Kidney Stones During Pregnancy: What Should You Do and Which Treatments Are Safe?

Severe side or back pain during pregnancy is frightening. Most women’s first worry is the baby, and their second is whether any scan, medicine or procedure is safe right now.

Short answer: Kidney stones in pregnancy are uncommon but real, and most can be managed safely without harming the baby. Ultrasound is the first test, with no radiation. Most stones pass on their own with fluids, safe pain relief and close monitoring. If a stone causes infection, blocks the kidney or causes pain that cannot be controlled, a urologist can relieve the blockage with a stent or a small drainage tube, or remove the stone with ureteroscopy (URSL), which is considered safe in selected patients. Shock wave lithotripsy (ESWL) and PCNL are not used during pregnancy.

This guide explains how stones present in pregnancy, which tests and treatments are safe in each situation, what to avoid, and when to go to hospital straight away.

How Common Are Kidney Stones in Pregnancy?

Studies report kidney stones in roughly 1 in 200 to 1 in 1,500 pregnancies. Although uncommon, stone pain is one of the most frequent non-obstetric reasons pregnant women are admitted to hospital. Most episodes happen in the second and third trimesters.

Why pregnancy matters:

• Hormonal changes (especially progesterone) relax the ureter, slowing urine flow.
• The growing uterus presses on the ureters, more often on the right side.
• Urine chemistry changes, with more calcium passing through the kidneys.
• Mild swelling of the kidneys is normal in many pregnancies, which can make stones harder to spot.

For general risk factors in women, read what causes kidney stones in women.

Symptoms: How It Feels in Pregnancy

Stone symptoms in pregnancy are similar to those in anyone else, but they are easily confused with pregnancy discomfort, a urine infection or labour pain.

• Sharp pain in the side or back, often coming in waves, that may spread to the lower abdomen or groin
• Nausea and vomiting, sometimes mistaken for morning sickness
• Blood in urine, visible or found on a urine test
• Burning, frequent urging or passing small amounts of urine
• Fever or chills, which signal infection and need urgent attention

Back pain that comes and goes in waves can also be labour, so any severe or new pain in pregnancy needs prompt assessment by your obstetrician. Read kidney stone symptoms in women and kidney stone pain in stomach.

Go to Hospital Immediately If You Have

• Fever, chills or shivering with side or back pain
• Pain that is not controlled by the medicine your doctor has allowed
• Persistent vomiting, so you cannot keep fluids down
• Very little or no urine
• Contractions, leaking fluid, vaginal bleeding or reduced baby movements
• Only one kidney

A blocked kidney with infection can become dangerous for both mother and baby within hours. In pregnancy, do not wait it out at home. Read UTI vs kidney infection and hydronephrosis causes and treatment.

Which Tests Are Safe in Pregnancy?

One common source of confusion: many pregnant women have mild swelling of the kidney on ultrasound even without a stone, because of pregnancy itself. Your doctor will judge the scan along with your symptoms and urine tests, not the swelling alone. Read about the role of ultrasound and CT in diagnosing kidney stones.

Treatment Step 1: Conservative Care (Most Women)

If there is no infection, the kidneys are working well and pain is controlled, the first approach is watchful care:

• Hydration: steady fluids through the day, as advised by your doctor
• Pain relief that is safe in pregnancy: paracetamol (acetaminophen) is usually the first choice. Anti-inflammatory painkillers (NSAIDs such as ibuprofen or diclofenac) are generally avoided in pregnancy, and stronger painkillers are used only under close supervision. Never take any painkiller in pregnancy without your obstetrician’s or urologist’s advice.
• Anti-nausea medicine if prescribed
• Medicine to relax the ureter (such as tamsulosin) is sometimes used after discussion with the obstetrician
• Regular review with repeat urine tests and ultrasound

Reported rates of stones passing on their own in pregnancy are as high as 70 to 80%, although researchers note the true rate may be lower.

Many women ask whether they can simply wait until the baby is born. Sometimes yes, sometimes no — it depends on the stone’s size, location, symptoms and whether infection develops, as the sections below explain.

Treatment Step 2: Relieving a Blockage (Stent or Nephrostomy)

If the stone causes infection, a blocked kidney, worsening kidney function, or pain that cannot be controlled, the kidney must be drained. There are two options:

DJ stent. A thin, soft tube placed from the kidney to the bladder through the natural urinary passage, without any cut, usually under ultrasound guidance with minimal or no X-ray. Read DJ stent explained.

Nephrostomy tube. A small tube placed from the back directly into the kidney under ultrasound guidance, draining into a bag outside the body.

Both work equally well to relieve the blockage. The catch in pregnancy is that stents and tubes crust up faster, so they often need to be changed every 4 to 6 weeks until delivery, and stents are less well tolerated in pregnancy. This is why many urologists now prefer to remove the stone definitively in suitable patients instead of leaving a stent in for months.

