What is the management of hydrops (hydrops fetalis)?

Management of Hydrops Fetalis

Management of hydrops fetalis is fundamentally driven by identifying the underlying etiology through systematic evaluation, followed by etiology-specific interventions when treatable causes exist, with delivery timing based solely on obstetric indications rather than prematurity concerns.

Initial Diagnostic Evaluation

The cornerstone of management begins with comprehensive diagnostic workup to determine if the hydrops is immune or non-immune, and to identify treatable etiologies 1:

• Perform indirect Coombs test (antibody screen) to verify non-immune etiology and rule out red cell alloimmunization 1
• Conduct detailed fetal sonography including comprehensive anatomic survey, fetal echocardiography, and assessment for cardiac arrhythmias 1
• Measure middle cerebral artery (MCA) Doppler peak systolic velocity to evaluate for fetal anemia, which is the critical decision point in the diagnostic algorithm 1, 2
• Obtain fetal karyotype and/or chromosomal microarray analysis regardless of whether structural anomalies are identified, as aneuploidy confers poor prognosis 1
• Evaluate placental anatomy for abnormalities, as thickened placenta occurs more frequently (80%) in anemia-associated hydrops 3

Etiology-Based Management Categories

The Society for Maternal-Fetal Medicine categorizes cases into three management pathways 1:

1. Treatable Etiologies Requiring Urgent Intervention

These cases require immediate referral to specialized fetal therapy centers 1:

• Fetal anemia (from any cause): Intrauterine transfusion(s) 1, 4
• Cardiac arrhythmias: Antiarrhythmic medications 1
• Large pleural effusions: Thoracentesis or thoracoamniotic shunting 1
• Congenital pulmonary airway malformations (CPAMs): Corticosteroid therapy 1
• Twin-twin transfusion syndrome: Laser coagulation of placental anastomoses 1
• Parvovirus B19 infection: Intrauterine transfusion with potential for complete resolution 4, 5

2. Lethal Prognosis Cases

Pregnancy termination or comfort care should be offered for conditions with uniformly poor outcomes 1:

• Lethal chromosomal abnormalities
• Severe structural anomalies incompatible with life
• Pregnancy termination should be offered if hydrops is identified prior to viability given the overall poor prognosis 1

3. Idiopathic or Uncertain Prognosis Cases

These require expectant management with intensive surveillance 1:

• Consider candidates for antenatal corticosteroids for fetal lung maturity 1
• Implement antepartum fetal surveillance protocols 1
• Monitor closely for maternal complications, particularly mirror syndrome 1

Delivery Management

Preterm delivery should be undertaken only for obstetric indications, as prematurity worsens prognosis 1:

• Avoid iatrogenic prematurity - the gestational age at delivery significantly impacts survival 1
• Mirror syndrome development is an indication for delivery in most cases, as this represents severe maternal preeclampsia associated with fetal hydrops 1
• Deliver at tertiary centers with capability to stabilize and treat critically ill neonates for all non-lethal or potentially treatable etiologies 1

Maternal Monitoring

Serial maternal blood pressure monitoring is essential to detect mirror syndrome, a form of severe preeclampsia that develops in association with fetal hydrops 1:

• Monitor for signs of maternal edema, hypertension, and proteinuria
• Mirror syndrome necessitates delivery in most cases 1

Prognostic Considerations

Overall neonatal survival is often less than 50% even in the absence of aneuploidy 1:

• Aneuploidy confers particularly poor prognosis 1
• Treatable causes (fetal arrhythmia, parvovirus B19) have better outcomes 1
• Independent risk factors for death include younger gestational age, low 5-minute Apgar score, and need for high-level respiratory support 1
• Chylothorax as the underlying etiology may have mortality as low as 6% when isolated 1

Critical Pitfalls to Avoid

• Do not deliver prematurely unless there are specific obstetric indications - prematurity significantly worsens outcomes 1
• Do not miss treatable causes - cardiovascular abnormalities (20% of cases), anemia, and arrhythmias require urgent intervention 1
• Do not overlook maternal complications - failure to monitor for mirror syndrome can result in severe maternal morbidity 1
• Do not skip genetic testing even with obvious structural anomalies - chromosomal abnormalities account for 10-30% of cases and dramatically alter prognosis 1