Kidney Stones During Pregnancy

By trimester

Weeks 1–13

1st trimester

Ultrasound remains the first imaging step. When pain is controlled, kidney function is stable, infection is absent, and fluids stay down, the urology and obstetric teams may use observation while confirming that the stone passes.

Weeks 14–27

2nd trimester

If symptoms continue or obstruction threatens the kidney, ureteroscopy can be considered at an experienced center. The decision is individualized with obstetrics, urology, radiology, and anesthesia rather than delayed solely because of pregnancy.

Weeks 28–birth

3rd trimester

Physiologic hydronephrosis is common and can make ultrasound harder to interpret. Worsening pain, fever, kidney dysfunction, or concern for an obstructed infected system can justify additional imaging or urgent drainage despite late gestation.

What does the evidence show for kidney stones?

• Pregnancy kidney stones typically cause sharp or wave-like pain in the back, side, lower abdomen, or groin and may cause blood in urine, urinary urgency or pain, nausea, or vomiting. Fever, chills, inability to urinate, or very low urine output may signal a more serious problem. 1
• Multidisciplinary pregnancy guidance recommends renal and bladder ultrasound first for suspected obstructing stones. Hydronephrosis alone is not proof of a stone because physiologic dilation can occur in up to 90% of pregnancies; ureteral jets, resistive indices, and transvaginal views can add useful information. 2
• If ultrasound is inconclusive, second-line imaging depends on urgency. Repeat ultrasound or noncontrast MRI may be discussed in a stable patient, while low-dose noncontrast CT is supported when fever, low blood pressure, intractable symptoms, or an intervention-level decision requires diagnostic certainty. 2
• A stone with infection and obstruction requires urgent urinary drainage. Without infection or kidney threat, initial care is often a supervised trial of passage with hydration and pain control; persistent obstruction or uncontrolled symptoms can lead to ureteroscopy or temporary drainage. 3
• A 2024 review of 28 ureteroscopy publications found low overall adverse-event rates and no severe complication in the included studies, but evidence quality was low. Outcomes were better associated with higher center caseload, supporting experienced urology and obstetric teams rather than a blanket safety promise. 4

When should I call my provider about kidney stones?

Seek emergency-department assessment for flank or abdominal pain with fever, chills, faintness, low blood pressure, inability to urinate, or very low urine output because an infected obstructed kidney needs urgent drainage. Get urgent same-day assessment for uncontrolled pain or repeated vomiting that blocks fluid intake. Severe pain in pregnancy can also reflect an obstetric or abdominal emergency. Trust your read on your own body. If something feels off beyond the list above, please consult your healthcare provider rather than waiting it out.