5mm Kidney Stone: Will It Pass on Its Own? Timeline & Tips
Probability of passing a 5mm stone – by location
A 5mm kidney stone sits right at the borderline where spontaneous passage is possible but not guaranteed. The likelihood depends almost entirely on where the stone is located in the ureter. Based on 2025 meta‑analysis data (over 12,000 patients):
| Stone location | Probability of spontaneous passage within 4‑6 weeks |
|---|---|
| Lower ureter (near bladder – UVJ) | 65‑75% |
| Mid ureter (pelvic brim) | 50‑60% |
| Upper ureter (near kidney – UPJ) | 40‑50% |
| Inside kidney (non‑obstructing) | N/A – will not pass until it enters ureter |
A 5mm stone in the lower ureter has a good chance of passing. In the upper ureter, it is a coin toss. If the stone is still inside the kidney (not yet in the ureter), it cannot pass spontaneously – it must first drop into the ureter, which may happen unpredictably.
Typical timeline for passage
If a 5mm stone is going to pass, here is when it usually happens:
- First 1‑2 weeks: About 40‑50% of stones that will eventually pass do so within this period.
- Weeks 3‑4: Another 20‑30% pass. Pain episodes may be intermittent.
- Weeks 5‑6: Only 5‑10% pass. If you reach 6 weeks without passage, spontaneous passage is unlikely.
- Beyond 6 weeks: Less than 5% pass. Risk of kidney damage (hydronephrosis) increases significantly.
At Vivekananda Hospital, we recommend a maximum waiting period of 6 weeks for a 5mm stone. If it has not passed by then, schedule URS.
Factors that increase or decrease passage chance
Not all 5mm stones are equal. These factors affect passage probability:
- Stone location (as above). Lower ureter = better.
- Stone shape: Smooth, oval stones pass more easily than jagged, irregular stones.
- Stone composition: Uric acid stones are smoother and may pass easier. Calcium oxalate monohydrate stones are rough and may get stuck.
- Ureteral anatomy: Previous surgeries, congenital strictures, or a narrow ureter reduce passage.
- Hydration: 2.5‑3 litres of water daily significantly improves passage.
- Medical expulsion therapy: Tamsulosin increases passage rate by 30‑40%.
- Pregnancy: Physiological ureteral dilation may help passage, but imaging and treatment are limited.
Medical expulsion therapy (tamsulosin)
Medical expulsion therapy (MET) is the standard of care for stones <6mm. It does not dissolve the stone but relaxes the ureter, allowing it to pass faster and with less pain.
Regimen:
- Tamsulosin (Flomax) 0.4 mg once daily, preferably at bedtime.
- Continue for 4‑6 weeks or until the stone passes.
- Side effects: nasal congestion, dizziness, retrograde ejaculation (harmless, reversible).
- Alternative: nifedipine 30 mg daily (less common).
Do not take tamsulosin if: You have severe liver disease, are on other alpha‑blockers, or have a history of intraoperative floppy iris syndrome (eye surgery).
At Vivekananda Hospital, we prescribe tamsulosin for all patients attempting spontaneous passage of a 5mm stone, provided no contraindications.
When to stop waiting and choose surgery
Do not wait indefinitely. Stop the trial of passage and proceed to URS if:
- No passage after 6 weeks.
- Increasing hydronephrosis (kidney swelling) on follow‑up ultrasound.
- Pain becomes severe or uncontrollable with oral painkillers.
- You develop fever or chills (possible infection above the stone).
- The stone does not move on repeat imaging after 2‑3 weeks.
- You have a solitary kidney or pre‑existing kidney disease.
Surgery options if it does not pass
If your 5mm stone fails to pass, the best surgical option is URS (ureteroscopy) with laser. Here is why:
- URS success rate: 95‑98% in one session.
- Recovery: Same‑day procedure, back to work in 2‑3 days. A stent is often placed for 7‑14 days.
- ESWL alternative: Success rate 60‑70% for a 5mm stone. Often requires multiple sessions. We generally do not recommend ESWL for stones this size when URS is so effective.
At Vivekananda Hospital, URS with laser for a 5mm stone costs ₹45,000‑70,000. Most insurance plans cover it.
Interactive FAQ – 5mm kidney stone
If it passes, most do so within 2‑4 weeks. Some take up to 6 weeks. Beyond 6 weeks, passage is very unlikely.
Yes. If it does not pass within 6‑8 weeks, it may become impacted in the ureter. This requires surgical removal and can cause ureteral stricture if left too long.
No, it is medium. Stones are classified as small (<5mm), medium (5‑10mm), and large (>10mm). A 5mm stone is at the upper limit of “may pass spontaneously”.
Yes, you will likely feel sharp, colicky pain as it moves down the ureter. The pain may come in waves. Once it reaches the bladder, pain stops abruptly. You may see the stone in urine.
Yes. Aim for 2.5‑3 litres of water daily. This increases urine volume and hydrostatic pressure, helping push the stone down. Do not rely on water alone – add tamsulosin.
If it completely obstructs the ureter for several weeks, it can cause hydronephrosis and permanent kidney damage. That is why we limit waiting to 6 weeks.
ESWL can break a 5mm stone, but the stone‑free rate after one session is only 60‑70%. URS is much more reliable (95‑98%). We recommend URS if you choose surgery.
Pain can range from mild flank discomfort to severe, debilitating colic. If oral painkillers (ibuprofen) do not help, or if you are vomiting from pain, go to emergency – the stone may be stuck.
Yes, unless you have a contraindication. Tamsulosin increases passage rates by 30‑40% and reduces pain. It is the standard of care for medical expulsion therapy.
Disclaimer: A 5mm kidney stone may pass, but you need medical supervision. If you have severe pain, fever, or no passage after 6 weeks, consult a urologist at Vivekananda Hospital.