From the Guidelines
Kidney stones during pregnancy typically present with severe, colicky flank pain, nausea, vomiting, and hematuria, and their management should prioritize observation as first-line therapy for patients with well-controlled symptoms, as recommended by the American Urological Association/Endourological Society guideline 1. The clinical manifestations of kidney stones during pregnancy can be diverse and may include severe flank pain, often radiating to the groin, accompanied by nausea and vomiting. Unlike non-pregnant patients, pregnant women may experience more diffuse abdominal pain due to anatomical changes in the urinary tract. Hematuria, which occurs in about 75-95% of cases, may be microscopic or visible 1.
Key Clinical Manifestations
- Severe, colicky flank pain
- Nausea and vomiting
- Hematuria (blood in urine)
- Urinary symptoms like frequency, urgency, and dysuria
- Fever if the stone causes urinary obstruction leading to infection (pyelonephritis)
Diagnostic Challenges
Diagnosis can be challenging as the typical symptoms may overlap with normal pregnancy discomforts or other pregnancy complications like preterm labor or placental abruption. The physiological hydronephrosis of pregnancy (dilation of the collecting system) can predispose to stone formation and complicate diagnosis 1.
Management
Observation should be the initial therapy for pregnant patients with ureteral stones and well-controlled symptoms 1. If symptoms are not well-controlled, or if observation fails, ureteral stent, nephrostomy tube, or ureteroscopy (URS) may be considered as alternative options, with frequent stent or tube changes usually being necessary 1. Non-steroidal anti-inflammatory agents (e.g., ketorolac) are contraindicated in pregnancy, and the use of medical expulsive therapy (MET) has not been adequately investigated in the pregnant population 1. Ultrasound is the preferred initial imaging method due to its safety in pregnancy, though it has lower sensitivity for detecting stones compared to CT scans 1. These manifestations require prompt evaluation as kidney stones during pregnancy can increase risks of preterm labor, preeclampsia, and urinary tract infections if not properly managed.
From the Research
Clinical Manifestations of Kidney Stones in Pregnancy
- Kidney stones during pregnancy can present with acute renal colic, which is associated with risks to both mother and fetus 2.
- The situation is more complicated than in non-pregnant women due to imaging limitations and treatment restrictions 2.
- Acute nephrolithiasis is associated with a unique set of complications during pregnancy, including the risk of infection and the need for urgent decompression 3, 4.
- The risk of symptomatic kidney stones increases during the second and third trimesters, peaks at 0 to 3 months after delivery, and returns to baseline by 1 year after delivery 5.
Diagnosis and Management
- Ultrasonography remains the gold-standard first-line diagnostic imaging modality for kidney stones during pregnancy 2, 4.
- Second-line alternatives, such as non-contrast CT, may be used in cases where ultrasound results are equivocal 6.
- First-line management is generally conservative, with a trial of passage and pain management, and is associated with a high rate of stone passage 2.
- Ureteroscopy can be offered if clinically appropriate, but temporary drainage with ureteral stent or nephrostomy tube may be indicated in some circumstances 2, 4.
- Shockwave lithotripsy and percutaneous nephrolithotomy are contraindicated during pregnancy 2.
Complications and Risks
- Pregnancy increases the risk of a first-time symptomatic kidney stone, with the risk peaking close to delivery and improving by 1 year after delivery 5.
- Having a prior pregnancy is also associated with a first-time symptomatic kidney stone 5.
- The risk of kidney stones during pregnancy is associated with anatomical and physiological changes, including changes in urine composition and renal function 5.