Most ureteral kidney stones pass on their own, but the timeline and likelihood depend almost entirely on the stone’s size. Stones smaller than 4mm pass about 98% of the time without intervention. Stones between 4 and 5mm still have roughly a 65-81% chance of passing, while stones 6mm or larger rarely make it through on their own. Understanding where your stone falls on that spectrum determines whether you’re looking at home management, medication, or a procedure.
How Size Affects Your Chances
The ureter is only about 3-4mm wide in its narrowest sections, so anything close to that width creates friction and resistance. A large European study tracking nearly 400 ureteral stones over 20 weeks found a clear drop-off in passage rates as size increased:
- Under 3.5mm: 98% passed without intervention
- 3.5 to 4.4mm: 81% passed
- 4.5 to 5.4mm: 65% passed
- 5.5 to 6.4mm: 33% passed
- 6.5mm or larger: only 9% passed
Location matters too. Stones closer to the bladder (in the lower ureter) tend to pass more easily than those stuck higher up near the kidney. If your imaging shows a small stone already in the lower third of the ureter, the odds are strongly in your favor.
Managing Pain While You Wait
The pain from a ureteral stone comes in waves as the ureter spasms around the obstruction. It typically hits the flank, wraps around toward the groin, and can be severe enough to send people to the emergency room. Anti-inflammatory pain relievers like ibuprofen or naproxen are the better first choice over opioids for this kind of pain. A Cochrane review of multiple trials found that patients given anti-inflammatories were less likely to need additional pain medication afterward (about 19% needed rescue doses compared to 25% with opioids) and experienced significantly less vomiting (6% versus 20%).
Opioids still work for pain relief, but they come with more side effects, particularly nausea. If you’re already vomiting from the stone itself, adding an opioid can make that worse. Anti-inflammatories also reduce the swelling in the ureter wall, which may help the stone move.
What Helps a Stone Pass Faster
Your doctor may prescribe an alpha-blocker, a medication that relaxes the smooth muscle in the ureter to widen the passage. This is called medical expulsive therapy. It’s most useful for stones in the 5-10mm range that have a reasonable but not guaranteed chance of passing. The medication is typically taken once daily at bedtime, and most stones that respond to this approach pass within about 5 to 10 days.
Fluid intake is the other major lever you can pull. The American Urological Association recommends drinking enough to produce at least 2.5 liters of urine per day. That’s roughly 3 liters (about 12-13 cups) of water, though the exact amount depends on your activity level and climate. The goal is to keep a steady flow of urine pushing behind the stone. Sipping consistently throughout the day works better than drinking large amounts at once.
Staying physically active also helps. Light movement like walking, cycling, or even jumping jacks can encourage the stone to shift through the ureter. Lying still for long periods won’t help it along. That said, don’t push through severe pain to exercise. Move when you can, rest when you need to.
When Conservative Treatment Isn’t Enough
Guidelines from the American Urological Association recommend giving conservative management (fluids, pain control, and medication) a window of 4 to 6 weeks. If the stone hasn’t passed by then, or if complications develop sooner, it’s time for a procedure. You shouldn’t wait indefinitely. A stone blocking urine flow for too long can damage the kidney.
Several situations call for faster intervention. Fever or chills alongside a ureteral stone suggest infection behind the blockage, which can become dangerous quickly. Persistent vomiting that prevents you from keeping fluids or medication down is another red flag. Pain that doesn’t respond to any medication, or signs of reduced kidney function, also push the timeline forward. If you develop a fever with a known ureteral stone, that’s a situation to address the same day.
Procedures to Remove a Stuck Stone
When a stone won’t pass on its own, there are two main approaches depending on its size and location.
Ureteroscopy
This is the most common procedure for ureteral stones. A thin, flexible scope is passed through the urethra and bladder into the ureter. The surgeon can see the stone directly and either grab it with a tiny basket or break it into fragments using a laser. There are no incisions. Recovery is typically quick, with most people back to normal activities within a few days to a week. You may have some soreness and blood in your urine for a short period afterward.
Shock Wave Lithotripsy
This option uses focused sound waves from outside the body to break the stone into smaller pieces that can pass naturally. It works best for stones in the upper ureter or kidney and is less effective for very hard or very large stones. The procedure is noninvasive, but you’ll still need to pass the fragments over the following days or weeks, which can cause some discomfort.
After either procedure, your urologist may place a ureteral stent, a small flexible tube that holds the ureter open. Stents prevent swelling from blocking urine flow during healing and help any remaining fragments pass. Most stents stay in for a few days to a few weeks before being removed in a brief office visit. Stents can cause some bladder irritation and a frequent urge to urinate while they’re in place, but these symptoms resolve once the stent comes out.
Why You Should Catch the Stone
Whether your stone passes naturally or gets removed surgically, try to collect it. Your doctor will likely give you a small mesh strainer to urinate through. Once captured, the stone goes to a lab for chemical analysis. Knowing the stone’s composition (calcium oxalate, uric acid, or another type) shapes the prevention plan to reduce your risk of forming another one. About half of people who’ve had one kidney stone will develop another within 10 years, so this analysis is genuinely worth the minor inconvenience of straining your urine for a few days.