What is the best treatment approach for a 26-week pregnant woman with persistent moderate flank pain and hydronephrosis?

Management of Symptomatic Hydronephrosis in a 26-Week Pregnant Woman

For a 26-week pregnant woman with persistent moderate flank pain and hydronephrosis requiring prolonged hospitalization, retrograde ureteral stenting is the preferred first-line intervention when conservative management fails. 1

Initial Assessment and Conservative Management

• Hydronephrosis is common during pregnancy (70-90% of pregnant women), typically appearing after 20 weeks due to mechanical compression from the enlarging uterus and hormonal changes that reduce ureteric peristalsis 1
• Only 0.2-4.7% of pregnant women develop symptomatic hydronephrosis requiring intervention, with higher prevalence in advancing trimesters 1
• Initial management should include conservative measures: adequate rest, hydration, analgesia, and antiemetics, which have a 70-80% success rate in cases without infection 1
• The patient should be closely monitored with ultrasound to assess progression of hydronephrosis 2

Indications for Intervention

• Persistent moderate to severe flank pain despite conservative management 2
• Prolonged hospitalization requirements, as in this case 1
• Risk of preterm labor if left untreated (the most significant risk of urinary tract obstruction during pregnancy) 1
• Presence of infection or pyonephrosis, which requires immediate intervention 3

Recommended Interventional Approach

First-Line Intervention: Retrograde Ureteral Stenting

• Retrograde ureteral stenting is the preferred first-line intervention for pregnant patients with persistent symptomatic hydronephrosis requiring treatment 1
• Advantages of retrograde stenting:
  • Minimal radiation exposure to the fetus 1
  • Significant advancements in ureteroscopy techniques have made the procedure safe and feasible 1
  • Can be performed under local anesthesia in many cases 4
  • Improved imaging resolution and smaller caliber scopes have enhanced safety 1

Technical Considerations for Stent Placement

• Fluoroscopy during stent placement should be avoided or minimized 1
• Ultrasound guidance can be used to confirm appropriate stent positioning 1
• The stent typically remains in place until after delivery 1, 5
• Complications to monitor for include ureteral injury, perforation, or sepsis that could lead to preterm labor 1

Alternative Intervention: Percutaneous Nephrostomy (PCN)

• PCN should be considered when retrograde ureteral catheterization is not technically possible 1
• PCN can safely provide temporary urinary tract decompression 1
• The incidence of spontaneous abortion or preterm labor related to PCN tube placement is exceedingly low 1
• PCN can be performed using ultrasound guidance alone to limit radiation exposure to the fetus 1
• The nephrostomy catheter typically remains in place until after delivery, with definitive stone intervention performed postpartum if needed 1

Special Considerations

• Percutaneous antegrade ureteral stenting is not recommended during pregnancy due to increased fluoroscopy time and radiation exposure to the fetus 1
• Prolonged manipulation in cases with active infection can lead to systemic inflammatory response syndrome or urosepsis 1
• For cases with urolithiasis, the risk of preterm labor completely ceases once the stone passes or is removed 1
• A multidisciplinary approach involving the urologist, obstetrician, and anesthesiologist is essential for optimal management 6

Follow-up and Monitoring

• Regular ultrasound monitoring to assess resolution of hydronephrosis 2
• Close monitoring for signs of infection or worsening obstruction 1
• Definitive treatment of any underlying cause (such as stone removal) is typically delayed until after delivery 1, 5