You have identified an absent ductus venosus, an aberrant intra-abdominal venous channel, or a confirmed Umbilical–Portal–Systemic Venous Shunt (UPSVS) on prenatal ultrasound. What happens next?
This guide provides a structured, step-by-step framework for what to do after the anatomical diagnosis has been established — from the immediate workup on the day of diagnosis through prenatal surveillance, genetic counselling, delivery planning, and postnatal follow-up protocols.
1. Immediate Workup: Day of Diagnosis Checklist
On the day UPSVS is first identified, the following assessments should be initiated or planned without delay:
Detailed Fetal Echocardiogram
• Cardiothoracic Area Ratio (C/T): Normal < 0.35. Values > 0.35 indicate cardiomegaly from volume overload.
• Tricuspid Regurgitation (TR): Assess presence, jet velocity, and duration. Progressive TR signals decompensation.
• RV/LV Disproportion: Right heart dominance beyond physiological range.
• Myocardial Performance Index (Tei Index): Assess global ventricular function.
• Associated Structural CHD: Complete segmental analysis — AVSD, VSD, coarctation, and outflow tract anomalies have documented associations.
Portal Venous System Assessment
• Document whether the Intrahepatic Portal Venous System (IHPVS) is present, hypoplastic, or absent.
• Trace the “hockey stick” L-shaped Left Portal Vein and confirm Right Portal Vein branching.
• This single finding is the strongest prognostic factor — intact IHPVS = better outcomes.
Genetic Evaluation & Amniocentesis
• Amniocentesis with Chromosomal Microarray (CMA) is recommended for all UPSVS types.
• Type II (DVSS) is the most critical — Trisomy 21 detected in 21% (only group with proven aneuploidy in the Achiron cohort).
• Consider Noonan/RASopathy gene panel for Type I with cardiomegaly and structural CHD.
Maternal-Fetal Medicine (MFM) Referral
• Refer to a tertiary fetal medicine center with pediatric cardiology, hepatology, and neonatal surgery capability.
• Multidisciplinary counseling session should be scheduled within 1–2 weeks of diagnosis.
2. Risk Stratification: Isolated vs. Non-Isolated UPSVS
The most important determinant for management intensity and prognosis is whether the UPSVS is isolated or associated with additional anomalies:
| Risk Category | Definition | Surveillance Intensity |
|---|---|---|
| Isolated UPSVS | UPSVS with normal karyotype, no structural CHD, no extracardiac anomalies, and IHPVS present. | Fetal echo every 3–4 weeks. Growth scan every 3–4 weeks. Good prognosis expected (especially Type II). |
| UPSVS + Absent IHPVS | UPSVS with absent or severely hypoplastic intrahepatic portal system (CAPVS). Normal karyotype. | Fetal echo every 1–2 weeks. High risk for progressive cardiomegaly and hydrops. Postnatal hepatic workup mandatory. |
| Non-Isolated UPSVS | UPSVS with aneuploidy, structural CHD, extracardiac malformations, or hydrops fetalis. | Fetal echo every 1–2 weeks. Detailed genetic counselling. Palliative care discussion for severe cases. Multidisciplinary team management. |
3. Prenatal Surveillance Protocol
Serial Fetal Echocardiography
The primary goal is to detect the onset and progression of cardiac decompensation. At each visit, systematically evaluate:
- Cardiothoracic ratio (C/T): Progressive increase indicates worsening volume overload.
- Tricuspid regurgitation: New onset or worsening TR is an early sign of right ventricular failure.
- Pericardial effusion: Even a thin rim is an ominous early sign of hydrops.
- Ductus Venosus waveform (if DV is present — Types II, some IIIa): Increasing pulsatility or a-wave reversal indicates rising central venous pressure. (See: DV Waveform Analysis Guide)
Growth & Doppler Surveillance
- Growth scans: Particularly critical for Type IIIa (IHPSS), where 58% develop intrauterine growth restriction (IUGR).
- Umbilical Artery PI: Monitor for placental insufficiency.
- Middle Cerebral Artery (MCA) PSV: Rule out fetal anemia from hepatic dysfunction.
- Cerebroplacental Ratio (CPR): A falling CPR in the context of IUGR signals impending decompensation.
Hydrops Surveillance Checklist
At every scan, systematically check for the five compartments of fetal hydrops:
- Pericardial effusion (4-chamber view)
- Pleural effusion (coronal thorax)
- Ascites (transverse abdomen)
- Subcutaneous edema / skin thickening (> 5 mm)
- Polyhydramnios (deepest vertical pocket > 8 cm)
4. Counselling Framework by Shunt Type
Type I (Umbilical–Systemic Shunt)
Counselling tone: Guarded. Live birth rate is less than 1/3. Over 50% have major associated anomalies. Complete absence of the portal system (CAPVS) in 2/3. Discuss realistic expectations for survival and quality of life. When associated with lethal anomalies, offer compassionate / palliative care pathway with full parental support.
Type II (Ductus Venosus–Systemic Shunt)
Counselling tone: Cautiously optimistic. The best prognosis among all types. Intact portal system in 100%. However, Trisomy 21 is detected in 21% — genetic testing is non-negotiable. When karyotype is normal and no structural anomalies are present, reassurance can be offered as the majority achieve survival with normal outcomes.
