Kidney Week

Abstract: FR-PO0996

Severe Hyponatremia in the Setting of Triplet Pregnancy with Preeclampsia

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

• Onuchic, Fernando, Yale New Haven Health, New Haven, Connecticut, United States

Fernando Onuchic, MD

• Marnet, Erica, Yale New Haven Health, New Haven, Connecticut, United States

Erica Marnet, MD

• Aklilu, Abinet Mathias, Yale New Haven Health, New Haven, Connecticut, United States

Abinet Mathias Aklilu, MD, MPH

Introduction

We present a case of a woman with preeclampsia and severe hyponatremia in the 3^rd trimester of multiple gestation pregnancy.

Case Description

31yo G1 woman at 31w 2d of a previously uncomplicated triplet pregnancy presented with 2 weeks of lower extremity edema and malaise. She had a blood pressure of 189/100mmHg and hyponatremia with sNa 111mmol/L. She denied any neurologic symptoms but reported decreased food and increased fluid intake. She had 3+ LE edema and pulmonary edema on CXR. Labs showed creatinine 0.9mg/dL, potassium 6.0mmol/L, urine sodium<13mmol/L, urine osmolality 374mOsm/kg and normal LFTs except for serum albumin 2.2g/dL. Urine protein/creatinine ratio (uPCR) was 6.5mg/mg. She was given hydralazine, nifedipine, IV furosemide, magnesium sulfate, and started on 3% NaCl. Fetal US showed no distress. Echocardiogram showed no abnormalities. Given reassuring fetal status and BP normalization, 3% NaCl was continued with sNa correction at rate of 6-8mmol/L per 24 hours with plan for delivery once sNa improved to moderate range. Around 48h after presentation, she underwent cesarean delivery when sNa was 127mmol/L. sNa gradually corrected to normal range without further intervention after (Fig 1). At discharge, sNa was 139, sCr had improved to 0.5mg/dL, and uPCR had improved to 2.25mg/mg.

Discussion

Hyponatremia occurs in 10-15% of women with preeclampsia. Severity is correlated with worse fetal and maternal outcomes. The mechanism is complex and related to increased arginine vasopressin due to low effective arterial blood volume and decreased placental vasopressinase production, which can be exacerbated by high fluid intake. Though severe hyponatremia is rarer, multiple gestations carry a higher risk. While our patient had hypervolemic hyponatremia, both SIADH and hypovolemic hyponatremia have also been reported. Management depends on severity and involves fluid restriction, hypertonic saline if needed and expedited delivery. However, benefit of urgent delivery should be weighed against the risk of osmotic demyelination for both the fetus and the mother as hyponatremia may quickly resolve after.