What is the most common type of glomerulonephritis (GN) associated with the third trimester of pregnancy?

Membranoproliferative Glomerulonephritis is the Most Common Type of GN in the Third Trimester of Pregnancy

Membranoproliferative glomerulonephritis (MPGN) is the most common type of glomerulonephritis associated with the third trimester of pregnancy.

Pathophysiology and Presentation

MPGN in pregnancy is characterized by:

• Mesangial cell proliferation and thickening of the glomerular basement membrane
• Often presents with nephrotic syndrome, hematuria, and hypertension
• May be primary (idiopathic) or secondary to underlying conditions
• Typically worsens during the third trimester due to increased hemodynamic stress and immune system changes

Epidemiology and Risk Factors

• MPGN has the highest incidence of maternal and fetal complications among primary glomerulonephritides in pregnancy 1
• Risk factors for poor outcomes include:
  • Pre-existing hypertension
  • Impaired renal function before pregnancy
  • Nephrotic-range proteinuria
  • Severe vessel lesions on renal biopsy 2

Maternal and Fetal Outcomes

MPGN in pregnancy is associated with:

• Increased risk of fetal loss (up to 20% of pregnancies) 2
• Higher rates of prematurity (15-18%) 2
• Increased risk of small-for-gestational-age infants (15%) 1
• Maternal complications including:
  • Worsening hypertension (in up to 48% of pregnancies)
  • Increased proteinuria (in up to 53% of pregnancies)
  • Decline in renal function (in 3-15% of pregnancies) 2, 3

Management Approach

Pre-pregnancy Counseling

• Optimize disease control before conception
• Assess baseline renal function, proteinuria, and blood pressure
• Modify medications to pregnancy-safe alternatives

During Pregnancy

1. Monitoring:

   • Regular assessment of renal function, proteinuria, and blood pressure
   • Monitor for signs of preeclampsia (which can be difficult to distinguish from worsening MPGN)
   • Fetal growth surveillance

2. Treatment Options:

   • Corticosteroids are most commonly used for active disease 4
   • Consider antiplatelet therapy (low-dose aspirin started before 16 weeks gestation) to reduce preeclampsia risk
   • In severe cases, plasmapheresis may be considered 4
   • Blood pressure control using pregnancy-safe antihypertensives (labetalol, nifedipine)

3. Delivery Planning:

   • Timing of delivery depends on maternal and fetal status
   • Early delivery may be necessary with worsening maternal condition

Distinguishing Features from Other Pregnancy-Related Conditions

• Unlike preeclampsia, MPGN typically has evidence of glomerular disease before pregnancy
• HELLP syndrome presents with hemolysis, elevated liver enzymes, and low platelets, which are not typical of MPGN
• Lupus nephritis flares are associated with serological markers of lupus activity

Special Considerations

• Joint management between nephrology and obstetrics is essential 5
• Renal biopsy can be safely performed in the first trimester if diagnosis is uncertain 5
• Post-partum monitoring is crucial as some patients experience permanent worsening of renal function or hypertension after pregnancy 1

Conclusion

MPGN represents the most common form of glomerulonephritis specifically associated with the third trimester of pregnancy and carries significant risks for both mother and fetus. Early recognition and appropriate management are essential to optimize outcomes.