Type IIIa (Intrahepatic Portal–Systemic Shunt)
Counselling tone: Moderate concern. In-utero hemodynamics are often stable, but 58% develop IUGR and 50% have abnormal postnatal liver function. Emphasize the need for growth surveillance and planned delivery at a center with pediatric hepatology. The portal system is intact — a favourable factor — but the portal-hepatic vein steal reduces effective hepatic perfusion.
Type IIIb (Extrahepatic Portal–Systemic Shunt / Abernethy)
Counselling tone: Good in-utero, critical postnatal. Fetal hemodynamics are often reassuring, which may falsely reassure. However, 100% have abnormal postnatal liver function. IHPVS is absent in 50%. Counsel extensively about the need for lifelong hepatology follow-up and the risks of hyperammonemia, portopulmonary hypertension, hepatic adenomas, and potential need for surgical correction or liver transplantation in severe Abernethy Type I cases.
5. Delivery Planning
Where to Deliver
All fetuses with confirmed UPSVS should be delivered at a tertiary perinatal center with the following capabilities available on-site or on immediate referral:
- Level III NICU with ventilatory and hemodynamic support
- Pediatric cardiology with neonatal echocardiography
- Pediatric hepatology / gastroenterology
- Pediatric surgery (for potential Abernethy shunt correction)
- Genetic medicine / dysmorphology service
Timing of Delivery
- Isolated, stable UPSVS (Type II with normal karyotype): Expectant management until 37–39 weeks. No indication for preterm delivery if the fetus remains hemodynamically stable.
- UPSVS with progressive cardiomegaly, worsening TR, or early hydrops: Individualized timing based on gestational age, lung maturity, and severity of cardiac decompensation. Consider antenatal corticosteroids if delivery anticipated before 34 weeks.
- UPSVS with IUGR (Type IIIa): Follow standard IUGR delivery guidelines based on Doppler surveillance (UA, MCA, CPR, DV waveform) and CTG patterns.
Mode of Delivery
UPSVS alone is not an indication for Caesarean section. The mode of delivery should be determined by standard obstetric indications. However, if the fetus has severe cardiomegaly, hydrops, or is hemodynamically fragile, a planned Caesarean may be considered to allow immediate neonatal resuscitation in a controlled setting.
6. Postnatal Protocol: First 72 Hours & Beyond
Neonatal Echocardiogram (Day 1)
Confirm prenatal findings. Assess for patent DV remnant, cardiac chamber sizes, ventricular function, and any associated structural CHD. Document closure or persistence of the aberrant shunt.
Abdominal Doppler Ultrasound (Day 1–3)
Map the portal venous system. Confirm whether IHPVS exists postnatally. Identify any persistent portosystemic shunts (Abernethy malformation). This is the definitive postnatal anatomical assessment.
Blood Work (Day 1–3)
• Liver Function Tests (LFTs): AST, ALT, GGT, Alkaline Phosphatase, Direct/Indirect Bilirubin.
• Serum Ammonia: Elevated levels indicate hepatic bypass — critical in Types I, IIIa, IIIb.
• Coagulation Profile: PT, INR, Fibrinogen — hepatic synthetic function assessment.
• Serum Albumin & Total Protein: Evaluate for hypoproteinemia.
Long-Term Hepatology Follow-Up Plan
• Hepatic adenoma / FNH surveillance: Serial abdominal ultrasound at 3, 6, and 12 months, then annually.
• Pulmonary hypertension screening: Echocardiographic assessment of TR velocity and estimated PA pressure at 1, 3, and 6 months.
• Neurodevelopmental monitoring: Ammonia-related encephalopathy screening for shunts with hepatic bypass.
• Surgical consultation: In Abernethy Type I (complete portal diversion) — evaluate for shunt ligation or liver transplantation candidacy.
7. Summary: The Complete Post-Diagnosis Roadmap
| Phase | Actions | Timeline |
|---|---|---|
| Day of Diagnosis | Fetal echo (C/T, TR, MPI) + IHPVS assessment + Amniocentesis referral + MFM referral | Immediate |
| Genetic Results | CMA + Noonan/RASopathy panel. Multidisciplinary counselling session. | 1–3 weeks |
| Prenatal Surveillance | Serial echo (1–4 weekly based on risk), growth scans, Doppler surveillance, hydrops checklist | Ongoing until delivery |
| Delivery Planning | Tertiary center. Timing by risk category. Neonatology & cardiology on standby. | 32–39 weeks |
| Postnatal | Neonatal echo + Abdominal Doppler US + LFTs/Ammonia/Coag + Hepatology/Cardiology follow-up plan | Day 1–3, then serial |
📚 Complete Fetal Venous Assessment Series
1. Achiron R, Kivilevitch Z. Fetal umbilical-portal-systemic venous shunt: in-utero classification and clinical significance. Ultrasound Obstet Gynecol. 2016;47(6):739-747.
2. Shen O, et al. In utero classification of umbilical-portal-systemic venous shunts: clinical implications. Prenat Diagn. 2020;40(12):1540-1549.
3. Hofstaetter C, et al. Absent ductus venosus: review of anatomical variations and clinical outcome. Fetal Diagn Ther. 2012;31(2):90-98.
4. ISUOG Practice Guidelines: sonographic examination of the fetal heart (updated). Ultrasound Obstet Gynecol. 2013;41(3):348-359.