Abstract: FR-PO0986
Clinical Significance of Kidney Biopsy for New-Onset Nephrotic Syndrome in Early to Mid-Pregnancy: A Case Series
Session Information
- Women's Health and Kidney Diseases
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Women's Health and Kidney Diseases
- 2100 Women's Health and Kidney Diseases
Authors
- Nakai, Anna, Tokyo Joshi Ika Daigaku, Shinjuku, Tokyo, Japan
- Ushio, Yusuke, Tokyo Joshi Ika Daigaku, Shinjuku, Tokyo, Japan
- Manabe, Shun, Tokyo Joshi Ika Daigaku, Shinjuku, Tokyo, Japan
- Takahashi, Rina, Tokyo Joshi Ika Daigaku, Shinjuku, Tokyo, Japan
- Kataoka, Hiroshi, Tokyo Joshi Ika Daigaku, Shinjuku, Tokyo, Japan
- Hoshino, Junichi, Tokyo Joshi Ika Daigaku, Shinjuku, Tokyo, Japan
Introduction
New-onset nephrotic syndrome (NS) during early to mid-pregnancy is associated with severe maternal and fetal complications and may prompt consideration of pregnancy termination for maternal indications. Although renal biopsy during pregnancy is often avoided because of bleeding concerns, treatment without a histological diagnosis may lead to inappropriate management. We report two cases of new-onset NS in which renal biopsy before 20 weeks of gestation enabled distinct biopsy-guided management strategies and successful continuation of pregnancy.
Case Description
Case 1: A 29-year-old woman with a twin pregnancy was admitted at 18 weeks of gestation with NS (urine protein-to-creatinine ratio [UPCR] 4.85 g/gCr) and mild renal dysfunction. Renal biopsy demonstrated IgA nephropathy with crescent formation. Because progressive renal injury was a major concern, steroid pulse therapy followed by prednisolone was initiated. Prednisolone was selected because it is largely inactivated by placental 11β-hydroxysteroid dehydrogenase type 2, thereby minimizing fetal exposure. Proteinuria and renal dysfunction rapidly improved, and she delivered healthy twins by cesarean section at 35 weeks of gestation.
Case 2: A woman in her 20s developed NS (UPCR 4.8 g/gCr) at 8 weeks of gestation. Renal biopsy at 14 weeks revealed PLA2R-positive primary membranous nephropathy. Given preserved renal function and concern regarding fetal risks associated with immunosuppressive therapy, conservative management with supportive care and low-dose aspirin was selected. Proteinuria gradually improved to partial remission without immunosuppressive treatment. She delivered a healthy male infant (2,550 g; Apgar scores 8/9) by scheduled cesarean section at 37 weeks and 4 days. Postpartum proteinuria further decreased to 0.82 g/day.
Discussion
Histological diagnosis is essential in patients with severe NS during early pregnancy to objectively reassess the necessity of pregnancy termination and guide individualized management. Renal biopsy enabled aggressive immunosuppressive therapy in one case while avoiding unnecessary fetal exposure in the other. When carefully performed, renal biopsy during early to mid-pregnancy can provide critical diagnostic information that supports personalized multidisciplinary care and favorable maternal and fetal outcomes.