What is the management of mirror syndrome in a pregnant woman?

Mirror Syndrome: Definition and Management

What is Mirror Syndrome?

Mirror syndrome is a rare but serious maternal complication where the mother develops edema that "mirrors" the edema of her hydropic fetus, representing a form of severe preeclampsia that requires urgent recognition and treatment. 1

Clinical Presentation

The syndrome is characterized by a triad of maternal, fetal, and placental edema (also called "triple edema"), with the following clinical features: 1

• Maternal edema occurs in approximately 90% of cases 1
• Hypertension develops in 60% of cases 1
• Proteinuria is present in 40% of cases 1
• Pulmonary edema represents the major maternal morbidity, occurring in 21% of cases 1

Additional clinical findings include: 1

• Headache and visual disturbances
• Oliguria
• Elevated uric acid, liver enzymes, or creatinine levels
• Thrombocytopenia
• Anemia and hemodilution

Pathophysiology

The hydropic placenta becomes severely dysfunctional and edematous, releasing excessive anti-angiogenic factors (soluble fms-like tyrosine kinase-1 and soluble endoglin) into maternal circulation, triggering systemic endothelial dysfunction identical to severe preeclampsia. 2 This imbalance of angiogenic and anti-angiogenic factors causes widespread endothelial dysfunction throughout maternal vasculature. 2

Management of Mirror Syndrome

Primary Management Strategy

For most cases of nonimmune hydrops fetalis without a treatable etiology, development of mirror syndrome necessitates immediate delivery. 1 This is a Grade 1C recommendation from the Society for Maternal-Fetal Medicine. 1

Critical Decision Point: Is the Fetal Hydrops Treatable?

The management algorithm hinges on whether the underlying cause of fetal hydrops can be treated: 1, 3

If Treatable Etiology Exists:

Attempt fetal therapy first, as successful treatment can resolve both fetal hydrops AND maternal mirror syndrome: 1, 2, 4

Treatable causes include: 1, 2

• Fetal cardiac arrhythmias (supraventricular tachycardia, atrial flutter): Treat with transplacental antiarrhythmic medications 1
• Fetal anemia (parvovirus B19, fetomaternal hemorrhage): Perform intrauterine blood transfusion 1, 5
• Large pleural effusions (hydrothorax, chylothorax): Drain via thoracoamniotic shunt 1, 5
• Fetal bladder obstruction: Perform appropriate decompression 1

Evidence for this approach: Recent case series demonstrate that fetal therapy leads to resolution of hydrops in 85% of cases and resolution of mirror syndrome in 95% of cases, with median time to mirror syndrome resolution of 10 days and pregnancy prolongation by a median of 10 weeks. 4 Multiple case reports document complete resolution of maternal mirror syndrome following successful intrauterine transfusion and pleuroamniotic shunt placement. 5

If No Treatable Etiology or Maternal Deterioration:

Proceed immediately to delivery, regardless of gestational age. 1 Delivery should not be delayed if the maternal condition deteriorates, even if this results in significant prematurity. 1

Monitoring During Expectant Management (If Attempting Fetal Therapy)

This approach should be taken only with extreme caution: 1

• Serial maternal blood pressure monitoring 1, 3, 6
• Monitor for worsening edema, particularly pulmonary edema 1
• Assess for symptoms of severe preeclampsia: right upper quadrant/epigastric pain, headache, visual disturbances 2
• Laboratory monitoring: platelet count, liver enzymes, creatinine, uric acid 1, 2
• Close fetal surveillance to assess response to therapy 4

Delivery Considerations

Mode of delivery: 1, 6

• Cesarean delivery is indicated if the fetus is potentially viable and delivery is based on maternal deterioration or fetal surveillance findings 1, 6
• Consider potential for dystocia due to severe fetal edema and effusions 1

Location of delivery: 1, 3, 6

• All deliveries must occur at tertiary centers with level-III NICU capability to stabilize and treat critically ill neonates 1, 3, 6

Prognosis and Resolution

The syndrome is completely reversible: 1, 2

• Resolution occurs with either successful treatment of the underlying fetal hydrops OR with delivery 1
• When hydrops resolves, anti-angiogenic factor levels normalize and maternal preeclampsia syndrome resolves, proving the causal relationship 2
• Case reports document resolution following spontaneous intrauterine fetal demise of the hydropic twin in multiple gestations 7

Common Pitfalls

Do not mistake mirror syndrome for simple preeclampsia or heart failure exacerbation - the key distinguishing feature is the presence of fetal hydrops. 8 In patients with pre-existing cardiac disease, overlapping signs of edema can make diagnosis particularly challenging. 8

Do not delay delivery for fetal benefit if maternal condition deteriorates - maternal safety takes absolute priority, and the risks of expectant management of severe preeclampsia apply equally to mirror syndrome. 1