What is the recommended treatment for nephrotic syndrome during pregnancy?

Treatment of Nephrotic Syndrome During Pregnancy

For nephrotic syndrome during pregnancy, compatible medications including hydroxychloroquine, prednisone, azathioprine, and calcineurin inhibitors (especially tacrolimus) should be continued at safe dosages throughout pregnancy and lactation. 1

Medication Management

First-Line Medications (Safe in Pregnancy)

• Corticosteroids (Prednisone): Can be safely used throughout pregnancy
• Hydroxychloroquine: Should be continued during pregnancy 1
• Azathioprine: Safe alternative immunosuppressant 1
• Calcineurin Inhibitors: Tacrolimus preferred over cyclosporine 1

Medications to Avoid During Pregnancy

• Mycophenolate mofetil (MMF): Must be withdrawn at least 3-6 months before conception 1
• Cyclophosphamide: Contraindicated during pregnancy 1
• ACE inhibitors and ARBs: Must be discontinued during pregnancy 1

Management Algorithm Based on Underlying Cause

For Lupus Nephritis

1. Pre-pregnancy planning:

   • Aim for UPCR below 500 mg/g for at least 6 months before conception 1
   • GFR should be >50 mL/min 1
   • Switch from MMF to azathioprine 3-6 months before planned conception 1

2. During pregnancy:

   • Continue hydroxychloroquine, prednisone, azathioprine, and/or tacrolimus 1
   • Add low-dose aspirin to reduce pre-eclampsia risk 1
   • Monitor every 4 weeks with multidisciplinary team including obstetrician 1
   • For flares: Treat with acceptable medications and pulses of IV methylprednisolone if severe 1

For Primary Nephrotic Syndrome (Non-Lupus)

1. Symptomatic management:

   • Careful diuresis: Furosemide 0.5-2 mg/kg per dose (up to six times daily) 1, 2
   • Albumin infusions for severe hypoalbuminemia 2
   • Consider anticoagulation for high thrombosis risk 3, 2

2. Disease-specific therapy:

   • For primary FSGS: Glucocorticoids may be considered 3
   • For membranous nephropathy: Calcineurin inhibitors (tacrolimus) preferred 1

Monitoring During Pregnancy

At Each Visit (Every 4 Weeks)

• Body weight and blood pressure
• Estimated GFR, serum albumin
• Proteinuria (UPCR or 24-hour collection)
• Complete blood count
• Urine sediment examination 1

Additional Monitoring

• Fetal growth assessment
• Screen for pre-eclampsia
• Monitor for thrombotic complications 3, 4

Complications to Watch For

Maternal Complications

• Thrombotic events: Increased risk of renal vein thrombosis, pulmonary embolism, and deep vein thrombosis 3, 4
• Pre-eclampsia: Occurs in approximately 27% of cases 4
• Acute kidney injury: Reported in 23% of pregnancies with nephrotic syndrome 4
• Infections: Particularly cellulitis due to edema 4

Fetal Complications

• Preterm delivery: Mean gestational age at delivery is 34-35 weeks 2, 4
• Low birth weight: Occurs in over 50% of cases 4
• Intrauterine growth restriction: Common complication 4, 5
• NICU admission: Required in approximately 30% of cases 4

Important Caveats

• Early-onset nephrotic syndrome in pregnancy (before 20 weeks) carries particularly poor prognosis 5, 6
• Kidney biopsy may be necessary during pregnancy if diagnosis is uncertain and would change management 4
• Even with optimal management, pregnant women with nephrotic syndrome remain at high risk for complications 4
• Multidisciplinary care involving nephrology and high-risk obstetrics is essential 2
• Post-delivery, continue immunosuppression at stable doses for at least 3 months 1

Pregnant women with nephrotic syndrome require close monitoring and aggressive management to optimize both maternal and fetal outcomes, with medication choices limited to those proven safe in pregnancy.