What is the recommended approach for managing kidney stones in pregnancy?

Management of Kidney Stones During Pregnancy

In pregnant patients with kidney stones and well-controlled symptoms, observation should be offered as first-line therapy, with close monitoring for recurrent or persistent symptoms due to increased risk of maternal and fetal morbidity. 1

Initial Evaluation and Diagnosis

• Renal colic is the most common nonobstetric cause of abdominal pain requiring hospitalization during pregnancy 1
• Ultrasonography should be the initial imaging modality of choice to limit radiation exposure to the fetus 1
• If ultrasound is nondiagnostic and symptoms are severe, limited options include:
  • Magnetic resonance urography (MRU) as a second-line test 1, 2
  • Limited intravenous pyelogram (with minimal films) if absolutely necessary 1
  • Low-dose CT should only be considered as a last resort 2

Management Algorithm

Step 1: Conservative Management

• Observation is the first-line approach for pregnant patients with well-controlled symptoms 1
• Spontaneous passage rates in pregnant women are similar to non-pregnant patients 1
• Conservative management includes:
  • Adequate hydration
  • Appropriate pain control (avoiding NSAIDs which are contraindicated in pregnancy) 1
  • Close monitoring for symptom progression or complications 1

Step 2: Medical Expulsive Therapy (MET)

• If considering MET, patients must be counseled that these medications have not been adequately investigated in pregnancy and are being used "off-label" 1
• Alpha-blockers may be considered with appropriate caution and obstetric consultation 1, 3

Step 3: Interventional Management (if conservative measures fail)

• Ureteroscopy (URS) should be offered to patients who fail observation 1

  • URS provides definitive treatment by accomplishing stone clearance 1
  • Multiple studies have reported successful outcomes with low morbidity 1, 4
  • When intracorporeal lithotripsy is necessary, holmium laser is preferred due to minimal tissue penetration 1

• Alternative options include:

  • Ureteral stent placement - requires frequent exchanges due to rapid encrustation during pregnancy 1
  • Percutaneous nephrostomy tube - also requires frequent exchanges 1

• Contraindicated procedures during pregnancy:

  • Shock wave lithotripsy (SWL) 5
  • Percutaneous nephrolithotomy (PCNL) 5

Special Considerations

• All pharmacological and surgical interventions should be coordinated with the obstetrician 1
• Urgent intervention is required in cases of obstructive nephrolithiasis with associated infection 5
• Multidisciplinary approach involving urology, obstetrics, and anesthesiology is essential for optimal outcomes 6, 4

Potential Complications and Pitfalls

• Kidney stones during pregnancy carry increased risk of maternal and fetal morbidity 1
• Temporary drainage devices (stents/nephrostomy tubes) encrust rapidly during pregnancy, necessitating frequent exchanges 1
• NSAIDs are contraindicated for pain management during pregnancy 1
• Radiation exposure should be minimized or avoided whenever possible 1, 2
• Untreated obstructive stones with infection can lead to sepsis and preterm labor 1, 5