) flow. Two different counseling periods were compared regarding pregnancy management and postnatal outcome.
Results
In the first period (2000-2010), 5 cases were diagnosed; 4 were type I with an 80% termination rate.
In the second period (2011-2021), 6 cases were diagnosed; with only a 16% termination rate in type I cases.
Two type II cases were reclassified to type I postnatally and corrected successfully.
Of the six born alive, five had early surgical/endovascular corrections, and one experienced spontaneous closure. All the cases resulted in a successful rescue of the IHPVS with good outcomes.
Conclusions
During our developing insights we realized that: 1) the adult classification according to the IHPSVS is not relevant for prenatal prognostic counseling. 2) Prenatal diagnosis of FEPSVS is essential in promoting early postnatal investigation and corrective intervention, which might prevent the appearance of postnatal complications.