Treatment Step 3: Removing the Stone With Ureteroscopy (URSL)

For a stone that is stuck in the ureter and not passing, ureteroscopy can remove it during pregnancy. A thin telescope is passed through the urinary passage to the stone, which is broken with a laser and removed. There is no cut on the body.

What the evidence shows:

• Outcomes in pregnant women are broadly similar to those in non-pregnant patients when it is done by experienced teams in carefully selected cases.
• The reported risk of triggering preterm labour after ureteroscopy is very low, around 0 to 1%.
• The second trimester is usually considered the best time, with the early third trimester also an option.
• It is planned together with the obstetrician, with the baby monitored around the procedure.

Read about URSL and how ureteral stones are treated.

Treatments That Are Not Used in Pregnancy

A kidney stone found in pregnancy that is not causing symptoms is normally monitored and treated after delivery with RIRS, ESWL or Mini PCNL, depending on its size and position.

Does a Kidney Stone Harm the Baby?

The stone itself does not harm the baby. The risks come from untreated infection, severe pain and dehydration. Symptomatic stones in pregnancy have been linked with a higher risk of preterm labour, premature rupture of membranes, low birth weight and preeclampsia. That is why prompt assessment and treatment of infection or blockage matter more than the stone itself.

With timely care shared between your obstetrician and urologist, most women with kidney stones go on to have healthy pregnancies and deliveries.

After Delivery: Do Not Skip This

• Get a follow-up scan a few weeks after delivery to check whether any stone remains.
• Remove any stent or tube on time. Never leave a pregnancy stent in after delivery without a removal plan.
• Treat any remaining stone before your next pregnancy, to avoid a repeat episode.

Find out why you formed it: stone analysis and urine tests guide prevention. Read how to avoid kidney stone recurrence.

Prevention During Pregnancy

• Drink steadily through the day, enough to keep urine pale yellow, unless your doctor has told you to limit fluids.
• Do not cut out milk, curd or paneer. Normal dietary calcium is important for you and the baby, and cutting it can raise stone risk.
• Keep salt and packaged salty foods low.
• Take calcium and vitamin supplements only as prescribed by your obstetrician.

Our kidney stone diet planner lets you mark pregnancy and creates a diet chart to discuss with your doctor. Read how much water should you drink to prevent kidney stones.

Get Expert Help

Kidney stones in pregnancy need a urologist and an obstetrician working together. Use our kidney stone checker, see all kidney stone treatment options, or book a consultation with Dr. Deepanshu Gupta, MCh Urology. If you have fever, uncontrolled pain or pregnancy warning signs, go to the nearest emergency department first.

Frequently Asked Questions

Can kidney stones cause a miscarriage?

The stone itself does not cause miscarriage. Untreated infection and severe illness can harm a pregnancy, which is why fever with stone pain needs urgent treatment. With prompt care, most women have healthy pregnancies.

Is a CT scan safe for kidney stones in pregnancy?

CT is not the first choice. Ultrasound is used first, then MRI if needed. A low-dose CT may be used only when other tests are inconclusive and a treatment decision cannot wait, after weighing the benefits and risks with you.

Which painkiller is safe for kidney stone pain in pregnancy?

Paracetamol is usually the first choice. NSAIDs such as ibuprofen and diclofenac are generally avoided in pregnancy. Take any painkiller only on the advice of your obstetrician or urologist.

Can a kidney stone pass naturally during pregnancy?

Yes, many do. Reported spontaneous passage rates are as high as 70 to 80% with fluids, pain control and monitoring, though the real rate may be somewhat lower.

Is kidney stone surgery safe during pregnancy?

Ureteroscopy (URSL) can be performed safely in selected pregnant women by experienced teams, ideally in the second trimester, with a very low reported risk of preterm labour. ESWL and PCNL are not used in pregnancy.

Will I need a stent for my entire pregnancy?

Not always. If a stent or nephrostomy is needed, it usually requires changing every 4 to 6 weeks because it crusts faster in pregnancy. Many urologists prefer removing the stone with ureteroscopy in suitable cases to avoid repeated changes.

Can I have a normal delivery if I have a kidney stone?

Usually yes. A kidney stone is not, by itself, a reason for a caesarean section. Your obstetrician decides the mode of delivery based on obstetric factors.

Can I wait until after delivery to treat my kidney stone?

If the stone is not causing infection, blockage or uncontrolled pain, yes, monitoring until after delivery is often the plan. If any of those problems develop, treatment cannot wait.

References

Miller DT, Semins MJ. Current Era Management of Urolithiasis during Pregnancy: What Have We Learned? AUA News, July 2021. https://auanews.net/issues/articles/2021/july-2021/current-era-management-of-urolithiasis-during-pregnancy-what-have-we-learned

Kominsky HD, Dai JC. Nephrolithiasis in Pregnancy: A Guide for Management. AUA News, December 2022. https://auanews.net/issues/articles/2022/december-2022/nephrolithiasis-in-pregnancy-a-guide-for-management